A MANUAL 
OF 
PRACTICAL HYGIENE 
FOR 
STUDENTS, PHYSICIANS, AND MEDICAL OFFICERS 
BY 
CHARLES g^RRINGTON, M.D. 
Assistant Professor of Hygiene in the Medical School of Harvard University. 
ILLUSTRATED WITH TWELVE PLATES AND ONE HUNDRED 
AND FIVE ENGRAVINGS 
LEA BROTHERS & CO. 
PHILADELPHIA AND NEW YORK 
1901 Entered according to the Act of Congress in the year 1901, by 
LEA BROTHERS & CO. 
In the Office of the Librarian of Congress. All rights reserved. PREFACE. 
In preparing this work the object of the author has been to pro- 
vide a students' text-book which should cover the most important 
topics included in the wide domain of Hygiene and be useful in the 
laboratory and as a reference book for practitioners and health officers. 
The subject is so broad that it is impossible to treat it in its entirety 
in a thorough manner in a single volume; therefore, certain topics 
which find a place in some of the larger works and which are of 
interest chiefly to a somewhat limited circle of specialists, have not 
been considered. 
Of late, it has become the custom to incorporate in works on hy- 
giene a chapter on elementary bacteriology. It has seemed to the au- 
thor that, inasmuch as a knowledge of this closely allied science is 
recognized as a very essential part of the equipment of the modern 
medical practitioner and is taught, as its importance deserves, either 
as a separate subject or in connection with pathology, it would be as 
much a work of supererogation to give a brief description of species 
and technic herein as to include a chapter on elementary chemistry, 
physics, or other affiliated great subject. It is assumed that the reader 
has already acquired at least a fair working knowledge of bacteriology, 
or that, lacking it, he will turn rather to special works in which the 
science can be fully treated. 
Again, certain topics, which are not infrequently included in works 
of this nature, but which lie more properly within the fields of engi- 
neering and architecture, such, for example, as the construction of 
aqueducts and sewers, the nature and strength of building materials, 
and the arrangement of hospitals, have been deemed as hardly within 
the province of the hygienist and, consequently, have been excluded. 
To those who, by their writings and otherwise, have been of assist- 
ance in the preparation of this book, the author extends his sincere 
thanks ; and especially to his friend and colleague Professor Harold 
C. Ernst for taking the photomicrographs from which the plates illus- 
trative of the starches and trichinae have been prepared. 
688 Boylston Street, Boston. 
C. H. CONTENTS. 
CHAPTER I. 
Foods 
g 1. General Considerations 17 
g 2. Animal Foods; Meats, Fish, Eggs and Meat Products 23 
g 3. Milk and Milk Products 73 
g 4. Vegetable Foods 123 
g 5. Beverages 153 
g 6. Condiments, Spices and Bakers' Chemicals 186 
g 7. Food Preservation., 193 
g 8. Contamination of Foods by Metals 202 
CHAPTER II. 
Air , 206 
CHAPTER III. 
The Soil 250 
CHAPTER IV. 
Water 297 
CHAPTER V. 
Habitations, Schools, Etc. 
g 1. General Considerations 399 
g 2. Ventilation and Heating 402 
g 3. Lighting 424 
g 4. Plumbing 431 
CHAPTER VI. 
Disposal of Sewage 466 
CHAPTER VII. 
Disposal of Garbage 484 
CHAPTER VIII. 
Disinfectants and Disinfection 488 VI 
CONTENTS. 
CHAPTER IX. 
Quarantine 540 
CHAPTER X. 
Military Hygiene 574 
CHAPTER XI. 
Naval and Marine Hygiene 629 
CHAPTER XII. 
Tropical Hygiene 639 
CHAPTER XIII. 
Hygiene of Occupation 648 
CHAPTER XIV. 
Vital Statistics 672 
CHAPTER XV. 
Personal Hygiene. 
§ 1. Care of the Person 692 
§ 2. Regulation of the Diet 694 
g 3. Rest and Recreation 694 
g 4. Physical Exercise 695 
g 5. Clothing 700 
CHAPTER XVI. 
Vaccination 709 
CHAPTER XVII. 
Disposal of the Dead 714 ERRATA. 
Page 107. Paragraph headed Orleans. The word Orleans, which is a synonym for 
Annatto, is superfluous, and the matter down to the heading, " Detection of Preserva- 
tives" should have immediately preceded Caramel, on page 106. 
Page 130. Fifth line under Rye. In the sentence beginning "A typical American 
wheat," the word wheat should be rye. Practical Hygiene. 
CHAPTER I. 
FOODS. 
Section 1. GENERAL CONSIDERATIONS. 
Foods may be said to include everything taken into the system 
capable of being utilized directly or indirectly to build up normal 
structure, repair waste, or produce energy in any form, but in the 
common acceptation of the term they include only those substances 
which can be oxidized in the system, thus excluding water and air 
without which the functions of the body can not be performed. Diet 
is a mixture of food materials of various kinds habitually taken in such 
quantity as is needed to maintain or improve the condition of the system. 
The Nutritive Value of Foods. 
The potential energy of food is measured by the amount of heat 
which can be obtained by its complete combustion, and is expressed in 
units of heat Or calories. The amount of energy required to raise the 
temperature of one kilogram of water 1 ° C. is known as a large calorie ; 
that required to raise the temperature of one gram to the same extent 
is known as a small calorie ; thus one large calorie equals one thousand 
small calories. When the term is used without qualification, large 
calories are understood. These heat units correspond to 425.5 units 
of work; that is to say, the same amount of energy required to raise 
the temperature of the given weight of water 1 ° C. is sufficient to raise 
425.5 times the weight one meter. The amount of work done is ex- 
pressed in kilogram-meters. 
The heat unit of the English system is the amount of energy required 
to raise the temperature of a pound of water 1° F., and its mechanical 
equivalent is 772 units of work; that is to say, the same amount of 
energy will raise 772 pounds one foot. According to the English 
method work done is expressed in foot tons rather than in foot pounds. 
The calorimetric values of different food materials express also their 
physiological values as nutriment. Rubner1 determined the calori- 
metric value of the proximate principles as follows : 
One gram of proteids =4.1 calories. 
One gram of carbohydrates = 4.1 " 
One gram of fat =9.3 " 
1 Lehrbuch der Hygiene, Leipsic, 1900, p. 430. 18 
FOODS. 
In the system the carbohydrates and fats are completely burned to 
carbonic acid and water, but the proteids leave a residue of urea capable 
of still further oxidation. It is estimated that the physiological value 
of the proteids averages only about 75 per cent, of their calorimetric 
value. 
The calorimetric value of different foods of the several classes is 
not to be understood as being exactly the same. Thus, two kinds of 
sugar or two kinds of fat, or two kinds of proteid have not exactly the 
same calorimetric values, and the figures above given are to be under- 
stood only as fair averages. Rubner 1 has determined by actual ex- 
perimentation the relative calorimetric values of certain food materials, 
and has shown that 100 grams of fat are equivalent to 225 syntonin, or 
232 starch, or 234 cane sugar, or 243 muscle fiber, or 256 grape sugar. 
In other words, these several amounts of food material are isodynamic. 
Amount of Food Necessary. 
For the maintenance of a proper degree of health and strength the 
individual must ingest an amount of food sufficient to meet the daily 
loss of nitrogen and carbon. This must necessarily vary according to cir- 
cumstances, and hence no rule can be laid down to fit all cases. The best 
that can be done is to make certain general rules based on the amount 
of work performed, for the greater the amount of work done, the greater 
the amount of food required to meet the necessary consumption of fuel 
and to repair the tissues. When undergoing heavy labor, the naturally 
increased desire for food is shown particularly in the direction of fats, 
and secondarily of proteids. 
It has been estimated by Voit after much experimentation and from 
voluminous data, that a man weighing 70 to 75 kilos (154 to 165 
pounds) and working at moderately hard labor 9 to 10 hours a day 
requires 118 grams of proteids, 56 of fat, and 500 of carbohydrates. 
This is equivalent to 3,054.6 calories, and is generally regarded as the 
most accurate estimate obtainable. From Voit's and other figures a 
number of writers have endeavored to construct standard dietaries for 
the various conditions of bare subsistence, rest, and the performance of 
different amounts of daily labor, the subsistence diet being reckoned as 
sufficient only for the internal work of the body in the absolutely passive 
condition, and that for rest as meeting the requirements of very gentle 
exercise. 
The constituents of the standard diets are prescribed in the follow- 
ing proportions : for each part of proteids, two-thirds of a part of fat, 
three and one-sixth parts of carbohydrates, and one-fourth of a part of 
mineral matter. The proportion of 1 part of nitrogen to 15 of carbon 
should be maintained as nearly as possible. In all dietaries it is 
necessary to have the different constituents properly proportioned, and 
in addition to vary from day to day the articles belonging to the same 
classes, since otherwise they will become distasteful. The question of 
1 Lehrbuch der Hygiene, Leipsic, 1900, p. 438. 19 
COMPOSITION OF FOODS. 
nutritive value while paramount is not all, for taste and variety of flavor 
are important in a high degree, and the palate must be flattered. 
Knowing the composition of various food materials, the nutritive 
value of a given weight, and problems of supplying given amounts of 
proteids, fats, and carbohydrates from means at hand can be worked 
out mathematically. 
Composition of Foods. 
The constituents of food materials are partly organic and partly in- 
organic. The organic constituents include proteids, fats, carbohydrates, 
and organic acids ; the inorganic include water and mineral salts. 
Proteids.-The proteids are the most important constituents of both 
animal and vegetable foods, and their presence is necessary for the 
carrying on of all the phenomena of life. They are very complex 
colloid substances composed of carbon, oxygen, hydrogen, nitrogen, and 
sulphur, possessing common properties and connected in very close 
genetic relationship. They are divided into animal proteids and vege- 
table proteids, but between the members of the one class and those of 
the other there are no important chemical differences, and they are 
about equal in nutritive value. Some of the vegetable proteids are not 
colloids, for according to Schmiedeberg, Weld, Maschka, and others 
they are found in crystalline form in the tissues of certain plants and 
notably in the bean, pea, lentil, and various nuts. 
Proteids when completely split up by acids yield as end products 
ammonia, nitrogen, organic bases, and amido acids. 
They are never completely absent from animal and vegetable tissues, 
but their amount in different substances is very widely variable, some 
foods being very rich in them, while in others they exist only in traces. 
Ingested in great excess of the needs of the system they are likely 
to cause general disturbance, diarrhoea and albuminuria, while a diet 
from which they are practically excluded will cause rapid loss of 
strength, ansemia, great prostration, and greatly diminished resistance 
to invasion by specific diseases, especially tuberculosis and pneumonia. 
The animal proteids are more rapidly digested than the vegetable 
proteids, some of which are largely wasted through imperfect digestion. 
The proteids, whatever their source, yield in the main the same prod- 
ucts of digestion, and consequently may replace each other in the diet. 
The most complete classification of proteids is that of Wroblewski1 
by whom they are divided into three groups as follows : 
Group I. Albuminous bodies closely related to egg albumin. 
1. Albumins. Soluble in water. Egg albumin, serum albumin, 
lactalbumin, muscle albumin, vegetable albumin. 
2. Globulins. Insoluble in water, soluble in dilute salt solution. 
Egg globulin (vitellin), serum globulin, lactoglobulin, fibrinogen, 
myosin, vegetable globulin. 
3. Proteids soluble in alcohol. Substances very slightly soluble in 
1 Berichte der deutschen chemischen Gesellschaft, 1897, 30, pp. 3045, 3052. 20 
FOODS. 
water and salt solutions, soluble in dilute alcohol, some in strong alcohol. 
Chiefly of vegetable origin. Very rich in carbon. 
4. Albuminates. Products of the action of alkalies on albumins. 
Slightly soluble in water, easily soluble in alkalies. 
5. Acid albumins. Products of the action of acids on albumins. 
Soluble in very dilute acids and alkalies. Syntonin, etc. 
6. Coagulated albumins. Proteid substances coagulated by the ac- 
tion of heat or enzymes. Fibrin, para-casein, etc. 
Group II. Compound proteids composed of molecules which consist 
of an albumin group (aj plus another group, usually of a non-pro- 
teid nature. 
1. Glyco-proteids. plus a carbohydrate group. Mucin, etc. 
2. Haemoglobins. ax plus a coloring-matter group. 
3. Nucleo-albumins. ax plus a nuclein group. 
4. Caseins. They contain no true nuclein group. With rennet 
they give a characteristic coagulation reaction. They are not coagu- 
lated by heat like albumin nor by enzyme action like fibrin. Milk 
casein, legumin, etc. 
5. Nucleins. ax plus a nuclein acid group. 
6. Amyloids. 
Group III. Albuminoids. 
a. Frame-work substances. 
1. Keratins. Constituents of horn. Attacked with difficulty by pep- 
sin and trypsin. They contain much sulphur and yield much tyrosin. 
2. Elastins. Constituents of elastic tissue. They contain less sul- 
phur and yield less tyrosin. 
3. Collagens. Constituents of connective tissue, bone, and cartilage. 
They contain very little sulphur, and yield no aromatic amido-acids. 
Gelatin, isinglass, chondrin, collagen, etc. 
b. Albumoses and Peptones. Products of hydrolytic splitting of 
various proteid substances. Their molecules are much smaller than 
ose of the albumins. 
c. Enzymes. Bodies which when present in very small amounts have 
the property of breaking up very large amounts of certain other sub- 
stances, including proteids, fats, starches, etc. 
The albumins are not precipitated by alkaline carbonates, common 
salt, or dilute acids, but they are coagulated by being heated to 65- 
73° C. Casein, legumin, conglutin, syntonin, and albuminates, on the 
contrary, are not coagulable by heat, but are precipitated by common 
salt, sodium acetate, and trisodium phosphate. The albumoses are 
widely distributed throughout the vegetable kingdom, and are found 
largely in the cereals. In the animal kingdom, they are intermediate 
products of the action of pepsin on ordinary proteids, becoming even- 
tually converted to peptones. The collagens are very rich in nitrogen, 
but have an inferior nutritive value. Gelatin, for instance, contains 
17-18 per cent., while the albumins contain but 16. 
Fats.-The fats are compounds of the triatomic alcohol, glycerin, 
with fatty acids, mainly stearic, palmitic, and oleic. These several COMPOSITION OF FOODS. 
21 
compounds are known as stearin, palmitin, and olein. The two first 
mentioned are solids at usual temperatures, while olein is a liquid. 
Most fats are combinations of two or all of these substances, and some, 
as for example, butter, contain additional glycerides in small amount. 
Stearin and palmitin being solids, and olein liquid, the consistency of 
a fat is dependent upon the proportions in which these substances are 
present. Stearin is a component of most animal fats, but is never 
found in vegetable fats. The chief constituent of animal fats is pal- 
mitin, and this occurs also in nearly all vegetable fats. Olein exists 
in both. Butyrin, caprin, caproin, and caprylin are glycerides of 
volatile fatty acids present in the fat of milk. 
Fats consist of carbon, hydrogen, and oxygen, and contain no nitro- 
gen. The hydrogen and oxygen are not present in the proportions in 
which they exist in water and in carbohydrates, the oxygen being de- 
ficient. 
As taken in food they are chiefly in the form of neutral substances, but 
more or less free fatty acid is always present, and in some foods which 
have been kept for a time, particularly in well-ripened cheese, fatty 
acids may be present in a free state in quite large proportion. 
The fats play an important part in the maintenance of animal heat 
and mechanical energy. When hard labor is being performed, an excess 
of fat is instinctively taken. 
Carbohydrates.-The carbohydrates include the starches, sugars, 
and cellulose. 
The Starches though presenting very different appearances under the 
microscope according to source, are of equal value as foods, and have 
the same composition. Starch is insoluble in water, but heated with 
it to 72° C. the cells swell and burst, and produce a sort of mucilage. 
Heated with dilute mineral acids it is converted into dextrose. Sub- 
jected to the action of diastase it is converted into maltose. 
Starch is found almost exclusively in vegetable cells. It forms the 
chief part of the seeds of the cereals and of the dried residue of other 
vegetable products, such as potatoes. A form of starch known as ani- 
mal starch or glycogen is found in the liver and muscles, and also in 
some of the mollusca. Dextrin is an artificial product formed from 
starch by the action of ferments or of dilute acids and heat. 
The Sugars are of vegetable and animal origin and include the 
following: 
1. Sucrose, cane sugar. A disaccharid. From sugar cane, sorg- 
hum, sugar maple, sugar beet, and some other vegetable sources. In- 
soluble in strong alcohol, does not reduce copper, not directly fer- 
mentable. Boiled with dilute acids is converted to invert sugar, a 
mixture of dextrose and leevulose. 
2. Dextrose, glucose, grape sugar. A monosaccharid. Found in 
many fruits and flowers. Formed from cane sugar, maltose, starch 
and dextrin by boiling with dilute acids. In the presence of decom- 
posing proteids splits into two molecules of lactic acid. Fermented 
with yeast splits into alcohol and carbonic acid. 22 
FOODS. 
3. Maltose, malt sugar. A disaccharid. (Two molecules of dex- 
trose.) Formed from starch by the action of diastase. 
4. Laevulose, fruit sugar. A monosaccharid. Found in honey and 
various fruits. Rotates the ray of polarized light to the left. Does 
not form crystals. Isomeric with dextrose. 
5. Lactose, milk sugar. A disaccharid. (Dextrose and galactose.) 
Found only in milk. Behaves like dextrose. 
6. Galactose. A monosaccharid. Formed from lactose by boiling 
with dilute mineral acids. 
7. Inosite, muscle sugar, phaseomannite. Found in certain animal 
tissues, as the heart's muscle, and in certain plants as peas, beans, and 
grapes. Has no rotatory power, does not reduce copper and is not fer- 
mentable. It contains the benzene ring and hence is not a true sugar. 
In the presence of decomposing proteids it is converted into lactic and 
butyric acids. 
Cellulose.-Cellulose, while of value as a food for herbivora, has no 
nutritive value for man. It is converted to dextrose by boiling with 
dilute sulphuric acid. 
Pectin.-Pectin is a substance not uncommonly classified as a car- 
bohydrate. It is composed of carbon, hydrogen, and oxygen, but its 
precise composition is unknown. It is found in various fleshy fruits 
and in roots, and is believed to be formed from pectose by the action 
of vegetable acids. It is known also as vegetable jelly. 
Pectose.-Pectose is an insoluble substance found in unripe fruits 
and roots : an earlier stage of pectin. 
The carbohydrates play an important part in the maintenance of 
heat and the production of force. They lessen the need of fat and 
form fatty tissue. Excessive ingestion interferes with the metamor- 
phosis of nitrogenous tissue, causes deposition of fat in excess, and is 
likely to produce digestive disturbances. Deprivation for a time can 
be borne provided the system receives sufficient fatty food, but not 
otherwise. 
Organic Acids.-The organic acids exist in foods either in the free 
state or in combination as salts. In the system they are converted to 
carbonates which exercise a most important influence in controlling 
the alkalinity of the blood and other fluids. Deprivation leads to a 
peculiar disturbance of the system resulting in scurvy. They include 
malic, acetic, lactic, oxalic, citric, and tartaric acids. Malic acid is a 
constituent of apples, pears, and some other fruits. Acetic acid is the 
essential element of vinegar. Oxalic acid is found in sorrel and 
rhubarb. Lactic acid is present in fresh meats and in milk. The 
two most important acids are citric and tartaric. The former is found 
in oranges, lemons, limes, and other fruits ; the latter largely in grapes. 
Not all vegetables contain these acids, and, therefore, not all have anti- 
scorbutic properties. Potatoes, cabbage, and roots are very efficient in 
this respect, while peas and beans are notable examples to the contrary. 
Inorganic Salts.-The important inorganic salts taken into the 
system with food include sodium and potassium chlorides, sodium, ANIMAL FOOLS-MEATS. 
23 
potassium, magnesium and calcium phosphates, and compounds of iron. 
The sulphates are of minor importance and are ingested in only small 
amounts. The sulphur essential to growth is taken into the system 
in combination in the proteids. The chlorides keep the globulins of 
the blood and other fluids of the body in solution, and are the source 
of the hydrochloric acid of the gastric juice. The phosphates are very 
essential to the growth of bone and to the nervous system, and iron is 
needed for the haemoglobin of the blood. Deficiency of calcium and 
magnesium salts leads to rickets and other abnormal conditions. 
Section 2. ANIMAL FOODS; MEATS, FISH, EGGS, 
AND MEAT PRODUCTS. 
The foods of animal origin used by man include the flesh and various 
organs of the herbivora and swine, domestic-and wild fowl, eggs, fish 
and shellfish, milk and milk products. The flesh of all carnivorous 
animals except fish is unpalatable, and, therefore, undesirable as food, 
though under stress of circumstances it may be borne. Thus during 
the siege of Paris, about 5,000 cats and 1,200 dogs are said to have 
been eaten when the food supply had become so meagre that anything in 
the form of flesh was acceptable. In Germany, according to a com- 
munication of Consul-General Guenther to the State Department at 
Washington under date of May 26, 1900, the statistical year-book 
shows that on account of the high price of other meats not only horses 
but also dogs are much used as food. At Breslau, Chemnitz, Dresden, 
Leipzig, Zwickau, and other places dogs are extensively slaughtered for 
this purpose and regularly inspected. 
Pirl1 reports that in Saxony during 1894, 295; in 1895, 388; 
in 1896, 399 ; and in 1897, 474 dogs were slaughtered and inspected. 
In Dessau between 1893 and 1898 the number averaged 251 yearly, 
and inspection showed that one in 202 was trichinous. According 
to Tempel,2 of 289 killed at Chemnitz during 1897, 1.391 per cent, 
and of 147 killed during the first half of the year 1898, 2.04 per 
cent, were found to be trichinous. The meat is eaten chiefly in the 
roasted state, but also, in many parts of Saxony, raw but highly sea- 
soned. The same animals are commonly eaten by the Chinese, and the 
Canada lynx and the skunk are rated as delicacies by the North Ameri- 
can Indians. 
MEATS. 
The value of meat as food depends upon the presence of proteids, 
fat, and mineral salts. The nitrogenous extractive matters (creatin, 
etc.), sometimes called " meat bases," formed by cleavage of the pro- 
teids, give flavor, but have little value as foods. The carbohydrates 
play but an insignificant part, being present chiefly as muscle sugar 
and to only a very small extent. All meat, however lean, contains 
1 Zeitschrift fiir Fleisch- und Milchhygiene, X., No. 1. 
2 Ibidem, IX., No. 1. 24 
FOODS. 
fat, some of which is visible and some indistinguishable from the muscle 
fibers by which it is surrounded. The visible fat varies widely in 
amount. Very fat beef may contain more than a quarter of its weight 
of visible fat, and fat pork meat more than a half, while chicken and 
veal contain comparatively little. 
The content of water varies very widely and in general may be 
said to be governed by the richness in fat, for while the proteids are 
fairly constant in amount, the balance in weight is almost wholly water 
and fat, and the greater the amount of the one, the less the amount of 
the other. The more water a meat contains/the less, therefore, its rel- 
ative nutritive value. 
Digestibility.-While the amount of nutriment contained in meats 
chiefly determines their food value, the latter is to no inconsiderable 
extent dependent upon the ability of the alimentary tract to digest and 
absorb them. Gastric digestion is by no means to be accepted as a 
measure of the true digestibility of a food, and the same is true of the 
results of artificial laboratory experiments; hence many of the accepted 
statements bearing on this subject, based upon the oft-quoted experi- 
ments on Alexis St. Martin and upon test-tube observations, may be 
wholly disregarded. 
Raw meat is more easily but less completely digested than that which 
has undergone the process of cooking, and roasted meat is more com- 
pletely digested than that which has been boiled. Fat meats, as beef 
and mutton, and especially pork, require more time for digestion than 
those which, like chicken and veal, contain but little fat. In general it 
may be said that meats are more easily assimilated than vegetable foods. 
Flavor.-The flavor of meats depends largely upon the nature and 
amounts of nitrogenous extractives which they contain, and is greatly 
modified by the condition of the animal when killed, its age, sex, and 
the character of its food. The high flavor of birds and game is due to 
the richness in extractives, while in the case of meats deficient in these 
substances, as for example mutton and pork, the flavor is due largely to 
their contained fats. Most meats are improved in flavor by being kept 
for a time during which additional flavors due to decomposition prod- 
ucts similar to the extractives are developed. The meat of young ani- 
mals is less highly flavored than that of adults, and that of females 
than that of males, though in the case of the goose this condition is re- 
versed, and in that of swine no difference is observable. 
Asexualization by spaying or castration produces a fatter, more 
tender, and better flavored meat. Thus the flesh of oxen is far pref- 
erable to that of bulls or cows, and that of capons and poulards to 
that of cocks and hens. 
Texture.-Whether a given meat is tough or tender depends upon 
the character of the walls of the muscle tubes and upon the amount of 
connective tissue present. The tube walls are thin and delicate, and 
the connective tissue is small in amount in the young and well-fed, but 
as the animal becomes older or is made to work, the tubes thicken and 
become hard, the connective tissue increases in amount, the fat may FOODS-MEATS. 
25 
diminish, and the result is a coarser flesh. Very young animals have 
a very watery, gelatinous, and flavorless flesh. 
The texture of meat undergoes very considerable change after 
slaughter. When freshly slaughtered it is tender and juicy, but as 
rigor mortis supervenes it becomes hardened and tough. The stage of 
rigor is succeeded by the first steps of decomposition during which lac- 
tic acid is formed. This acts upon the connective tissue and causes 
softening and tenderness, and as the process of decomposition proceeds 
within proper limits, increase of flavor is developed. 
Effects of Cooking.-When meat is cooked, the connective tissue is 
softened, the bundles of fibrillae are loosened from each other, the albu- 
min is coagulated, flavors are improved and new ones developed, para- 
sites and micro-organisms are destroyed, and the whole mass is ren- 
dered more acceptable to the eye and palate. In the process of roasting 
or broiling, considerable shrinkage due to loss of water occurs. The 
heat to which the meat is subjected should be sufficiently intense to 
produce speedy coagulation of the exterior and prevent the meat juices 
from becoming dried up. In order that the surface shall not be burned, 
the meat must be basted from time to time with hot melted fat which 
forms a protective coating. In the case of large joints, the heat must 
be less intense than with small, since before the heat can penetrate well 
into the interior the outer parts will become burned. 
In boiling, the temperature of the water into which the meat is im- 
mersed varies according to the object sought. If a rich broth is de- 
sired the meat is placed in cold water which is then heated gradually. 
During the heating process the soluble albumins together with a por- 
tion of the salts and the extractives are dissolved out. When the tem- 
perature reaches 134° F. the albumin begins to coagulate, and above 
160° the connective tissue is changed to gelatin and dissolved. The 
solution of certain of the constituents is assisted by the small amounts 
of lactic acid formed. 
If, on the other hand, it is desired to have the juices and flavors re- 
tained within the mass, the meat must be plunged into boiling water 
which quickly coagulates the albumins at the surface and causes thereby 
the formation of a protective coating. After this is formed, the tem- 
perature should be lowered to about 180°, for otherwise the meat be- 
comes tough even to the center. The shrinkage in meat that has been 
properly boiled amounts to from 20 to 40 per cent, of its weight. 
In frying, the meat is dropped into very hot fat, as lard or vegetable 
oil, which causes speedy coagulation of the surface such as is brought 
about in the process of boiling, whereby all the flavors and juices are 
retained. It is essential that the fat be very hot, since otherwise it 
will penetrate the tissues and cause the meat to become greasy and un- 
palatable. 
In stewing, the meat is cut into small pieces and placed in cold water 
which is then slowly heated to about 180° F. at which temperature 
the whole is kept for several hours. If heated above 180°, the meat 
becomes tough, stringy, unpalatable, and of diminished digestibility. 26 
FOODS. 
Characteristics of Good Meat.-Meat should have a uniform color, 
neither abnormally pale nor inclined to purplish. It should have little 
or no odor, and such as it has should give no disagreeable impression 
such as the sickly cadaveric smell characteristic of diseased or decom- 
posing flesh. It should be firm and elastic, and should not pit or crackle 
on pressure. On being handled it should scarcely moisten the fingers, 
and with keeping, the exterior should become dry rather than wet. 
There should be no evidence whatever of the presence of parasites. 
Beef has a bright red color and a marbled appearance, due to the 
presence of fat between the bundles of muscular fibers. This marbling 
is much less apparent in the flesh of animals that have not been well 
fed and of old cows and bulls. Bull meat is darker than that of oxen 
and cows, and is coarse, stringy, and of strong flavor. 
Veal is much paler than beef and less firm to the touch, and coming 
from a very young animal, " bob-veal," it is flabby and watery, and its 
fat has a tallowy appearance. 
Mutton should be of a dull-red color and firm to the touch. Its 
fat is white, sometimes yellowish, and hard. 
Lamb is somewhat less firm to the touch and has a decidedly lighter 
color. 
Pork is much less firm to the touch than beef and mutton, and its 
fat is quite soft in comparison. 
Horse meat, the use of which is increasing rapidly abroad and to a 
much greater extent in this country than is commonly believed, is 
darker and coarser than beef and possesses a very different odor. The 
fat is yellow and oily and has a rather disagreeable odor. 
The flesh of birds is not marbled like that of mammals. That of 
wild fowl that feed on fish has a strong flavor which is not improved 
by keeping. 
Comparative Digestibility of Meats.-Beef is commonly and cor- 
rectly regarded as one of the most digestible of meats, but according to 
the experience and testimony of many victims of dyspepsia it is infe- 
rior in this respect to mutton. Pork is without doubt digested with 
greater difficulty than any other meat, on account of its high content 
of fat. The evidence as to veal is most conflicting, some holding that 
it is very easily digested, while others maintain the contrary view. 
Certain it is that many persons bear it very badly. The white meat 
of chickens, fowls, and turkeys, is more delicate and more easily di- 
gested than the dark meat, probably by reason of its smaller amount 
of fat. The flesh of ducks and geese is harder, richer, and more diffi- 
cult of digestion. Game birds are less fat than poultry and are often 
much better borne. Their habits of life are unfavorable to the depo- 
sition of much fat. Liver, kidneys, and heart are generally regarded 
as unsuitable as foods for persons with weak stomachs, but tripe and 
sweetbreads are usually easily borne. 
Composition of Meats.-In the following tables showing the com- 
position of the edible portions of meats, the figures given are taken, 
unless otherwise stated, from Bulletin No. 28 (revised edition) of the COMPOSITION OF MEATS. 
27 
Office of Experiment Stations of the U. S. Department of Agriculture : 
The Chemical Composition of American Food Materials C 
BEEF. 
Cut. 
Number of 
Analyses. | 
Water. 
Proteids. 
a 
Ash. 
Fuel value 
per pound. 
(Calories.) 
3 
54.6 
15.8 
28.5 
0.9 
1495 
Chuck, including shoulder. 
1 
73.8 
22.3 
3.9 
0.8 
580 
1 ean 
2 
71.3 
20.2 
8.2 
1.0 
720 
medium fat 
4 
68.3 
19.6 
11.9 
0.9 
865 
f^^; 
4 
62.3 
18.5 
18.8 
0.9 
1135 
very fat 
2 
53.2 
17.2 
29.0 
0.9 
1555 
Average 
13 
65.0 
19.2 
15.4 
0.9 
1005 
1 
75.8 
22.2 
1.4 
1.1 
470 
lean 
11 
71.3 
19.5 
8.3 
1.0 
715 
medium frit 
7 
62.7 
18.5 
18.0 
1.0 
1105 
fat 
2 
52.0 
16.6 
31.1 
0.8 
1620 
Average 
21 
66.8 
19-0 
13.4 
1.0 
920 
Flank very lean 
3 
70.7 
25.9 
3.3 
1.2 
620 
lean 
3 
67.8 
20.8 
11.3 
1.0 
865 
medium fat 
5 
60.2 
18.9 
21.0 
0.9 
1240 
fat 
3 
54.2 
17.1 
28.4 
0.8 
1515 
very fat 
2 
34.7 
14.0 
51.8 
0.7 
2445 
Average 
16 
59.3 
19.6 
21.1. 
0.9 
1255 
Loin very lean 
3 
70.8 
24.6 
3.7 
1.3 
615 
lean 
12 
67.0 
19.7 
12.7 
1.0 
900 
medium fat 
32 
60.6 
18.5 
20.2 
1.0 
1190 
fat 
6 
54.7 
17.5 
27.6 
0.9 
1490 
very fat 
3 
49.7 
17.8 
32.3 
0.9 
1695 
Average 
56 
61.3 
19.0 
19.1 
1.0 
1155 
Porterhouse steak 
7 
60.0 
21.9 
20.4 
1.0 
1270 
Sirloin steak 
21 
61.9 
18.9 
18.5 
1.0 
1130 
Top of sirloin 
1 
42.2 
13.8 
43.7 
0.8 
2100 
Tenderloin 
6 
59.2 
16.2 
24.4 
0.8 
1330 
Ribs very lean 
4 
65.7 
21.9 
1.1 
0.7 
455 
lean 
6 
67.9 
19.6 
12.0 
1.0 
870 
medium fat 
15 
55.5 
17.5 
26.6 
0.9 
1450 
fat 
9 
48.5 
15.0 
35.6 
0.7 
1780 
very fat 
1 
45.9 
14.6 
38.7 
0.6 
1905 
Average 
35 
57.0 
17.8 
24.6 
0.9 
1370 
Rib rolls, verv lean 
2 
73.7 
20.8 
5.0 
1.0 
600 
lean ' 
3 
69.0 
20.2 
10.5 
1.0 
820 
medium fat 
4 
63.9 
19.3 
16.7 
0.9 
1065 
fat 
2 
51.5 
17.2 
31.3 
0.8 
1640 
Average 
11 
64.8 
19.4 
15.5 
0.9 
1015 
Round, very lean 
6 
73.6 
22.6 
2.8 
1.3 
540 
lean 
31 
70.0 
21.3 
7.9 
1.1 
730 
medium fat 
18 
65.5 
20.3 
13.6 
1.1 
950 
fat 
5 
60.4 
19.5 
19.5 
1.0 
1185 
very fat 
2 
55.9 
18.2 
26.2 
0.8 
1445 
Average 
62 
67.8 
20.-9 
10; 6 
1.1 
835 
1 Government Printing Office, Washington, 1899. 28 
FOODS. 
Cut. 
( Number of ' 
j Analyses, j 
Water. 
Proteids. 
Ash. 
Fuel value , 
per pound. 
(Calories.) 
Round, second cut 
2 
69.8 
20.4 
8.6 
1.1 
740 
Rump, very lean 
4 
71.2 
23.0 
5.1 
1.2 
645 
lean 
4 
65.7 
20.9 
13.7 
1.0 
965 
medium fat 
10 
56.7 
17.4 
25.5 
0.9 
1400 
fat 
5 
4/. 1 
16.8 
3b. / 
0.8 
1820 
very fat 
1 
40.2 
15.0 
44.3 
0.8 
2150 
Average 
24 
57.9 
IS. 7 
23.1 
0.9 
1325 
Beef heart 
■ 
2 
62.6 
16.0 
20.4 
1.0 
1160 
Kidney (carbohydrates 0.4) 
3 
76.7 
16.6 
4.8 
1.2 
520 
Liver (carbohydrates 1.5) 
6 
71.2 
20.7 
4.5 
1.6 
605 
Marrow 
1 
3.3 
2.2 
92.8 
1.3 
3955 
Tongue 
3 
70.8 
18.9 
9.2 
1.0 
740 
Lungs 
1 
79.7 
16.4 
3.2 
1.0 
440 
Suet 
9 
13.7 
4.7 
81.8 
0.3 
3540 
Roast beef (cut not specified) 
7 
48.2 
22.3 
28.6 
1.3 
1620 
Sirloin steak, baked 
1 
63.7 
23.9 
10.2 
1.4 
875 
Broiled tenderloin 
6 
54.8 
23.5 
20.4 
1.2 
1300 
Round steak 
18 
63.0 
27.6 
7.7 
1.8 
840 
Canned corned beef 
15 
51.8 
26.3 
18.7 
4.0 
1280 
Canned roast beef. 
4 
58.9 
25.9 
14.8 
1.3 
1105 
Canned whole tongue 
5 
51.3 
19.5 
23.2 
4.0 
1340 
Canned tripe 
2 
74.6 
16.8 
8.5 
0.5 
670 
Corned beef (all cuts) 
10 
53.6 
15.6 
26.2 
4.9 
1395 
Tongues, pickled 
2 
62.3 
12.8 
20.5 
4.7 
1105 
Tripe (carbohydrates 0.2) 
4 
86.5 
11.7 
1.2 
0.3 
270 
beef.- Continued. 
PORK. 
Cut. 
O tn 
a'S 
W ater. 
Proteids. 
Ash. 
Fuel value 
per pound. 
(Calories.) 
Ham, fresh, lean 
2 
60.0 
25.0 
14.4 
1.3 
1075 
medium fat 
10 
53.9 
15.3 
28.9 
0.8 
1505 
fat 
5 
38.7 
12.4 
50.0 
0.7 
2345 
visible fat largely removed 
3 
64.5 
19.2 
16.2 
0.9 
1040 
Loin (chops), lean 
1 
60.3 
20.3 
19.0 
1.0 
1180 
medium fat 
19 
52.0 
16.6 
30.1 
1.0 
1580 
fat 
4 
41.8 
14.5 
44.4 
0.7 
2145 
Tenderloin 
11 
66.5 
18.9 
13.0 
1.0 
900 
Shoulder 
19 
51.2 
13.3 
34.2 
0.8 
1690 
Feet 
8 
50.7 
8.3 
17.4 
0.4 
1090 
Head cheese 
3 
43.3 
19.5 
' 33.8 
3.3 
1790 
Kidneys 
2 
77.8 
15.5 
4.8 
1.2 
490 
Liver (carbohydrates 1.4) 
1 
71.4 
21.3 
4.5 
1.4 
615 
Ham, smoked, lean 
3 
53.5 
19.8 
20.8 
5.5 
1 215 
medium fat 
14 
40.3 
16.3 
38.8 
4.8 
1940 
fat 
4 
27.9 
14.8 
52.3 
3.7 
2485 
smoked, boiled 
2 
51.3 
20.2 
22.4 
6.1 
1320 
Shoulder, smoked, medium fat 
3 
45.0 
15.9 
32.5 
6.7 
1665 
fat 
2 
26.5 
15.1 
53.6 
5.2 
2545 
Salt pork, fat 
7 
07.9 
1.9 
86.2 
3.9 
3670 
lean ends 
4 
19.9 
8.4 
67.1 
5.7 
2985 
Bacon, smoked, lean 
2 
31.8 
15.5 
42.6 
11.0 
2085 
medium fat 
17 
18.8 
9.9 
67.4 
4.4 
3030 COMPOSITION OF MEATS. 
29 
VEAL. 
Cut. 
Number of 
Analyses. 
1 „ 
। Proteias. 
Ash. 
Fuel value 
per pound. 
(Calories.) 
Prpast, loan 
5 
72.1 
21.7 
5.6 
1.1 
640 
medium fat 
7 
66.0 
19.5 
14.0 
1.0 
955 
T jpg, lean 
9 
73.5 
21.3 
4.1 
1.2 
570 
medium fat 
10 
70.0 
20.2 
9.0 
1.2 
755 
cutlets 
3 
70.7 
20.3 
7.7 
1.1 
705 
Loin lean 
5 
73.3 
20.4 
5.6 
1.2 
615 
medium fat 
6 
69.0 
19.9 
10.8 
1.0 
825 
fat 
2 
61.6 
18.7 
18.9 
1.0 
1145 
Heart 
1 
73.2 
16.8 
9.6 
1.0 
720 
Kidnevs 
2 
75.8 
16.9 
6.4 
1.3 
585 
Liver 
2 
73.0 
19.0 
5.3 
1.3 
575 
MUTTON. 
Cut. 
; Number of 
1 Analyses. 
Water. 
। Proteids. 
Ash. 
Fuel value 
per pound. 
(Calories.) 
Hind leg, lean 
3 
67.4 
19.8 
12.4 
1.1 
890 
medium fat 
11 
62.8 
18.5 
18.0 
1.0 
1105 
fat 
1 
55.0 
17.3 
27.1 
0.9 
1465 
Loin, medium fat without kidney and tallow. 
13 
50.2 
16.0 
33.1 
0.8 
1695 
fat without kidney and tallow 
3 
43.3 
14.7 
41.7 
0.8 
2035 
very fat without kidney and tallow 
1 
30.8 
10.6 
58.7 
0.5 
2675 
Fore quarter 
10 
52.9 
15.6 
30.9 
0.9 
1595 
Hind quarter 
10 
54.8 
16.7 
28.1 
0.8 
1495 
Roast leg, cooked 
2 
50.9 
25.0 
22.6 
1.2 
1420 
Kidneys 
1 
69.5 
16.9 
12.6 
0.9 
845 
Liver (carbohydrates 5.0) 
2 
61.2 
23.1 
9.0 
1.7 
905 
LAMB. 
Cut. 
Number of 
Analyses. 
Water. 
Proteids. 
Ash. 
Fuel value 
per pound. 
(Calories.) 
Hind leg, medium fat 
2 
63.9 
19.2 
16.5 
1.1 
1055 
fat 
1 
54.6 
18.3 
27.4 
0.9 
1495 
very fat 
1 
51.8 
17.6 
30.1 
0.9 
1595 
Tjoin without kidnev find tallow 
4 
53.1 
18.7 
28.3 
1.0 
1540 
Fore quarter 
1 
55.1 
18.3 
25.8 
1.0 
1430 
Hind quarter 
1 
60.9 
19.6 
19.1 
1.0 
1170 
Broiled chops 
4 
47.6 
21.7 
29.9 
1.3 
1665 
Ron st leg 
1 
67.1 
19.7 
12.7 
0.8 
900 30 
FOODS. 
POULTRY. 
Cut. 
Number of 
Analyses. 
Water. 
Proteids. 
Un 
Ash. 
' Fuel value 
per pound. 
(Calories.) 
Broiler chickens 
3 
74.8 
21.5 
2.5 
1.1 
505 
Fowls 
26 
63.7 
19.3 
16.3 
1.0 
1045 
Young goose 
1 
46.7 
16.3 
36.2 
0.8 
1830 
Turkey 
3 
55.5 
21.1 
22.9 
1.0 
1360 
Chicken liver (carbohydrates 2.4).... 
1 
69.3 
22.4 
4.2 
1.7 
640 
Goose liver 
1 
73.8 
19.6 
5.8 
1.0 
610 
Horse Meat.-The mean of twelve analyses of horse meat as given 
by Konig1 is as follows : 
Water 74.27 
Proteids 21.71 
Fat 2.55 
Ash 1.01 
Meat Preparations. Meat Extracts. - These are preparations 
which are often erroneously supposed to contain all the nutritive parts 
of the meats from which they are made, but they are to be regarded as 
stimulants rather than foods, since they represent the extractives and 
not the substances which determine the true food value. In point of 
fact, so far as their nutritive properties are concerned, it has been 
shown that animals will die more quickly of starvation when fed ex- 
clusively upon these stimulating preparations than when entirely de- 
prived of food. They are, however, of considerable value in their 
proper place, particularly in conditions of great fatigue and exhaustion. 
Meat Powder.-Meat may be easily treated so as to retain all of its 
nutriment and yet have a very much diminished volume. The lean 
parts are cut into small strips, dipped for a few minutes into very hot 
fat (fried), drained, and then slowly dried in an oven. When com- 
pletely dry they are ground in an ordinary spice mill or coffee mill to 
a fine powder which keeps well, has an agreeable taste and a pleasant 
odor, is easily digested, and can be used in a great many different ways. 
Sausages.-Sausage is generally understood to mean an article of 
food consisting chiefly of finely chopped meat, mainly pork and beef, 
with or without the addition of a small amount of meal, highly sea- 
soned with spices, herbs, and other flavorings, and stuffed into casings 
made from the cleaned and prepared intestines. Their nutritive value 
is, therefore, about the same as average meat. As may be supposed, 
the best cuts of meat are not used in their manufacture, but only such 
parts as cannot be disposed of in pieces of fair size and of attractive 
appearance. But there are sausages and sausages. There are those 
made from meat of good quality and others from materials which 
would not be salable in any other form. 
1 Zusammensetzung der menschlichen Nahrungs- und Genussmittel, Berlin, 1882. A N1MAL FO ODS-MEA TS. 
31 
Many of the so-called Frankfurters sold at very low rates, and the 
cheap Bolognas are said to consist largely of horse meat, immature 
veal, and the flesh of cows that are no longer in condition to produce 
milk. Certain it is that a not inconsiderable number of persons gain 
a fair livelihood by going about in the country buying up newly born 
calves and decrepit cows, tuberculous and otherwise, and horses, and 
that these animals are not taken to comfortable stables and inviting 
pastures, but to small slaughtering establishments the output of which 
is not very largely butchers' meat. To the cheap grades of sausages 
the saying of Jean Paul, "Only a god can eat sausage, for only such 
can know of what it is made " applies very aptly. Even sausages 
made from pork, especially those which have undergone a process of 
cooking before being stuffed, are not always beyond suspicion, for the 
trichinous pork condemned by government inspectors at public abat- 
toirs is neither destroyed nor converted into fertilizers, but is allowed 
to be sold after being subjected to a heat sufficient to kill the parasites ; 
and cooked pork is not commonly to be found on sale as such. 
Horse meat is said to combine two advantages in the preparation of 
sausage; it is inexpensive, and it lends a firmness which increases as 
the sausage is boiled. A number of chemical processes have been pro- 
posed for its detection, and among them the following : Humbert1 
boils about 50 grams for an hour in 200 cc. of water, adds about 10 
cc. of strong nitric acid after cooling, and then filters through paper. 
Some of the filtrate contained in a test-tube is then treated with a 
volume of freshly prepared iodine water by careful addition so that 
the liquids do not mix. At the line of junction a reddish violet zone 
will be seen if the specimen contained any considerable proportion of 
horse meat. 
This reaction of iodine upon glycogen, which is a normal constituent 
of horse flesh, forms the basis of a number of processes for the detec- 
tion of this meat, but it is criticised by Niebel2 and others as uncertain 
since glycogen is also present in liver, meat extracts, and very young 
veal, and since dextrin resulting from added starches gives a similar 
coloration. Another process suggested differs from the above in that 
acetic acid is added during the boiling process, and the reagent em- 
ployed is a stronger preparation of iodine, being a 10-per-cent. solution 
with potassium iodide. 
The objection to the use of horse flesh as food is wholly sentimental. 
It has not the pleasant flavor of beef to which we are accustomed, but 
when eaten in ignorance of its true character, it makes no unpleasant 
impression. Its use is steadily increasing in Europe and is beginning 
to find favor in America. In Paris at the beginning of 1899 there 
were 193 places for the sale of the flesh of horses, mules, and donkeys. 
During 1898, 21,667 horses, 52 mules, and 310 donkeys were slaugh- 
tered for food, and of these but 734 horses, 1 mule, and 7 donkeys 
were condemned as unsalable. The best cuts brought about a franc 
'Becueil de Medicine Vet^rinaire, 1895. 
zZeitschrift fur Fleish- und Milchhygiene, 1895, p. 86. 32 
FOODS. 
(19.3 cents), and the inferior parts 10 centimes (2 cents) per pound. 
During 1896, 822 horses and mules were slaughtered in Strassburg; 
in 1897 the number increased to 899, and in 1898 to 1,099. The 
price of horse meat ranged in February, 1899, from 6 to 8 cents per 
pound. 
FISH. 
In the ordinary sense of the word, fish includes, in addition to the 
varieties of fish in its narrow sense, mollusks (clams, oysters, mussels, 
etc.) and crustaceans (lobsters, crabs, crawfish, and shrimps). 
Many prejudices have existed from the earliest times, and to a cer- 
tain extent still exist against the use of fish in the diet. The ancient 
belief that a fish diet is a common cause of leprosy still obtains to a 
certain extent even among enlightened people, in spite of all scientific 
evidence to the contrary. Thus Mr. Jonathan Hutchinson1 main- 
tains that this disease is so caused especially if the fish is poorly cooked 
or partially decomposed. He asserts that the disease prevails near the 
sea and is disappearing before the advance of agriculture; but op- 
posed to this is the fact that in the interior of India the disease is very 
common among people whose religion forbids the use of fish, and who 
cannot obtain it even if it were desired. 
Some varieties of fish cannot be eaten because of their inherent 
poisonous properties. But few of these are, however, found north of 
the tropics. Some of them are always poisonous, and others only at 
certain times, and in some cases individuals of certain species may be 
and others may not be noxious. Some varieties of fish are the hosts 
of parasites, some of which are injurious to man, but unless eaten in 
the raw state they are not likely to produce harm. 
There is a very general belief that fish is particularly valuable as a 
brain food, on account of the supposed high percentage of phosphorus 
that it contains. The amount of phosphorus is, however, so far as is 
known, no higher in fish than in meat and, moreover, this element is 
no more essential to the brain and nervous system than any others 
which are present. If there were any truth in this common belief we 
should naturally expect to find men of commanding intellect among 
those whose diet consists mainly of fish, but, as is well known, such 
people are of a low order of intelligence, though not by reason of 
their diet. 
In spite of the high amount of nutriment contained fish has not the 
same satisfying properties that belong to meats, but it is an exceed- 
ingly valuable food and in many parts of northern countries is the 
principal animal food. The flavor of fish is greatly influenced by the 
nature of the food supply and by the content of flit. Generally speak- 
ing, salt-water fish from deep water where the current is strong are 
better than those from shallow, warm, and quiet water, and both salt- 
water and fresh-water fish taken from rocky and sandy bottoms are 
preferred to those from muddy bottoms. 
1 Archives of Surgery, April, 1899. ANIMAL FOODS-FISH. 
33 
Condition is dependent npon a variety of circumstances. Some 
fish are regarded most highly during their spawning season (shad and 
smelts), while others are looked upon with disfavor at this period. 
Fish caught by the gills in gill nets die slowly, but decompose rapidly, 
and such are of inferior flavor and value. Fish taken from the water 
alive and killed at once remain firm and retain their flavor longer than 
those allowed to die slowly. 
Digestibility.-So far as is known the digestibility of fish and meat 
is about equal, but, as is true of meats, different varieties of fish are 
differently digestible. Thus, those which contain the greatest per- 
centages of fat, as salmon, eels, and mackerel, are the most difficult of 
digestion. The processes of drying, smoking, salting, and pickling 
lessen digestibility, and fish so treated are in consequence less suited 
to the needs of invalids and dyspeptics. The mollusks are generally 
regarded as most digestible, while the crustaceans are believed to tax 
the digestive powers much more than any other animal food. Many 
persons are unable to digest them in any form, and others who suffer 
no inconvenience so far as digestion is concerned are obliged to prac- 
tice self-denial, because of idiosyncrasy which manifests itself in dis- 
tressing eruptive disorders of the skin, dizziness, and other nervous 
symptoms. Lobsters and crabs are much alike, but the former is less 
likely to disagree. The claws of the lobster are more tender and deli- 
cate than the tail, which is much closer grained and firmer. Shrimps 
are generally rated as more difficult of digestion than lobsters and 
crabs, but with many they are more easily borne. 
The mollusks are more digestible in the raw state than when cooked. 
The hard part of the oyster, the adductor muscle, is very trying to 
some persons, and in such cases is best removed and rejected. 
Keeping Qualities.-Fish flesh differs very greatly from meats in 
keeping qualities. While the latter are improved up to a certain point 
by hanging, fish should be eaten while fairly fresh since decomposition 
sets in very quickly. Some varieties, as halibut, cod, haddock, and 
turbot, may be kept a week or more when properly cared for, while 
others begin to deteriorate almost immediately. So long as the flesh 
is firm and stiff all fish is edible, but when it is readily crushed by 
gentle pressure between the fingers it is unsound and should be re- 
jected. Mollusks and crustaceans decompose very quickly and the 
latter when boiled a short time after natural death have but little flavor. 
Composition.-The white-fleshed fish, the haddock, cod, hake, sole, 
turbot, halibut, etc., contain but little fat. The salmon is regarded as 
approaching meat more closely than other fish and is the fattest of all, 
surpassing in this respect the eel, mackerel, and herring which are 
commonly known as fat fish. 
In the following table taken from the report of the United States 
Commissioner of Fish and Fisheries for 1888 (page 741), fish are 
classified according to the percentages of flesh which they yield. 34 
FOODS. 
Kinds of fish. 
No. of 
specimens 
analyzed. 
Flesh. 
Containing 60 per cent, or over of flesh. 
per cent 
Spanish mackerel 
1 
65.4 
Salmon 
4 
64.7 
1 
60.0 
Containing between 60 and 50 per cent, of flesh. 
58.1 
Smelt 
2 
1 
57.3 
Cisco 
1 
57.3 
1 
57.2 
2 
56.4 
5 
55.4 
Pompano 
2 
54.5 
1 
54.2 
1 
54.0 
2 
52.9 
Spent land-locked salmon 
2 
52.7 
1 
52.3 
3 
51.9 
1 
50.8 
2 
50.5 
Containing between 50 and 40 per cent, of flesh. 
49.9 
Shad 
7 
1 
48.1 
Cod 
2 
47.5 
1 
46.5 
Small-mouthed black bass 
1 
46.4 
6 
45.1 
Large-mouthed black bass 
1 
44.0 
1 
43.9 
1 
43.8 
Lake trout, " Mackinaw trout " 
1 
43.7 
1 
43.4 
Pike perch, ' ' Wall-eyed pike " 
1 
42.8 
1 
42.1 
Tomcod 
1 
40.1 
Porgy 
3 
40.0 
Containing between 40 and 30 per cent, of flesh. 
39.9 
Blackfish 
2 
White perch 
2 
37.5 
Yellow perch 
1 
37.3 
Pike perch, ' ' gray pike " 
1 
36.8 
Bed bass 
1 
3b. 5 
Sheepshead 
1 
34.0 
Common flounder 
1 
33.2 COMPOSITION OF FISH. 
35 
In the same work they are classified according to their richness in 
fat as follows: 
Kinds of fish. 
No. of 
specimens 
analyzed. 
Water. 
Fats. 
Containing over 5 per cent, of fats. 
per cent. 
per cent. 
California salmon 
2 
63.6 
17.9 
1 
71.4 
14.4 
5 
63.6 
13.4 
Lamprey eel 
1 
71.1 
13.3 
2 
69.1 
11.4 
1 
70.0 
11.0 
1 
69.0 
11.0 
Shad ° 
7 
70.6 
9.5 
Spanish mackerel 
1 
68.1 
9.4 
Salt-water eel 
2 
71.6 
9.1 
2 
72.8 
7.6 
6 
73.4 
7.1 
AVbitcfisb 
1 
69.8 
6.5 
3 
75.4 
5.2 
3 
75.0 
5.1 
Containing between 5 and 2 per cent, of fats. 
2 
74.4 
4.9 
1 
74.9 
4.6 
White perch 
2 
75.7 
4.1 
Sheepshead 
2 
75.6 
3.7 
Spent salmon 
2 
76.7 
3.6 
1 
76.2 
3.5 
Spent land-locked salmon 
2 
78.5 
3.0 
Striped bass 
6 
77.7 
2.8 
1 
76.3 
2.5 
Small-mouthed black bass 
1 
74.8 
2.4 
1 
79.0 
2.4 
Small-mouthed red-horse 
1 
78.6 
2.4 
Brook trout 
3 
77.7 
2.1 
Containing less than 2, the majority less than 1 per cent- 
of fats. 
1 
78.7 
1.9 
2 
79.2 
1.8 
Skate 
1 
82.2 
1.4 
Tllackfisb 
4 
79.1 
1.4 
1 
78.5 
1.3 
Red snapper 
3 
78.5 
1.0 
Large-mouthed black bass 
1 
78.6 
1.0 
"Kingfish 
1 
79.2 
1.0 
1 
70.0 
0.8 
Yellow perch 
2 
79.3 
0.8 
Pike perch, Gray pike 
1 
80.9 
0.8 
Hake 
1 
83.1 
0.7 
Common flounder 
2 
84.2 
0.7 
2 
79.4 
0.6 
Pike (pickerel?) 
1 
79.8 
0.6 
Spa. bass • • • • 
1 
79.3 
0.5 
Pike perch, Wall-eyed pike 
1 
79.7 
0.5 
"Pickerel 
2 
79.7 
0.5 
Ttpd bass . 
1 
81.6 
0.5 
T'oTncod ... 
1 
81.6 
0.4 
Cod ... 
5 
82.6 
0.4 
Winter flounder 
1 
84.4 
0.4 
Haddock. 
4 
81.7 
0.3 
Cusk 
1 
82.0 
0.2 36 
FOODS. 
The chemical composition of the edible portions of many varieties of 
American fish is given in the following table compiled from the same 
report: 
- 
- 
- 
- 
Kinds of fish. 
In flesh. 
Proteids. 
Fat. 
Ash. 
Total. 
Water. 
Fuel value 
per pound. 
per ct. 
per ct. 
per ct. 
per ct. 
per ct. 
Calories. 
California salmon 
17.46 
17.87 
1.06 
36.39 
63.61 
1,080 
Eel 
15.82 
18.74 
0.93 
35.49 
64.51 
1,085 
Salmon 
20.77 
12.09 
1.38 
34.24 
65.76 
895 
Spanish mackerel 
20.97 
9.43 
1.50 
31.90 
68.10 
790 
Lake trout 
18.22 
11.38 
1.26 
30.86 
69.14 
820 
Whitefish 
22.06 
6.49 
1.62 
30.17 
69.83 
685 
Butterfish 
17.81 
11.03 
1.14 
29.98 
70.02 
795 
Shad 
18.55 
9.48 
1.35 
29.38 
70.62 
745 
Lamprey eel 
14.93 
13.29 
0.66 
28.88 
71.12 
840 
Turbot 
12.92 
14.41 
1.28 
28.61 
71.39 
850 
Mackerel 
18.77 
8.21 
1.40 
28.38 
71.62 
695 
Herring 
18.19 
8.02 
1.69 
27.90 
72.10 
675 
Pompano . 
18.65 
7.57 
1.00 
27.22 
72.78 
665 
Alewife 
19.17 
4.92 
1.47 
25.56 
74.44 
565 
Small-mouthed black bass 
21.50 
2.44 
1.24 
25.18 
74.82 
505 
Halibut 
18.35 
5.18 
1.05 
24.58 
75.42 
560 
Sheepshead 
19.54 
3.69 
1.22 
24.45 
75.55 
520 
White perch 
19.03 
4.07 
1.19 
24.29 
75.71 
525 
Pollock 
21.65 
0.78 
1.55 
23.98 
76.02 
435 
Cisco 
19.12 
3.48 
1.25 
23.85 
76.15 
505 
Muskellunge 
19.63 
2.54 
1.57 
23.74 
76.26 
470 
Striped bass 
18.31 
2.83 
1.16 
22.30 
77.70 
460 
Brook trout 
18.97 
2.10 
1.21 
22.28 
77.72 
440 
Red snapper 
19.20 
1.03 
1.31 
21.54 
78.46 
400 
Bluefish 
19.02 
1.25 
1.27 
21.54 
78.46 
405 
Large-mouthed black bass 
19.24 
0.96 
1.19 
21.39 
78.61 
400 
Small-mouthed red-horse 
17.90 
2.35 
1.19 
21.44 
78.56 
430 
Sturgeon 
17.96 
1.90 
1.43 
21.29 
78.71 
415 
Skate 
18.82 
0.93 
1.43 
21.18 
78.82 
390 
Weakfish 
17.45 
2.39 
1.19 
21.03 
78.97 
425 
Blackfish 
18.47 
1.35 
1.08 
20.90 
79.10 
400 
Smelt 
17.36 
1.80 
1.68 
20.84 
79.16 
400 
Kingfish 
18.66 
0.95 
1.18 
20.79 
79.21 
385 
Sea bass 
18.75 
0.49 
1.44 
20.68 
79.32 
370 
Grouper 
18.80 
0.60 
1.15 
20.55 
79.45 
375 
Yellow perch 
18.49 
0.70 
1.29 
20.48 
79.52 
375 
Pike perch, Wall-eyed pike 
18.42 
0.47 
1.37 
20.26 
79.74 
360 
Pickerel 
18.64 
0.50 
1.18 
20.32 
79.68 
370 
Pike perch, Gray pike 
17.26 
0.76 
1.13 
19.15 
80.85 
355 
Haddock 
17.10 
0.26 
1.25 
18.61 
81.39 
330 
Tomcod 
17.08 
0.38 
0.99 
18.45 
81.55 
335 
Red bass 
16.68 
0.53 
1.23 
18.44 
81.56 
335 
Cusk 
16.92 
0.17 
0.90 
17.99 
82.01 
320 
Cod 
16.00 
0.30 
1.24 
17.54 
82.46 
310 
Hake 
15.24 
0.67 
0.98 
16.89 
83.11 
310 
Common flounder 
13.82 
0.69 
1.28 
15.79 
84.21 
285 
Winter flounder 
14.01 
0.44 
1.20 
15.65 
84.35 
280 
Spent fish. 
Spent salmon 
18.52 
3.60 
1.14 
23.26 
76.74 
495 
Spent land-locked salmon 
17.24 
2.98 
1.24 
21.46 
78.54 
445 37 
COMPOSITION OF FISH. 
Fish. 
Edible portion. 
Energy in 1 pound. 
'cS 
Nutrients. 
Water. 
Proteids. 
Ash. 
Total. 
per et. 
per ct. 
per ct. 
per ct. 
per ct. 
Calor. 
per ct. 
Desiccated codfish (fish meal) 
74.46 
1.90 
5.41 
84.75 
15.25 
1,465 
2.88 
Salt codfish 
21.42 
0.34 
1.62 
46.42 
53.58 
410 
23.04 
Salt mackerel 
18.88 
25.12 
2.59 
56.99 
43.01 
1,410 
10.40 
Smoked haddock 
33.68 
0.17 
1.53 
27.44 
72.56 
445 
2.06 
Smoked halibut 
20.57 
15.03 
2.06 
50.62 
49.38 
1,015 
12.96 
Smoked herring 
36.44 
15.82 
1.53 
65.45 
34.55 
1,345 
11.66 
Canned salmon 
20.06 
15.70 
1.32 
38.12 
61.88 
1,035 
1.04 
Canned mackerel 
19.91 
8.68 
1.30 
31.82 
68.18 
735 
1.93 
Canned tunny 
21.52 
4.05 
1.69 
27.26 
72.74 
570 
Fish. 
Proteids. 
Fat. 
Carbo- 
hydrates. 
Ash. 
Total. 
Water. 
Oysters 
9.78 
2.05 
5.89 
1.98 
19.70 
80.30 
Oyster liquor 
1.48 
0.03 
0.75 
2.13 
4.39 
95.61 
Canned ovsters 
7.41 
2.07 
3.95 
1.31 
14.74 
85.26 
Long clams 
14.55 
1.79 
2.94 
2.76 
22.04 
77.96 
Long clams canned 
17.73 
2.89 
1.59 
3.16 
25.37 
74.63 
Round clams 
11.59 
0.74 
7.21 
2.22 
21.76 
78.24 
Round clams canned 
16.70 
1.27 
4.14 
2.33 
24.44 
75.56 
Mussels 
12.51 
1.67 
5.42 
1.73 
21.33 
78.67 
Scallops 
14.75 
0.17 
3.38 
1.38 
19.68 
80.32 
Lobster 
14.49 
1.84 
1.71 
Lobster canned 
18.13 
1.07 
2.47 
Crab 
16.64 
1.96 
3.13 
Crab canned 
15.80 
1.55 
1.94 
Shrimps (canned) 
25.38 
1.00 
2.58 
Terrapin 
21.23 
3.47 
1.02 
Green turtle 
19.84 
0.53 
1.20 38 
FOODS. 
From the tables of analyses contained in Bulletin No. 28 mentioned 
on page 26 the following figures have been taken : 
Variety. 
Proteids. 
Pm 
Carbo- j 
hydrates. 
Ash. 
Total. 
W ater. 
Calories 
per pound. 
Ale wife 
19.2 
4.9 
1.5 
25.60 
74.40 
570 
Bass, Black 
20.4 
1.7 
1.2 
23.30 
76.70 
455 
Bass, Red 
16.7 
0.5 
1.2 
19.40 
81.60 
335 
Bass, Sea 
18.8 
0.5 
1.4 
20.70 
79.30 
390 
Bass, Striped 
18.3 
2.8 
1.2 
22.30 
77.70 
465 
Bluefish 
19.0 
1.2 
1.3 
21.50 
78.50 
410 
Butterfish 
17.8 
11.0 
1.2 
30.00 
70.00 
800 
Cod 
15.8 
0.4 
1.2 
17.40 
82.60 
325 
Cusk 
16.9 
0.2 
0.9 
18.00 
82.00 
325 
Eel 
18.3 
9.1 
1.0 
28.40 
71.60 
730 
Flounder 
13.9 
0.6 
1.3 
15.80 
84.20 
290 
Haddock 
16.8 
0.3 
1.2 
18.30 
81.70 
335 
Hake 
15.2 
0.7 
1.0 
16.90 
83.10 
315 
Halibut 
18 4 
5 2 
1 0 
24 60 
75 40 
565 
Herring 
18.9 
7.1 
1.5 
27.50 
72.50 
660 
Kingfish 
18.7 
0.9 
1.2 
20.80 
79.20 
390 
Mackerel 
18 3 
7 1 
1 2 
26 60 
73 40 
645 
Muskellunge 
19 6 
2 5 
1 6 
23 70 
76 30 
480 
Perch, White 
19 1 
4 0 
1 2 
24 30 
75 70 
530 
Perch, Yellow 
18 7 
0 8 
1 2 
20 70 
79 30 
380 
Pickerel 
18 6 
0 5 
1 1 
20 20 
79 80 
370 
Pollock 
21 7 
0 8 
1 5 
24 00 
76 00 
435 
Pompano 
18 7 
7 5 
1 0 
27 20 
72 80 
665 
Red snapper 
19 2 
1 0 
1 3 
21 50 
78 50 
410 
Salmon 
21 2 
12 8 
1 4 
35 40 
64 60 
950 
Shad 
18 6 
9 5 
1 3 
29 40 
70 60 
750 
Shad roe 
20 9 
3 8 
2.6 
1 5 
28 80 
71 20 
600 
Sheepshead 
19 5 
3 7 
1 2 
24 40 
75 60 
530 
Smelt 
17 3 
1 8 
1 7 
20 80 
79 20 
405 
Spanish Mackerel 
21 0 
9 4 
1 5 
31 90 
68 10 
795 
Trout 
18 9 
2 1 
1 2 
22 20 
77 80 
445 
Salmon trout 
17 7 
10 3 
1 2 
29 20 
70 80 
765 
Turbot 
12 9 
14 4 
1 3 
28 60 
71 40 
885 
Weakfish 
17 4 
2 4 
1 2 
21 00 
79 00 
430 
Whitefish 
22 1 
6 5 
1 6 
30 20 
69 80 
700 
Canned Salmon 
21 8 
12 1 
2.6 
36.50 
63.50 
915 
Sardines 
22.4 
19 7 
5 6 
47 70 
52 30 
1260 
Caviare 
30 0 
19 7 
7.6 
4.6 
61 90 
38 10 
1530 
Frogs' legs 
15 1 
0.2 
1.0 
16 30 
83 70 
295 
Clams 
8 6 
1 0 
2 0 
2 6 
14 20 
240 
Little Neck Clams 
2.1 
0.4 
4.2 
2.7 
13.80 
86.20 
215 
Crabs 
16 6 
2 0 
1 2 
3 1 
22 90 
77 10 
415 
Lobster 
16 4 
1 8 
0.4 
2 2 
20.80 
79 29 
390 
Oysters 
6 2 
1.2 
3.7 
2.0 
13.10 
86 90 
235 
Scallops 
14 8 
0.1 
3.4 
1.4 
19.70 
80.30 
345 
Shrimps 
25 4 
1.0 
0.2 
2.6 
29.20 
70.80 
520 
Mussels 
8 7 
1.1 
4.1 
1.9 
15.80 
84.20 
285 
Salt Cod (Boneless) 
25.7 
0.3 
19.0 
45.00 
55.00 
490 
Smoked Haddock 
23.7 
0.2 
3.6 
27.50 
72.50 
440 
Smoked Halibut 
20.6 
15.0 
15.0 
50.60 
49.40 
1020 
Smoked Herring 
36.4 
15.8 
13.2 
65.40 
34.60 
1355 
Salt Mackerel ..r. 
17.3 
26.4 
12.9 
56.60 
43.40 
1435 ME A T AND FISH AND PARASITIC DISEASE. 
39 
Meat and Fish and Parasitic Disease. 
Man is subject to several parasitic troubles due to the ingestion of 
infested meat and fish. Of these the most common is the tapeworm 
of which at least ten species are known, though only three have been 
demonstrated as having any connection with food. These are the 
Tsenia saginata (T. mediocanellata) due to measly beef, Taenia solium 
from measly pork, and Bothriocephalus latus due to infested sturgeon, 
pike, perch, and salmon. The latter is very rare in this country 
though not uncommon along the Baltic. This is the only parasitic 
worm of the large number which infest fish known to be conveyed to 
man. It is very quickly killed if the fish is properly cooked. 
The larval forms of the T. saginata and T. solium exist in beef and 
pork respectively as the Cysticercus bovis and C. cellulosae. The lat- 
ter is found rarely also in mutton. Meats infested with these forms 
are known as " measly " or " measled," and the animals from which 
the meats are derived are known as the intermediate hosts, man being 
the final host. The life history of the tapeworm is much more simple 
than that of many other parasites. Beginning with the adult tape- 
worm in man the cycle is as follows : From each individual segment 
which is possessed of a complete reproductive system great numbers of 
eggs are discharged. The latter are expelled from the intestine with 
the feces, and some of them may eventually enter the digestive tract of 
cattle or swine through the food or water. In the intestine the embryos 
become liberated from the eggs, and they then make their way in large 
numbers to the muscular tissues, brain, liver, and other parts where 
they come to rest and develop as bladder worms. 
The bladders are variable in size, the smallest being about inch, 
and the largest about inch across, and in the flesh are embedded be- 
tween the muscular fibers. The living animal shows nothing in his 
appearance to indicate the presence of the parasite, excepting when the 
cysts can be seen in the under side of the tongue or between the tongue 
and the lower jaw. If now the animal is slaughtered and the meat is 
eaten raw or imperfectly cooked, the Cysticercus is freed from its en- 
veloping capsule and proceeds to develop into an adult tapeworm, and 
the cycle is complete. The Cysticercus bovis dies within two or three 
weeks after the slaughter of its host, and, therefore, measled beef kept 
for three weeks in cold storage becomes incapable of producing harmful 
effects. It is killed within 24 hours by pickling solutions of common 
salt when brought into intimate contact. 
The Cysticercus cellulosse lives rather longer in cold storage : prob- 
ably a month or more. Both of these larvae are killed by exposure 
to a temperature of 140° F. for five minutes, and as this is lower than 
the temperature in the interior of well-cooked meat it is necessary only 
to make sure that the meat is properly cooked to escape danger. 
Neither parasite is destroyed by ordinary smoking or salting, but both 
are killed by hot smoking. 
The sale of measled meat is permitted in many countries of Europe 40 
FOODS. 
but it must be sold as such and only in specially designated places. It 
finds a ready market at a low price, and the purchasers are warned 
that it must be thoroughly cooked. According to Virchow, since the 
introduction of systematic meat inspection the proportion of tapeworm 
in the human subject dissected in Berlin has fallen from 1 in 31 to 
1 in 280. 
A parasite of far greater importance is the Trichina spiralis which 
is found almost exclusively in pork and only occasionally in the flesh 
of other mammals and of birds and frogs. Trichinae are small thread- 
like worms, much longer than one would suppose on passing examina- 
tion of fairly thick microscopic preparations since they are coiled with 
several turns within the minute cysts in which they are lodged. In 
Plate I., Fig. 1 is shown one of the parasites in the free state. In the 
pig the worm infests both the fat and the voluntary muscles but chiefly 
the latter and especially the diaphragm, the intercostals, and the mus- 
cles of the jaw. When encapsulated in the flesh their location may be 
evident to the naked eye as small white specks. Thin sections of 
muscles treated a few minutes in weak caustic potash solution (1:10) 
are soon made sufficiently clear to reveal the coiled worm under a lens of 
low power. If very much fat is present or if the capsule has become 
calcareous and thick it may be necessary to employ ether or acetic acid 
before applying the potash. When the parasites are very numerous 
the flesh is both speckled and pale. 
Our first knowledge of the serious effects which may result from 
eating infested pork dates back only to 1860, although the parasite had 
been discovered in the muscles of a human subject by James Paget in 
1833 and named by Richard Owen. It was long regarded as a harm- 
less parasite and curiosity, and its effects were mistaken for rheuma- 
tism, typhoid fever, and other diseases of common occurrence. The 
case which finally revealed its capacity for harm was that of a young 
woman admitted to the hospital at Dresden suffering, it was supposed, 
from typhoid fever. 
In a short time a train of symptoms quite unlike those of that dis- 
ease appeared, the most marked one being most acute pain involving 
the entire muscular system, and intensified on attempting to move. 
On account of the agony induced extension of the arms and legs was 
quite impossible. In a short time pneumonia supervened, and in a 
few days the victim died. The autopsy revealed the parasite in vast 
numbers in the muscles, and this led to further investigation which 
showed that four days before the first symptoms of illness appeared she 
had eaten freshly killed pork. Some of this was secured in the form 
of ham and sausage, and examination demonstrated the presence of the 
parasite. 
The first extensive outbreak which caused the disease to be looked 
upon as one of great importance occurred in Prussia in 1863, when 
more than 20 persons died within a month after a dinner in which 103 
had participated, and at which smoked sausages made from an infested 
pig had been served. The parasites were discovered in the muscles MEAT AND FISH AND PARASITIC DISEASE. 
41 
of those who died, and in the sausages that remained. Since that 
time it has been customary in most large slaughtering establishments 
to examine pork for evidence of the parasite before passing it as fit for 
food. But examination is not always a safeguard even in countries 
where it is most carefully observed. In Germany, for instance, where 
all meats are supposed to be examined with scrupulous care, particu- 
larly those from the United States, the disease is very common. 
In 1883, on account of the alleged dangers which lurked in Amer- 
ican meats, importation was interdicted for a time, but in the succeed- 
ing 15 years there were in Prussia alone 3,003 cases and 207 deaths 
not one of which could be traced to American meat either salted, 
pickled, canned, or made into smoked sausages. Over 40 per cent, 
of the cases were traced to European meat which had been passed as 
free from trichinae, and the balance were due to European meat which 
had been found to contain the parasite, but had nevertheless been 
handled by the trade. During 1898 the parasites were found by the 
microscopists of the U. S. Department of Agriculture in 13,325 out 
of 1,881,309 specimens of pork examined. 
In spite of the danger of eating trichinous meat there are those who 
are not deterred by fear from eating it. In Germany, for instance, it 
has happened a number of times that hogs which have been condemned 
and ordered buried by the sanitary authorities have been dug up sur- 
reptitiously and eaten.1 
Trichinosis bears certain resemblances to typhoid and to acute tu- 
berculosis, but in addition is accompanied by oedema and intense pain. 
It arises from eating the infested meat in a raw or not well cooked 
condition. The trichinae are killed by a heat of 155° F. if they are 
not encapsulated ; otherwise by a temperature of 158 to 160°. 
They are not affected by intense cold or by putrefactive processes 
or by ordinary smoking, but are killed by long pickling. 
The first symptoms appear in a few days after ingestion, and indi- 
cate irritation of the alimentary canal. These are followed by febrile 
symptoms and intense muscular pains. Death may occur within a 
few weeks. In case of recovery the parasites become encysted and 
then are incapable of producing further injury to their host. 
The manner in which they produce their efforts is as follows : When 
the infested meat reaches the stomach the digestive juices dissolve the 
capsule and the parasite is thus left in a free state. In the intestine 
it finds conditions favorable to its growth, and in a few days' time it 
grows so large that it can be seen with the naked eye and appears like 
a piece of fine thread. 
The female parasites when fully mature begin to produce young, 
each to the extent of upwards of 500. These begin at once a migra- 
tion through the walls of the intestine and find their way to all parts 
of the body, and it is during this stage that the fever and intense pain 
are caused. 
1 For an account of such a case consult Zeitschrift fur Fleisch- und Milchhygiene, 
1897, VII., p. 104. 42 
FOODS. 
In Plate I., Fig. 2, and Plate II., Fig. 1, are seen thin sections of 
muscle from a human subject, a victim of the disease, showing the 
worm coiled up and the thickened capsule formed about it. In Plate 
II., Fig. 2, it may be seen within the muscle of an infested pig. 
The sheep disease which is known as rot, which term, it must be 
said, is used to include a large number of abnormal conditions, but 
which in its strict application means a parasitic disease of the liver, is 
believed by many to be of sufficient importance to warrant the con- 
demnation of the flesh of the animal, but the scientific evidence on this 
point is to the effect that no possible harm can come to the consumer 
even though the liver itself be eaten. The parasite infests not alone 
sheep but cattle as well, and is known as the fluke. Of the many 
varieties of flukes there are but two known in the United States ; these 
are the common liver fluke (leberwurm, leberegel, schafegel, douve 
hSpatique) and the large American fluke. The former infests cattle 
and sheep; the latter, only cattle. 
The life history of the worm is exceedingly complicated and is as 
follows : The adult or hermaphroditic worm, fertilizes itself in the 
biliary passages of the liver, and produces an exceedingly large num- 
ber of eggs, which pass to the intestine of the host with the bile, and 
are expelled in the feces. Such of the eggs as eventually reach water 
give rise after a longer or shorter period according to temperature, to 
a ciliated embryo, which on its escape from the egg becomes a free 
swimming ciliated miracidium, and enters the body of certain species 
of snails, where it comes to rest. Here the organism grows, and after 
a time certain germ cells in its posterior portion develop a still differ- 
ent form of life, the ridise. These wander to the host's liver and in- 
crease in size, and in turn develop from their germ cells the next gen- 
eration which are called cercarise. These leave the body of the snail 
and swim about in the water, and some become attached to blades of 
grass where they form enveloping cysts and undergo some anatom- 
ical changes. 
For their next stage it is necessary that they be received into the 
stomach of some herbivorous animal by which they will be swallowed 
with the grass. On reaching the stomach the cysts are destroyed and 
the parasites wander to the liver and become adult hermaphrodites, 
thus completing the cycle. Occasionally they wander to the lungs 
and other parts of the body. In the liver, the parasites attach them- 
selves to the walls of the bile ducts which may become completely 
blocked, and they cause the breaking-down of the surrounding tissues 
and general symptoms due to structural changes. The parasite cannot 
be transmitted directly from animal to man since it requires an inter- 
mediate host, and in the stage preceding its final development it is not 
attached to material constituting human food. There are, to be sure, 
some instances of the disease in man, though not by direct transmis- 
sion from meat. The condition caused by flukes is known variously 
as rot, liver rot, fluke disease, and distomatosis. PLATE I. 
Fig. 1. 
Free Trichina, (x 38.) 
Fig. 2. 
Trichinae in Human Muscle, (x 75.) PLATE II. 
Fig. 1. 
Trichinae in Human Muscle, showing Thickened 
Capsule, (x 75.) 
Fig. 2. 
Trichinae in Pig Muscle, (x 75.) TRANSMISSION OF DISEASE BY MEAT AND FISH. 
43 
TRANSMISSION OF DISEASE BY MEAT AND FISH. 
Living pathogenic bacteria in diseased meat and fish may gain ac- 
cess to the stomach in limited numbers and beget no disease. If they 
are not destroyed by the gastric juice they have to contend with my- 
riads of organisms normal to the intestines, and it is only when the 
conditions are such as to favor extensive multiplication that they are 
likely to produce harmful effects. Pathogens in meat that is thor- 
oughly cooked are killed by the heat to which they are subjected. 
It is well known that the stomach has a wonderful protective power 
in its own natural functions, since certain violent organic poisons may 
be taken into the stomach without injury, while if the same are intro- 
duced into the circulation the results are fatal; thus the venom of poi- 
sonous serpents is digested and made harmless by the stomach juices. 
An instance of the immunity conferred by cooking or by the process 
of digestion or by both together, and of the fatal result of the admis- 
sion of the harmful element of the same meat to the system through 
cuts and abrasions is given by Lardier.1 
A cow died suddenly of anthrax and was dressed for food. The 
meat was eaten by a large number of people, none of whom suffered 
the slightest inconvenience or injury. A number of cats, however, 
which ate some of the waste matters and licked up the blood died with 
some suddenness. A woman who bought the head and wounded herself 
in the process of cutting it up had a charbon at the place of injury and 
died. Two men who helped skin the cow had charbon, but recovered. 
A calf belonging to one of these two died of anthrax, and another man 
removing the skin cut himself and died. The skin of the original 
animal was sold and the purchaser put it in a shed on his farm. Some 
time later one of his cows died suddenly, and the man who dressed the 
carcass wounded himself during the process, acquired a charbon and 
died. How much farther this series of fatalities might have extended 
cannot be known, since the authorities took steps in the matter and 
prevented further fatalities. 
Many instances are known in which the flesh of cattle dead of infec- 
tious disease has been eaten with perfect impunity. During the siege 
of Paris, for example, when the food supply was exceedingly limited 
in amount, no one paid the slightest attention to the condition of meat 
in respect to disease, even glandered horses finding a ready market, 
and so far as is known no ill effects resulted. 
Many years ago when the rinderpest was very prevalent in Bohemia, 
the diseased cattle were killed and buried by order of the government, 
but the poorer class dug up the carcasses and cooked and ate them 
without suffering any evil consequences. 
During the prevalence of the same disease in England in the early 
sixties, the meat from the diseased animals in all stages of the distem- 
per was sent in enormous quantities to the market and sold and eaten 
without evil effects. A similar immunity has often been noticed after the 
1 Revue d'Hygiene, 1898, No. 5, p. 431. 44 
FOODS. 
consumption of the carcasses of animals dying from acute pleuro-pneu- 
monia. In ordinary cases of this disease which is peculiar to beef cat- 
tle, the effects are localized in the lungs. Sometimes in very pro- 
nounced cases the flesh is altered in appearance, becoming dark and 
discolored and it is also moist and flabby. It is believed that the meat 
is perfectly good to eat if it possesses a normal appearance. The meat 
in rinderpest undergoes no marked change in appearance, excepting 
in advanced cases when it is dark in color and flabby and of disagree- 
able odor. 
In ordinary cases of foot and mouth disease, it appears that the car- 
cass is perfectly good to eat, but in exceptional cases, when the animal 
has suffered for a long time, the flesh may be so deteriorated as to be 
undesirable. As a rule, although the disease is very infectious, its 
course is mild and interferes only slightly, if at all, with the condition 
of the meat which generally cannot be distinguished from that of 
healthy animals. 
Although many instances are known that show that the meat of 
animals suffering with anthrax may be eaten without injury, it is the 
unanimous opinion of those who have given the matter attention that 
no matter how good the meat may appear it should be condemned and 
destroyed. If the meat is well cooked accidents are rare, but many 
cases of fatal injury involving a large number of victims have been 
traced to the use of such meat, presumably not thoroughly cooked. 
In spite of the protection conferred by cooking there is such an ele- 
ment of danger even in the handling of the meat that its use should 
be discouraged and forbidden. In Scotland it is a common practice 
with the farm laborers and other poor to eat the meat of sheep which 
have died of acute inflammatory diseases, even of anthrax. The car- 
cass of an animal dying of disease is the perquisite of the herdsman 
and is almost invariably eaten after being salted. No precaution is 
taken except to cut away the darker portions of the meat which 
show stagnation of the blood. Occasionally, serious consequences 
due either to imperfect cooking or to insufficient salting result from its 
consumption. 
It is generally held that the flesh of animals that have died from 
actinomycosis, puerperal fever, "strangles," hog cholera, and sheep scab 
is quite unfit for human food. 
The cattle disease most commonly known in this country, if not 
elsewhere, is tuberculosis, and concerning the advisability of using the 
flesh of its victims there is much difference of opinion here and abroad. 
The disease is more common in cows, especially those kept in confine- 
ment, than in steers and oxen. It is almost an unknown disease in 
the great herds roaming the western plains. In Berlin in 1892-93, 
15.1 per cent, of all cattle, 1.55 per cent, of swine, 0.11 per cent, of 
calves and 0.004 per cent, of sheep slaughtered showed some evidence 
of the existence of the disease. In Copenhagen in the years 1890-93 
the figures were somewhat higher than those of Berlin excepting in the 
case of sheep. They were as follows : 17.7 per cent, of cattle, 15.3 TRANSMISSION OF DISEASE BY MEAT AND FISH. 
45 
per cent, of swine, 0.2 per cent, of calves, and only one sheep out of 
337,014. At the abattoirs of Leipzig, in 1897, nearly half of the 
cows and about 20 per cent, of the other cattle were found to be tuber- 
culous ; 2.78 per cent, of swine, 0.2 per cent, of calves, and 8 sheep 
out of 49,559. 
Out of over 8,000 beeves of American origin landed, slaughtered, 
and examined at Hamburg, 4 were found to be tuberculous, while of 
the same number of native animals, 640, or 160 times as many, were 
found to be afflicted with the disease. At this time the German press 
had been carrying on one of its periodical agitations against the impor- 
tation of American beef cattle on account of the dangers to which na- 
tive breeds were thereby subjected. 
In Mexico about one-third of the beeves slaughtered are tuberculous. 
In the State of New York, it is said by veterinarians that in some dis- 
tricts in which the herds are mainly of the hardy grades of the Ayr- 
shire, Holstein, and Short-horn families, about 1 per cent, of the cows, 
and in others where Jerseys and Guernseys are more common, about 
2 to 3 per cent, are tuberculous. In Massachusetts, those in a position 
to be best informed state that among cows the disease is much more 
frequent than in New York, but that it is rarely to be found in calves, 
steers, and oxen. 
The organs involved most frequently in tuberculosis of animals are 
the liver, lungs, kidneys, brain, and udder. The muscles themselves 
are very rarely affected although the bacilli have been found in the 
expressed juice. 
Calves born of tuberculous cows are generally quite free from the 
disease, and when not so the mother has in almost all cases tubercular 
endometritis. MacFaydean reported a case of congenital tuberculosis 
before the Pathological Society of London in May, 1899, in which the 
lesions were of the spleen, liver, and kidneys, with slight involvement 
of the lungs and almost universal invasion of the lymphatic glands. 
Of three other cases which had come under his observation since 1897, 
in one the cow had tuberculosis of the uterus, in another the disease 
was limited to the lungs, and in the third no information as to the 
condition of the mother was obtainable. 
At what stage of the disease meat becomes unfit for food is a ques- 
tion over which there is much controversy. Extremists on the one side 
believe in condemning the entire carcass on the slightest evidence of 
disease in any part thereof, while those on the other side maintain that 
the entire animal can be used as food without injury. In England the 
practice is to condemn any carcass in which the disease has made such 
extensive progress that the flesh has become deteriorated. The Royal 
Commission on Tuberculosis1 concluded that meat from tuberculous 
animals may be consumed with impunity if sufficient discrimination 
and care are exercised in slaughtering and dressing. Every part con- 
taining tubercle should be removed and destroyed, and the whole car- 
cass itself in advanced or general tuberculosis. 
'The Veterinary Journal and Annals of Comparative Pathology, June, 1895. 46 
FOODS. 
The French law excludes carcasses with generalized tuberculosis and 
those in which local lesions have involved the greater part of an organ. 
The same is true in Austria. In Prussia, the meat is held to be unfit 
for food if the animal has begun to show emaciation, but is passed as 
fit for human consumption if the disease occurs only in one organ, and 
in general if the animal is well nourished. In Belgium, the law of 
September 30, 1895, permits the sale of meat of tuberculous animals 
after sterilization. 
Meat from tuberculous cattle is infective in a varying and somewhat 
irregular manner. As a rule the more advanced the disease the more 
likely is the meat to be infective. Experiment has shown that infec- 
tion depends not upon the lesions present in the muscular tissue itself, 
but rather upon contamination of the meat either by the knife, hands, 
or cloths used in the process of dressing, which have been in contact 
with tuberculous matter. Again, tuberculous glands are not infre- 
quently left in the carcass, and unless these are thoroughly cooked they 
may be a source of danger. 
Lesions in the muscular tissue itself are not at all common and can- 
not account for the positive results obtained from inoculation or in 
feeding experiments, yet Kastner obtained positive results in nine out 
of eleven experiments in which he injected the expressed juice of the 
meat of seven tuberculous animals. Steinheil has demonstrated that 
the disease can be transmitted to guinea-pigs by the expressed juice of 
meat in which no tubercles can be detected. Positive results are very 
readily obtained by feeding guinea-pigs, swine, and other animals on 
tuberculous lung tissue and other material, but in these cases the 
lesions produced are limited as a rule to glandular organs, and almost 
never involve the muscular tissues. 
While there is abundant evidence that the disease can be trans- 
mitted from one animal to another, and that the bacillus of the human 
subject is fatal to many of the lower animals, the fact remains that, 
according to the careful researches of Professor Theobald Smith and 
others, the human bacillus fails to find in the bovine body the condi- 
tions necessary to its multiplication. Whether the bovine bacillus by 
reason of its higher pathogenic power may pass to the human subject 
is, according to Smith,1 a question concerning which we have, as yet, 
no definite knowledge. He has demonstrated that the bovine and 
human bacilli present fairly pronounced differences in several respects, 
but concedes that from the clinical evidence at hand it appears pos- 
sible that bovine tuberculosis may be transmitted to children when 
very large numbers of bacilli are taken into the system in milk of 
cows with disease of the udder. 
Whatever danger may reside in tuberculous matter is diminished by 
thorough cooking, since thereby the bacillus is quickly killed. Since 
raw meat is frequently used as food, particularly in some conditions of 
disease, it is necessary that the meat so used shall be free from infective 
properties. 
'Journal of Experimental Medicine, Vol. 3, Nos. 4 and 5. TRANSMISSION OF DISEASE BY MEAT AND FISH 
47 
Fish are commonly regarded as incapable of becoming infected with 
tuberculosis, but one instance has been recorded in which the contrary 
has proved to be the case. Drs. Dubar, Bataillon, and Terre commu- 
nicated to the French Academy of Medicine the details of this case 
which are as follows : The sputa and discharges of a woman suffering 
from advanced tuberculosis of the lung and of the intestines were 
regularly thrown into a pond in which were large numbers of carp. 
After a time many of the fish were found to be dead, and on examina- 
tion their livers and other organs were found to be full of tubercle 
bacilli. Healthy fish fed experimentally on this and similar material 
became tuberculous within a few weeks, but the infected fish were 
proved to be quite devoid of power to affect warm-blooded animals, 
and, therefore, it appears that there can be little danger from the con- 
sumption of tuberculous fish. 
The danger from other animal diseases will be discussed under meat 
poisoning. 
Foods of all kinds may be made the bearers of infection to man 
though themselves in good condition. Particularly is this noticeable 
with regard to oysters which have many times been the carriers of ty- 
phoid fever and cholera. As long ago as 1880, Sir Charles Cameron 
called attention to the possibility of the existence of a relation between 
the consumption of specifically polluted oysters and typhoid fever, and 
in 1893 Sir R. Thorne-Thorne, in a report to the Local Government 
Board on cholera, stated his belief that this disease had been disseminated 
in England through the distribution of shellfish from polluted waters. 
In 1894 occurred the outbreak of typhoid fever among the students of 
Wesleyan College at Middletown, Conn., which was the first case in 
which the causal relation of the oysters was demonstrated beyond any 
doubt. The students who ate oysters in the raw state were the only 
ones affected, those who ate them cooked suffering not at all. The 
oysters consumed had been transferred from their original bed and 
placed in a current of fresh water which was contaminated by domes- 
tic sewage containing the discharges of a number of patients suffering 
with the disease. 
In 1896 the French Academy of Medicine took official notice of the 
connection between infected oysters and typhoid fever, and came to 
the conclusion that suspected oysters may be made safe by removal 
for several days to pure sea water away from all possible chance of 
contamination. According to Dr. Klein the period which should elapse 
is at least sixteen days. He found that the bacilli in typhoid-con- 
taminated oysters were harbored from four to sixteen days after 
removal to clean water. Dr. Newsholme1 after a thorough investiga- 
tion of the subject concluded that no less than 30.7 per cent, of the 
total number of cases of typhoid fever in Brighton, England, in 1897, 
were definitely traceable to the eating of sewage-contaminated oysters 
or mussels, and that the percentages in other years were 38.2 in 1894, 
33.9 in 1895, and 31.8 in 1896. 
1 Public Health, Sept., 1898. 48 
FOODS. 
Poisoning by Meat and Fish. 
Animal foods are the frequent cause of most distressing disorders 
which not rarely have a fatal termination. Some of these are due to 
poisonous properties inherent in the living animal, some to bacterial 
poisons formed in meats showing no evidence of unwholesomeness, 
and some to decomposition products developed during storage or putre- 
faction. 
1. Poisoning Due to Substances Normally Present in the Living 
Organism.-As has been stated, certain species of fish are always poi- 
sonous and others only at times, and in some cases only individual 
members are so constituted. Certain species are so well known to be 
poisonous in perfectly fresh condition that they are never eaten by the 
natives of the places where they are found except for purposes of sui- 
cide. Some have poisonous glands connected with their fins, some 
have poisonous ovaries, and others are poisonous throughout. Some 
are poisonous only in the raw state, and others whether cooked or not. 
The symptoms produced vary widely, sometimes indicating gastro- 
enteritis, sometimes involvement of the central nervous system. 
The mussel is not uncommonly regarded as an intrinsically poison- 
ous shellfish, but the weight of evidence indicates that mussel poisoning 
is due to conditions of disease or infection arising from residence in 
polluted water. Its poisonous properties have long been recognized, 
and have been the subject of a number of dissertations by early writers ; 
thus, Behrens, De affectionibus a comestis mytulis, Hannover, 1735, and 
Moehring, Mytulorum quorundam venenum et ab eo natas papulas cuti- 
culares Epistola, Nuremberg, 1744. In France, where great quantities 
of mussels are eaten, cases of poisoning therefrom are rare, owing 
doubtless to the fact that those taken from polluted harbors are kept 
for a week or more in clean water elsewhere. 
2. Poisoning Due to Bacterial Products in Meats Apparently 
Wholesome.-What is commonly known now as meat-poisoning is due 
to the products of a number of organisms having no connection with 
the usual diseases of man. They include certain spore-bearing anaerobes 
isolated by Van Ermengem (Bacillus botulinus), and Klein (Bacillus 
enteritidis sporogenes), a number of derivatives of the Bacillus coli 
isolated by Gaertner (B. enteritidis), Basenau (B. bovis morbificans), 
Kaensche (B. Breslaviensis and B. Morseelenensis), Gaffky and Paak 
(B. Friedebergensis), Abel, Gunther, and others, besides B. proteus 
vulgaris and probably a large number of species not yet discovered. 
In general it is caused by the meat of animals slaughtered while suffer- 
ing from diseases other than those to which public attention is drawn 
by reason of wide destruction of sheep, swine, and cattle when raging 
in epidemic form. Instances of poisoning due not to a diseased condi- 
tion of the animal, but to bacterial contamination of otherwise whole- 
some meat are, however, not uncommon, and meat may become infected 
even after it has been cooked just as easily as when it is raw. 
The most dangerous forms of meat poisoning are those due to the POISONING BY MEAT AND FISH. 
49 
pyaemias, septicaemias, and pneumoenteritis, and the greatest intensity 
of action is produced by preparations made from the entrails. 
The symptoms caused are those indicating either gastro-enteritis or 
poisoning of the central nervous system (" Botulism or, more fre- 
quently, both. The involvement of the central nervous system gives 
rise to a great variety of manifestations, but in outbreaks traceable to 
a common cause the different individuals present, in general, the same 
train of symptoms. A peculiar tendency to relapses is often observed. 
The patient begins to improve, when suddenly the original symptoms 
reappear with equal, greater, or diminished intensity. Improvement 
may be succeeded again by a relapse, and this condition may obtain 
for many months. The toxins secreted by the original invading bac- 
teria are antagonized by antitoxins produced by the system and im- 
provement occurs; then during this interval the spore bearers find 
opportunity to develop a new crop of bacteria, which, again producing 
toxins, cause a recurrence of the original symptoms. 
In a majority of the reported outbreaks the meat has been consumed 
either raw or only imperfectly cooked, or after being kept a day or two 
after being cooked. The meats most commonly the cause are pork 
and its preparations, and veal. Both yield a considerable amount of 
gelatin, and this fact has been suggested as having an important bear- 
ing since this material is a medium which offers favorable opportunities 
for the growth of bacteria. 
Most of the reported outbreaks have occurred in the countries of 
Europe where the meat supply in consequence of being very restricted 
is utilized to its fullest extent. Viscera which with us are rejected as 
refuse, and the flesh and viscera of animals slaughtered in consequence 
of sickness with the consent and approval of official veterinarians are 
sold and eaten. Another reason for the frequency of the outbreaks is a 
very common preference for scraped or minced raw meats and for sau- 
sages of domestic manufactures made in most unsanitary surroundings. 
3. Poisoning Due to Synthetic Putrefactive Products.-The 
changes produced in the ripening process of meats are succeeded by 
those of true decomposition. The flesh becomes changed in color and 
texture, and develops unpleasant odors. The process of decomposition 
is due to the action of micro-organisms which break up the complex 
organic matters into less complex substances, and then by synthesis 
cause the production of new compounds in great variety and in variable 
amount. These in turn are split up, and with the main bulk of the 
mass are converted into products of diminishing complexity until the 
final results are water, hydrogen, carbonic acid, sulphuretted hydrogen, 
ammonia, nitrogen, and salts. During the process certain organic 
bases known as ptomains are formed. Some of these are poisonous, 
but the great majority of those thus far isolated are wholly inert. All 
contain nitrogen, but not all contain oxygen, thus resembling the vege- 
table alkaloids. 
The variety of ptomains formed depends upon the nature of the 
organisms at work, the nature of the substance, and the conditions of 50 
FOODS. 
temperature, access of air, and other attendant circumstances. One 
species of bacteria may produce no ptomains from one kind of material, 
and poisonous or inert ones from another. At one stage of decompo- 
sition no ptomains may be formed, at another several may be present, 
and later these may have disappeared completely, for they are but 
intermediate products. 
Brieger has isolated a number of varieties of ptomains from decom- 
posing meats and fish, including neurine, choline, and one which ap- 
pears to be identical with muscarine (all three of these are antagonized 
in their poisonous action by atropine), and neuridine, putrescine, cada- 
verine, another which produces effects similar to those of curare, and 
others. Vaughan discovered the very important ptomain, tyrotoxicon, 
in milk and cheese. 
Many of the poisonous compounds formed during putrefaction retain 
their active character long after the organisms through whose agency 
they have been produced have perished. This was noted as early as 
1856 by Panum, who found that the poison of certain putrid meat re- 
tained its activity even after it had been boiled eleven hours, and his 
observation has been repeatedly confirmed by others. Naturally no 
amount of cooking will suffice to render such meat harmless. 
The physiological action of these poisons is widely different. Some 
cause intense gastro-intestinal irritation, some act directly on the 
heart, some act on the general nervous system, and some on particular 
centers. Very different effects are produced in different people owing 
perhaps to varying degrees of susceptibility and also to unequal dis- 
tribution of the poison through the mass of meat. 
The extent to which the putrefactive process has advanced is by no 
means the important point in the determination of the question of pos- 
sible ill effects, but more the nature of the engaged bacteria and of 
their products, for meat may be extremely putrid and yet not be poison- 
ous, and on the other hand may be apparently normal and yet deadly 
in its effects. Many savage peoples prefer putrid fish and meat, and 
the more rotten it is, the greater their enjoyment in its consumption. 
In less degree the same is true of many of the most enlightened people 
who prefer game when decomposition is fairly well advanced. On the 
other hand the severest outbreaks of food poisoning have followed the 
eating of meat apparently not actually decomposing. Indeed, most 
persons will reject meat which has the slightest taste indicating begin- 
ning putrefaction, since even this makes it repugnant to the senses. 
In many cases the poisonous principles appear to be developed after the 
meat has been eaten, through changes occurring within the intestines. 
In outbreaks due to bacterial poisons the symptoms come on with 
great suddenness, and when many persons are involved the attention 
is drawn to food as the probable common cause. The sudden appear- 
ance of the symptoms indicates bacterial poisons rather than direct 
bacterial action. Doubtless many single cases of serious general dis- 
turbances are due to putrefactive products though wrongfully ascribed 
to some other possible cause. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
51 
In treatment of all forms of food poisoning the first object is to re- 
move the offending substances by the usual appropriate methods, to 
support the system, and to combat the poison by such remedies as are 
indicated by the symptoms. 
Cases Illustrative of Poisoning by Fish and Meats. 
Poisoning by Mussels. Case I.-At Wilhelmshaven in 1885 sev- 
eral longshoremen and their families, 19 persons in all, were stricken 
with very severe symptoms shortly after eating a meal of mussels. 
The symptoms were in general the same in all regardless of the amount 
eaten, and included nausea and vomiting without abdominal pain or 
purging, trembling, constriction of the throat, dizziness, and diminished 
coordination of movement similar to that due to alcoholic intoxication. 
There was no fever. Speech was difficult and thick, and in a short 
time the legs were unable to support the body. The pupils were di- 
lated and unresponsive to reaction tests. The extremities were cold 
and numb. Four deaths occurred, one within two hours, one in three 
and a-half, and the others within five hours from the time of inges- 
tion. The autopsy in the only case examined revealed enteritis, enor- 
mous enlargement of the spleen, numerous hemorrhagic infarctions 
and fatty degeneration of the heart, liver, and kidneys. 
In this case the sudden onset and rapid fatal termination indicates 
a true poisoning rather than an invasion of the system by bacteria, and, 
indeed, the poison was proved by Salkowski and Brieger to be a ptomain 
to which they gave the name mytilotoxin. 
Case II.-Dr. James S. Combe,1 of Edinburgh, reported in 1828 
an outbreak which involved a large number of persons of the lower 
class ranging in age from 2 to 70 years. The first case seen was a 
man of 60 who complained of thirst, heat in the mouth, difficulty in 
swallowing, tension about the jaws and throat. The pulse was small 
and weak, the respiration normal, the surface cool. The hands were 
numb and the legs unable to support the body. He had supped the 
evening before with a friend who died during the night. They had 
eaten mussels boiled with salt, but had noticed no peculiarity of taste. 
In his case recovery followed purgative treatment. 
The next case seen was a man of thirty who, on the previous even- 
ing, had picked a few mussels, not over five or six, and had eaten 
them raw. No effects were noticed until morning, excepting slight 
burning of the lips and tongue. On attempting to get up he found 
that he could not stand, although he, like the other, could move his 
legs about in bed. Although hundreds of cases, with many deaths, 
were said to have occurred, in consequence of which the magistrates 
issued a warning against the use of mussels, Dr. Combe found but 
thirty cases with two deaths. In all, the symptoms presented a strik- 
ing uniformity, though they varied much in severity. Most of the 
victims had eaten the mussels boiled with salt and pepper, and none 
Edinburgh Medical and Surgical Journal, XXIX., 1828, p. 86. 52 
FOODS. 
had noticed any unusual taste. In general the symptoms appeared in 
an hour or two. 
The man who died had vomited a few hours after eating. He lay 
down, had occasional general trembling, was rational to the last and 
died as if by increasing weakness. On section a few dark-red patches 
were found in the ileum. The stomach was empty and presented no 
abnormal appearance. The other fatal case was of a woman who died 
in three hours after eating. The autopsy revealed a full stomach con- 
taining mussels and potatoes, and beyond a few red patches in the in- 
testine the viscera were quite normal. 
In his report Dr. Combe referred to a case related by Captain Van- 
couver (Voyage of Discovery, Vol. IV., p. 45) a number of whose 
men ate a breakfast of roasted mussels. Soon several were seized with 
numbness about the face and extremities, followed by involvement of 
the whole body. One man, who died in five and a-half hours after 
eating, was unable to swallow, and though he could row in the boat 
while sick, he was unable to stand on leaving it. 
Poisoning by Herrings.-A case involving five persons, reported 
by Dr. R. David,1 is remarkable for the variety of manifestations, the 
length of time that elapsed before the appearance of the symptoms 
and, in two of them, the severity and duration of the illness. The 
afflicted persons, adult members of one family, ate on March 19, 1898, 
some raw red herrings, which gave off odor indicative of commencing 
putrefaction. Each ate the same amount, a whole fish, but whether 
each fish was equally advanced in decomposition cannot, of course, be 
determined, and the differing degrees of severity of effects may be ex- 
plained by unequal susceptibility. The father and mother aged, re- 
spectively, sixty-five and sixty-seven years, suffered least; the son, 
aged thirty-one, was affected more seriously; the two daughters pre- 
sented unusually severe and complicated symptoms. 
The first effects were manifested by the son who, on the second day, 
was seized with loss of appetite, disagreeable eructations, vomiting, 
diarrhoea, dryness of the throat, and general weakness. On the follow- 
ing day he was better, but soon became worse. Diarrhoea was followed 
by obstinate constipation, which finally yielded with difficulty to ca- 
thartics. Five days later he had dimness of sight, which was followed 
after a week by double vision and difficult deglutition. The symp- 
toms gradually abated and on May 27th there was distinct improve- 
ment of sight. On June 2d glasses were hardly needed. 
The mother first showed symptoms on the fifth day, when nausea, 
constipation and dryness of the throat appeared. Several days later 
she had double vision and difficult deglutition. The father's case be- 
gan on the ninth day and presented similar symptoms, which disap- 
peared in six weeks. One of the daughters was seized on the third 
day with bad taste in the mouth, constipation and dryness of the 
throat, followed in six days by dimness of near vision, then by double 
vision, paralysis of accommodation, and difficult swallowing. As was 
1 Deutsche medicinische Wochenschrift, 1899, No. 8. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
53 
the case with the others, the temperature, circulation, and urine re- 
mained normal. On May 2d there was complete inability to swallow 
and it was necessary to introduce food by means of a stomach-tube. 
There was slight ptosis of the right eye, then of both, the voice was 
nasal, the gait was affected and the pulse became very small, though 
not very rapid. 
On May 9th bladder symptoms, which had been gradually appear- 
ing, culminated in paralysis of that organ, and after the 13th there 
came a variety of bladder and abdominal symptoms. In the first part 
of July she felt completely well, but a month later she suffered a 
slight relapse, with reappearance of constipation, difficult deglutition, 
and disturbance of vision, which persisted to some extent into Septem- 
ber. Complete recovery did not occur until October, almost seven 
months after the disturbance began. 
The other daughter showed the first symptoms after the lapse of a 
week. These were in the main like those of her sister, but were 
more severe and extensive. She began to improve in May, and then 
ensued alternate improvement and loss of ground, better one day and 
worse the next. On the 15th there was pain in the left hypochon- 
drium ; on the 17th an eruption like that of scarlet fever over the 
whole body, with albuminuria, but no casts. On the 19th severe pain 
in the left hypochondrium, less in the right, and tenderness in the re- 
gion of the kidneys, with epistaxis, disappearance of the rash, slight 
desquamation, and improved vision. At the end of May the albumi- 
nuria and pain in the region of the kidneys had nearly disappeared, 
and deglutition was perfect. On June 2d heart complications appeared, 
which persisted into November, when hypertrophy was established. 
In August, after a general improvement, there was a relapse like that 
which occurred in the case of her sister. Improvement was well es- 
tablished in October, and in November she had almost wholly re- 
covered. 
It was unfortunately impossible to make a bacteriological and chem- 
ical examination of the fish, because no material was obtainable. 
Poisoning by Salmon.-Professor Vaughan 1 reports the following 
case. " K., a very vigorous man of 34 years, ate freely of canned 
salmon. Others at the table with him remarked that the taste of the 
salmon was peculiar and refrained from eating it. Twelve hours later 
K. began to suffer from nausea, vomiting, and a griping pain in the 
abdomen. Eighteen hours after he had eaten the fish the writer saw 
him. He was vomiting small quantities of mucus, colored with bile, 
at frequent intervals. The bowels had not moved and the griping 
pain continued. He was covered with a scarlatinous rash from head to 
foot. His pulse was 140, temperature 102° F., and respiration shal- 
low and irregular." After appropriate treatment he began to improve. 
" The next day the rash disappeared, but the temperature remained 
above the normal for four or five days, and it was not until a week 
later that the man was able to leave his house." Vaughan examined 
1 Ptomains, Leucomains, Toxinsand Antitoxins, 1896, p. 56. 54 
FOODS. 
the salmon and found a micrococcus present in great numbers. This 
organism grown for twenty days in a sterilized egg produced a most 
potent poison. The white became thin, watery, markedly alkaline, 
and ten drops sufficed to kill white rats. 
Poisoning by Oysters.-The following case of oyster poisoning 
with a fatal termination is reported by Brosch.1 An officer ate a num- 
ber of oysters toward midnight, and within six hours was seized with 
headache, pain in the side, nausea, dimness of sight, difficult degluti- 
tion, retention of urine, and salivation. Toward noon, right facial 
paralysis, dilatation of the right pupil, and thickness of speech ap- 
peared, followed shortly by cyanosis, ptosis of the right eyelid, great 
muscular relaxation, and paralysis of respiration. Autopsy revealed 
punctiform ecchymoses in various parts, enlargement of the spleen, 
and fatty degeneration of the liver and kidneys. 
Poisoning by Veal.-According to Vallin in a communication to 
the Academy of Medicine in 1895, a large number of outbreaks of 
poisoning in Germany, Switzerland, and elsewhere are due to the con- 
sumption of veal from animals either sick or too immature. Drs. 
Darde and Drouineau2 relate that they have seen nearly the whole 
strength of a military company, 135 out of 147, poisoned by eating 
roast veal. The symptoms appear generally in from six to twenty-four 
hours and include vomiting, purging, and great prostration. Dilata- 
tion of the pupil is common but not constant. Occasionally skin erup- 
tions appear. 
By Vallin,3 and by others as well, it is deemed probable that veal 
poisoning is due largely to the existence of septic pyaemia and septic 
pneumo-enteritis in calves, and Van Ermengem has suggested that a 
variety of septic diseases of these animals are commonly grouped under 
the head of diarrhoea. He has fed the fresh meat of one of these 
calves to mice and guinea-pigs which have died within a few days with 
enteritis. From the bone marrow he has isolated an organism which 
appears to be closely related to Gaertner's Bacillus enteritidis and which 
on inoculation into animals produces a fatal enteritis. 
Case I.-Dr. Y. Boyer4 reports the following case of sextuple 
poisoning by veal. The persons affected were members of one house- 
hold, and ranged widely in point of age, the youngest being children of 
three and six years. The symptoms appeared in the night, about six 
hours after the food was taken, and began with vomiting and violent 
colic. In the morning all had intense gastric irritability, coated tongue, 
pain on pressure, especially in the right iliac fossa, rumbling, slight 
tympanites, and scanty urine. The cook had markedly dilated pupils, 
sensation of suffocation, constriction and dryness of the throat, and in- 
tense suffusion of the face. The child of six years had dilated pupils 
and disturbance of vision, and finally pain and stiffness of the muscles 
of the neck. The younger of the two children and the mother were 
1 Wiener klinische Wochenschrift, 1896, No. 13. 
2 Archives de Medicine et de Pharmacie Militaires, 1895. 
3 Revue d'Hygiene, 1895, XVII., p. 473. 
4 Lyon Medical, May 14, 1899. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
55 
less affected than the others, and made a more rapid recovery. The 
chambermaid had at first a certain degree of aggravation of symptoms, 
with a tendency to syncope and great muscular weakness, which latter 
effects were also marked in the case of the cook, who continued for 
some time to be troubled by dilatation of the pupils and disturbed 
vision. At the end of nine days there was no further appearance of 
danger, and the two most severely affected were well on the way to 
recovery. 
Unfortunately no bacteriological examination was made either of 
the meat or the discharges, but the nature of the symptoms leaves no 
room for doubt as to their cause. 
Case II.-Drs. Wilkinson,1 Ashton, and Durham have recorded an 
extensive outbreak of poisoning due to imperfectly cooked veal pies. 
All the cases, somewhat over fifty in number, presented very similar 
symptoms, the chief of which were severe and uncontrollable vomiting 
and diarrhoea, accompanied at first by shivering, and followed by col- 
lapse. In some there were violent abdominal pains, and in several the 
abdomen was swollen and tender. Many had severe pains in the 
back. The symptoms began in from five to fourteen hours after eat- 
ing, and, as a rule, were severe from the start. The motions were first 
grass-green, then dark green, and highly offensive. The severity of 
the diarrhoea increased on the second day ; one patient was purged forty 
or more times in a single day. In very few cases the dejecta contained 
a little blood. 
In the worst cases the patients became semi-comatose, restless, and 
delirious in the course of a few hours. Occasionally there were dis- 
turbances of vision, which lasted until the temperature, which ranged 
from 100° in the mildest to 104.5° in the severest cases, became nor- 
mal. The pulse was very rapid, weak, and dicrotic. In many cases 
the patient was markedly cyanotic and had some difficulty in breath- 
ing. Some had cramps, and nearly all had muscular pain and stiffness. 
In very many cases herpes appeared about the lips on the third to the 
sixth day, and some had a rash, followed by desquamation. Conva- 
lescence in the severe cases was very prolonged ; some were still weak 
even after three and a-half months. Four cases terminated fatally, 
and in two of these autopsies were secured. The brain surface showed 
slight congestion ; the small intestines showed congested patches, which 
became larger and more numerous lower down, and did not correspond 
with Peyer's patches. The whole lower third was highly congested, 
and contained some yellow, diarrhoeic fluid. Otherwise the organs of 
the body were found to be in a fairly healthy condition. 
Investigation of the cause of the outbreak yielded the following 
facts : On Tuesday, July 26th, an apparently healthy calf was slaugh- 
tered, and two days later the fore quarter and breast were delivered to 
a baker who made the meat into the pies which were shown to have 
been the cause of the outbreak. Other portions of the animal were 
sold to others who made pies which caused no trouble. A portion of a 
1 Public Health, January, 1899, and British Medical Journal, December 17, 1898. 56 
FOODS. 
knuckle end, which was still in the possession of the butcher when the 
investigation was begun, was to all appearances perfectly good meat. 
The baker to whom the trouble was traced made, on the day he re- 
ceived the meat, 160 veal pies and 108 pork pies. The pastry was 
the same for the entire lot, and both kinds were treated to the same 
lot of jelly, which was made by boiling the veal bones with two pigs'- 
feet in four quarts of water. Inasmuch as the pork pies caused no 
disturbance of any kind, no responsibility could be attached to the 
pastry or to the jelly. The veal pies were baked in not less than three 
nor more than five batches, hence the batches would have included about 
thirty-two, forty, or fifty-three pies. The time occupied in baking 
each batch was said to have been about twenty minutes. The number 
of persons affected was somewhat over fifty, and as in some cases single 
pies were shared by two, three, and four persons, it is obvious that less 
than fifty pies produced all the trouble. Since no other parts of the 
animal produced any sickness, there can be no doubt that the contami- 
nation of the meat occurred after the sale and delivery. 
According to the findings of Dr. Durham, based on a study of the 
blood of a number of the patients as to the behavior of the serum 
when tested for clumping properties with various micro-organisms, 
with controls of serum from normal persons, the outbreak was due to 
the Bacillus enteritidis. This limitation of the inquiry was necessitated 
by the fact that it was impossible to secure either one of the pies, or 
part of one, or any of the first vomitings. The conclusion arrived at, 
strengthened by the fact that all four fatal cases were from pies which 
were two or more days old when eaten, which period allowed enormous 
multiplication, makes most probable the further conclusion that one 
whole batch was so insufficiently cooked as to preclude the killing of 
the organisms, which, according to Basenau, cannot survive exposure 
for one minute to a temperature of 70° C. 
Poisoning by Pork. Case I.-Dr. Meredith Young1 records a 
case of pork poisoning in which five persons were affected. The of- 
fending meat was three-quarters of a pound of " pig's cheek " which 
was eaten at half past four in the afternoon, between which time and 
the onset of symptoms nothing else was eaten. On the following 
morning Mr. A. was seized suddenly with vomiting, purging, and 
severe abdominal pain, and shortly afterward became very feverish 
and weak, and suffered from severe frontal headache. His wife had 
severe abdominal pain, and toward noon was strongly purged. She 
suffered nausea, retched, but could not vomit; had fever and severe 
headache, and was much more prostrated and took more time to re- 
cover than her husband. She was unable to take food for three days. 
Their daughter was taken sick at the same time and with the same 
symptoms, though less severely. Her chief symptom was a strong 
and overpowering tendency to sleep. 
A fourth person who ate but little as compared with the amounts 
ingested by the others was slightly purged, but suffered nothing more. 
1 Public Health, June, 1899. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
57 
The remaining member showed no effects until during the second 
night. On the following morning she was feverish, had severe head- 
ache and abdominal pain and retched unsuccessfully. Purging did 
not occur until the afternoon. As was the case with the daughter, the 
most prominent symptom after the onset was somnolence. Recovery 
followed in every case. Investigation showed that the cheeks had 
been cooked two days before and had been placed together to cool and 
" set." It was estimated that between fifty and sixty persons had pur- 
chased of them, but all but a small proportion were unknown to the 
seller and so no systematic inquiry could be made. Only four could 
be followed up, and two of these reported no trouble ; a third was made 
severely sick and lost two days' work, and the fourth, after eating, 
drank so much beer that he was made sick and lost it all by vomiting 
and yet was affected like the others, but not so actively. It was im- 
possible to procure any of the meat or vomited matter or dejections 
for bacteriological examination. 
Case II.-At the Seventh International Medical Congress held in 
London, in 1881, Dr. Ballard1 read before the section on State Medi- 
cine an account of a very serious outbreak, now generally known as 
the Welbeck case. This involved seventy-two persons who attended 
a sale of timber and machinery on the estate of the Duke of Portland 
at Welbeck, which lasted from Tuesday, June 15, 1880, through the 
week. Refreshments were served by the keeper of a public house and 
among the articles furnished were seven hams to which the entire 
trouble was traced. While many complaints were made that the ham 
was not sufficiently cooked, that the fat was yellowish or greenish, that 
it was too salt, that it 11 tasted queer " and that it had no true flavor of 
ham, many made no complaint and no one said that it was tainted. 
Of the seventy-two persons seized, four died. The history of these 
cases is as follows : 
1. W. W., aged sixty-four, ate ham on Wednesday and Friday 
and was seized on Friday night, when he complained of feeling cold. 
On Saturday morning he ate but little and said he ached all over. 
In the course of the day he suffered from vomiting and diarrhoea with 
severe pain and cramps in the legs. The evacuations were exceedingly 
offensive and passed involuntarily. The pulse was 128 ; temperature 
not taken. On Monday he began to collapse and on Friday he died. 
The post-mortem examination revealed little noteworthy, but micro- 
scopic examination of the kidneys showed severe parenchymatous 
inflammation and distension and plugging of the afferent arterioles 
and capillaries of the Malpighian corpuscles by emboli of bacilli. 
2. Mrs. L., aged sixty-two, ate some scraps of the ham on Wed- 
nesday and was seized on Friday with faintness, diarrhoea, vomiting, 
and abdominal pain. On the following day she fell into a state of 
collapse and .on the following Tuesday she died. The mucous mem- 
brane of the stomach and intestines was highly congested; otherwise 
the autopsy revealed nothing abnormal. 
1 Supplement to 10th Annual Report of the Local Government Board, 1881, p. 36. 58 
FOODS. 
3. Mr. S., aged thirty-seven, ate four sandwiches on Thursday. 
In the evening he vomited and diarrhoea began. In the morning of 
the following day he complained of burning pain in the lower part of 
the abdomen. The vomiting and purging continued. Though cold 
and clammy to the touch he complained that he was " all on fire." 
He had cramps in the legs and was very restless. His mind was clear 
to the last. The discharges were watery and offensive at first and 
later were dark-green in color. He was very thirsty and drank freely 
of water. He died on the following Friday. Only a partial autopsy 
was made. This revealed bright-red patches in the stomach. 
The period of incubation was accurately determined in 51 cases ; in 
five it was 12 hours or less, in 34 it was between 36 and 48, and in 4 
it exceeded 48 hours. In many cases the onset was sudden and in 
others it was preceded by greater or less indisposition. The most con- 
stant of all the symptoms was diarrhoea. " In about a third of the 
cases the first definite symptom was a sense of chilliness usually with 
rigors or trembling, in one case accompanied by dyspnoea ; in a few 
cases it was giddiness with faintness, sometimes accompanied by a cold 
sweat and tottering; in others the first symptom was headache or pain 
somewhere in the trunk of the body, e. g., in the chest, back, between 
the shoulders or in the abdomen, to which part the pain, wherever it 
might have commenced, subsequently extended. 
" In one case the first symptom noticed was a difficulty in swallowing. 
In two cases it was intense thirst. But, however the attack may have 
commenced, it was usually not long before pain in the abdomen, diar- 
rhoea and vomiting came on, diarrhoea being of more certain occurrence 
than vomiting. The pain in several cases commenced in the chest or 
between the shoulders, and extended first to the upper and then to the 
lower part of the abdomen. It was usually very severe indeed, quickly 
producing prostration or faintness with cold sw'eats. It was variously 
described as ' crampy,' 'burning,' ' tearing,' etc. 
" The diarrhoeal discharges were in some cases quite unrestrainable, 
and (where a description of them could be obtained) were said to have 
been exceedingly offensive, and usually of a dark color. Muscular 
weakness was an early and very remarkable symptom in nearly all 
cases, and in many it was so great that the patient could only stand by 
holding on to something. Headache, sometimes severe, was a common 
and early symptom ; in most cases there was thirst, often intense and 
most distressing. The tongue, when observed, was described usually as 
thickly coated with a brown velvety fur, but red at the tip and edges. 
"In the early stage, the skin was often cold to the touch, but after- 
wards some fever set in, the temperature arising in some cases to 101°, 
103°, and 104°. In a few severe cases where the skin was actually 
cold, the patient complained of heat, insisted on throwing off the bed 
clothes, and was very restless. The pulse in the height of the illness 
became quick, counting in some cases 100 to 128. 
" The above were the symptoms most frequently noted. Other symp- 
toms occurred, however, some in a few cases, and some in only solitary CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
59 
cases. These I now proceed to enumerate. Excessive sweating, 
cramps in the legs, or in both legs and arms, convulsive flexion of the 
hands, aching pain in the shoulders, joints, or extremities, a sense of 
stiffness of the joints, prickling or tingling or numbness of the hands 
lasting far into convalescence in some cases, a sense of general com- 
pression of the skin, drowsiness, hallucinations, imperfection of vision, 
and intolerance of light. 
" In three cases (one that of a medical man) there was observed 
yellowness of the skin, either general or confined to the face and eyes. 
In one case, at a late stage of the illness, there was some pulmonary 
congestion, and an attack of what was regarded as gout. In the fatal 
cases death was preceded by collapse like that of cholera, coldness of 
the surface, pinched features and blueness of the fingers and toes, and 
around the sunken eyes. The debility of convalescence was in nearly 
all cases protracted to several weeks. 
" The mildest cases were characterized usually by little remarkable 
beyond the following symptoms, viz., abdominal pains, vomiting, diar- 
rhoea, thirst, headache, and muscular weakness, any one or two of 
which might be absent." 
Investigation of the hams showed absence of trichinae and the pres- 
ence of a bacillus which on inoculation into animals was found in most 
cases to produce a pneumonia. 
The period of incubation indicates that in these cases there was a 
true bacterial infection. 
Case III.-Another epidemic investigated by Dr. Ballard 1 involved 
a far greater number of persons and had an unusual attendant mor- 
tality, nearly 500 persons out of a population of about 100,000 
(Middlesbrough) dying during the year of a peculiar form of pleuro- 
pneumonia. 
The cause of this remarkable epidemic was proved to be the con- 
sumption of what was known as "American bacon," a food product 
prepared from imported salt pork at a number of local establishments 
conducted under most unsanitary conditions. Twenty samples of 
bacon, some obtained at shops and some at the homes of victims, 
were examined, and fourteen were found to be distinctly poisonous to 
animals. The lesions discovered in the dead animals corresponded 
with those in the organs of the persons who had died, which included 
destructive changes in all the principal viscera and more particularly 
in the lungs. Dr. Klein discovered in the lung a short bacillus which 
had never before been described. Inoculation experiments on animals 
produced results identical with those following feeding experiments 
with the so-called bacon. 
Case IV.-A remarkable outbreak due to raw pickled ham has 
been recorded by Professor Van Ermengem2 and carefully investigated 
by himself and others. Over twenty members of a musical society at 
Ellezelles, in Belgium, were seized with serious illness after eating the 
'Supplement to 18th Annual Report of the Local Government Board, 1889, p. 163. 
2Zeitschrift fur Hygiene und Infectionskrankheiten, XXVI., p. 1. 60 
FOODS. 
greater part of a raw pickled ham; three died within a week, and ten 
were in a critical condition. Other parts of the animal from the same 
pickling tub were eaten in a raw state without ill effects, and pieces of 
the particular ham had been consumed a short time before, also with- 
out results. Only those persons who ate of the ham were taken with 
the very peculiar train of symptoms recorded. Most of them were 
seized in from twenty to twenty-four hours, three in less than that 
time, and a few as late as thirty-six hours after eating. 
The first symptoms were gastric pain, nausea, and vomiting of un- 
digested food and gelatinous blackish matters. Instead of diarrhoea, 
which one would expect, there was obstinate constipation in all but 
two cases, and the first dejections, with or without cathartics, were 
black and viscid. In every case, in from thirty-six to forty-eight 
hours, there were profound disturbances of vision, amphodiplopia, 
marked dilatation of the pupils, with absence of reaction to light, 
ptosis of both lids, and a peculiar fixed stare. There was burning 
thirst with a strangling sensation in the throat. Swallowing, even of 
liquids, was difficult or impossible, and every attempt was accompanied 
by decided choking. 
In some instances the saliva was suppressed and the mucous mem- 
brane dry and glossy. The voice was weak, and with some there was 
total aphonia. Dysuria and anuria were common. There was but little 
disturbance of respiration and circulation ; the pulse never reached 
over ninety, respiration was quiet, temperature normal. Consciousness 
and general sensibility remained intact throughout except in the fatal 
cases, in which alone several hours before death there occurred col- 
lapse, dyspnoea, small irregular pulse, light delirium and coma. 
There was obstinate insomnia in many during the first period. The 
extremities and trunk muscles showed neither complete paralysis nor 
atrophy, but there was great general muscular weakness, and slight 
movements caused extreme fatigue. After two or three weeks the eye 
symptoms began to improve. The dilated pupils began to contract, 
the cloudiness to disappear, and the half-paralyzed eyelids to regain 
their power. Diplopia disappeared only when both eyes were fixed 
laterally. Paralysis of accommodation lasted a long time after the 
disappearance of all the other symptoms, and normal vision did not 
wholly return until after six to eight months. 
Autopsy in two cases showed no characteristic changes in the organs, 
only remarkable hypersemia of the kidneys, liver, and meninges, and 
softening and extraordinary friability of the stomach-walls. In one 
the liver showed marked degeneration, and the brain punctiform 
hemorrhages. Neither the liver nor kidneys showed anything unusual 
on bacteriological examination, but the spleen yielded an anaerobic 
bacillus which proved later to be related to botulism. 
The pig from which the ham came was killed some months pre- 
viously, and what was not eaten at once was pickled in the usual way. 
During the time that elapsed between the pickling and this occasion 
the greater part of the animal had been consumed without causing any CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
61 
sickness, but the ham which was nearly intact was the last to be eaten, 
lay on the bottom of the tub, and was the only part that was com- 
pletely immersed in the weak brine. What was left of it gave off no 
odor of putridity, but had a distinct odor like that of rancid butter. 
That the ham had a bad taste, was agreed by nearly all who ate of it. 
It appeared normal to the eye, but was pale like any meat which has 
been soaked some time in water. There was no evidence of decompo- 
sition, and neither ptomains nor other poisonous alkaloids were present. 
Bacteriological examination proved in different parts the presence of 
an hitherto unknown spore-bearing bacillus in great abundance, the 
same organism as that isolated from the spleen of one of the victims. 
It produces an extraordinarily virulent toxin which was isolated by 
Brieger from cultures supplied by the discoverer, by whom the organ- 
ism was named Bacillus botulinus. The toxin is rendered inert by a 
temperature of 60° to 70° C., therein agreeing with other bacterial 
toxins thus far isolated, and differing from the cause of ordinary meat- 
poisoning from cooked meats. 
Attempts to discover the organism in the feces of various animals 
and in filth of various kinds, and in specimens from where the pig was 
raised were negative in results. 
Feeding-experiments conducted on various kinds of animals with the 
meat itself and with aqueous triturations of it added to other foods 
produced, as a rule, fatal results with the same train of symptoms as 
above mentioned. Subcutaneous injections of the watery extract pro- 
duced the same results as feeding-experiments. 
The aqueous extract in a sealed tube kept in the dark retained its 
strength unimpaired for ten months, and small pieces of the meat kept 
in cotton-stoppered tubes without any special precautions retained their 
original virulence even longer. The poison resists the effects of putre- 
faction, and proved to be equally poisonous after four days' standing 
in a mixture with feces, decomposing blood and urine, and filtration 
through porcelain. A fresh filtrate, to which were added B. prodig- 
iosus, B. proteus liquefaciens, B. fluorescens putrides, and B. coli, was 
found at the end of a week to be as active as ever. 
Professor Brieger and Dr. W. Kempner1 succeeded in isolating the 
active poisonous principle from cultures of B. botulinus, and proved it 
to be closely related chemically to the toxins of diphtheria and tetanus. 
Next, Kempner2 investigated the subject of immunity to the toxin, 
employing bouillon cultures killed by the application of toluol, culture 
filtrates free from bacteria, and the concentrated and purified poison, 
the strength of which was accurately determined with guinea-pigs. 
The first experiments in immunizing guinea-pigs and rabbits proved 
that with them active immunity cannot be attained even when begin- 
ning with the smallest possible dose, since in every case, after a shorter 
or longer interval, every animal perished. With goats it was found 
that immunity can be conferred by continued increasing subcutaneous 
1 Deutsche medicinische Wochenschrift, 1897, No. 33. 
2Zeitschrift fur Hygiene und Infectionskrankheiten, XXVI., p. 481. 62 
FOODS. 
injection, and that the serum of the immunized animal possesses a very 
high protective power, as is shown by the fact that prevention is 
accomplished by injection performed thirty hours before the introduc- 
tion of the poison, and that it is manifested also by direct application 
in the stomachs of cats poisoned by the mouth. It was found also that 
the antitoxin would cure guinea-pigs when administered twenty-four 
hours after inoculation with a dose which would be fatal ordinarily in 
forty-eight, and even when decided clinical signs of poisoning were 
already present. 
Later, Kempner and Dr. E. Schepilewsky1 began a research on the 
possible affinity of nerve-substance for the toxin which, as shown by 
clinical symptoms and pathological examination, exhibits a decided 
tendency to certain points of the central nervous system. The test 
poison was so standardized that 0.000005 cc. represented twice the 
dose necessary to kill white mice of 15 grammes weight in from two 
to three days. The brains of freshly killed guinea-pigs were rubbed 
finely with physiological salt solution in the ratio of 3.3 grammes to 
10 cc., and the cords were treated in a similar manner. Both emul- 
sions were practically neutral in reaction. Pieces of the liver, kidney, 
spleen, muscles, and marrow were treated in the same way, to be used 
for comparison. 
In the first series of experiments 1 cc. of the brain or cord emulsion 
mixed with three to four times the fatal dose of the toxin was injected 
under the skin of a number of mice, and as controls other mice were 
injected with the same amount of toxin alone, and others with the toxin 
mixed with the emulsions of other organs. The results showed that 
the brain and cord possess and exert a decided preventive and cura- 
tive influence, and that the other organs do not. With mixed in- 
jection it was always possible with 1 cc. of the emulsion to counteract 
three times the fatal dose, while with four times the dose about half the 
animals died. With separate but simultaneous injections only about 
half of the animals would survive twice the fatal dose, the others dying 
about as quickly as the controls. As ji curative agent in cases where 
the poison had been exhibited six and twelve hours previously the 
emulsions did not give such favorable results, for those treated after 
twelve hours died as soon as the controls, and the others lived but a 
day longer. 
Whatever the protecting substance may be, it was proved that it is 
in combination with nerve-substance and insoluble iu water; its influ- 
ence is materially altered by high temperatures, but not by keeping 
several days in ice. 
Milk, butter, yolk of egg, and other animal fats were tried in the 
same way, but no results were obtained excepting with butter with 
which two guinea-pigs were protected, but which failed with other ani- 
mals. A thin oil emulsion mixed with two and even four times the 
fatal dose was successful. 
Lecithin and cholesterin, substances normally present in nerve- 
1 Zeitschrift fiir Hygiene und Infectionskranklieiten, XXVII., p. 213. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
63 
substance, proved to have antitoxic power which was unimpaired by 
boiling or heating; but quite large amounts were necessary. Other 
substances, as cerebrin, nuclein, and bile, proved to be inert, but anti- 
pyrin in larger amounts than 0.10 gramme (0.15 to 0.20) proved able 
to neutralize 0.00003 cc. of the toxin. Given in doses of 0.10 
gramme, antipyrin had no effect, the animals dying at the same time 
as the controls, but when the animals were treated with antipyrin as a 
preliminary measure the above dose would act. 
Poisoning by Beef.-Beef poisoning has been noticed with consid- 
erable frequency after the use of meat from animals slaughtered while 
sick, and it has been pointed out by several observers that certain sep- 
tic diseases of cattle are especially prone to render meat poisonous. 
These include the septic form of calf paralysis, hemorrhagic enteritis 
of calves, septic metritis of cows, various intestinal disorders, the sep- 
tico-pyaemic diseases and a number of others. Gaertner's Bacillus en- 
todtidis was originally discovered by him in the flesh of a cow that had 
been slaughtered on account of a severe diarrhoea and in the spleen of 
a person who died in consequence of eating it. He showed that not 
only the bacillus, but also its boiled bouillon cultures are highly toxic. 
Many deaths have been recorded as a consequence of eating the 
cooked meat of cows slaughtered on account of puerperal fever, and it 
was from such an animal that Basenau isolated the Bacillus bovis mor- 
bificans. This cow showed such lesions of the viscera that the director 
of the Amsterdam abattoir forbade the use of the meat. 
Basenau 1 has examined the flesh of beeves which had succumbed to 
a variety of diseases and has isolated a number of species of bacteria 
bearing a close resemblance to his B. bovis morbificans, all of which 
were fatal to mice. Some of them produce poisonous matters which 
withstand boiling without impairment of their properties. Ordinary 
inspection being useless for showing whether such meat is infected, he 
recommends that bacteriological and feeding experiments should be in- 
stituted together within twenty-four hours after slaughtering. If no 
colonies are observed at the end of twenty-four hours and no bacteria 
are seen in the tissues, the meat may be regarded as safe to eat. If 
colonies are yielded, the acceptance or rejection of the meat must de- 
pend upon the results of the feeding experiments. If the mice fed on 
the raw meat die and those fed on the cooked meat survive, it may be 
concluded that the meat is safe if thoroughly cooked. If both die, the 
meat must be unhesitatingly condemned. 
From the large number of cases of poisoning due to beef the fol- 
lowing are selected as illustrations. 
Case I.-In December, 1841, over 40 cases of poisoning occurred 
in New York from eating smoked beef. As a rule the symptoms 
began several hours after eating. They began with pain and uneasi- 
ness in the epigastrium, extending to the back and loins. Vomiting 
and purging were followed by great thirst and burning pain at the pit 
of the stomach which became so irritable that it could tolerate neither 
1 Archiv fur Hygiene, XXXII., p. 219. 64 
FOODS. 
food nor drugs. Extreme prostration followed, the functions of the 
nervous and muscular system being greatly affected. One victim died, 
and with the others convalescence was extremely slow. Autopsy re- 
vealed nothing beyond, inflammation of the ileum. 
Case II.-In May, 1888, at Frankenhausen, 58 persons were made 
sick by eating the meat of a cow killed while afflicted with diarrhoea 
and passed as edible by the veterinary. The symptoms were in gen- 
eral nausea, vomiting, diarrhoea, fever, drowsiness, dizziness, and great 
depression. Those who ate the meat in the raw state were seized 
without exception, and the severity of the seizure was directly pro- 
portionate to the amount eaten. One victim who ate a pound and a- 
half died within 35 hours, while those who ate least suffered least. 
Those who ate the cooked meat fared differently. Not all were at- 
tacked, nor did the severity of the symptoms bear any relation to the 
amount taken. Thus some who ate freely suffered but little, while very 
severe effects were caused by slight amounts of the meat and even by 
small portions of the broth. Thirty-six who ate the cooked meat 
escaped altogether. From a portion of the meat and from the spleen 
of the person who died, Gaertner1 isolated the organism B. enteritidis 
which since then has been shown to have been the cause of numerous 
other outbreaks. 
Case III.-In June, 1889, 137 persons, including 50 children, in 
and about Cotta, in Saxony,2 were made ill by eating the meat of a 
cow slaughtered on June 17th, because of an inflammatory condition 
of the udder. On the 11th she had suddenly stopped giving milk 
and had refused food and drink. The meat appeared to be normal in 
every way and was sold on the day after slaughter. The first cases 
appeared during the night of the day of sale. Most of the victims 
had eaten the minced meat in the raw state, some only after it had 
been cooked, and some had eaten only broth. The butcher who sold 
it tasted as much as would cover a knife blade and suffered from 
diarrhoea, headache, and abdominal pain for three days. His assistant 
did the same and fared even worse. 
In one case the symptoms began with a chill; in another with diffi- 
cult deglutition, double vision and anxiety; in the rest with nausea, 
vomiting and diarrhoea, headache, abdominal pain, dizziness, great 
lassitude, restlessness or lethargy, and unquenchable thirst. In many 
cases the eyes were glassy and the pupils much dilated. The tongue 
was commonly dry and coated. The children affected were extra- 
ordinarily weak and some had fever running as high as 104.7° F. 
The bacillus isolated by Johne was found by Gaertner to be not the 
same in all respects as the one discovered by himself. 
Case IV.-Poisoning by canned corned beef at Sheffield reported 
by Dr. W. N. Parker.3 On October 11, 1899, a six-pound tin of 
corned beef was opened and about two-thirds were sold, chiefly in 
1 Correspondenz-Blatter des allgemeinen arztlichen Vereins von Thiiringen, 1888, 
No. 9. 
2 21st Jahresbericht ueber das Medicinalwesen im Konigreich Sachsen, p. 104. 
'British Medical Journal, November 11, 1899. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
65 
quarter pounds. Beyond the fact that the meat seemed less solid than 
usual and the jelly rather oily, nothing unusual was noticed. It had 
no odor, its taste was normal though quite salt, and but one consumer 
found its flavor disagreeable. So far as is known none who ate escaped; 
24 persons ranging in age from 2 to 89 years were affected. The fol- 
lowing serves as an example, though each case presented one or more 
symptoms peculiar to itself. 
A woman of 35 ate two ounces of the meat at 12:30, and in two 
hours was seized with sudden faintness, dizziness, and drowsiness, fol- 
lowed by nausea and great muscular weakness especially of the legs. 
Persistent vomiting with frequent retching soon occurred, accompanied 
by intense frontal headache, and followed by colic which was not re- 
lieved by purging. One hour after seizure she was taken to the hos- 
pital where she lay on a couch in a state of collapse with her knees 
drawn up. Her face was pale, with livid patches around the eyes, and 
bathed in perspiration. The skin was cold and clammy, the pulse 
small and rapid, the respiration shallow, the temperature subnormal, 
and the pupils dilated. Her stomach was washed out and in a short 
time the pain and retching ceased, the character of the pulse improved, 
drowsiness was diminished, and only the headache and purging re- 
mained. Within an hour the condition of collapse and other symptoms 
reappeared but with less severity. The stomach was again washed 
out and this time the good effects were permanent. On the following 
morning all that was complained of was slight frontal headache. 
The approximate latent period varied between one and three and a- 
half hours. Only two, however, took more than two and a-half hours. 
Frontal headache was present in all but 4, vomiting in all but 1, pain 
in only 12, marked collapse in 12, profuse discharges in all but 6. 
The initial symptoms were the same in all, that is, drowsiness or gid- 
diness or both together. 
Only one case resulted fatally, that of a boy seven years old who ate 
two ounces. His symptoms were especially severe ; collapse was very 
marked and he had to be stimulated constantly. About ten hours after 
the onset he had a series of clonic contractions of the flexor muscles of 
the neck, arms, and legs. The movements were violent, rapid and al- 
most rhythmical, commencing first in the neck and arms but soon af- 
fecting the legs. The eyes were fixed and staring, and the pupils 
widely dilated. After lasting an hour and a-half the convulsions 
ceased. They reappeared in half an hour, affecting first the right arm 
and right side of the face, but soon becoming general. The collapse 
gradually deepened and the boy died 15 hours after seizure. Autopsy 
showed nothing more than a general hypersemia of the stomach and in- 
testines with a few hemorrhagic erosions in the gastric mucous mem- 
brane. A microscopic examination of the kidney showed cloudy 
swelling of the cortex with a few scattered hemorrhages. 
All the other victims convalesced rapidly and were discharged from 
the hospital within 48 hours. Stimulants chiefly in the form of strych- 
nine and brandy were freely administered. The meat was examined 66 
FOODS. 
bacteriologically about 11 hours after the tin was said to have been 
opened. In the outer parts of the meat many varieties of organisms 
were found. The only organism present both in cultures from the 
center of the meat and in those from the surface was the bacillus of 
Gaertner. 
Case V.-An outbreak at Mansfeld in which 65 persons became 
ill after eating the flesh of a cow slaughtered in consequence of trau- 
matic pericarditis has been reported by Dr. G. Wesenberg.1 Only 
those who ate of the minced meat in a raw state or of the partly cooked 
liver were affected ; those who ate of the well-cooked meat escaped 
without exception. The symptoms were vomiting and diarrhoea, vio- 
lent headache and abdominal pain, general muscular weakness, dizzi- 
ness and lassitude. The discharges were sometimes greenish, some- 
times brownish, and always extremely offensive. With few exceptions 
the symptoms abated in from three to five days, and all recovered ex- 
cept one, and that a doubtful case of a child who was not known with 
certainty to have partaken, and whose symptoms might have been due 
to other causes. 
The unconsumed meat when received for examination was already 
fairly well advanced in decomposition and partly maggoty. All ex- 
cept one piece, which was faintly acid to litmus paper, was alkaline in 
reaction. Cultures on agar and in bouillon were made from a piece 
token from a part which was apparently not yet in process of decom- 
position. Inoculation of the bouillon cultures and of small bits of the 
meat into white mice produced fatal results, in some cases within from 
eighteen to twenty-eight hours and in others within three days. A 
guinea-pig which received a subcutaneous injection of the bouillon cul- 
ture of the crushed meat died in forty-eight hours, having shown 
marked lassitude and profuse diarrhoea. Section showed in all cases 
enlargement of the spleen, which was bluish-red in color, strong injec- 
tion of the small intestine, and marked redness of the medullary sub- 
stance of the kidneys. Cover-glass preparations from the spleen 
showed fairly long and broad bacilli, and some organisms were devel- 
oped on agar from the meat itself. 
Poisoning by Horse Meat.-Gaff ky and Paak2 investigated an 
outbreak in the district of Lowenberg which was known to involve at 
least thirty and probably more individuals. The offending materials 
were horse meat, horse liver, and horse sausage. The patients com- 
plained very soon after eating, in one case within a half hour, of 
nausea, headache, abdominal pain, borborygmus, diarrhoea, dizziness, 
trembling, and great thirst. The temperature rose to 104° F. One 
case terminated fatally. Bacteriological examination revealed a bacil- 
lus which differed in some respects from that of Gaertner. This was 
the first outbreak of meat poisoning everjnvestigated bacteriologically. 
Poisoning by Sausages.-Sausage has long been recognized as a 
very common cause of poisoning and has a much larger record of acci- 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXVIII., p. 484. 
2 Arbeiten aus dem kaiserlichen Gesundheitsamte, VI., p. 159. CASES ILLUSTRATIVE OF POISONING BY FISH AND MEATS. 
67 
dents than any other meat or meat compound. This is due in large 
part to a very common practice of making use of all manner of unin- 
viting fragments and scraps of meat, offal, and the flesh of sick and 
ill-conditioned animals in preparing sausage meat, and perhaps to a 
greater extent to the extremely unsanitary methods of manufacture which 
obtain in those districts where this form of poisoning is most preva- 
lent. In many instances the symptoms caused are due to the presence 
of ptomains, and in many to the contained bacteria and their toxins. 
In most instances it is impossible to fix the blame upon any indi- 
vidual constituent, nor aside from its scientific interest is this of any 
special importance. The symptoms present as wide variations in char- 
acter as are observed in any other form of food poisoning. 
Case I.-Dr. Tripe1 reported in November, 1879, an outbreak 
which included 64 out of 66 persons who had eaten of a single batch 
of sausages. The onset was characterized by vomiting, purging, and 
dizziness, which came on after intervals of varying length. There was 
extreme weakness, and many had severe cramps in the legs and pains 
in the abdomen. In the majority of cases the vomiting and purging 
lasted from 36 to 48 hours. The discharges were very offensive and 
looked like dirty wash water. There was marked cerebral disturbance, 
and a sensation of acridity in the throat was common. 
One of the victims died, but the autopsy revealed nothing unusual 
beyond a number of red patches in the intestine. The remaining 
sausages were found to have a tainted and putrid odor. 
Case II.-The Limmetshausen case. 
The liver of a healthy pig was made into sausages which were then 
smoked for a number of days and hung up. On the eighth day they 
were eaten by a family and a number of invited guests, one of whom 
objecting to their peculiar taste refrained from eating and escaped the 
trouble that came to all the rest. The symptoms, which appeared 
within a short time, were the same in kind in all, but differed in severity. 
They included abdominal pain, vomiting, dizziness, dryness of the 
mouth and throat, and difficult deglutition. The pupils became di- 
lated and vision was much impaired and finally lost. The muscular and 
nervous systems were very much affected ; the pulse was rapid and 
weak ; respiration became embarrassed, swallowing and speaking im- 
possible. Death ensued in three cases, preceded by great lividity of 
the face and spasms of the extremities. 
Case III.-Van Ermengem 2 relates an instance in which the re- 
maining sausages of a lot which had caused illness in several persons 
were apparently so wholesome and looked so inviting that the expert 
and his assistants to whom they were sent ate them and themselves 
became ill. The expert died on the sixth day, and autopsy showed 
gastroenteritis, acute nephritis, and fatty degeneration of the liver. 
Gaertner's Bacillus enteritidis was found both in the organs and in the 
sausages. The latter were made of horse meat. 
1 Medical Times and Gazette, November 29, 1879. 
2 Revue d'Hygiene, 1896, p. 761. 68 
FOODS. 
Case IV.-Dr. Carl Gunther1 reports that in several places in 
Posen a large number of persons were made sick after eating pork sau- 
sages and blood, all of which had been supplied by one butcher. The 
most important symptoms were abdominal pain, vomiting, purging, 
great weakness and lassitude. One man of 47 years died after hardly 
a day's sickness. Gunther examined portions of the deceased and also 
samples of meat and blood found in the house, and sausage and meat 
from the shop of the butcher. From the victim's spleen and liver he 
isolated the B. enUritidis, but while a variety of organisms were found 
in the foods this bacterium was not detected, perhaps having perished 
through the influence of the other species present. 
Case V.-This interesting case of poisoning by sausage composed 
of pork and beef is related by Dr. W. Silberschmidt2 and serves as an 
illustration of the methods commonly employed in the manufacture of 
sausages. Nearly fifty people were poisoned by eating a kind of sau- 
sage known in Switzerland as Landjiiger. It is made of beef, often, 
also, horse meat with pig fat. The materials are chopped rather 
coarsely, spiced, put into casings, pressed flat for a day, smoked two 
days, dried in the air several more days and then eaten in the raw 
state. The sausages in this instance were made of cow beef from ani- 
mals that had been certified as sound by the veterinarian, and pork 
that had been bought about two weeks previously and kept with pre- 
servative salt, and had appeared quite fresh and unchanged when used. 
In the morning of the first day that the sausages were on sale, a man 
and his wife ate one of them together, and both were made so sick 
toward evening and during the night that a physician was called. In 
the afternoon of the same day nineteen fishermen ate of them, and on 
the following day it was reported that all of them had been made sick. 
In the evening another man ate one, and it pleased him so much that 
he took another home to his wife and children. On the next day he 
had abdominal pains, headache, vomiting, diarrhoea, thirst, and a chill. 
In the afternoon his wife and two children who had eaten were simi- 
larly seized. A boatman who ate two whole sausages suffered no 
inconvenience beyond a little pain on the following day. Another, 
who was sick eighteen days and then returned to his work, was seized 
again ten days later with the same train of symptoms. 
One young man, aged eighteen years, entered the hospital in the 
morning of the second day, and died during the night, two days and a- 
half after ingestion of the sausage. At the time of entrance the ab- 
domen was sensitive, and he was passing grayish watery stools; in the 
afternoon he was delirious, and his pulse was very small, irregular, 
and rapid. During the night he collapsed and died. Section after 
twelve hours showed a spleen of normal size, swollen mesenteric glands, 
and hypersemia of the stomach and intestines. The follicles were much 
swollen, and in the ileum were several areas from 4 to 6 cm. in length 
by 1 cm. in breadth, where the mucous membrane was discolored and 
1 Archiv fiir Hygiene, XXVIII., p. 146. 
2Zeitschrift fiir Hygiene und Infectionskrankheiten, XXX., p. 328. 69 
MEAT INSPECTION AND SLAUGHTERING. 
eroded. Other organs were normal. Six others of those affected were 
discharged from the hospital after from seven to fifteen days' treatment. 
In an adjoining town, where sausages of the same lot were sold, 
there were sixteen other cases, all with the same symptoms. Taking 
all the cases together, the symptoms of prominence were as follows : 
Very severe, partially crampy, abdominal pains; very profuse diar- 
rhoea, the stools numbering from eight to twelve per day, and in color 
varying between gray, greenish, and yellow; usually vomiting, the re- 
jected matters being watery and brownish ; sunken eyes, high fever, 
great lassitude, tenderness over abdomen, cramps in the calves, great 
thirst, and, occasionally, meteorism. In most of the cases the symp- 
toms appeared on the day after eating. The duration of the illness 
ranged between one and thirty days, the greater number recovering in 
two weeks, and becoming fit for work in three. 
As is commonly the case in these food outbreaks, the attention of 
the authorities was not drawn to the matter in either town until some 
days had elapsed. Chemical analyses of unused sausages were made 
at both places. One analyst reported negative results; the other re- 
ported the presence of ptomains, but did not further particularize. 
Bacteriological investigation revealed the presence of a variety of 
organisms, as was to have been anticipated, and among them, espe- 
cially marked, Proteus vulgaris, but no specific pathogenic bacteria were 
found. 
Silberschmidt calls attention to the fact that the smoking to which 
the sausages had been subjected, while not destructive to the bacteria 
of putrefaction, was successful in masking any unpleasant smell or 
taste due to the process, and urges warning the public against eating 
smoked sausages in the uncooked state. In this case there was noth- 
ing to indicate that the animals from which the meat was derived were 
not in a perfectly healthy condition. 
Meat Inspection and Slaughtering. 
The value and advisability of thorough inspection of meats before 
they are placed on sale is universally conceded. 
In this country under the inspection law of March 3, 1891, all meat 
intended for export is required to pass a very strict system of inspec- 
tion. The animals are inspected before being slaughtered and their 
carcasses are examined microscopically by officials of the Bureau of 
Animal Industry before being packed. The inspection of meat for 
local consumption is wholly a matter of local authority; some States 
have inspection laws and others have none; many cities have special 
regulations which are enforced by officials who may or may not be 
competent through proper training. In Germany the system of in- 
spection is very rigid, particularly in the case of meats from foreign 
countries. This is due very largely to the activity of the agricultural 
interests in protecting themselves from outside competition, and under 
the benevolent plea of protecting the health of meat consumers much 70 
FOODS. 
care and attention are given to the hunt for excuses for excluding Amer- 
ican meats which have already been inspected. 
In inspecting meats special attention should be paid to the connec- 
tive tissue and glandular organs. The odor of a carcass should be 
sweet and the meat should communicate no unpleasant smell to a 
wooden skewer thrust into it and withdrawn. The muscles should be 
firm and elastic, but not tough. Any variation from the natural color 
should be regarded with suspicion, very dark color suggesting febrile 
condition, or that the animal was not slaughtered, or was slaughtered 
in a dying condition. Such meat undergoes decomposition much more 
rapidly than normal meat. Animals that have been drowned or have 
been killed by accident without being bled yield a dark and discolored 
meat that is likely to decompose more rapidly than that of animals 
that have been regularly slaughtered, but an animal that has been in- 
jured, but not killed, may be slaughtered, properly bled and dressed, 
and its meat is then perfectly good. 
In most large communities the slaughtering establishments are few 
in number and are under the direct supervision of public officials. 
Thus, in Paris there are but three slaughtering houses, namely, Vil- 
lette, Grenelle and Villejuif, and at these three places during the year 
1896, 300,243 head of stock were slaughtered. In small places, on 
the other hand, where less attention is paid to inspection, the slaught- 
ering establishments are commonly more numerous; in the country 
districts where no inspection is carried on, each butcher may do his 
own slaughtering in his own establishment. 
Animals should be kept without food for at least twelve hours before 
slaughter, and the carcasses should be hung for a number of hours to 
cool. Many diseases are more clearly indicated after the body has 
cooled. 
The Jewish method of slaughtering is regarded by many as far su- 
perior to any other. According to Dembo 1 it is the most rational 
from a hygienic standpoint, since the animal is rapidly and completely 
bled, and the convulsive movements cause the meat to be more tender 
and of more attractive appearance. Lactic acid is developed and 
through its chemical action on potassium phosphate, potassium lac- 
tate, and acid phosphate of potassium are formed. The latter hin- 
ders the development of micro-organisms, delays the formation of 
ptomains and other poisonous matters, and improves the taste. Rigor 
mortis comes on more quickly, and the meat is, therefore, more quickly 
available for use, and also will keep several days longer than ordinarily. 
A process of slaughtering originating in Denmark appears to have 
borne the test of a hard three-months' trial in a very satisfactory 
manner, and recommends itself for adoption in the tropics where 
meats decompose with exceeding rapidity. The animal is shot in the 
forehead and killed or stunned, and as it falls an incision is made over 
the heart and the ventricle is opened for two purposes :-to allow the 
blood to escape and to admit of the injection of a solution of salt 
1 Deutsche Vierteljahrschrift fur offentliche Gesundheitspflege, XXVI., p. 688. 71 
EGGS. 
through the blood vessels by the aid of a powerful syringe. The proc- 
ess requires but a few minutes, and the carcass can be cut up at once. 
Eggs form a valuable substitute for meats, being fairly rich in fats 
and proteids, and are well adapted to the stomach of the invalid and 
convalescent when meats cannot be borne. The nutritive part of the 
white is practically limited to proteids which amount to about 12 per 
cent. ; the yolk is richer in proteids and contains in addition about 33 
per cent, of fat. The albumin of the white is in a condition of solu- 
tion in cells with very thin walls. The fatty matters of the yolk are 
in a condition of emulsion, being held in suspension by the vitellin. 
The entire yolk is held together by an enveloping membrane and is sus- 
pended in the white, being held in position by an albuminous band at 
either end. 
It is a commonly accepted idea in some parts of the country that 
eggs with brown shells are of greater richness than others, and that 
the degree of richness is directly proportionate to the depth of color. 
In some markets, on the other hand, the white egg is held in higher 
esteem. According to the results of an extensive study of the chem- 
ical composition of eggs carried on at the California Experiment Station 
mainly for the purpose of determining what differences, if any, exist 
between them, there is no basis of fact for the popular belief. In fact 
the very slight differences noted were in favor of the white eggs, but 
the average differences between the two kinds were less than the fluc- 
tuations between individual specimens of the same group. The figures 
obtained are presented in the following table taken from Farmers' 
Bulletin No. 87.1 
EGGS. 
Analysis of Brown-shelled and White-shelled Eggs. 
Water. 
Protein. 
Fat. 
Ash. 
Shell. 
Total. 
Broton-shelled eggs: 
per ct. 
per ct. 
per ct. 
per ct. 
per ct. 
per ct. 
Yolk 
49.59 
15.58 
33.52 
1.04 
99.73 
White 
86.60 
11.99 
.21 
.54 
99.34 
Entire egg 
65.57 
11.84 
10.77 
.64 
10.70 
99.52 
White-shelled eggs: 
Yolk 
49.81 
15.49 
33.34 
1.05 
99.69 
White 
86.37 
12.14 
.35 
.56 
99.42 
Entire egg 
64.79 
11.92 
11.22 
.67 
10.92 
99.52 
The question of influence of breed on composition has been investi- 
gated at the Michigan Experiment Station. The results showed that 
the variations in composition are too slight to be of any practical value, 
and as with the brown and the white eggs, so slight as to be less than 
the variations between individual specimens from the same breed. The 
influence of the nature of the feed was also investigated and found to 
be of little or no importance. 
1 Government Printing Office, Washington, 1899, p. 24. 72 
FOODS. 
The digestibility of eggs has been studied at the Minnesota Experi- 
ment Station.1 It was shown that while the method of cooking has 
some effect on the rate of digestion, the total digestibility is not affected. 
Eggs boiled 3, 5, and 20 minutes and digested for five hours with 
pepsin solution showed at the expiration of that time respectively 8.3, 
3.9, and 4.1 per cent, of undigested proteids. Cooked for five and ten 
minutes in water at 180° F. and similarly treated they left no undi- 
gested residuum. 
LARD. 
Lard is the semi-solid fat of the slaughtered hog separated from the 
tissues by the aid of heat. According to the parts from which it is de- 
rived it is classified as follows : (1) Neutral lard. This is derived from 
the fresh leaf which is reduced to a pulp after being cooled and then 
rendered in the kettle. A part of the fat is separated at from 105° to 
120° F. and the residue is sent to the rendering tanks for further 
treatment. The lard obtained is washed while hot with water contain- 
ing a trace of sodium carbonate, common salt, or dilute acid. (2) 
Leaf lard. This is obtained from the residue above mentioned which 
is subjected to steam heat under pressure. (3) Choice kettle rendered 
lard. This is obtained from the remaining portions of the leaf to- 
gether with the fat cut from the backs. Both the leaf and back fat 
are passed first through a pulping machine. (4) Prime steam lard. 
This is made from the head, the fat of the small intestines, trimmings, 
and other fatty parts. 
The spleen, pancreas, trachea, and all other refuse parts and trim- 
mings with the exception of the small intestine, the liver, lungs, and 
part of the heart go into the rendering kettle for what fat there 
may be in them, and the product is variously but not graphically 
designated. 
" Refined lard " is a term used to designate a lard composed chiefly 
of cotton oil and stearin. It is more often known as " lard compound." 
Physical and Chemical Properties of Lard.-At 40° F. the specific 
gravity is about .890 ; at 100°, about .860 ; it differs not very mate- 
rially from that of the substances used as adulterations excepting cot- 
ton-seed oil which is notably heavier. The melting point ranges from 
39.1 ° to 44.9° C. according to the part of the carcass from which the fat 
is derived and hence it cannot be taken as a safe guide in the determi- 
nation of purity. 
Pure lard melted and mixed with strong sulphuric or nitric acid will 
give only a slight color which may be yellowish, pinkish, or inclined 
to light brownish. Cotton-seed oil and other seed oils, and mixtures 
containing them, similarly treated yield any color between yellowish 
brown and very brownish black or even black. The refractive index 
of pure lard is materially lower than that of cotton-seed oil. 
Pure lard contains only traces of volatile fatty acids, 5 grams yield- 
ing an amount which is neutralized by one or two fifths of a cc. of 
1 Fanners' Bulletin No. 87, Government Printing Office, Washington, 1899, p. 25. 73 
MILK AND MILK PRODUCTS. 
decinormal sodium hydrate solution. The non-volatile fatty acids are 
present to the extent of about 95 per cent. The iodine absorption 
number varies according to the part of the carcass from which the fat 
is derived, but averages about 60. The iodine number of cotton-seed 
oil is about 109, and that of stearin is approximately 20. Thus, 
these substances used as adulterants may be mixed in such a propor- 
tion as to yield the normal iodine number of lard. 
With nitrate of silver solution pure lard causes no more than the 
very slightest amount of reduction and generally none at all, but cot- 
ton-seed oil causes a very marked reduction of the salt to the metallic 
state with the result that the mixture has a brownish or black appear- 
ance from the minute black particles formed. 
A small amount of lard dissolved in a mixture of equal parts of 
alcohol and strong ether in a test tube and allowed to stand in a cool 
place will, when the solvent is in large part evaporated, show masses 
of crystals which on examination under the microscope are seen to be 
rhombic and extremely variable in size. Beef stearin similarly treated 
shows fan-shaped and dumbbell-shaped clusters of needle crystals. 
Mixtures of pure lard and beef stearin will show both forms of crys- 
tals. Sometimes when crystallization proceeds rapidly, the crystals 
from pure lard are extremely small and are clustered in such a way 
as to be distinguished from beef stearin crystals only with great diffi- 
culty. It is essential that the crystallizing process should proceed 
slowly and that the amount of lard dissolved in half a test tube of the 
solvent should be quite small, not larger than a large pea. The mouth 
of the test tube should be stopped with cotton. 
Section 3. MILK AND MILK PRODUCTS. 
MILK. 
Milk is a solution of sugar, mineral matter, and proteids, with other 
proteids and fat in suspension. Its composition is very variable not 
alone as between different species of mammalia by which it is pro- 
duced, but as between different individuals of the same species. 
Among the domestic animals, the ass and mare produce milk which 
most closely approximates that of woman in composition, but our chief 
interest in milk as an article of food in general use lies in that pro- 
duced by cows and, to a certain extent, in that of goats, which is very 
similar in composition. While the composition of milk of other ani- 
mals than those already mentioned can have for most of us merely a 
scientific interest, it may be of some practical utility in the manage- 
ment of breast-milk to bear in mind that the milk of animals whose 
diet is largely or chiefly meat is richest in those elements, the proteids, 
that are most commonly at the bottom of digestive disturbances in 
breast-fed children. 
Composition of Cow's Milk.-The composition of milk of average 
good quality may be fairly expressed in round numbers as follows : 74 
FOODS. 
Fat 4.00 
Sugar 5.00 
Proteids 3.30 
Mineral matter 0.70 
Total solids 13.00 
Water 87.00 
100.00 
According to Vieth the average composition of over 120,000 sam- 
ples analyzed in England was : 
Fat 4.10 
Solids not fat 8.80 
Total solids 12.90 
Water 87.10 
100.00 
The average of a large number of analyses made in this country 
showed-1 
Fat 4.00 
Sugar 4.95 
Proteids 3.30 
Mineral matter 0.75 
Total solids 13.00 
Water 87.00 
100.00 
The milk yielded by 426 cows from private farms in Massachusetts 
and by 175 more belonging to public institutions was analyzed by the 
author and his associates and found to give the following results :2 
426 cows from private farms, total solids 13.36 
175 cows from public institutions, total solids 13.00 
601 cows (both classes), total solids 13.26 
Fat.-The fat of milk exists in very minute globules which vary 
widely in size, the largest being between 6 and 7 times larger than the 
smallest, but the latter are most abundant. Whether or not they have 
an albuminous envelope is a matter of doubt, the evidence for and 
against being about equal, and of no great importance. 
It consists of glycerides of 10 different fatty acids, 5 of which be- 
long to the non-volatile and 5 to the volatile class. The glycerides of 
the former group constitute by far the greater part. They are stearin, 
palmitin, olein, myristin, and butin ; the last two are present in very 
minute amounts. Those of the latter group give the characteristic 
butter flavor. They are butyrin, caproin, caprylin, caprin, and laurin ; 
the first two are the important ones and together amount to somewhat 
over 7 per cent, of the whole fat; the other three are present in but 
small and insignificant traces. 
The fat being the lightest part of the milk tends to rise to the sur- 
face when the milk is allowed to stand, and then forms a layer which 
we know as cream. This contains not fat alone but all of the con- 
'American Experiment Station Record, V., No. 10. 
2The detailed analyses with data as to breed, nature and amount of feed, etc., can 
be found in the pamphlet issued by the State Board of Health : Results of Inquiries 
Relative to the Quality of Milk as Produced in Massachusetts. Boston: February, 1887. MILK AND MILK PRODUCTS. 
75 
stituents of the milk, and is, therefore, simply milk containing an ex- 
cessive amount of fat. 
It is a common error to regard the depth of the cream layer which 
forms on standing a given length of time as an infallible measure of 
the richness of the milk by which it is yielded. But the cream does 
not always rise well in rich milk even after standing more than 24 
hours. The author has repeatedly found the percentage of cream 
thrown up by a specimen of milk in a 100 cc. graduate in 24 hours, as 
measured by the lines of graduation, to be less than the actual percent- 
age of fat as shown by analysis. The rapidity with which the fat finds 
its way to the surface depends largely upon the size of the fat globules. 
The largest rise first, and the very smallest may not rise at all. In 
the second place, a watered milk throws up its fat more quickly than a 
normal specimen though it does not contain as much. It appears, 
therefore, that a milk of inferior grade may under some circumstances 
show a deeper cream layer than one of unusual richness. Generally 
speaking, however, a rich milk will usually show its quality on standing. 
The first part of a milking is always poor in fat, the middle portion 
contains about the average amount of the whole, and the last portion 
is always the richest. The first portion is known as " fore-milk," the 
last as " strippings." A specimen of " strippings " analyzed by the 
author gave the following results : 
Fat 9.82 
Sugar 4.00 
Proteids. 4.21 
Ash 0.79 
Total solids 18.82 
Water 81.18 
fooToo 
Milk Sugar.-Lactose, or sugar of milk, is peculiar to milk alone. 
It is much less soluble in water than dextrose and sucrose. Heated to 
100-131° C. it becomes changed in color to brownish, and at higher 
temperatures loses water of crystallization and undergoes further 
change. At 175° C. lactocaramel is formed. When heated in solu- 
tion, in milk itself for example, it begins to undergo decomposition 
changes at 70° C. and above. Through the action of the lactic fer- 
ments it gives rise to lactic acid. In the polariscope it is dextro- 
rotary. 
Proteids.-The greater part of the proteids of milk, about 80 per 
cent., is casein, or, as it is sometimes called, caseinogen. It contains 
both sulphur and phosphorus and is in intimate combination with cal- 
cium phosphate. It is not coagulated by heat, but is precipitated by 
acids by which the combination is broken up. In the presence of lactic 
acid in small amounts, clue to the breaking up of lactose, coagulation 
is hastened by the application of gentle heat. This phenomenon is 
very commonly observed in the case of milk which to the taste is 
apparently sweet, but which is "just on the turn." 
The chief part of the balance of the proteids is lactalbumin. This 76 
FOODS. 
is coagulated by heating to 65-73° C. but not by dilute acids. It 
contains sulphur but no phosphorus. In amount it ranges from 0.2 
to 0.8 per cent. It is much more abundant in colostrum. 
The remaining proteids are lactoglobulin, which is coagulated by 
heat, lactoprotein, coagulable by neither heat nor dilute acids, and 
fibrin. Each exists in but very small amounts. 
Mineral Matter.-The mineral matter contained in milk consists of 
phosphates and chlorides of potassium, sodium, calcium and magnesium, 
and extremely minute traces of iron. Of the bases, potassium is the 
most abundant, with calcium, sodium, and magnesium in the order 
given. The phosphates predominate over the chlorides. Part of the 
calcium exists in combination as phosphate with the casein, and part 
of the magnesium in combination with citric and other organic acids. 
In very small amounts these are normal constituents of milk of various 
animals. In human milk, citric acid is present to the extent of about 
0.05 per cent., and in cow's milk it is about three times as abundant. 
Specific Gravity.-The specific gravity of cow's milk of normal com- 
position ranges from 1.029 to 1.034. It increases very slightly for 
about 5 hours after the milk is drawn, and then becomes stationary. 
The increase is believed to be due to molecular modification of the 
casein and not to the escape of gases. It is lowered by fat and water, 
and by the presence of bubbles of air, and is raised by removal of 
cream. 
Reaction.-When freshly drawn, milk shows the so-called amphoteric 
reaction, that is, it is acid to litmus and alkaline to turmeric. The 
alkaline reaction is intensified on warming, but the acid reaction is not 
influenced thereby. On standing, the alkaline reaction is overcome 
by the lactic acid which is gradually formed from the sugar, and the 
acid reaction is increased in consequence of the same. The original 
acid reaction is due to the presence of phosphates, the alkaline to 
alkaline carbonates. Human milk is normally alkaline, and that of 
carnivora is acid. 
Appearance.-The normal appearance of milk is too familiar to need 
description, but under certain rare abnormal conditions milk may 
assume different colors including blue, yellow, violet, and red. These 
changes of color are due to the action of certain bacteria and are always 
evidence of unsanitary conditions to which the milk is exposed at the 
dairy or during distribution and storage. 
Blue milk is due to the action of the Bacillus cyanogenes which 
produces a blue color in no other food material. For its development 
it requires the presence of lactic ferments, and, therefore, has no effect 
on milk that is sterile. Another organism capable of producing the 
same effect is B. cyaneoflnorescens. 
A red color may be caused by B. prodigiosus or B. lactis erythro- 
genes; sometimes by blood, and, it is said, by madder and other red 
coloring matter in the feed. Yellow is caused by B. synxanthus, and 
violet by B. violaceus. 
All of these abnormal milks are, aside from their uninviting appear- MILK AND MILK PRODUCTS. 
77 
ance, unfit for food since they are likely to cause gastro-intestinal 
irritation. 
Another abnormal condition caused by a large variety of organisms 
is characterized by alteration of the natural consistence to one of 
sliminess which appears only some hours after the milk is drawn. 
Slimy or 11 ropy " milk throws up no cream and cannot be churned, 
but though it is most repugnant to the senses it causes no digestive dis- 
turbances if ingested. 
Taste.-The flavor of milk is very sensibly modified by the charac- 
ter of the feed and by the absorption of gases and volatile matters of 
all kinds. It is very readily affected by turnips, garlic, wild onion, 
mouldy hay and grain, distillery swill, and damaged rotten ensilage. 
Distillery swill not only causes a decidedly bad flavor but may in ad- 
dition, and contrary to a generally accepted idea, cause an alcoholic 
milk. Thus according to H. W. Weller,1 a sample of milk derived 
from cows fed on distillery refuse containing 5.90 per cent, of alcohol 
yielded in addition to a high proportion of milk solids, 0.96 per cent, 
by weight of alcohol. The milk was complained of on account of an 
unpleasant after-taste. 
That alcohol or something connected therewith may be eliminated 
in milk, is shown also by a case reported by Vallin.2 A nursing in- 
fant was seized with convulsions with great regularity on Mondays and 
Thursdays, but was quite well on all other days. Investigation showed 
that the wet-nurse on Sundays and Wednesdays, her 11 days out," was 
in the habit of drinking freely of alcoholics. The curtailment of the 
privilege was followed by disappearance of the difficulty. 
Bitterness of taste may be due either to some constituent of the feed 
or to bacteria. When due to feed the taste is bitter from the very 
first, but when caused by bacterial agency it develops some time after 
milking, when the organisms which produce it have had the opportu- 
nity to act upon the proteids or whatever constituent may be concerned. 
It may be due also to inflammatory conditions of the udder, in which 
case it may or may not be noticeable when the milk is freshly drawn. 
The bacteria concerned in producing bitterness may exist in the ducts 
of the teats or may come from stable filth. Damman3 mentions a 
case in which the persistently bitter taste disappeared after the floor 
of the stable was cleaned and disinfected and the ducts of the teats 
syringed out with disinfectant solution. Strong smelling disinfectants 
cannot be used in dairies because of the readiness with which milk 
will absorb odors. This absorptive capacity is so well recognized that 
milk is commonly stored in separate compartments of refrigerators 
away from foods which evolve distinct odors. 
Colostrum.-The milk secreted before and in the early stage of 
lactation is known as colostrum. It is a yellow, somewhat viscid fluid 
of strong odor and acid reaction. In composition it differs very ma- 
1 Forschungsberichte uber Lebensmittel, etc., 1897, p. 206. 
2 Revue d'Hygiene, 1896, p. 953. 
3 Deutsche thierarztliche Wochenschrift, 1897, No. 1. 78 
FOODS. 
terially from milk, particularly in its percentage of proteids. It con- 
tains, sometimes, so large a percentage of lactalbumin and lactoglobulin 
that it is coagulated by boiling. Its content of casein is about normal, 
but it is not coagulated by rennet or at most imperfectly. In the early 
stages its sugar is dextrose and not lactose. According to Tiemann 1 
it ranges in specific gravity from 1.0299 to 1.0594, in fat from 0.56 
to 9.28, in proteids from 4.66 to 21.78, in ash from 0.82 to 1.25, and 
in total solids from 12.93 to 32.93. 
Under the microscope it shows large corpuscles, known as colostrum 
corpuscles, which disappear within two weeks at most after the time 
of calving. 
Changes Produced in Milk by Boiling.-Boiling causes greater 
coalescence of the fat globules, changes in the character of the sugar, 
coagulation of lactalbumin, and destruction of micro-organisms and 
ferments. Boiled milk, therefore, will keep better than raw milk. 
The scum which forms on the surface is largely fat and casein and 
lactalbumin, and occurs in consequence of rapid evaporation at that 
point. Boiled milk is slightly less readily digested than raw milk, 
and sour milk is more readily digested than either. 
Changes Due to Bacterial Action.-At ordinary temperatures 
milk soon begins to undergo changes initiated and carried along by 
various species of micro-organisms which exist in the ducts of the teats, 
or fall into the pail from the external surface of the udder or surround- 
ing parts, or from the air, or from the hands and clothes of the milker, 
or which are already present in the pail or other vessel into which the 
milk is received. The most common change is brought about by the 
lactic ferments of which more than a hundred species have already 
been identified. They attack the milk sugar and cause the formation 
of lactic acid which on accumulating in sufficient amount causes the 
milk to curdle. Their multiplication proceeds most rapidly at tem- 
peratures ranging from 25 to 30° C. Therefore, in order to inhibit 
their action as far as possible, milk should be cooled without delay and 
kept in storage at low temperature. 
In addition to the lactic ferments there are others which are known 
as casein ferments. These produce a substance much like rennet in its 
action. They may act in the absence of the lactic ferments, and then 
their action is accompanied by the development of alkalinity. 
Under certain conditions, in addition to changes in taste, color, and 
consistency already noted, intensely poisonous benzene derivatives are 
formed, the most important of which, diazobenzene, called by its dis- 
coverer, Prof. V. C. Vaughan, tyrotoxicon, is the exciting cause of the 
train of symptoms commonly known as milk poisoning, cheese poison- 
ing, and ice-cream poisoning. 
A number of other organisms constitute the group of so-called 
butyric ferments many of which are of the class of casein ferments. 
They cause the production of butyric acid in the decomposition of pro- 
teids. 
1 Zeitschrift fur physiologische Chemie, 1898, p. 363. MILK AND MILK PRODUCTS. 
79 
In consequence of the action of the various species of organisms it 
is important that bacteria in general should be excluded as completely 
as possible from milk by the observance of the utmost cleanliness in 
milking, handling, and storing. The milk of cows stalled in badly 
ventilated unclean stables and of cows with unclean udders will decom- 
pose much more rapidly than that of cows kept under better sanitary 
conditions. Even when the cow and her surroundings are kept in a 
cleanly state, the very first part of a milking should be rejected on ac- 
count of the very large numbers of bacteria present in the ducts of 
the teats. Under even the best of conditions, many bacteria are pres- 
ent in freshly drawn milk, and these increase rapidly in number un- 
less killed by the action of heat or other germicides. Indeed, it has 
been found impossible in the majority of experiments to obtain sterile 
milk even when the greatest precautions have been observed to ex- 
clude extraneous organisms. The B. coll communis is almost always 
present in raw milk. 
The first part of a milking is richest in bacteria because those which 
have multiplied within the ducts of the teats since the previous milk- 
ing are expelled mostly with the fore-milk, but even the very last 
portions of the strippings may contain as many as 500 bacteria per cc. 
Thus, Schultz 1 found in the first portions of cow's milk 97,240 per 
cc., in the strippings 500, and in goat's milk 78,718 and 665. For 
the attainment of the best results as to keeping qualities, all dirt 
should be brushed from the cow before milking and the udder and 
flank should be dampened in order that dust, fine dirt, and bacteria 
may be retained in situ, and not fall into the milk-pail. This should 
always be perfectly clean before use. 
The difference in the number of bacteria which fall into milk when 
proper precautions are observed and when they are neglected is very 
considerable. Thus, Soxhlet found that the milk of a cow with a 
dirty udder, stalled in a dirty stable, kept sweet 50 hours at ordinary 
temperature, and that when her udder was washed and she was milked 
in the open air it remained sweet a day and a-half longer. Still more 
instructive are the results obtained by Dr. R. G. Freeman,2 who ex- 
posed plates of equal size, 3.5 inches in diameter, for two minutes as 
follows : one in the open air, one inside a barn, and a third in front of 
the milk pail under a cow in the same barn while being milked. The 
first showed 6, the second 111, and the third 1,800 colonies. Such a 
number of bacteria falling upon so small a surface within so short a 
time is an index of the enormous number which may fall into the pail 
during the time required for a complete milking. 
The hastening of decomposition processes by improper handling and 
by storage under unsanitary conditions is a matter of such general 
knowledge as to require no specific illustration. 
Preservation of Milk.-The keeping quality of milk is influenced 
by cold, which retards the growth and multiplication of bacteria which 
bring about decomposition ; by heat which destroys them ; and by pre- 
1Archivfiir Hygiene, XIV., p. 260. 
2 Medical Record, March 8, 1896. 80 
FOODS. 
servatives which either kill them or retard their growth. Preservation 
by cold is in many respects preferable to either of the other methods. 
The constituents are in no way altered in character, there is no change 
in digestibility, and no element is introduced into the system with the 
milk to exert any harmful influence upon the digestive processes. In 
places where ice is expensive or not obtainable, this method is not 
available, but where it is cheap and plentiful it is the one in most com- 
mon use. In some parts of Europe milk is frozen into solid blocks by 
the ammonia process and shipped in that form to market. A large 
part of the milk supply of Copenhagen is received from a distance in 
large air-tight cans into each of which a block of frozen milk, weighing 
about 25 pounds, is placed to keep the milk in which it floats at a low 
temperature. 
Preservation by heat includes pasteurization and sterilization. In 
pasteurization the whole bulk of the milk is heated to not over 
158° F. (70° C.), maintained at that temperature for 10 or 15 minutes,, 
and then cooled rapidly in order to preserve the fresh flavor and pre- 
vent the multiplication of such of the bacteria as survive. The length 
of time required for the destruction of bacteria varies with the tempera- 
ture employed. Thus about 70 per cent, of saprophytic bacteria are 
killed in an hour at 140° F., in 15 minutes at 150°, in 10 minutes at 
158°, in 5 minutes at 176°, in 2 minutes at 194°, and in 1 minute at 
203°. It is essential that all apparatus and vessels used iu cooling 
and storing shall be clean and sterile. This process is quite sufficient 
for all practical purposes and hygienic requirements unless the milk is 
to be kept for a longer time than usual, in which case it must be re- 
peated at the end of 24 hours. 
Temperatures higher than 158° F. cause the milk to acquire a 
cooked flavor which to many persons is disagreeable. According to 
Dr. H. Bitter 1 all pathogens in milk are killed with absolute certainty 
by exposure to 68° C. (154.4° F.) for a half hour, and the milk is al- 
tered thereby in neither appearance nor taste. Under ordinary cir- 
cumstances 20 minutes' exposure is quite sufficient. Some authorities 
assert that temperatures of 140 to 147° are quite high enough for the 
purpose, but Professor Theobald Smith2 has shown that while tubercle 
bacilli are destroyed within 20 minutes at 140° F., the formation of 
a surface pellicle into which they are carried by fat globules shields 
them from the heat so that they may survive an exposure of over an 
hour to 149°. 
The lactic ferments are all very easily destroyed, but some of the 
casein ferments are very resistant, and their spores still more so, and 
are not killed by boiling for a number of hours ; and it is to the presence 
of these hardy varieties that the difficulty of complete sterilization is 
due. 
Sterilization requires continuous heating under pressure for about 
two hours at 120° C. (248° F.), at which temperature not alone the 
1Zeitschrift fur Hygeine, VIII., p. 240. 
2 Journal of Experimental Medicine, 1899, p. 217. MILK AND MILK PRODUCTS. 
81 
bacteria and their spores are destroyed, but the normal appearance and 
taste of the milk as well. Part of the sugar is converted to caramel, 
part of the casein is precipitated, and the milk will no longer form a 
cohesive coagulum with rennet. 
In the opinion of many practitioners neither pasteurization nor 
sterilization is free from objection in infant feeding since even a temper- 
ature of 155° F. influences the nutritive value injuriously. To meet 
this objection Freeman 1 proposes that the cream be allowed to rise and 
then be removed and subjected alone to sterilization, after which it may 
be mixed in proper proportion with the skimmed milk which contains 
only a very small number of bacteria, since about 99 per cent, of them 
are carried upward into the cream layer by the fat globules. 
Preservation of milk by the addition of antiseptics is unnecessary, 
unjustifiable, and possibly injurious. If milk is properly drawn from 
decently clean animals into clean vessels by clean milkers, and stored 
in clean places, it will keep sweet quite as long under ordinary circum- 
stances and under the usual conditions of frequent delivery as is desired 
by the consumer. The addition of antiseptics, which only retard 
growth of bacteria without destroying them, enables the vendor to 
supply stale milk in place of fresh, and to dispense with part of the 
sanitary precautions otherwise necessary. The substances used are by 
no means wholly innocent in their action on the human system even 
in very small doses, and, moreover, it is impossible to control the 
amount added by a single individual, or to be sure that successive 
handlers have not contributed additional doses. 
The substances used as milk preservatives are boric acid, borax, 
salicylic acid, formaldehyde, carbonate of sodium, and chromates. The 
first two mentioned are generally used in combination with each other, 
experience having shown that the mixture is more efficient than either 
alone. The minimum efficient quantity of the mixture is about 10 
grains to the quart, an amount which even for an adult may well be 
regarded as a fairly large medicinal dose. In addition to its action on 
the general system it exerts a varying effect on the digestion according 
to the amount present. According to Prof. R. H. Chittenden, borax 
retards the amylolytic action of saliva, boric acid in amounts less than 
one per cent, favors it, and both increase gastric digestion in small 
amounts and retard it in large. 
The use of salicylic acid in milk is not extensive. It is a fairly ef- 
ficient preservative. Formaldehyde has come into use within a few 
years. It is a most efficient preservative and not alone inhibits growth 
but kills the bacteria. According to tests made by Dr. C. P. Wor- 
cester,2 one part of commercial formalin in 100,000 of milk will post- 
pone the curdling point 6 hours; 1 in 50,000, 24 hours; 1 in 20,000, 
48 hours ; 1 in 10,000, 138 hours; 1 in 5,000, 156 hours. 
Although nothing is known as to the action of small amounts of 
'Archives of Pediatrics, August, 1899. 
2 Twenty-ninth Annual Report of the State Board of Health of Massachusetts, 1897, 
p. 559. 82 
FOODS. 
formaldehyde on the general system, it is not right to assume that in 
the absence of evidence to the contrary it is necessarily harmless or 
beneficial. While the occasional ingestion of a small amount of for- 
maldehyde may produce no effect, we cannot reason that its daily use 
over a long period of time will be equally non-productive. An occa- 
sional drink of water containing lead will do no injury, while its daily 
use may cause lead paralysis, and in the same way formaldehyde may 
be the cause of serious disturbances attributed to something else. 
But whether harmful or not, the use of this agent and of others is 
unnecessary and unjustifiable. Aside from its possibly poisonous ac- 
tion there is the objection that it alters the character of the milk pro- 
teids ; the casein becomes uncoagulable by rennet, except in thick clots, 
and much less digestible, or wholly indigestible, by the proteolytic fer- 
ments. Certain it is that anything that lays additional burdens on 
the digestive function of infants and invalids can hardly be regarded as 
a proper substance for use in food. Dr. H. E. Annet1 after a study of 
formaldehyde and boric acid as milk preservatives concludes that they 
are injurious, especially to young infants, and suggests the possibility of 
a causal relation between their use and the great infant mortality dur- 
ing the hot months. 
Carbonate of sodium is a weak agent and does not postpone decom- 
position to an extent sufficient to encourage its wide adoption. So far 
as is known, there can be no objection to its use on the score of injury 
except in so far as the assertion that sodium lactate, formed by its de- 
composition by the free lactic acid, acts as a mild cathartic, is worthy 
of credence. 
The chromates are not extensively employed, but have been found 
present in preservative powders used in France. M. Deniges 2 found 
the normal chromate of potassium in two of these preparations, and 
the dichromate and chromate together in a third. The latter was 
recommended in the proportion of two grams to 50 liters of milk. 
According to J. Froidevaux3 such an amount of potassium dichromate 
is insufficient to retard coagulation and imparts an abnormal intense 
yellow color to the milk. 
The further discussion of the subject of milk preservatives may be 
looked for below under the general subject of food preservatives. 
Adulteration of Milk.-This most important article of food is more 
subject to adulteration than any other since it lends itself so readily to 
fraudulent manipulation. The principal adulterations are the addition 
of water and the abstraction of cream. The former diminishes the 
nutritive value, and, if the water used is from an unclean source, in- 
creases the possibility of disseminating disease ; the latter robs the milk 
of one of its most valuable constituents. The detection of these adul- 
terations by analysis is not always possible, since a rich milk may be 
slightly watered or only partially skimmed and still show average qual- 
xThe Lancet, November 11, 1899. 
2 Revue International des Falsifications, IX., p. 36. 
3 Journal de Pharmacie et de Chemie, 1896, p. 155. CONDENSED MILK. 
83 
ity. Again, even though the watering be fairly extensive, it cannot 
always be proved that the milk was not of low grade from natural 
causes, since some cows give milk which on analysis is far below aver- 
age good milk and bears every resemblance to watered milk. Further, 
a milk containing but very little fat may be naturally poor in that 
constituent or may be the first part of a milking. 
In consequence of the difficulty of proving the addition of water or 
abstraction of cream and because of the enormous importance of secur- 
ing a public supply of at least average good quality, most States have 
fixed legal standards to which milk intended for sale must conform. 
The standard for total solids is commonly 13, 12.5, or 12 per cent., 
and for fat, 3, 3.5, 3.7, and 4 per cent. By the adoption of a legal 
standard all milk of low grade, whether so by reason of fraudulent 
practices or because of poor feed or individual peculiarity of the cow, 
must be treated alike. By prohibiting the sale of all milk not of a 
certain grade it becomes unnecessary to prove fraud or criminal 
knowledge, the allegation of inferior quality being sustained by the 
results of the analysis. 
Other forms of adulteration include the addition of coloring matters 
for the purpose of concealing watering or skimming, or to give a creamy 
tint to a very white milk, and the addition of preservatives, and, occa- 
sionally, of other foreign substances. 
It is a common belief even among people of more than average in- 
telligence that milk as found in the market is very largely a mixture 
of chalk and water. Upon what this foolish tradition is based it is 
difficult to surmise, since even though a person were led to practice 
such a miserable fraud he would discover that chalk and water will 
need constant stirring to maintain even the outward semblance of milk, 
and that a few minutes' standing is sufficient for complete separation 
into a deposit of chalk and a fairly clear supernatant liquid. A less 
common but equally absurd notion that calves' brains are a common 
adulterant of milk arose about half a century ago from a report of a 
microscopical examination of a milk sediment in which certain parti- 
cles were detected which bore some resemblance to nerve tissue. Calves' 
brains do not lend themselves readily to the making of emulsions, the 
supply is limited, and they find a fairly good market in their true 
character. 
Cane sugar is said to have been found at rare intervals, and gelatin 
is occasionally used as a thickening for cream. 
CONDENSED MILK. 
Condensed milk is prepared by evaporating milk to about a third or 
a fourth of its volume in vacuum pans. It is sold in bulk for immedi- 
ate use, and in hermetically sealed tin cans for use as occasion demands. 
Most of that sold in tins is made from skimmed milk and is, therefore, 
very deficient in fat; and much of it contains a large proportion of cane 
sugar which is added to increase its keeping qualities. Condensed 84 
FOODS. 
milk is in many respects and under certain conditions a valuable food 
preparation, but its use in infant feeding when other milk is obtainable 
is not a wise one, since it is deficient in one of the most important ele- 
ments and contains another which is not a normal constituent. 
KOUMISS AND KEFIR. 
These are fermented preparations containing lactic and carbonic 
acids and a small amount of alcohol. They are produced through the 
action of micro-organisms which induce fermentative changes and bring 
about a partial conversion of the proteids to albumoses and peptones. 
Both had their origin in Russia where they have been in use for very 
many years. Koumiss is generally made from the milk of mares, but 
can be made from that of cows with the assistance of added sugar. 
Kefir is more commonly made from the milk of cows. Both are effer- 
vescent liquids having somewhat the taste of butter-milk, and are valu- 
able in the feeding of the sick and of those with impaired digestive 
function. The " kefir grains " are small, hard, granular particles 
which contain the requisite organisms. They are added to the milk 
after being soaked until soft, and their action is completed in two or 
three days. 
CREAM. 
Cream, as already stated, may be defined as milk containing a large 
excess of fat and correspondingly lacking in water. The degree of 
richness is dependent upon the method employed in its separation from 
the original volume of milk. That obtained by the common method 
of skimming contains ordinarily about 16 to 24 per cent, of fat, while 
that separated by the centrifugal machine contains from 20 to upwards 
of 50 per cent, according as the machine is regulated for " light " or 
" heavy " cream. The latter is so thick as to give rise to a common 
notion that corn starch is used as an adulteration. This substance, 
however, is rarely if ever used in this way. Gelatin is employed as 
an adulterant to a limited extent. A preparation largely advertised to 
the trade at one time as a " cream thickener " was analyzed by the 
author and found to be a mixture of gelatin, borax, and boric acid. 
The common adulterants of cream are preservatives and coloring 
agents. The former are used mostly during the hot months, the latter 
during the winter, when on account of the difference in feed the cream 
has not the characteristic yellow tint so highly prized. 
Milk as a Factor in the Spread of Disease. 
Milk may act as a carrier of disease or cause of functional disturb- 
ance through infectious or poisonous matters originally present or re- 
ceived or evolved during handling and distribution. Thus, milk may 
be poisonous by reason of matters derived from the feed or of sub- 
stances formed after it is drawn; it may contain organisms of various 
kinds connected with bovine diseases; it may become contaminated in MILK AS A FACTOR IN THE SPREAD OF DISEASE. 
85 
various ways with matter containing the exciting cause of various 
human diseases. 
Poisonous Milk.-Certain plants eaten by cows may cause milk to 
become unfit for drinking because of toxic properties. Poison ivy 
(Rhus toxicodendron), for example, causes in cows a condition known 
as " trembles " during the continuance of which their milk is said to 
cause severe gastric symptoms with great weakness. The most promi- 
nent symptoms are pain, nausea, vomiting, constipation, and subnormal 
temperature. If the milk be boiled, the poisonous properties are de- 
stroyed. The leaves of the common artichoke are said 1 to cause ab- 
dominal pain, vomiting, and diarrhoea. 
As stated on a previous page, milk may undergo a peculiar form of 
decomposition resulting in the production of an intensely violent 
poison, a benzene derivative, known as tyrotoxicon. Fortunately, this 
is a quite uncommon change, but it betrays to the consumer no sign 
of its occurrence at the time of drinking. The effects produced are 
various, and are well illustrated by the following cases : 
Case I.-Reported by Dr. W. K. Newton and Mr. S. Wallace.2 
On August 7, 1886, 24 guests of a hotel at Long Branch, and 19 
of another at the same place were taken sick soon after supper with 
the same train of symptoms, which were nausea, vomiting, cramps and 
collapse, dryness of the throat, and burning sensation in the oesopha- 
gus ; in many cases there was absence of diarrhoea, and in several there 
was active diarrhoea and no vomiting. Many had violent vomiting fol- 
lowed by collapse, and as a rule the nausea and vomiting were per- 
sistent and obstinate and accompanied by a tendency to exhaustion 
and collapse. A week later, 30 guests of still another hotel were 
seized in precisely the same manner. The onset occurred in from one to 
four hours after eating, but in one instance the symptoms appeared 
almost immediately after drinking about a quart of milk. 
Investigation showed that the trouble was due wholly to milk, for 
only the milk drinkers were seized and those who had no other food 
were the worst sufferers. The three hotels were served by one dealer 
who made two deliveries daily. The milk of the second delivery was 
the cause of the mischief in each outbreak. It was drawn at noon, and 
without being cooled at all was carted eight miles in the heat of the day. 
The cows were healthy and well fed. In a portion of the milk that 
caused the third group of cases the presence of tyrotoxicon was 
demonstrated. 
Case II.-This was a most extraordinary outbreak limited to a 
family consisting of father, mother, son, and daughter, of whom all 
but the first mentioned died. The family physician called Professor 
V. C. Vaughan in consultation after the fourth member of the family 
was seized, and from his report of the case the following facts are 
taken. The first one seized was the father, a man of 50 years. When 
first seen he was vomiting severely, his face was flushed, and his 
temperature subnormal (96° F.). There was marked throbbing of the 
1 Milchzeitung, 1891, p. 40. 
2 Medical News, September 25, 1886, p. 343. 86 
FOODS. 
abdominal aorta, the tongue was heavily coated, and the breathing was 
very labored. The pupils were dilated, and much of the body was 
covered with a rash. The vomiting continued some hours, the vomitus 
colored with bile. The bowels had not moved, but under the influence 
of a cathartic a stool occurred on the next day. Retching and vomit- 
ing continued during that day and night, and there was persistent 
stupor. During the next three days there was but little change, and 
then began a slow recovery which required a month. 
The son, a strong young man of 18, was the next to be seized, but 
his symptoms did not appear until four days after those of his father. 
The symptoms were the same, but were more violent, and there was no 
rash. On the following evening the mother, about 45, was seized in the 
same way, and on the next, the daughter also. On the day following 
the last seizure, none of the cases showed any improvement. The tem- 
peratures were subnormal, 94 and 95. All complained of a burning 
constriction in the throat and difficult swallowing, and called frequently 
for ice. 
Two days later the mother and son died; the daughter grew worse, 
became unconscious, remained so three days, and then died. 
Post-mortem examination in the case of the daughter revealed no 
characteristic lesions to account for death. The outbreak was most care- 
fully and thoroughly investigated from every standpoint, and the con- 
clusion reached was that the whole mischief had been caused by tyro- 
toxicon. The milk was kept in a buttery which was in a most 
unsanitary condition. During three years the family had suffered fre- 
quent attacks of like character, but much less severe. Fresh milk 
placed in the buttery over night and then analyzed for tyrotoxicon 
gave unmistakable chemical and physiological evidence of this poison. 
Fresh milk inoculated with dirt from the buttery floor also developed 
it, as did also other portions treated with vomitus, stomach con- 
tents, and aqueous extract of the intestines, while a fifth specimen un- 
treated remained free from it. All the evidence in this case pointed 
to the more or less constant presence of poison in the milk, and the 
wide variation in the time of seizure in the final outbreak indicates 
that all were not affected by the same day's supply. 
Diseased Milk.-The milk of cows sick with rinderpest, foot-and- 
mouth disease, and anthrax is more or less altered in composition and 
properties, and there appears to be some evidence that it may be ac- 
tually dangerous. In rinderpest, the proteids are much increased, in 
fact, more than doubled; the mineral constituents are considerably in- 
creased, and the fat and sugar are diminished. In foot-and-mouth 
disease, the total solids are considerably increased or diminished at 
different stages, and the milk will sometimes coagulate on boiling on 
account of the excessive amount of coagulable proteids. There seems 
to be reason for the belief that this disease can be communicated to 
other animals through the agency of milk, and there is some evidence 
that the use of such milk by man will produce local effects in the 
mouth and throat. MILK AS A FACTOR IN THE SPREAD OF DISEASE. 
87 
Notter and Firth 1 mention an epidemic of sore throat at Dover in 
1884 in which there were 205 cases of vesicular eruption of the throat 
or lips, enlarged tonsils, and in most cases enlarged glands of the neck, 
all occurring within a week in persons supplied by a single dairy 
where the disease existed. 
Pott2 asserts that the unboiled milk of cows suffering from foot-and- 
mouth disease may induce a similar infection in man, and especially in 
children. 
In anthrax the milk has a bad appearance and decomposes rapidly. 
The specific organism has been isolated from it still in active condition 
by Boschetti3 as late as 14 days after it was drawn. 
The milk of cows afflicted with garget, an inflammatory condition of 
the milk ducts, is believed to have caused epidemics of gastro-intestinal 
irritation, and there is some reason to believe that it may be a common 
cause of cholera infantum. The disease is most common among cows 
kept under most unsanitary conditions. The milk of cows suffering 
from actinomycosis, particularly of those in which the udder is in- 
volved, should be avoided, although there appears to be but little di- 
rect evidence bearing upon the transmission of this disease to man by 
this means. It is certain, however, that the disease does sometimes 
occur in man, and though in the matter of transmission of disease from 
animals to man nothing should be taken for granted, it is commend- 
able in such cases of lack of positive knowledge to err on the side of 
safety and to avoid and prohibit the use of such milk. Many of our 
States and a number of foreign governments forbid the sale of any milk 
which comes from diseased cows, without specifying any of the diseases 
to which they are subject, and some forbid the feeding of such milk to 
other animals except after thorough boiling. 
The milk of a cow suffering from a specific enteritis has been re- 
ported by Gaffky4 as the cause of sickness of three persons connected 
with the Institute of Hygiene at Giessen. The symptoms included 
nausea, vomiting, diarrhoea, and mental confusion. One recovered in 
a few days, the others in about four weeks. The milk was drunk in 
the raw state. 
Concerning the agency of milk of tuberculous cows in spreading 
tuberculosis there is, as in the case of tuberculous meat, a wide diver- 
gence of opinion. There can be no doubt that the milk of such cows 
can convey the infection to other animals, but whether to man cannot 
be definitely stated, because of the impossibility of experimentation and 
since in any case of supposed transmission very many other possible 
agencies must be eliminated. It is commonly asserted that the use of 
milk from tuberculous cows is a positive danger to public health, and 
attention is directed to the persistently high rate of mortality from 
tuberculosis in all its forms among very young children, and to im- 
provement in the death rates from other causes. It is asserted that 
1 The Theory and Practice of Hygiene, London, 1896, p. 305. 
2Miinchener medicinische Wochenschrift, July 25, 1899. 
3Giornale di Medicina Veterinaria, 1891. 
4 Deutsche medicinische Wochenschrift, 1892, No. 14. 88 
FOODS. 
this condition can be explained in only one way, that is, that a very 
large proportion of market milk is derived from tuberculous cows and 
thus the bottle-fed children if at all susceptible become infected. 
There can be no doubt that much of the supply is derived from 
diseased animals and that it is largely consumed by very young infants, 
but if the use of the milk is the sole cause of the persistently high 
mortality we would naturally expect to find in the great majority of 
cases evidence of infection through the alimentary canal. But this 
evidence fails, and a majority show instead infection through the air 
passages. Yet the proportion of cases which do show primary infection 
through the alimentary canal is so high as to be decidedly striking 
and to demand most thoughtful consideration. 
There can be no doubt that the tubercle bacillus finds its way into 
milk, particularly if the udder is involved, but even when not. This 
was asserted so long ago as 1889 by Prof. H. C. Ernst,1 who, after 
a very extended inquiry, proved that the milk of cows with tubercu- 
losis in any part of the body and with no local lesion of the udder 
whatever may contain the bacillus. This has been confirmed by a 
number of more recent observations. Especially noteworthy are the 
results obtained by Drs. Rabinowitsch and Kempner2 who obtained 
positive results from inoculation experiments on guinea-pigs with the 
milk of 10 out of 15 cows that had reacted to tuberculin. Of these 
10 animals only one showed any clinical evidence of involvement of 
the udder, and only one other showed any sign of it on microscopical 
examination. Others who have obtained positive results from animals 
with normal udders include Bollinger, Dekpine, Bang, and Adami. 
As to the probable proportion of infected market milk, owing to the 
wide differences in results obtained by various investigators no definite 
statement can be given. Rabinowitsch for example, found it to be 28 
per cent.; Massone3 by inoculation experiments placed it at 9 ; Ott4 
at 11.6. Sladen 5 found that over half of the samples taken from the 
supply of the colleges at Cambridge (England) conveyed tuberculosis 
to guinea-pigs on inoculation, while Eastes6 found the bacillus in but 
11 out of 186 samples of milk which he examined. Others have ob- 
tained results anywhere within the range of 6 to 50 per cent. Doubt- 
less the differences are due to variations in local conditions, to differ- 
ences in technic, and to accidents always attending hap-hazard securing 
of any article of food in open market. 
Taking the mean of the figures given, and accepting that as a fair 
approximation of the extent to which our public supplies are infected, 
it must be agreed that if infection through milk is possible the amount 
of disease so caused must be quite small in proportion to the number 
of the population who are daily exposed to the danger. There are 
1 American Journal of Medical Sciences, November, 1889. 
2 Zeitschrift fiir Hygiene und Infectionskranklieiten, XXXI., p. 137. 
3 Annali d'lgiene Sperimentale, 1897, p. 939. 
4 Zeitschrift fiir Milch- und Fleischhygiene, 1898, No. 8. 
5 The Lancet, January 14, 1899. 
6 British Medical Journal, November 11, 1899. MILK AS A FACTOR IN THE SPREAD OF DISEASE. 
89 
but few reported cases in which the influence of other possible condi- 
tions can be so thoroughly excluded as to leave no reasonable doubt of 
the causal relation of milk. Single instances are necessarily of less 
value than groups of cases, and the latter are much less common than 
generally supposed. 
From the number available the following are selected as illustra- 
tions. Brouardel1 records the death of seven children with no heredi- 
tary taint, inmates of a convent, from tuberculosis supposedly induced 
by the use of milk from a cow with tuberculosis of the udder. An- 
other case reported by him and quoted by Freudenreich2 is one in which 
five of fourteen girls in a boarding school became infected and died. 
The milk which they had had daily came from a tuberculous cow. 
Demme3 reported as the only instances in his experience in which 
all other causes could be satisfactorily excluded, a group of four infants 
of healthy parentage fed upon uncooked milk of tuberculous cows. 
They all died of tuberculosis of the intestine, and the diagnosis was 
confirmed by autopsy. Later, he reported4 still another death from 
the same cause at four months. In this case also there was absolutely 
no family history of tuberculosis. After the confirmation of the diag- 
nosis by autopsy, the cow was slaughtered and found to be tuberculous. 
A more extensive outbreak among older children was reported by 
Ollivier to the Academy of Medicine, Paris, on February 24, 1891. A 
young woman of 21 years, of good family history, who had always 
enjoyed good health died of tubercular meningitis shortly after taking 
up her residence in a boarding house in which within a very short time 
eleven school girls had been seized with tuberculosis. It was learned 
that the milk supply was derived from a single animal which was ex- 
tensively tuberculous. Shortly afterwards, still another girl died of 
phthisis pulmonalis in the same house. 
Some of these cases, if not all, must be looked upon as very strong 
evidence that tuberculosis can be spread through the agency of milk. 
But if it is true that so large a proportion of the milk supply is from 
diseased cows, and that the disease is communicable in this way, it 
must follow that with the vast majority of drinkers of raw milk the 
bacilli perish or are discharged before they can gain entrance to the 
tissues. 
Contaminated Milk.-Milk may become contaminated with infec- 
tious matter in various ways. It may receive it from the hands, person, 
and clothing of the milkers and others by whom it is handled, whether 
they are themselves sick or convalescent or acting in the capacity of 
nurse or attendant for others ; it may acquire it from unclean vessels 
rinsed in polluted water, or from water with which it has been fraudu- 
lently mixed. Outbreaks traced to milk generally involve a consider- 
able number of persons and appear with some suddenness. In fact it is 
'Annates d'Hygiene Publique, XXIV., p. 65. 
2 Les Microbes et leur Role dans la Laiterie, Paris, 1894, p. 45. 
3 Jahresbericht uber die Thatigkeit des Jenner' schen Kinderspitals in Bern, 1882, 
p. 48. 
4 Ibidem, 1886, p. 20. 90 
FOODS. 
the simultaneous appearance of a large number of cases that draws 
attention to the water supply or milk as a common cause. Sporadic 
cases are rarely traceable to milk. 
On account of the danger of specific contamination of milk, no per- 
son sick with or convalescent from infectious disease, and no person 
having to do with the care of others so afflicted, or with the disposal 
of their excreta, or with the washing of their linen, should be allowed 
to handle milk destined for the use of others. Public authorities are 
rapidly becoming awakened to the importance of restrictive measures 
in this regard, and in many communities it has been made a criminal 
offense to fail to give notice of the presence of cases of infectious disease 
at the place of production of milk or among those engaged in its dis- 
tribution and sale. 
Diphtheria.-A large number of epidemics have been reported in 
which a positive connection with the milk supply appears to have been 
fairly well made out, but so far as is known there is no connection 
between any disease of the cow and that which we know as diphtheria, 
although a number of outbreaks of diphtheria have been reported as 
traced to garget. The specific organism of diphtheria may be intro- 
duced into milk from the discharges of persons employed in the hand- 
ling and distribution of milk before they have thoroughly recovered 
from the disease. Dr. J. W. H. Eyre1 found the bacillus of diphthe- 
ria in samples of milk supplied to a large school where a number of 
cases of the disease had occurred. The organisms gave the usual char- 
acteristics and no reason appears for doubting their identity. 
Schottelius2 proved that the bacillus of diphtheria can grow very 
rapidly in raw milk, less so in sterilized milk at ordinary temperature, 
but very much better at 37° C. Inasmuch as the organism may per- 
sist for long periods after the disease has apparently disappeared and 
may be present in the throats of persons in apparent health, it need 
not excite wonder when it is reported present in milk. 
Cholera.-Undisputed evidence of the connection between milk and 
Asiatic cholera is not very common. There is some disagreement as to 
the viability of the cholera organisms in milk ; thus, Hesse3 found that 
fresh, raw milk exerts a destructive influence on them ; that, in fact, 
they begin to die as soon as they are mixed with it. He found that 
they die at ordinary room temperature within 12 hours, and at incu- 
bator temperature in from 6 to 8 hours. The age of cultures, the 
nature of the culture media, and the addition of the latter to the milk 
with the bacteria appear not to affect the result. Sterilized milk was 
found to be a better culture medium. Basenau 4 disagrees with Hesse. 
He found that uncooked milk does not kill the organisms in 10 hours, 
that they are active after 38 hours, and that up to the point of coagu- 
lation of the milk they increase considerably in number. He found 
that in polluted milk they remain active at least 32 hours at different 
'British Medical Journal, Sept. 2, 1899. 
* Centralblatt fiir Bakteriologie, Abth. I., XX., No. 25. 
3Zeitschrift fiir Hygiene und Infectionskrankheiten, XVII., p. 238. 
4 Archiv fiir Hygiene, XXIII., p. 170. MILK ^45 A FACTOR IN THE SPREAD OF DISEASE. 
91 
temperatures, (room temperature, 24°, and 37° C.), and that they re- 
main active even after the milk has coagulated. 
Weigmann and Zirn 1 found that the length of time they remain ac- 
tive depends upon the ratio they bear to the number of other organ- 
isms present, and that in order to have any considerable lasting power 
they would have to be added to milk in exceedingly large numbers. 
The evidence that cholera can be disseminated through the agency 
of milk is exceedingly limited, and about the only case free from doubt 
is that recorded by Simpson2 who relates that nine cases of cholera 
broke out suddenly on a ship in the harbor of Calcutta, ten men of 
whose crew had obtained milk from a native. One drank but little 
and escaped, four died of undoubted cholera, and five were very sick 
with diarrhoea. Eight others who used condensed milk only, and 
those who used no milk whatever were unaffected. It was learned 
that the vendor had diluted the milk about one-fourth with water from 
a tank to which dejections from cholera patients gained access and in 
which their washing was done. 
Scarlet Fever.-In December, 1885, occurred what has become com- 
monly known as the Hendon outbreak of scarlet fever, due to a disease 
of cows, and since that time a number of other epidemics have been 
traced apparently to a common milk supply. In the Hendon case a 
number of cows were or had been sick with an infectious eruption of 
the udders, and there can be no doubt that the disease under considera- 
tion was spread through the agency of milk coming from this dairy; 
but other cows having the same disease caused no trouble, and the pos- 
sibility of contamination from human sources could not be absolutely 
excluded. A number of other outbreaks of the disease । have been 
somewhat doubtfully ascribed to similar teat eruptions, but in no case 
is the evidence in any way conclusive. On the other hand, there is 
undoubted evidence that the disease has many times been spread by 
milk from farms where children and others were sick with it. 
In tracing epidemics of this and other diseases to a common cause 
there is always danger of lending undue importance to coincidence and 
of coming thereby to unwarranted conclusions. As an illustration the 
following case may be cited. In 1897, in one of the out-lying wards 
of Boston, a large number of cases of scarlet fever occurred with some 
suddenness among children chiefly of the well-to-do class. Naturally 
there was much disturbance of the public mind, and an investigation 
was immediately undertaken. It was ascertained that nearly all of the 
families concerned were supplied by one milkman who raised all the 
milk which he handled, and the responsibility for the outbreak was at 
once laid at his door. 
His premises were examined by the health authorities and found to 
be in excellent condition. No case of disease or indisposition had oc- 
curred in his family or among his help within a number of months, nor 
had he or anybody on the place, so far as could be ascertained, been 
1 Centralblatt fiir Bakteriologie, etc., 1894, No. 8. 
2 Indian Medical Gazette, May, 1887. 92 
FOODS. 
in contact with any case of scarlet fever or of any other infectious dis- 
ease. His cows were examined by a thoroughly competent veterinarian 
and pronounced in every respect healthy. Nevertheless, public excite- 
ment ran so high that his business fell away until his route was very 
much reduced. Had a single cow shown the slightest evidence of an 
eruptive disease of the teats the epidemic might have been hailed as 
another Hendon outbreak and quoted in sanitary history as a note- 
worthy example. 
The fact that the great majority of cases occurred among his patrons 
was easily explainable for he was known to be a careful, cleanly, 
honest dealer, and was, therefore, the very sort of man to attract the 
particular class whose homes were invaded. The children affected be- 
longed to closely affiliated groups of playmates. Further investigation 
revealed the fact that the first case was of a lad whose family was not 
among the customers of the suspected dealer, and that immediately be- 
fore taking to his bed he had been playing with a number of those who 
were among the next to be seized. These in their turn had been asso- 
ciated with others, and so the infection had spread. Thus what might 
have served as a most useful example of a milk-borne epidemic of 
scarlet fever fell to the ground, and the unfortunate dealer was absolved 
from responsibility. 
Typhoid Fever.-There can be no doubt that in the spread of typhoid 
fever milk plays a part only second in importance to that of drinking 
water. A very great number of epidemics have been traced beyond a 
possibility of dispute to milk coming from farms where cases of the 
disease have occurred. The contamination is brought about by the 
hands of the milkers or other handlers, who in addition assist in nurs- 
ing, or by the addition of infected wrater, or through washing pails, 
cans, and other vessels in such water. 
From time to time tabulated analyses of outbreaks supposed to be due 
to contaminated milk have been published, but a very large proportion 
of the cases included are based on very insufficient evidence, some- 
times exceedingly slight, such as that a cow had drunk from water into 
which drainage from the barnyard had had access. But within recent 
years a number of extensive epidemics in this country and elsewhere 
have been traced with as much definiteness to the milk supply as have 
others to the water supply, and with the same and only defect that the 
bacteriological proof has been lacking. As is the case when outbreaks 
occur from polluted water, when attention is drawm to the possible 
cause the bacteriological evidence is no longer obtainable, the condi- 
tions having changed during the period of incubation. 
The State Board of Health of Massachusetts has traced a num- 
ber of extensive epidemics to the use of polluted milk, but in no in- 
stance has the organism been found in the milk. In the city of Bos- 
ton also, where the local authorities keep a constant eye on the reports 
of typhoid fever cases with particular reference to the possibility of 
dissemination through milk, a number of small outbreaks have been 
definitely traced to milk supplies derived from small farms where MILK AS A FACTOR IN THE SPREAD OF DISEASE. 
93 
persons sick with the disease were nursed by those who had milked 
the cows and handled the milk, and in these instances also the bac- 
teriological evidence is lacking. 
That the organism can retain its vitality in milk and even in sour 
milk, has been definitely settled. Hein found the organism in sour 
milk at 13-18° C. after thirty-five days, but not after forty-eight. 
Hesse has found it in sterilized milk after four months. Drs. 
Fraenkel and Kister1 having reason to believe that the unusual 
amount of typhoid fever at Hamburg during the summer of 1897 was 
due in part to infected buttermilk, undertook the study of the ques- 
tion whether the B. typhosus can exist in that fluid, concerning which 
point there had been more or less of conflicting testimony. Obtaining 
some samples, they first investigated the number and identity of the 
contained bacteria and learned that while the number varied widely, 
the species were always about the same. Finding no pathogenic or- 
ganisms, they sterilized specimens in test-tubes a half hour a day for 
three days, then planted the typhoid bacillus in them and kept them 
at different temperatures; on ice and at 22° C. and 37° C. 
Loops were taken from each from time to time and planted and each 
yielded positive results. The specimen kept at room temperature was 
under observation nine days; the others were not examined after the 
third. Then specimens of fresh buttermilk containing all its bacteria 
were planted and kept under the same conditions and from them the 
same results were obtained. Yet there was this difference, that there 
was always a diminution in the number of the pathogenic organisms, 
and this was the more marked and sometimes very rapid with increas- 
ing temperatures. 
Cholera Infantum.-In every large community it has become cus- 
tomary to expect as a normal condition a large death rate among chil- 
dren with the advent of hot weather. This increased death rate is 
limited very largely to the very early age periods and to children 
fed on cow's milk, and while children of the poor are the ones most 
commonly afflicted, those of the well-to-do are by no means free. 
During the siege of Paris the infant mortality was reduced to a half of 
its yearly average although the general death rate had doubled. This 
unusual condition was attributed, no doubt correctly, to the fact that 
mothers were obliged to nurse their infants when they could on ac- 
count of the great scarcity of cow's milk and other foods. 
The common milk bacteria are ordinarily quite harmless, but it ap- 
pears that some species under certain conditions produce toxins in suf- 
ficient amounts to cause gastric and intestinal disturbances. Accord- 
ing to Baginsky 2 a large part of the annual amount of cholera infantum 
is due to these products. 
Dr. E. W. Hope 3 investigated over a thousand cases of autumnal 
diarrhoea and found that of 233 deaths of infants under three months 
1Miinchener medicinische Wochenschrift, February 18, 1898. 
2 Berliner klinische Wochenschrift, 1894, Nos. 43 and 44. 
3 Public Health, July, 1899. 94 
FOODS. 
only sixteen had not received other than their natural food. That is 
to say, the deaths among artificially fed children under three months 
of age were fifteen times as numerous as among those nursed. In no 
less than 22 per cent, of the whole number of fatal cases other members 
of the household had suffered from diarrhoea. The most striking in- 
stance of the communicability of the disturbance was that at an in- 
fants' home in which were ten children under the age of five months, 
all in perfect health. An infant of two months was admitted in July 
with vomiting and diarrhoea, and within a few days six of the other 
infants and the nurses were sick in the same way. The other four 
children were taken away at once. The admitted child and the six that 
became infected all died. The four that were moved out were saved. 
Bacteriological examination of milk has shown the presence of ex- 
tremely active organisms, including the B. enteritidis sporogenes of 
Klein1 which has been found by its discoverer in the ileum contents of 
children and adults with diarrhoeal conditions, but not in a condition of 
health. It has been found by Andrewes in the discharges of cases of 
sporadic diarrhoea of adults and by Klein in three different outbreaks 
among the inmates of a single hospital. It is a common saprophyte 
found in sewage, in polluted rivers, and in manured garden soil, and is 
very commonly detected in milk the use of which has not been followed 
by untoward results. Under certain unknown conditions it becomes 
highly pathogenic, and recent milk cultures are intensely virulent when 
inoculated subcutaneously in guinea-pigs. 
Andrewes2 has described the third of the series of outbreaks referred 
to above, in which the offending cause was found to be rice pudding 
made with milk. The first and second outbreaks, in which no one article 
of food could be incriminated, involved respectively 59 and 146 patients; 
the third involved 86. In all three the great majority of the attacks 
were mild, but in some of the more severe cases the discharges con- 
tained mucus and blood. In all three the organism was found in the 
stools, and in the second it was found in the milk given out on the 
previous day. In the third it was impossible to obtain any of the milk, 
but the pudding made with it yielded the organisms in spite of the 
heat to which the compound had been subjected during its preparation. 
It was found by direct experiment that the interior of such a pudding 
did not attain a temperature above 98° C. during cooking, a tempera- 
ture below that necessary for the destruction of the spores which are 
among the most resistant known. 
Analysis of Milk. 
For ordinary purposes of determining the quality of milk, the pres- 
ence or absence of added water, and whether it has been robbed of its 
cream, a complete chemical analysis is by no means always necessary, 
since much may be learned from simple inspection by means of the 
1 Centralblatt fur Bacteriologie, etc., XXII., Abth. I., Nos. 20 and 21, XXIII., 
Abth. I., No. 13. 
2 The Lancet, Jan. 7, 1899. ANALYSIS OF MILK. 
95 
lactodensimeter, and the lactoscope. The lactodensimeter (Fig. 2), or 
lactometer, is merely a large hydrometer with a stem graduated to show 
specific gravities ranging from 1.015 to 1.040. The lactoscope, in- 
vented by Professor Feser, is an instrument designed to indicate the 
approximate fat content of milk. It consists of a glass cylinder into 
the base of which a smaller cylinder of white glass closed at the top 
and mounted on a metallic base is fitted. The larger cylinder is grad- 
uated along the side; the smaller one bears a number of black hori- 
zontal lines. The instrument is shown in Fig. 1. 
The principle of the instrument is based upon the fact 
that the opacity of milk is due 
mainly to the fat globules in sus- 
pension, and that, therefore, the 
richer a milk is in fat, the greater 
is its opacity, and the more it must 
be diluted to reduce the opacity to 
such an extent as to permit the pas- 
sage of light. 
The method of use is as follows : 
Four cc. of the specimen are de- 
livered from a pipette into the 
cylinder through the opening in its 
upper end, and water is then added 
in small portions and thoroughly 
mixed by inversion of the instru- 
ment, the orifice being kept closed 
by the tip of the forefinger. As soon 
as the successive additions of water 
have reduced the opacity of the mix- 
ture to such an extent that the 
black lines on the white cylinder 
can be discerned so distinctly that 
they can be counted, the height of 
the liquid on the scale is noted and 
the percentage of fat indicated is 
read. Four cc. of skimmed milk 
will require so little water that 
when the lines can be seen the level 
of the mixture will be very low on 
the scale, while with rich milk it 
will be correspondingly high, and with cream the whole cylinder will 
be filled and even then the lines cannot be made out. 
Control analyses show that the instrument gives very fairly accu- 
rate results. Neither of these two instruments alone can be depended 
upon to indicate the true quality of milk excepting in the case of sam- 
ples which are either very good or very bad. The specific gravity 
alone is especially fallacious as a guide for the following reasons. The 
specific gravity of normal milk at 59° F. ranges between 1.029 and 
Fig. 2. 
Fig. 1. 
Feser's lactoscope. 
Lactoden- 
simeter. 96 
FOODS. 
1.034. The removal of cream causes it to rise; the addition of water 
causes it to fall. A normal milk when robbed of its cream may show 
a specific gravity of 1.036, and then if a small amount of water is added, 
the gravity is brought down to 1.032, that is to say, within normal 
limits. Thus a milk after being doubly treated so as to reduce its 
nutritive value may show a normal specific gravity, and, on this test 
alone, be classed as pure. Nor is this the only objection to a system 
of inspection of this most important food based upon the use of the 
lactometer, since milks exceptionally rich in fat have a specific gravity 
below the normal and thus may be condemned as watered. 
The lactoscope alone is also not to be depended upon in all cases, 
since a milk which shows a normal content of fat may be one of con- 
siderable richness in that constituent and extensively watered. Thus 
a specimen containing originally 4.50 per cent, of fat may be watered 
very considerably and yet show 3.75 per cent, by the lactoscope. 
By combining the use of both instruments, however, the fallacies of 
either are exposed. A normal specific gravity shown by the one and a 
normal fat content revealed by the other will indicate that even if the 
milk has been tampered with it yet possesses average richness. A normal 
specific gravity with a low percentage of fat will indicate skimming and 
watering ; low specific gravity with normal or low fat, watering; and 
high specific gravity with low fat, skimming. Low specific gravity with 
very high fat will indicate unusual richness ; thus cream has a very low 
specific gravity due to its preponderance of fat. As a test of the accuracy 
of this process of examination the author 1 caused to be analyzed under 
his supervision 1,714 specimens which appeared by these tests to be of 
good quality, and of this number but 8 were found to have deviated 
materially from the statute requirement of 13 per cent, of total solids. 
Determination of Specific Gravity.-In taking the specific gravity 
by means of the lactodensimeter, the milk is thoroughly mixed in 
order to ensure homogeneity by pouring from one vessel into another, 
a cylinder of sufficient height to allow the instrument to float freely is 
filled, and the instrument carefully inserted, not dropped, down to the 
bottom and then released. When it comes to rest the reading of the 
stem at the level of the surface of the liquid is noted. It must be 
borne in mind that air bubbles are retained rather tenaciously by the 
milk and tend to lower the density, and, therefore, in mixing the milk 
too violent action must be avoided, and a short time should be allowed 
for those present to rise to the surface and escape. 
Inasmuch as the gravity varies with the temperature, and the in- 
strument is graduated for 59° F., either the milk must be brought to 
that temperature or a correction must be made according to the devia- 
tion above or below that point. If the milk is colder, the reading 
will be too high, and if warmer, too low. It is more convenient to 
make a correction for temperature than to heat or cool the specimen 
to the normal point. The deduction of a half degree of gravity for 
each five degrees of temperature below 59°, or the addition of the 
1 Thirty-first Annual Report of the Inspector of Milk, Boston, 1889, p. 11. SPECIFIC GRAVITY OF MILK. 
97 
Specific Gravity. 
Degrees of Fahrenheit's Thermometer. 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
53 
53 
54 
65 
56 
57 
58 
59 
60 
1.0270 
257 
257 
258 
258 
259 
259 
260 
260 
261 
261 
262 
263 
264 
265 
266 
266 
267 
268 
269 
270 
271 
1.0275 
261 
261 
262 
262 
263 
263 
264 
264 
265 
265 
266 
267 
268 
269 
270 
271 
272 
273 
274 
275 
276 
1.0280 
266 
266 
267 
267 
268 
268 
269 
269 
270 
270 
271 
272 
273 
274 
275 
276 
277 
278 
279 
280 
281 
1.0285 
270 
270 
271 
271 
272 
273 
273 
274 
275 
275 
276 
277 
278 
279 
280 
281 
282 
283 
284 
285 
286 
1.0290. 
275 
275 
276 
276 
277 
278 
278 
279 
280 
280 
281 
282 
283 
284 
285 
286 
287 
288 
289 
290 
291 
1.0295 
279 
279 
280 
280 
281 
282 
282 
283 
284 
284 
285 
286 
287 
288 
289 
291 
292 
293 
294 
295 
296 
1.0300 
284 
284 
285 
285 
286 
287 
287 
288 
289 
289 
290 
291 
292 
293 
294 
296 
297 
298 
299 
300 
301 
1.0305 
288 
288 
289 
290 
290 
291 
292 
293 
293 
294 
295 
296 
297 
298 
299 
301 
302 
303 
304 
305 
306 
1.0310 
293 
293 
294 
295 
295 
296 
297 
298 
298 
299 
300 
301 
302 
303 
304 
306 
307 
308 
309 
310 
311 
1.0315 
298 
298 
299 
300 
300 
301 
302 
303 
303 
304 
305 
306 
307 
308 
309 
311 
312 
313 
314 
315 
316 
1.0320 
303 
303 
304 
305 
305 
306 
307 
308 
308 
309 
310 
311 
312 
313 
314 
316 
317 
318 
319 
320 
321 
1.0325 
307 
307 
308 
309 
310 
311 
311 
312 
313 
314 
315 
316 
317 
318 
319 
321 
322 
323 
324 
325 
326 
1.0330 
312 
312 
313 
314 
315 
316 
316 
317 
318 
319 
320 
321 
322 
323 
324 
326 
327 
328 
329 
330 
331 
1.0335 
316 
316 
317 
318 
319 
320 
320 
321 
322 
323 
324 
325 
326 
328 
329 
330 
331 
333 
334 
335 
336 
1.0340 
321 
321 
322 
323 
324 
325 
325 
326 
327 
328 
329 
330 
331 
333 
334 
335 
336 
338 
339 
340 
341 
1.0345 
325 
325 
326 
327 
328 
329 
329 
330 
331 
332 
334 
335 
336 
338 
339 
340 
341 
343 
344 
345 
346 
1.0350 
330 
330 
331 
332 
333 
334 
334 
335 
336 
337 
338 
339 
341 
342 
343 
345 
346 
347 
349 
350 
351 
Table Showing Specific Gravity of Milk at 59° F. for Temperatures Below 60° F. 98 
FOODS. 
Specific Gravity. 
Degrees of Fahrenheit's Thermometer. 
60 
61 
62 
63 
64 
65 
66 
67 
68 
69 
70 
71 
72 
73 
74 
75 
76 
77 
78 
79 
80 
1.0270 
271 
273 
274 
275 
277 
278 
279 
281 
282 
283 
284 
286 
287 
288 
289 
291 
292 
293 
294 
296 
297 
1.0275 
276 
278 
279 
280 
282 
283 
284 
286 
287 
288 
289 
291 
292 
293 
294 
296 
297 
298 
299 
301 
302 
1.0280 
281 
283 
284 
285 
287 
288 
289 
291 
292 
293 
295 
296 
297 
299 
300 
301 
303 
304 
305 
307 
308 
1.0285 
286 
288 
289 
290 
292 
293 
294 
296 
297 
298 
300 
301 
302 
304 
305 
306 
308 
309 
310 
312 
313 
1.0290 
291 
293 
294 
295 
297 
298 
299 
301 
302 
303 
305 
306 
308 
309 
311 
312 
313 
315 
316 
318 
319 
1.0295 
296 
298 
299 
300 
302 
303 
304 
306 
307 
308 
310 
311 
313 
314 
316 
317 
318 
320 
321 
323 
324 
1.0300 
301 
303 
304 
305 
307 
308 
309 
311 
312 
313 
315 
316 
318 
319 
321 
322 
323 
325 
327 
328 
330 
1.0305 
306 
308 
309 
310 
312 
313 
314 
316 
317 
318 
320 
321 
323 
324 
326 
327 
328 
330 
332 
334 
335 
1.0310 
311 
313 
314 
316 
317 
319 
320 
322 
323 
324 
326 
327 
329 
330 
332 
333 
334 
336 
338 
340 
341 
1.0315 
316 
318 
319 
321 
322 
324 
325 
327 
328 
329 
331 
332 
334 
335 
337 
338 
339 
341 
343 
345 
346 
1.0320 
321 
323 
324 
326 
327 
329 
330 
332 
333 
335 
336 
338 
339 
341 
343 
345 
346 
347 
349 
351 
352 
1.0325 
326 
328 
329 
331 
332 
334 
335 
337 
338 
340 
341 
343 
344 
346 
347 
349 
350 
352 
354 
356 
357 
1.0330 
331 
333 
334 
336 
337 
339 
340 
342 
343 
345 
346 
348 
350 
351 
353 
355 
356 
358 
360 
362 
363 
1.0335 
336 
338 
339 
341 
342 
344 
345 
347 
348 
350 
351 
353 
355 
356 
358 
360 
361 
363 
365 
367 
368 
1.0340 
341 
343 
344 
346 
347 
349 
350 
352 
353 
355 
356 
358 
360 
361 
363 
365 
366 
368 
370 
372 
373 
1.0345 
346 
348 
349 
351 
352 
354 
355 
357 
358 
360 
361 
363 
365 
366 
368 
370 
371 
373 
375 
377 
378 
1.0350 
351 
353 
354 
356 
357 
359 
360 
362 
363 
365 
366 
368 
370 
371 
373 
375 
376 
378 
380 
382 
384 
Table Showing Specific Gravity of Milk at 59° F. for Temperatures Above 60° F. ANALYSIS OF MILK. 
99 
same amount for each four degrees above 59° will be found to be ap- 
proximately accurate corrections. 
The preceding tables give the correct specific gravity for each degree 
from 1.027 to 1.035 at all temperatures from 40 to 80° F. In making 
use of them, find the apparent specific gravity in the left-hand column 
and observe the figures in the same line at the column 
headed by the figure corresponding to the temperature of 
the sample. Example.-A specimen with a temperature 
of 47° F. has an apparent specific gravity of 1.034; in 
the line of 1.034 under the column headed 47 we find 
the figures 326 ; the correct specific gravity is, then, 
1.0326, instead of 1.034. 
Determination of Fat.-For the accurate determina- 
tion of fat several methods are in use including the fol- 
lowing : 
1. The Paper-coil Extraction Method.-This process 
requires strips of thick filter paper, free from substances 
soluble in ether and alcohol, about 6.25 by 62.5 cm., and 
a Soxhlet extraction apparatus. The most approved 
form of the latter consists of three separate pieces 
which fit together by ground-glass joints. (See Fig. 3.) 
The top and bottom pieces are respectively an upright 
Liebig condenser and a flask. The middle piece, which 
is the part in which the extraction process occurs, con- 
sists of a glass cylinder, closed at the bottom, from which 
a narrower cylinder with open end projects downward. 
The two cylinders are connected by a side tube which 
opens into the upper portion of each and also by a siphon 
which opens from the side of the bottom of the larger 
cylinder, extends upwards, then turns upon itself, pierces 
the middle part of the wall of the lower cylinder and 
terminates within and just below its lower end. 
When in use, the substance to be extracted is placed 
within the upper cylinder upon the bottom of which is 
placed a wad of absorbent cotton, which prevents the 
entrance of solid particles to the siphon tube, or it is 
confined within a cartridge of thick filter paper which 
fits loosely within the cylinder. When the cartridge is 
used it is best to plug its open end with absorbent cotton, 
in order to prevent the escape of fine particles of the con- 
tained substance by floating in the extracting medium. 
The three separate parts are joined together and then mounted on a 
waterbath. The ether or other extracting medium is contained in the 
flask which has been accurately weighed. The heat of the water-bath 
causes the ether to volatilize, and the vapor passes upward through the 
side tube into the extractor and thence to the condenser, where, com- 
ing in contact with the cold surface of the inner tube thereof, it con- 
denses and falls upon the substance to be extracted. 
Fig. 3. 
Soxhlet extrac- 
tion apparatus. 100 
FOODS. 
As the process continues the condensed liquid accumulates and grad- 
ually rises until it reaches the bend of the siphon which, when full, 
begins to act and discharges downward into the flask until the entire 
liquid has been returned to its starting point. During its accumula- 
tion it acts upon the substance within the cylinder and extracts more 
or less of the fat or other substance, as the case may be, which is car- 
ried in solution into the flask. The volatilization continues and the 
process is repeated again and again as long as is necessary, and in 
this way the whole of the extracted matter is finally within the flask, 
since, being itself non-volatile, it remains behind, while the liquid by 
which it is extracted is sent continually upon its errand. 
On the completion of the process the ether is again sent up into the 
cylinder, and before it reaches the level of the siphon the flask is dis- 
jointed. The remaining ether is cautiously expelled and the flask 
with its contents placed in an air-bath maintained at 100° C. until its 
weight is constant. The increase in the weight of the flask represents 
the amount of matter extracted. 
In determining the fat of milk by this process the method is as fol- 
lows : To one of the strips of filter paper, made into a coil, a definite 
weight of milk, about 5 grams, is applied in either of two ways. A 
small beaker containing about the required amount is weighed and then 
the coil is thrust into it, kept there until nearly the whole has been 
absorbed, and then carefully withdrawn and placed dry edge down- 
ward upon a sheet of glass. The beaker is then weighed again and 
the loss in weight, which represents the amount of milk absorbed, is 
noted. Or the beaker containing the milk and a small pipette is 
weighed, and then the necessary amount of milk is transferred to the 
coil from the pipette after which operation the weight of the beaker, 
pipette, and the remaining milk is noted, and the difference set down 
as the weight of the milk absorbed. The coil is then dried in an air 
bath at 100° C. for an hour or more, at the expiration of which time 
it is ready for insertion into the extractor. 
After it has been acted upon by the ether about a dozen times, the 
flask is detached and treated as above mentioned. After being allowed 
to cool the weight is noted and the percentage of fat calculated arith- 
metically. 
Example.-The amount of milk absorbed by the coil was 4.950 
grams. The increase in the weight of the flask was 0.173 gram. 
Then the amount of fat present in the sample is obtained by the equa- 
tion, 4.95 : 0.173 : : 100 : x, wherein x = 3.49. 
2. The Werner-Schmidt Method.-In this process equal volumes of 
milk and hydrochloric acid, about 10 cc. of each, are mixed together 
in a test tube and boiled for about a minute and a-half, or heated in 
the water bath or steam bath until the mixture is dark brown in color. 
It is then cooled, and the mixture is shaken with 30 cc. of ether. 
When the two liquids have separated the supernatant ether is with- 
drawn by means of a pipette or blown out with the assistance of a 
double tube such as is used in wash-bottles, the delivery tube extend- PLATE III. 
Babcock Flask, showing Fat in Neck. ANALYSIS OF MILK. 
101 
ing into the ether layer very nearly as far as the line of demarkation 
between the ether and the acid mixture. 
The operation is repeated with several fresh smaller portions of 
ether, and the whole of the ether used is then collected in a weighed 
flask. The ether is then distilled oif, and the flask with its residuum 
of fat is heated to constant weight in an air bath, cooled, and weighed. 
The process may be considerably shortened by treating the milk in 
a graduated tube and, after thorough shaking with ether, removing an 
aliquot part of the latter by means of a pipette and evaporating to dry- 
ness. From the weight of this residue the amount of fat in the whole 
volume of ether can be readily determined. 
Since the milk taken is measured and not weighed a correction 
must be made for gravity. 
Example.-Amount of milk used = 10 cc. Sp. gr. of specimen 
= 1.032. Weight of milk used = 1.032 x 10 = 10.32 grams. 
Amount of fat found = 0.397 gram. Percentage of fat in the original 
milk = x in the equation, 10.32 : .397 : : 100 : x. x = 3.84. 
3. The Babcock Centrifugal Method.-In this process equal volumes 
of milk and strong sulphuric acid are mixed together in flasks of special 
design with narrow graduated necks, and then whirled in a centrifugal 
machine for a definite length of time. On the completion of the proc- 
ess, the details of which are given below, the fat in a pure condition is 
within the graduated neck and the percentage is read directly off. 
The kind of flask used is shown in Plate III. It has a capacity of 
about 40 cc. The graduated portion of the neck has a capacity of 2 
cc. The details are as follows : 17.6 cc. of the milk are first measured 
by means of a pipette and introduced into the flask. Then an equal 
volume of sulphuric acid, specific gravity 1.800, is added, and the two 
liquids are thoroughly mixed by gentle rotary motion. The flask is 
then placed in a centrifugal machine made especially for the purpose, 
and whirled for five minutes, at the expiration of which time hot water 
is added up to the beginning of the neck. It is then whirled again for 
two minutes, and more hot water is added so as to bring the fat layer 
well up into the neck. After further whirling for one minute the 
depth of the fat layer is determined by reference to the scale. 
This process gives sufficiently accurate results for all practical pur- 
poses and is in common use at experiment stations in this country. It 
is much used at creameries for determining the butter value of milk sent 
in from the surrounding country. 
The employment of sulphuric acid having a higher specific gravity 
than that given, say 1.820, is objectionable in that it frequently hap- 
pens that it is impossible to obtain a clear fat layer. The fat itself 
may be turned a very dark color, and the sugar of the milk may be 
attacked to such an extent that charred portions of it will separate and 
accumulate within and beneath the column of fat and prevent a satis- 
factory reading. If the acid used is weaker than 1.80 the casein may 
not all be held in solution and portions of it may mingle with the fat 
and destroy the accuracy of the test. 102 
FOODS. 
In Plate III. is shown the fat layer in the stem as it should be, free 
from alteration of color and from charred sugar and particles of casein. 
It will be observed that the line of demarkation between the water and 
the fat in the stem is very sharp. For cream a flask with a much 
broader neck is employed. 
4. The Babcock Asbestos Method.-In this method the dried total 
solids obtained by the method described below (No. 2) are extracted 
in a Soxhlet extraction apparatus. 
Determination of Total Solids.-1. Weigh into a flat-bottomed plat- 
inum dish of about 2 inches (5 cm.) diameter, 5 grams of milk. Place 
on a water-bath for an hour and a-half. Remove to a hot-air bath 
maintained at 100° C. until its weight is constant. Cool in a desic- 
cator and weigh. The difference between this weight and that of the 
dish alone represents the total solids of the amount of milk taken, and 
multiplied by 20 expresses the percentage of total solids in the sample. 
If for any reason it is desired to use the total solids for extraction in 
the Soxhlet apparatus, the dish may be partly filled before weighing 
with fine, clean, dry sand, or with freshly ignited woolly asbestos. 
One objection to the use of the total solids in this way is that it is 
extremely difficult to remove the whole amount from the dish, to the 
sides and bottom of which a portion will adhere with great tenacity, 
and can only be removed by burning. To obviate this difficulty Dr. 
C. L. Spaulding has suggested the lining of the platinum dish with 
very thin tinfoil, which after the weight of the total solids has been 
noted, is withdrawn with the sand or asbestos and with it inserted into 
the extraction apparatus. 
The residue of the milk dried in the dish alone without sand or 
asbestos was formerly used for the determination of fat by the Wanklyn 
process, which consists in filling the dish with freshly distilled naphtha 
or with ether, and allowing it to act upon the residue and dissolve out the 
fat, several portions being used, after which the dish is again dried and 
weighed, and the loss in weight taken as the measure of the fat con- 
tained. Inasmuch as the solvent cannot penetrate the horny layer 
which forms on the bottom of the dish, not all the fat can be thus 
extracted, and the figures obtained are ordinarily about 0.5 too low. 
2. The Babcock Asbestos Method.-In this process the milk is 
weighed into a cylinder of perforated metal or into a filter paper cart- 
ridge filled loosely with freshly ignited woolly asbestos, subjected 
to a temperature of 100° C. until the weight is constant, and then 
cooled and weighed. The gain in weight represents the total solids of 
the amount of milk taken. The cylinder can then be slipped into the 
extraction apparatus and used for the determination of fat. 
3. Determination of Total Solids by Formula.-Knowing the correct 
specific gravity and the amount of fat, it is possible to determine fairly 
accurately the amount of total solids by the use of the formula of 
Hehner and Richmond. This formula is as follows: F= 0.859 T 
- 0.2186 G, in which F represents fat, T the total solids, and G 
the figures of the specific gravity beyond the first decimal place. ANALYSIS OF MILK. 
103 
Example.-The specific gravity of a specimen of milk is found to 
be 1.030, and its fat content 3.95. Then applying the formula, we 
have 
3.95 = 0.859 T- (0.2186 X 30) or 
3.95 = 0.859 T- 6.558 or 
0.859 T = 6.558 + 3.95 = 10.508, and T = 12.23. 
In other words, multiply 0.2186 by the figures expressing specific 
gravity, add the percentage of fat to the product, and divide the result 
by 0.859. 
The formula may also be used to determine the percentage of fat, 
the specific gravity and total solids being known. 
Determination of Milk Sugar.-The amount of lactose may be de- 
termined either chemically or by means of the polariscope. 
1. Method by Fehling Solution.-Reagents required, (a) Solution A. 
Dissolve 34.639 grams of pure sulphate of copper in distilled water 
and dilute to a liter. (6) Solution B. Dissolve 173 grams of potas- 
sium sodium tartrate (Rochelle salt) in distilled water, add 100 cc. of 
sodium hydrate solution of 1.393 sp. gr., and dilute the mixture with 
distilled water to a liter. 
In making a determination, 10 cc. of each solution are mixed in a 
boiling flask of about 300 cc. capacity. The amount of copper con- 
tained in 10 cc. of solution A requires for its reduction .050 gram 
dextrose, or 0.0667 gram lactose. 
Process.-Into a porcelain evaporating dish of suitable size, dis- 
charge from a pipette 25 cc. of milk. Add three or four times as much 
water and heat to 40° C. Add acetic acid, a drop at a time, with 
constant stirring until the mixture separates into curds and a fairly 
clear whey. Transfer the whole to a graduated 500 cc. flask, and 
dilute with water to the 500 mark. Filter a portion through a dry 
filter and use the filtrate for titration. Dilute the mixed reagents in the 
boiling flask with water and boil over a Bunsen flame. From a bur- 
ette graduated in tenths add the filtrate from the curds a little at a time 
and continue the boiling after each addition. As the blue color begins 
to appear faint the addition must be made cautiously in order not to 
overstep the end reaction. As soon as the blue color is completely 
discharged, note the reading of the burette. 
The calculation is exceedingly simple. Since 0.0667 gram of lac- 
tose is required to reduce the copper in the reagent, it follows that 
that amount of the substance is contained in the number of cc.'s of the 
whey used, and the percentage is obtained by the application of the 
rule of three. 
Example.-The color is discharged by 24.3 cc. of the diluted 
whey. Then in the whole amount of milk taken the amount of sugar 
will be x in the equation 24.3 : 0.0667 :: 500 : x. x - 1.372. The 
amount of milk taken was 25 cc., hence in 100 cc. the amount would 
be 5.49, and this amount divided by the specific gravity gives the per- 
centage by weight. Supposing the specific gravity to be 1.030, for 
example, the 100 cc. of milk weigh 103 grams, and the true percentage 104 
FOODS. 
of sugar will be x in the equation 103 : 100 :: 5.49 : x. x = 5.33. 
Inasmuch as the means of the first equation are constants, the reckon- 
ing resolves itself into dividing four times their product, 33.35, or 
133.4 by the number of cc.'s used and dividing this result by the spe- 
cific gravity of the specimen. 
2. Method by Polariscopy.-The determination of lactose and other 
sugars by means of the polariscope combines the advantages of accu- 
racy and of rapidity. The instruments in common use are of two 
kinds; those of which the normal sucrose weight, that is to say, the 
amount of sucrose which dissolved in water and made up to 100 cc. 
will show 100 degrees on the scale when observed through a 200-mm. 
tube, is 26.048 grams, and those in which it is 16.19 grams. Of the 
former the Ventzke-Scheibler and the Schmidt and Haensch modifica- 
tion, and of the latter the Laurent instrument may be regarded as 
types. The Schmidt and Haensch triple field, half-shadow instrument 
possesses the advantage of doing away with the matching of colors and 
hence may be used by those who are color-blind, and even with those 
not so afflicted gives, on the whole, the most satisfactory results. 
Process.-Into a flask graduated on the neck at 102.6 cc. if the in- 
strument used is one of which the sucrose normal weight is 26.048 
grams, weigh 65.95 grams of milk, or into one graduated at 101.6 cc. 
if it is one of the other class, weigh 40.990 grams, add 1 cc. of solu- 
tion of mercuric nitrate of pharmacopoeial strength, shake well, and di- 
lute with water up to the mark. Filter through a dry filter paper, fill 
the 200 mm. observation tube and note the reading of the scale when 
the field of observation is uniform. The reading divided by 2 equals 
the percentage by weight of lactose. 
The weights 65.95 and 40.99 represent twice the normal lactose 
weights of the respective types of instruments : the graduations 102.6 
and 101.6 are adopted instead of 100 cc. since the dried precipitated 
curds from the respective amounts of milk of average specific gravity 
have a bulk equal to the excess over 100 cc. 
Determination of Ash.-The ash can be determined by igniting 
the residue obtained in the determination of total solids, provided no 
other substance has been introduced into the dish with the milk. The 
ignition should be conducted at a low red heat until the ash is perfectly 
white. The dish is then cooled in a desiccator and again weighed. 
The difference between this final weight and the original weight of 
the empty dish represents the amount of mineral matter in the 
amount of milk taken. Or a larger amount of milk, say 20 grams, 
may be evaporated with a few cc. of nitric acid and the residue ignited 
as before. 
Determination of Proteids.-Having determined the total solids, 
fat, sugar, and ash, the proteids may be reckoned by difference, that is, 
by subtracting the sum of the fat, sugar, and ash from the total solids, 
or they may be determined directly by the Kjeldahl process which de- 
pends upon the conversion of the nitrogenous matter into ammonium 
sulphate which is then decomposed by an excess of strong alkali, am- ANALYSIS OF MILK. 
105 
monia being set free. This is expelled by heat, condensed with the 
accompanying steam, and received in acid of known strength. 
The process is as follows : Into a Kjeldahl digestion flask introduce 
a definite weight, say five grams of milk, about 0.7 gram of mercuric 
oxide, and 20 cc. of sulphuric acid of 1.840 specific gravity, free from 
nitrates and ammonium sulphate. Place the flask in an inclined posi- 
tion and heat below the boiling point of the acid for from five to fif- 
teen minutes or until frothing ceases. Then raise the heat until the 
mixture comes to boiling and continue the process until the liquid is 
clear and has no more than a very pale straw color. This will ordi- 
narily require less than an hour. Withdraw the lamp and drop in, in 
small quantities at a time, permanganate of potassium until, after shak- 
ing, the liquid has acquired a permanent green or purple color. This 
addition is not always or even usually necessary to secure complete 
oxidation, but since it is sometimes required it is best to make it a part 
of the routine. 
Allow the contents to cool and then transfer them with about 200 
cc. of distilled water, plus enough for thorough rinsing, to a distilling 
flask of about 550 cc. capacity, fitted with a rubber stopper and a 
bulb tube connected with a very long Liebig condenser, the delivery 
end of which is fitted with a glass tube bent at right angles, so that it 
may dip beneath the surface of the acid into which the distillate is to 
be received. Add a few pieces of pumice or granulated zinc, or about 
0.5 gram of zinc dust to prevent bumping, and 25 cc. of a four-per- 
cent. aqueous solution of sulphide of potassium, to prevent the forma- 
tion of compounds of ammonium and mercury which are not wholly 
decomposable by alkalies. Shake and then add of a saturated solution 
of sodium hydrate, free from nitrates, enough to make the reaction 
strongly alkaline, pouring it down the side of the flask so as not to 
mix at once with the acid contents. Next connect the flask with the 
condenser, mix the contents by gently rotating and apply the flame. 
Distil and receive the distillate in a vessel containing 50 cc. of deci- 
normal sulphuric acid. 
When about 175 cc. have passed over, it may be assumed that 
all ammonia has been expelled, and then the distillate is titrated with 
decinormal alkali, using cochineal or methyl orange as an indicator. 
From the difference in strength of the decinormal acid the amount of 
ammonia is calculated and from this the amount of nitrogen, and this 
multiplied by 6.25 gives the total proteids. 
Detection of Added Coloring Matters. Annatto.-To about 100 
cc. of milk in a cylinder about 1.5 inches in diameter, add a few cc.'s 
of sodium carbonate solution to insure a strongly alkaline reaction 
during the examination and then introduce a strip of heavy white filter 
paper about 0.5 by 5.5 inches, and set the whole away in a dark place 
over night. If any annatto color is present it will, through selective 
affinity, pass from the milk to the fiber of the paper which thereby 
acquires a salmon tint the depth of which is dependent naturally upon 
the amount of the substance present. The strip is withdrawn from the 106 
FOODS. 
milk, washed gently in running water, and laid upon a piece of paper 
of the same kind as itself. If so much as one part of the annatto solu- 
tion in 100,000 is present, the strip will show a distinct salmon tint. 
On dipping the strip into stannous chloride solution the color is 
changed to pink. 
Another method by means of which all the color of the amount of 
milk operated upon may be concentrated in a form best adapted for 
preservation and for exhibits in court, is as follows : Coagulate from 
100 to 150 cc. of the specimen by the application of heat and acetic 
acid and separate the coagulum by straining through a piece of cheese- 
cloth. The coloring matter being insoluble in acid media is precipi- 
tated with the curd, which, however, will show to the eye scarcely any 
indication of its presence. 
The curd is placed in a mortar and triturated with 50-75 cc. of 
ether, which is next transferred to a stoppered separating funnel and 
shaken with 10 cc. of a 1-per-cent, solution of caustic soda. When 
the two liquids become separated, the latter, which now contains the 
annatto color, is drawn off into two small porcelain or glass dishes 
about an inch in diameter in each of which a small disc of filter-paper 
is placed. They are then set aside in the dark and left over night. 
The discs are then removed and washed in fresh water. If annatto is 
present they will now have acquired a color varying in depth according 
to the amount of the dye in the sample. One is immersed in stannous 
chloride solution, the other in weak sodium carbonate, and then dried 
and mounted on a white card. The colors yielded by a specimen of 
milk to which no unusual amount of the adulterant has been added are 
shown in Plate IV. 
Caramel.-Pour 125 to 250 cc. of the suspected sample into an equal 
volume of 95 per cent, alcohol, and filter. The filtrate if not perfectly 
clear must be returned and passed through until it is quite free from 
turbidity. Any caramel present will be in solution in the alcoholic 
filtrate and may modify considerably its color which is normally yel- 
lowish or greenish according to season, the latter obtaining in spring 
and summer. To 100 cc. of the filtrate add 2 cc. of solution of basic 
acetate of lead which will precipitate the caramel together with any 
remaining proteids, the precipitate showing a slight brownish color if 
caramel has been used in sufficient amount to bring about the improved 
appearance which is the object of its employment. Filter, wash with 
distilled water, and dry in an air-bath. 
According as the amount of caramel present is large or small the 
horny residue on the filter-paper will have a more or less deep choco- 
late tinge. The residue yielded by a pure milk will be either almost 
colorless, or yellow, or slightly inclined to brownish but not to choco- 
late color. The appearance of the two kinds of residue is shown in 
Plate V. 
Caramel may also be shown if we proceed according to the second 
method described for the detection of annatto. The curd after being 
freed from the whey and triturated with ether gives up to this solvent PLATE IV. - 
A. Strip of Filter Paper Dyed by Immersion in Milk Colored with Annatto 
B. Same, after Treatment with Solution of Protoehloride of Tin. PLATE V 
Fig. 1. 
Residues obtained in testing Milk for Caramel. 
Fig. 1. From uncolored milk. 
Fig. 2. From milk containing caramel ANALYSIS OF MILK. 
107 
only fat and annatto. If caramel or anilins are present the curd will 
appear brownish in the one case and more or less intensely yellow in 
the other. If the curd is now shaken with hydrochloric acid one of 
the following changes will be observed. If orange anilin is present 
the color becomes bright pink almost immediately ; with caramel it be- 
comes gradually brownish blue; if neither is present, the change is to 
blue. 
Orleans.-The following process is recommended by O. Leys.1 Re- 
agents required. 1. Ammoniacal ether alcohol mixture ; alcohol 2,400 
cc., ether 3,200 cc., water 200 cc., ammonia water sp. gr. 0.92, 80 cc. 
2. Sodium sulphate solution 1 : 10. 3. Amyl alcohol. Process. Mix 
50 cc. of milk and 100 cc. of the ether mixture in a separatory funnel 
and shake. When the liquids separate, the upper one will contain 
the fat and the lower one the other constituents of the milk and the 
Orleans. 
After twenty minutes transfer the lower portion to another similar 
funnel and add half its volume of the sodium sulphate solution gradu- 
ally and without shaking. On the separation of the casein run the 
liquid through a metallic sieve into four test-tubes to about two-thirds 
their capacity. Fill them with amyl alcohol and mix thoroughly. 
Place them in a vessel of cold water on a water-bath and raise the 
temperature to 80° C. Decant the amyl alcohol into an evaporating 
dish and evaporate to dryness. Dissolve the dark yellow residue in 
ammonia plus a little water and alcohol, introduce some white cotton 
and again evaporate almost to dryness. The cotton is now dyed 
yellow, and is changed to rose pink when dipped into a weak solution 
of citric acid if Orleans was originally present. Normal milk gives the 
yellow color but not the rose. 
Several other processes have been recommended but they are the 
same in principle and possess no advantages over the above. 
Detection of Preservatives. Borax and Boracic Acid.-These sub- 
stances are easily detected either in the milk itself or in the ash after 
ignition of the residue. In the latter case, moisten the ash with a drop 
or two of strong sulphuric acid and after a few minutes add 3 or 4 cc. of 
strong alcohol. Dip a strip of turmeric paper into the mixture and 
allow it to dry without the aid of heat. In the presence of either of 
the substances sought for the paper will have, when dry, the char- 
acteristic red color due to boracic acid instead of the yellow color which 
will be maintained in its absence. While the paper is drying, place 
the dish in a dark place and ignite the contained alcohol. If boracic 
acid or its sodium compound is present the flame will show at its outer 
edge a characteristic greenish coloration. This is shown most strongly 
directly after the alcohol is ignited. 
In the original milk the test may be made in the following manner : 
Mix a few drops of the milk and an equal amount of fresh tincture of 
turmeric in a small porcelain dish and evaporate on a water-bath to 
dryness. Moisten the surface of the residue with dilute hydrochloric 
1 Journal de Pharmacie et de Cliemie, 1898, p. 286. 108 
FOODS. 
acid and dry again. If either of the substances is present the residue 
will be light pink to dark red in color, and the addition of a drop of 
ammonia water will change this to a green or greenish blue according 
to the amount of the preservative present. 
Salicylic Acid.-1. Acidify about 75 to 100 cc. of milk with hydro- 
chloric acid and separate the whey by filtration. Shake the acid whey 
with ether, decant the ether into a watch-glass and allow it to evapo- 
rate. To the residue on the watch-glass apply a drop of neutral ferric 
chloride when, if salicylic acid is present, the characteristic purple color- 
ation is produced. 2. Mix the milk with phosphoric acid and strain 
through cloth. Place the liquid in a flask, connect with a condenser, 
and distill. Test the distillate with ferric chloride from time to time. 
Any salicylic acid present will go over with the steam, most of it 
toward the end of the operation. 
Formaldehyde.-Many processes for the detection of this substance 
in milk have been devised, some exceedingly simple and others quite 
complicated. Those which give the best results and the greatest satis- 
faction are, on the whole, those which are the simplest in application 
and require the least expenditure of time. The test must be applied 
within a few days after the addition of the preservative, since after a 
time it cannot be detected. 
1. Method by Decolorized Fuchsine.-Through a solution of 
fuchsine 1 : 500 pass a current of sulphurous acid gas, obtained by 
heating copper wire or foil with sulphuric acid, until the color is dis- 
charged. Preserve in a glass-stoppered bottle. To 10 cc. of milk 
add 1 cc. of the reagent and let stand ten minutes. Add 2 cc. of 
strong hydrochloric acid and shake or stir briskly. The color which 
appears in the first instance is completely discharged by the acid if no 
formaldehyde is present, otherwise a violet-blue tinge remains. If the 
amount present is large the end color will be correspondingly intense. 
This method will detect the admixture of one part of formalin in 50,- 
000 of milk. If the milk be first distilled and the first part of the 
distillate treated with the fuchsine solution the test is delicate to the 
extent of revealing one in 500,000. 
2. Method by Phloroglucin.-Add to 10 cc. of milk in a test 
tube 2 or 3 cc. of a 0.10-per-cent. solution of phloroglucin and 5 to 
10 drops of 10-per-cent. solution of sodium hydrate and shake. In 
the presence of formalin a gradual red coloration appears, otherwise 
no such change is observed. This test is said to reveal one part in 
50,000, but such a claim appears, according to the experience of the 
author and others, not to be justified. 
3. Method by Ferric Chloride.-Mix in a porcelain dish 10 
cc. each of milk and hydrochloric acid (sp. gr. 1.2) and one drop oi 
ferric chloride solution. Heat and stir vigorously. If formalin has 
been added a violet color will appear before the boiling point has been 
reached, varying in intensity according to the amount present. This 
process is exceedingly delicate and will detect one part in 500,000 in 
the fresh condition. PLATE VI. 
Fig. 1. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Fig. i. Coloration Produced by Concentrated Sulphuric Acid, Sp. Gr. 1.840, in Contact with 
Pure Milk. 
Fig. 2. Coloration Produced by Sulphuric Acid of Sp. Gr. 1.700 in Contact with Pure Milk. 
Fig. 3. Coloration Produced by Sulphuric Acid of Sp. Gr. 1.700 in Contact with Milk Con- 
taining 1 Part of Formaldehyde in 25,000. 
Fig. 4. Coloration Produced by Sulphuric Acid of Sp. Gr. 1.700 in Contact with Milk Con- 
taining I Part of Formaldehyde in 50,000. ANALYSIS OF MILK. 
109 
4. Method by Commercial Sulphuric Acid.-This test is ex- 
ceedingly delicate and very easily applied. It cannot be performed 
with pure sulphuric acid since the presence of a trace of iron is neces- 
sary. If one desires to use a pure acid rather than the ordinary com- 
mercial grade the addition of a very small amount of ferric chloride 
will be quite sufficient. 
Take about 15 to 20 cc. of milk in a test-tube and pour about 5 cc. 
of the acid gently down the side so that it shall pass under rather than 
mix with the milk. Let stand a few minutes and then note the color 
at the junction of the two liquids. If formalin is present even in the 
slightest traces a violet coloration appears at the line of junction. In- 
asmuch as pure milk will show a somewhat purplish color when in 
contact with strong sulphuric acid, a color which may readily be mis- 
taken at first for that due to formaldehyde, and since also the charring 
that occurs at the line of junction will often obscure the reaction, the 
process as originally recommended is somewhat faulty. 
The objections are, however, removed by diluting the strong acid 
with water so that its specific gravity is reduced from 1.840 to 1.700. 
The action of the stronger acid on pure milk is shown in Plate VI., 
Fig. 1, which shows the dark color due to charring and the purplish 
color, above spoken of, due to the same cause. 
In Plate VI., Fig. 2, is shown the appearance of the line of junction 
of pure milk and the diluted acid. It will be observed that the color 
produced is but a faint yellow. In Plate VI., Figs. 3 and 4, are 
shown the zones produced in milk containing formaldehyde in the pro- 
portions 1 to 25,000 and 1 to 50,000 by the use of the diluted acid. 
As may be inferred, the reaction is produced rather more slowly with 
the weaker acid. It is best to allow the contact to endure at least an 
hour before noting a negative result. 
Chromates.-Froidevaux1 recommends dissolving the ash of about 
10 cc. of milk in a few drops of water acidulated with nitric acid and, 
after neutralizing with magnesium carbonate, adding a few drops of 
test solution of nitrate of silver, whereby a red precipitate, chromate of 
silver, is formed. As a control test he recommends taking up another 
portion of ash with water acidulated with sulphuric acid, and adding 
little by little some tincture of guaiacum. In the presence of chromates 
an intense blue color is produced which disappears very quickly. This 
process will detect 1 part in 50,000. Guerin 2 claims greater delicacy 
for the following method : To 5 or 10 cc. of milk add 2 drops of a 
1-per-cent, solution of sulphate of copper and 2 or 3 drops of freshly 
prepared tincture of guaiacum. Pure milk gives a greenish color, while 
milk containing 1 part in 100,000 will give an intense blue which 
reaches its maximum in a few minutes. 
Methods of Distinguishing between Raw and Cooked Milk.-To 
determine whether or not milk has been cooked Carcano3 recommends 
'Journal de Pharmacie et de Chemie, 1896, p. 155. 
2Chemiker Zeitung, 1897, p. 174. 
3Giornale di Farmacia di Trieste, 1896, p. 275. 110 
FOODS. 
placing a few cc. of the specimen in a porcelain dish, adding a few 
drops of not too old oil of turpentine, warming gently, and then adding 
tincture of guaiacum. If the milk has not been boiled a blue color 
appears, otherwise it does not. 
Dupouy 1 gives the following tests : 
1. Guaiacol. Equal volumes of milk and a 1-per-cent, solution of 
guaiacol in water are mixed together and treated with hydrogen per- 
oxide. An immediate yellow color indicates that the specimen has not 
been boiled. 
2. Hydroquinone. Three cc. of milk are mixed with 1 cc. of a 
fresh 10-per-cent. aqueous solution of hydroquinone and 15 drops of 
hydrogen peroxide. If the milk has not been boiled an immediate 
rose color appears, and in a few minutes green crystals are deposited. 
3. Pyrocatechin. Equal volumes of raw milk and an aqueous 10- 
per-cent. solution of pyrocatechin are brought together and treated 
with hydrogen peroxide. A yellowish brown color is produced. With 
boiled milk no color appears. 
4. a-Naphthol. Raw milk with an aqueous solution of a-naphthol 
and hydrogen peroxide gives a violet-blue color. Boiled milk gives 
none. 
p Detection of Gelatin in Cream.-For the detection of gelatin in 
cream to which it is sometimes added to give it body, Stokes 2 recom- 
mends the following procedure : 
Dissolve some mercury in twice its weight of strong nitric acid (sp. 
gr. 1.420); dilute with water to 25 times its bulk. To about 10 cc. 
of this solution add a like quantity of the cream and about 20 cc. of 
cold water. Shake the mixture vigorously, leave it for five minutes, 
then filter. If much gelatin be present it will be impossible to get a 
clear filtrate. To the filtrate or to a portion of it, add an equal bulk 
of a saturated aqueous solution of picric acid. If any gelatin be pres- 
ent a yellow precipitate will be immediately produced. The whole 
operation is performed in the cold and if the mercury solution is ready 
will not take more than 10 minutes. Picric acid will show the pres- 
ence of one part of gelatin in 10,000 parts of water. 
BUTTER. 
This valuable milk product is the result of violent agitation of cream 
until its fat coalesces into granular particles which are then separated 
from the residual buttermilk, " worked " to expel as much of the latter 
as possible, and with or without the addition of salt and coloring mat- 
ter formed into " prints " or " pats," or packed in bulk in boxes and 
firkins. Its natural color varies with the season, the so-called June 
butter made when the cows from whose milk it is produced are feeding 
on grass being bright yellow, while that made when they are stalled and 
fed on hay and other winter feed being almost white. 
1 Journal de Pharmacie et de Chemie, 1897, p. 397. 
2 The Analyst, December, 1897. BUTTER. 
111 
The popular demand being for a yellow article the year round, it is 
customary to secure this color out of season by the addition of annatto 
and other harmless vegetable coloring agents the use of which has al- 
most universally the sanction of law. 
The flavor is much influenced by the character of the feed, by the 
care exercised in manufacture, by the amount of added salt, by age, 
and by the circumstances of storage. Like milk it absorbs odors very 
readily, both those which improve and those which impair its flavor. 
Taking advantage of this fact, it is the custom in the valley of the Var 
and in some other localities to place the freshly made product in prox- 
imity to jasmine, violets, tuberoses and other flowering plants in order 
that their fragrance may be absorbed. This practice is known as 
" enfleurage." 
The most delicately flavored butter under natural conditions is that 
to which no salt has been added, but it has the disadvantage that 
within a short time it acquires a " cheesy " flavor due to decomposition 
processes. Owing to its lack of keeping qualities and to the very general 
preference for a more pronounced taste, the addition of salt in varying 
amounts is the rule. Butter of good quality has but slight odor, but 
that which has undergone the common changes due to bacterial action 
has the characteristic odor and taste of rancidity. This is due to de- 
composition of the small amount of curd which is entangled in the 
making and which cannot be wholly excluded. The fat itself when 
separated from the curd by melting keeps unchanged for long periods. 
In rancid butter, butyric and other acids are liberated, and others, as 
formic, are formed by absorption of oxygen. Under some unusual 
conditions not wholly understood, butter, without becoming rancid in 
the usual sense, undergoes a change to a perfectly white substance with 
a very marked tallowy odor. 
Butter varies considerably in composition, but a fair average may 
be stated as follows : 
Fat 84.00 
Water 12.00 
Curd 1.00 
Salts 2.50 
Lactose 0.50 
It may be made to contain a considerably higher percentage of water 
with correspondingly less fat. 
The fat is composed of glycerides of two groups of fatty acids 
which have already been mentioned in the description of milk. 
Those of the insoluble non-volatile acids, oleic, stearic, and palmitic 
constitute about 92.25 per cent, of the whole, and those of the soluble 
volatile acids, butyric, caproic, caprylic, and capric make up the balance. 
It is to the second group that butter owes its distinctive flavor. 
The amount of water depends very largely upon the thoroughness 
with which the buttermilk is worked out. In order that more water 
may be held and thus a greater profit realized, some makers have em- 
ployed gelatin as an adulterant. One gram of this substance will take 112 
FOODS. 
up about 10 of water and when mixed with butter in the right propor- 
tion will hold water in the above ratio without affecting the consistence 
injuriously. Others employ glucose both for this purpose and as a 
preservative. 
The salts include those natural to milk and those added for the pre- 
vention of rapid decomposition. The usual addition is common salt, 
but the use of boric acid and borax is gradually extending. 
Outside the use of preservatives and of agents to assist in retaining 
water, butter is not much subject to adulteration excepting in the sense 
that substitution of an article of less value when butter is called for is 
a form of adulteration. This substitute is variously known as artificial 
butter, butterine, oleomargarine, and margarine. Under the United 
States statutes all butter or substitutes therefor made to resemble it, 
containing fats other than cream, shall be known as oleomargarine. 
Following the original process it is made from fresh beef suet which 
after being cooled, washed, and cut into very fine pieces by machinery 
is subjected to a temperature of about 110° F. for several hours in 
order to separate the fat from the tissue. It is then drawn off and 
kept for a time at 80 to 90° F. at which temperature the stearin solidi- 
fies, and then is separated by pressure from the " oleo-oil." The latter 
is churned with milk or with milk and genuine butter, colored with 
annatto and otherwise treated like butter. 
At the present time it is made not alone from beef suet but to a much 
greater extent from " neutral lard," a product of leaf lard. Cotton- 
seed oil is used to some extent, but naturally it is not so well adapted 
to the purpose as the solid fats. 
Oleomargarine has been misrepresented to the public to a greater 
extent probably than any other article of food. From the time of its 
first appearance in the market as a competitor of butter there has been 
a constant attempt to create and foster a prejudice against it as an un- 
wholesome article made from unclean refuse of various kinds, a vehicle 
for disease germs, and a disseminator of tapeworms and other unwel- 
come parasites. It has been said to be made from soap grease, from 
the carcasses of animals dead of disease, from grease extracted from 
sewer sludge, and from a variety of other articles equally unadapted 
to its manufacture. 
The most absurd statement which the author has seen appeared in 
the annual report of the board of health of a community large enough 
and rich enough to be able to afford better service; this was that a 
large part of the annual output was made from the grease of dogs shot 
while suffering from rabies by the police in the streets of large cities. 
The publication of a great mass of untruth cannot fail to have its 
desired effect not solely on the minds of the ignorant, but even of some 
of those of over average intelligence. So it is that a prejudice was 
created against this valuable food product, but it is gradually becoming 
less and less pronounced. 
The truth concerning oleomargarine is that it is made only from the 
cleanest materials in the cleanest possible manner, that it is quite as BUTTER. 
113 
wholesome as butter, and that when sold for what it is and at its 
proper price it brings into the dietary of those who cannot afford the 
better grades of butter an important fat food much superior in flavor 
and keeping property to the cheaper grades of butter which bring a 
better price. Oleomargarine cannot be made from rancid fat, and in 
its manufacture great care must be exercised to exclude any material 
however slightly tainted. 
It is not and cannot be made from fats having a marked or dis- 
tinctive taste, and its flavor is derived wholly from the milk or genuine 
butter employed in its manufacture. It contains as a rule less water than 
does genuine butter, and consequently any difference in food value is in 
its favor. It undergoes decomposition much more slowly, and, indeed, 
may be kept many months without becoming rancid. Much has been 
said concerning its digestibility, and alarmists have gone so far as to 
claim that it is quite indigestible and likely to prove a prolific cause 
of dyspepsia, quite forgetting that the materials from which it is made 
have held a place in the dietaries of all civilized peoples since long 
before butter was promoted from its position as an ointment to that of 
an article of food. Many comparative studies have been made on this 
point and the results in general have shown that there is little if any 
difference. H. Luhrig1 has proved by careful experiment that the 
two are to all intents and purposes exactly alike in point of digesti- 
bility. 
Oleomargarine has been the subject of a vast amount of restrictive 
legislation wherever it is made or sold. This has been passed in the 
interest of the dairymen and because of the ease with which it may be 
fraudulently sold as butter at butter prices. To the practice of fraud 
in its retail sale is due very largely the passage of prohibitive laws, 
many of which, however, have been declared unconstitutional. In 
Massachusetts, for example, it had at one time a very large sale, and 
in the City of Boston alone were nearly 200 licensed dealers. But the 
amount of fraudulent dealing was so great that the Legislature passed 
an act prohibiting its sale if it contained any ingredient causing it to 
look like butter; in other words no annatto or other substance which 
would cause it to be yellow could be used in its manufacture. Since its 
natural color is almost white, and since white butter does not appeal to 
the eye, the result was practically the withdrawal of the article from 
open sale. 
In Germany on account of fraudulent practices in the adulteration 
of butter with oleomargarine, the government passed in 1897 a statute 
requiring the latter to contain 10 per cent, of oil of sesame so that any 
subsequent admixture with butter may be readily detected by Bau- 
douin's reaction. This is a red coloration brought about when oil of 
sesame, furfurol and hydrochloric acid are brought together, and it is 
sufficiently delicate to show the adulteration of butter with 2.5 per 
cent, of oleomargarine containing the oil in the proportion stated. 
Experiment has shown that butter made from the milk of cows fed on 
1Zeitschrift fur Untersuchung der Nahrungs- und Genussmittel, June, 1899, p. 484. 114 
FOODS. 
sesame does not yield the reaction, but the fat of the milk of goats fed 
partly on sesame has been found to give it. 
The principal chemical difference between butter and oleomargarine 
lies in the relative amounts of glycerides of the soluble and insoluble 
fatty acids. Genuine butter-fat contains nearly 8 per cent, of butyrin, 
caproin, caprin, and caprylin, while the artificial product contains these 
glycerides only as they are introduced in the amount of milk or butter 
with which it is churned, for they are not present in suet, lard, and 
other animal fats. 
Of late years high-grade butter has found another formidable com- 
petitor in what is variously known as renovated butter, process butter, 
and hash butter. The material from which this is made is gathered 
from dairies scattered over a wide expanse of country and differs 
widely in color, texture, age, and flavor. It is melted, purified of its 
rancidity by washing, made of the proper yellow color, and rechurned. 
Butter as a Carrier of Disease.-Since milk is known to be a car- 
rier of the germs of certain diseases under some conditions, the possi- 
bility that butter may act in the same way suggests itself, and the more 
strongly since in ordinary creaming of milk all but a very small pro- 
portion of the bacteria rise with the cream. Ordinary butter contains 
millions of bacteria to the gram, but whether the pathogenic forms can 
long survive has not been very extensively investigated, except in the 
case of the bacillus of tuberculosis. The bacteria of cholera and ty- 
phoid fever have been known to survive several days after being 
planted in butter, but beyond this we have little knowledge. 
Brusaferro, in 1891, produced tuberculosis in a rabbit through the 
injection of butter made from the milk of a cow with a tuberculous 
udder. Roth, in 1894, got similar results and found, moreover, that 
two out of twenty market samples of butter used by him yielded posi- 
tive results. Scliuchardt got negative results from forty-two samples, 
while Obermuller found the bacillus in every sample of Berlin butter 
used in his first series of experiments. Dr. Lydia Rabinowitsch 1 ex- 
amined eighty samples obtained partly in Berlin and partly in Phila- 
delphia and found genuine tubercle bacilli in not a single instance. 
She did, however, find a spurious organism which produced in guinea- 
pigs changes which required very careful examination for the revela- 
tion of their non-tuberculous character. This was present in 28.7 per 
cent, of the samples. 
Petri2 found the same organism in 37.2 per cent., the genuine ba- 
cillus in 32.4 per cent., and neither the one nor the other in 30.4 per 
cent. Obermuller3 using salted butter in a second series, determined 
that the injection of the butter fat itself introduced a cause of irritation, 
and used, therefore, in his next set the watery fluid separated from the 
butter by heat and centrifugating. Four samples out of 10 from the 
same source as his first lot gave undoubted evidence of the presence of 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXVI., p. 90. 
2 Arbeiten aus dem kaiserlichen Gesundheitsamte, 1898, p. 27. 
3Hygienische Rundschau, 1899, No. 2. 115 
ANALYSIS OF BUTTER. 
genuine tubercle bacilli. Otto Korn1 found them in 23.5 per cent, 
of samples purchased in Freiburg, and Dr. C. Coggi2 in only 2 out 
of 100 samples purchased in Milan, though in a number of them the 
spurious organism was present. Morgenroth3 has subjected oleomar- 
garine to the same investigation, since milk is used in its manufacture, 
and has reported positive results from 9 out of 20 samples. 
We have as yet no evidence whatever that tuberculosis has ever been 
spread through the agency of butter, but the subject deserves most 
thoughtful consideration. 
Analysis of Butter.-Ordinarily the examination of butter is lim- 
ited to the determination of whether or not it is mixed with or replaced 
by oleomargarine, but for the determination of its food value it is nec- 
essary to ascertain the proportions of fat and water. It is sometimes 
of interest also to determine the amount of salt and the presence of 
other preservatives. 
Determination of Water.-Weigh a gram or two of the sample 
into a platinum dish such as is used in the analysis of milk and dry to 
constant weight on the water-bath. 
Determination of Fat.-Extract the residue from the preceding 
determination with ether or freshly distilled naphtha, being careful not 
to remove any of the particles of curd or salt. The process of extrac- 
tion is very simple, consisting simply in filling the dish about half full 
of the solvent and after a short time decanting it carefully into another 
vessel, and repeating the operation until nothing is extracted. The 
solvent or an aliquot part thereof may be evaporated in a weighed 
beaker, or the dish may be again heated to a constant weight and the 
fat determined by difference. The residue now represents the curd, 
lactose and mineral matters. 
Determination of Salt, etc.-Ignite this residue at as low a tem- 
perature as possible and thus burn off the casein and lactose. Their 
combined weight is ascertained by weighing the dish anew. What 
now remains in the dish is mineral matter comprising the salts natural 
to milk and those added. Common salt may be determined by treat- 
ing the final residue with water acidulated with nitric acid and titrating 
in the usual way with standard solution of silver nitrate, using potas- 
sium chromate as an indicator. 
Another method of determining salt is as follows. Shake a known 
weight, 5-10 grams, of the sample with hot water in a stoppered sep- 
arating funnel until it is completely melted, let stand until the fat 
gathers on the surface of the water, and then draw off the latter through 
the stopcock. Repeat the operation with successive portions of about 
20-25 cc. of hot water until a few drops of the washings tested with 
silver nitrate fail to show a cloudiness due to silver chloride. Allow 
the combined washings to cool, and then in an aliquot portion deter- 
mine the chlorine by standard silver nitrate solution in the usual way. 
1 Archiv fur Hygiene, XXXVI., p. 57. 
2Giornale della R. Societa italiana d'igiene, July, 1899, p. 289. 
3Hygienische Rundschau, 1899, No. 21. 116 
FOODS. 
Determination of the Nature of the Fat.-To determine whether 
or not a specimen is or contains oleomargarine, an examination of the 
nature of the fat is necessary. As has been pointed out, genuine 
butter contains a considerable amount of volatile fatty acids, while the 
artificial product contains but very little; but, on the other hand, the 
genuine article is correspondingly poorer in the insoluble non-volatile 
fatty acids. 
It is upon these differences in the two kinds of fat that the determi- 
nation of the question of genuineness depends. The usual examina- 
tion is limited to the determination of the volatile fatty acids in a 
given weight of the melted fat freed from water, curd, and salt. The 
fat is saponified, the resulting soap is dissolved in water and then de- 
composed by means of sulphuric acid, and the volatile fatty acids thus 
freed from combination are then distilled over, and their amount esti- 
mated by means of decinormal sodium hydrate. Five grams of 
genuine butter fat will yield an amount which will require at least 
24 cc. of the alkali for complete neutralization, while an equal weight 
of oleomargarine yields so small an amount that as a rule less than 1 cc. 
is required. Mixtures give results between these limits, and from 
them one can estimate approximately the proportion of butter present. 
Process.-Heat a small piece of the sample on the water-bath in a 
suitable beaker until it is completely melted, and the contained water, 
salt, and curd have collected at the bottom. Decant a sufficient amount 
of the supernatant fat into a dry filter and allow it to pass into a 
shallow beaker. When about 10 grams have been collected, place the 
beaker in a basin containing water and ice and leave it until the fat 
has become hard. Place a small filter paper on one of the pans of the 
balance and counterbalance it exactly with weights on the other. Then 
weigh out as rapidly as possible 2.5 grams of the fat, transferring it to 
the paper by means of a spatula. 
Place the paper and fat in a 300 cc. Erlenmeyer flask, add 10 cc. 
of a 20-per-cent. solution of caustic potash in 70 per cent, alcohol, 
and then place the flask on the water-bath. In a short time, especially 
with gentle rotation of the flask, the fat becomes completely saponified. 
Continue the heat until the alcohol is expelled, and remove the last 
traces of the vapor by blowing into the flask with a bellows or by 
swinging it in the air. Add 50 cc. of hot water, and when the soap 
is brought completely into solution, add 25 cc. of 10-per-cent. sulphuric 
acid. 
The latter breaks up the soap, setting free both the soluble and in- 
soluble fatty acids, the latter in the form of curdg. Connect the flask 
with a Liebig condenser after introducing several pieces of pumice 
stone to prevent bumping, and then with the flask supported on a 
square of wire netting over a Bunsen lamp, distill slowly until 50 cc. 
have been collected. Titrate the distillate with decinormal sodium 
hydrate, using phenolphthalein as an indicator. With the amount of 
fat taken, at least 12 cc. of the alkali will be required for neutraliza- 
tion, if the specimen is genuine butter. 117 
ANALYSIS OF BUTTER. 
Many analysts prefer to employ 5 grams of fat and correspondingly 
larger volumes of water, and to distill 110 cc., whereof 100 is 
titrated. Some prefer also to carry on the process of saponification in 
a round-bottomed flask under pressure. Some measure the fluid fat 
directly into a weighed flask from a pipette, and ascertain the amount 
taken by reweighing after the fat has cooled and solidified. The 
saponifying agent is applied in different forms, and many other varia- 
tions in detail are recommended, but the end result is practically the 
same. The process described has been found in the experience of the 
author to be most satisfactory. 
The Leffmann-Beam process has much to recommend it, particularly 
in the saving of time. The saponifying agent is prepared by mixing 
20 cc. of 50-per-cent. caustic soda solution and 180 of pure concen- 
trated glycerin. To 5 grams of fat in an Erlenmeyer flask add 20 
cc. of this solution, and then heat over a Bunsen flame until saponifi- 
cation is complete. This requires but a few minutes; the completion 
of the process is shown by the clear condition of the mixture. The 
soap is diluted with 135 cc. of boiled water added at first in very 
small amounts to prevent foaming. Then 5 cc. of dilute sulphuric 
acid (200 cc. in 1,000) are added and the preparation is ready for im- 
mediate distillation. Distill 110 cc., mix thoroughly and pass through 
a dry filter, titrate 100 cc., and to the result add a tenth for the re- 
maining 10 cc. 
If one wishes to determine £he amount of insoluble fatty acids it can 
be done in the following manner, but it must be said that the process 
requires much more time and that the results are not always satisfactory, 
since the upper limit in the case of butter is so near the lower limit 
in that of oleomargarine that samples yielding results close to the 
dividing line may need further analysis before an unqualified opinion 
of the nature of the specimen can be given. A mixture of genuine 
butter and oleomargarine may give results well within the normal 
limits of butter. 
Process.-Into a weighed beaker decant a few grams of the fat, and 
when the latter has cooled, ascertain the amount taken by reweighing. 
Saponify as above described, evaporate the alcohol, dissolve the soap 
in water and decompose it by the addition of an excess of acid. Heat 
until the precipitated insoluble acids are melted, then allow the whole 
to cool. When the fatty layer has assumed the character of a solid 
•crust, break a small hole through it at a point on its circumference and 
another on the opposite side. Weigh a funnel and a dried filter of 
suitable size, place the latter within the former, wet it thoroughly and 
then filter the liquid from beneath the crust. Break up the crust, add 
boiling water, and transfer the whole to the filter. Wash repeatedly 
with boiling water until the washings have no longer an acid reaction, 
then let drain until no more water is discharged. The filter paper 
being wet, the melted fatty acids do not pass through with the washings. 
Place the funnel and its contents in the beaker and dry in an air-bath 
at 100° C. to constant weight. The increase in the combined weights 118 
FOODS. 
of the beaker, funnel, and paper represents the amount of insoluble 
fatty acids in the amount of fat taken. 
Examination of Fat by means of the Butyro-Refractometer.- 
A very simple and quick method of ascertaining the nature of butter 
fat without recourse to chemical analysis is that by means of the 
butyro-refractometer or other instrument designed for the purpose of 
measuring the refractive index. The instrument is shown in Fig. 4, 
with the prism casing wide open. Its application requires so little 
time that after a little practice a person working alone can readily ex- 
amine 15 or 20 samples in an hour. 
The method of use is as follows : The surface A and that to which 
it is opposed when the prism casing is closed must first be cleaned by 
means of a soft piece of linen 
moistened with a little alcohol 
or ether. Place the instru- 
ment so that the surface of 
the prism B is horizontal, 
then apply 2 or 3 drops of the 
clear fat, best from a small 
filter paper held between the 
fingers. Close the prism cas- 
ing and fasten it by means of 
the pin C. The surfaces of 
the two prisms are now sepa- 
rated from each other only by 
the very thin layer of fat. 
With the instrument in its 
original position, the mirror 
I) adjusted so as to illuminate 
the field clearly, and the upper 
part of the ocular so adjusted 
that the scale within is most 
clearly defined, read off at 
what point of the scale the 
line between light and shade 
falls. 
Since the degree of refraction is influenced by the temperature, it is 
necessary to have some arrangement whereby the temperature of the 
specimen between the prisms can be accurately determined. This 
is arranged in the following manner: A current of warm water is 
conducted by means of a rubber tube connected with the inlet E into 
the prism casing, thence through the rubber tube F to the upper 
part, from which it escapes through the outlet G. The bulb of the 
thermometer projects into the current of water. The standard tem- 
perature for observations with this instrument is 25° C., and at this 
temperature natural butter, which has a refractive index of 1.459- 
1.462, will give a reading of from 49.5 to 54 on the scale, while oleo- 
margarine, which has a refractive index of 1.465-1.470, will show 
Fig. 4. 
Zeiss butyro-refractometer. 119 
CHEESE. 
58.6 to 66.4, and mixtures of the one with the other will give from 
54 upward, according to the percentage of oleomargarine present. 
According to Wollny, to whom the invention of the instrument is 
largely due, any specimen which at a temperature of 25° C. gives a 
higher reading than 54 will invariably be found on chemical analysis to 
be adulterated, but he suggests in order to remove all chance of adul- 
terated butter escaping detection, that this limit be reduced to 52.5 and 
that all samples giving the latter reading be examined chemically. 
With temperatures other than 25° C., it is necessary to make cor- 
rections of 0.55 of a scale division for each degree C. The following 
table shows the maximum reading for pure butters at different tem- 
peratures. 
Temp. 
Sc. div. 
Temp. 
Sc. div. 
Temp. 
Sc. div. | 
Temp. 
Sc. div. 
25° 
52.5 
31° 
49.2 
37° 
45.9 
43° 
42.6 
26 
51.9 
32 
48.6 
38 
45.3 
44 
42.0 
27 
51.4 
33 
48.1 
39 
44.8 
45 
41.5 
28 
50.8 
34 
47.5 
40 
44.2 
29 
50.3 
35 
47.0 
41 
43.7 
30 
49.8 
36 
46.4 
42 
43.1 
There are other processes for the investigation of the character of 
butter fat, including the determination of the specific gravity, melting 
point, iodine absorption number, and saponification equivalent, but for 
all practical purposes the determination of the refractive index or of 
the volatile fatty acids is ordinarily sufficient, and the other determi- 
nations are merely corroborative. 
CHEESE. 
For thousands of years cheese has been known as a very valuable 
food and much attention has been paid to different methods of manu- 
facture. At the present time very many varieties are made, their 
nature depending upon that of the raw material, the method of pro- 
ducing the curd, the proportions of the several constituents, and the 
method of ripening. Most varieties are made from cow's milk ; some 
are made from that of ewes, and others from that of goats. 
The milk is used either in its natural condition or skimmed or with 
the addition of cream. Generally it is used in its natural condition. 
Whatever the kind, the following is the general process of manufac- 
ture. The milk, with or without coloring matter as desired, is heated 
to 80° F. or over, and then curdled by means of rennet or by the 
acids formed by the ordinary milk bacteria. Usually rennet is em- 
ployed ; sometimes sour whey. The coagulation should be complete 
in from 40 minutes to an hour. Too rapid coagulation causes the 
curd to be hard, tough, and unsuitable for the subsequent manipula- 
tion ; too slow action produces a soft curd difficult to work and not 
uniform in character. After the process of coagulation is complete, 
the curd is cut or broken into small pieces, and the whey is drawn off. 
The curd is then gathered into a heap and covered and allowed to 120 
FOODS. 
stand for an hour or more, during which time its increasing acidity 
assists in its hardening and promotes the separation of the remaining 
whey. When the curd has attained the proper consistence, it is placed 
in the cheese press and subjected to gradually increasing pressure, and 
after this process is completed it is removed to the curing place. 
For the proper ripening of cheese it is essential that the curd be of 
the proper consistence throughout and that only the favorable organ- 
isms be present, and these in not too great abundance. 
The curd produced by the action of sour whey is highly acid and 
inclined to be greasy. Owing to its high degree of acidity it is not a fa- 
vorable ground for the growth of many of the bacteria which are engaged 
in the production of the different kinds of flavor, and so the number 
of varieties possible of manufacture by sour whey is limited. Rennet, 
on the other hand, produces a curd which is elastic and not greasy or 
sticky, and which is a good culture medium for the bacteria whose as- 
sistance is needed. It acts best in milk which is slightly acid, for if 
the milk is neutral or only very slightly acid the coagulation proceeds 
very slowly and the curd will not contract sufficiently to expel the 
whey ; if the milk is too acid the process of coagulation is too rapid 
and the result too tough. A soft curd retains too much whey, and the 
fermentation of the milk sugar of the whey causes " huffing," or swell- 
ing, for the prevention of which preservatives are sometimes employed. 
The bacteria concerned in the process of ripening exist in the original 
milk or in the air of the place of manufacture. Sometimes the vari- 
eties which produce cheese " faults " gain a foothold on the premises 
and can be eradicated only by means of thorough cleaning and disin- 
fection. The ripening process is carried on at about 70° F. It is 
essentially a process of decomposition in which both bacteria and 
moulds are concerned, and for the production of the same kind of 
cheese the same varieties of organisms must be present, and the par- 
ticular variety producing a particular flavor must find the conditions 
such as are favorable to its predominance. It is not possible to start 
with milk which is entirely sterile and then to inoculate with the par- 
ticular varieties wanted, since to sterilize milk completely requires the 
application of such a degree of heat as will produce changes in the con- 
dition of the casein, interfere with the proper action of rennet, and in- 
jure the consistence of the curd. 
Ripening does not proceed satisfactorily when the curd has been 
produced through the action of acids. In ordinary ripening the casein 
is attacked by the organisms present, and ammonia, leucin, tyrosin and 
several kinds of fatty acids are produced. The latter unite with the 
lime salts, which up to this point have been in combination with the 
casein. The acids formed include butyric and valerianic. From the 
lactose we have in addition lactic acid. The process goes on at differ- 
ent rates with different kinds of cheese, and it may be short or long. 
In the production of certain forms of American and English cheeses 
the individual specimens are sealed hermetically in tin boxes and kept 
at a favorable temperature for as long as four years, the boxes being ADULTERATION OF CHEESE. 
121 
turned each day. The ordinary grades of cheese, however, undergo 
comparatively short periods of ripening. 
Composition of Cheese.-The composition of cheese varies very 
much according to the nature of the raw material and the process of 
manufacture. The fat shows the greatest variation in amount accord- 
ing as the cheese is made from whole milk, skimmed milk, or milk en- 
riched with cream. The most common American cheese is made from 
whole milk, as are also the leading varieties of English cheese as Ched- 
dar and Cheshire. The familiar Edam (Dutch) cheese is made from 
milk which has been partially skimmed. English Stilton is a type of 
cheese made from milk enriched with cream. The cheese richest of all in 
fat is what we know as cream cheese, but strictly speaking, this is not 
cheese at all, being simply fresh curd very rich in fat and not subjected 
to any process of ripening. The cheeses poorest in fat are those made 
from skimmed milk. They are tough, dry, and of but little flavor, and 
such as they have is inclined to be unpleasant. American cheeses of 
good quality may be said in general to contain about 36 parts of fat, 
30 of proteids, 30 of water, and the balance salts. The leading Eng- 
lish cheeses, excepting Stilton, contain rather more water, about 35 per 
cent., and correspondingly less fat. Swiss cheese has practically the 
same composition, but contains rather more proteids and correspond- 
ingly less fat. Skimmed milk cheeses are particularly rich in proteids, 
containing often as high as 50 per cent. With the exception of those 
made from skimmed milk, it may be said in general terms that cheese 
is about one-third fat and one-third proteids. 
Of the many varieties of cheese put up in small bulk mostly for use 
as a relish rather than as a substantial article of diet, the following may 
be mentioned. Roquefort is made from the partly skimmed milk of 
ewes. It does not vary much in its percentage of fat and proteids from 
American and English cheeses. Gorgonzola is very similar to Roque- 
fort in composition and also in the method of manufacture. Both are 
ripened with the assistance of moulds which are mixed with the curd 
with powdered bread crumbs on which they have been cultivated, and 
they are also inoculated after being shaped. Parmesan cheese is made 
from partly skimmed goat's milk. It is very rich in proteids and con- 
tains only about half as much fat as American cheese. Camembert 
cheese is a soft cheese containing rather more than 50 per cent, of water 
and about 20 per cent, each of fat and proteids. It is ripened by a 
peculiar process which gives it a much more pronounced and perme- 
ating odor than almost any other known variety. 
Adulteration of Cheese.-At the present time the only extensive 
form of adulteration of cheese consists in the substitution of lard for 
the usual and proper kind of fat. Lard and skimmed milk colored 
with annatto are mixed together, heated to about 140° F. in tanks, 
and emulsionized with the assistance of appropriate machinery; the 
mixture is then coagulated in the same way as in the ordinary process 
of making cheese. Such cheese is now designated in the United States 
statutes relating to such products as " filled cheese," which includes 122 
FOODS. 
" all made of milk or skimmed milk with the admixture of butter, an- 
imal oils or fats, vegetable or any other oils, or compounds foreign to 
such milk." 
A decree promulgated in Belgium on September 21, 1899, defines 
cheese as a product obtained from pure milk, skimmed milk, milk coag- 
ulated by the aid of rennet or acidification, or any other product obtained 
by heating milk mixed or not with coloring matter, salt, and spices, 
and subjected to pressure and fermentation. It forbids the sale except 
when properly labelled in such way as to reveal its true nature, of all 
cheese containing any other substance than those mentioned, such as 
oleomargarine or other foreign fat, potatoes, and bread. An exception 
is made, however, in favor of Roquefort in which bread crumbs are 
present not as an adulteration but for the serving of a useful purpose. 
Cheeses mixed with mineral matter other than salt and with antiseptics 
in general are forbidden. 
In some parts of Germany, bean meal and potatoes are used some- 
what as adulterants, and there and elsewhere a great variety of sub- 
stances are said to have been used to a greater or less extent in times 
gone by. In general it may be said that outside of lard and other 
foreign fats the only adulteration of any importance consists in the 
admixture of preservatives. These are more commonly added to 
skimmed milk cheeses than to those of good quality. 
Analysis of Cheese. 
Determination of Water.-Cut the specimen into small bits or 
thin slices. Weigh out about 5 grams in a platinum dish containing 
sand or asbestos fiber and dry to constant weight. 
Determination of Ash.-Ignite the dried residue at as low a tem- 
perature as possible, and, after cooling, note the increase in weight over 
that of the dish and its original contents. 
Determination of Fat.-Triturate about 25 grams of the specimen 
in a mortar with about an equal bulk of fine beach sand. Transfer 
the whole to a Soxhlet extractor and proceed in the manner described 
under the analysis of milk. 
Determination of Proteids.-Proceed in the manner given under 
analysis of milk, using about 2 grams of the sample. 
Determination of the Nature of the Fat.-For the detection of 
foreign fats the method of procedure is the same as described under 
the analysis of butter, after obtaining the fat in a pure condition. 
The residue obtained in the determination of the amount of fat will 
serve fop this purpose. 
Cheese as a Cause of Poisoning. 
For many years cheese has been known to be an occasional cause of 
single and multiple cases of poisoning, and various theories concerning 
the nature of the poisonous agent have been promulgated. It was not 
until 1884 that the cause was revealed by Professor V. C. Vaughan VEGETABLE FOODS. 
123 
whose attention was drawn to outbreaks in Michigan during 1883 and 
1884, in which over 300 persons were affected. He traced the whole 
trouble to twelve different cheeses, from several of which he isolated 
the poisonous principle, a ptomain, to which he gave the name " tyro- 
toxicon." The symptoms caused in the outbreaks referred to included 
vomiting, diarrhoea, abdominal pain, dryness and constriction of the 
throat, feeble and irregular pulse, and marked cyanosis. In some 
cases, vomiting and diarrhoea were followed by marked nervous pros- 
tration. In some the pupils were dilated. 
Within a short time after Vaughan's discovery, the poison was 
found by Wallace 1 in some cheese that was the cause of poisoning of 
not less than 50 persons out of about 60 who had eaten of it. The 
onset appeared in from 2 to 4 hours. The most constant and severe 
symptoms were vomiting and chills. These were succeeded by severe 
epigastric pain, cramps in the legs and feet, purging and griping, 
numbness especially marked in the legs, and very marked prostration. 
Vomiting and diarrhoea lasted from 2 to 12 hours; chills and cramps 
from 1 to 2 hours. No deaths occurred, and all recovered within 3 
days. The severity of the symptoms bore no relation to the amount 
eaten; some of the severest cases were of persons who ate but spar- 
ingly- 
Tyrotoxicon has been found by a number of others in cheese, milk, 
and ice cream. 
So far as is known, cheese does not act as the carrier of pathogenic 
bacteria. Experiments have shown that the ordinary pathogens when 
introduced into cheese retain vitality for but a short time. 
The vegetable foods may be conveniently divided into several 
classes as follows : 
1. Farinaceous seeds. 
(a) Cereals. (6) Legumes. 
2. Farinaceous preparations. 
3. Fatty seeds. (Nuts.) 
4. Vegetable fats. 
5. Tubers and roots. 
6. Herbaceous articles. ("Vegetables.") 
7. Fruits used as "vegetables." 
8. Fruits in the narrower sense. 
9. Edible fungi. 
10. Saccharine preparations. 
The words fruit and vegetable are capable alike of broad and narrow 
meanings. In the strict sense the cereals, legumes, nuts, and many of 
the articles commonly called vegetables are fruits, but popular usage 
has narrowed the latter term to include the pulpy substance enclosing 
the seeds of various trees and plants, and only such as are pleasant to 
Section 4. VEGETABLE FOODS. 
1 Medical News, July 16, 1887, p. 69. 124 
FOODS. 
the taste and edible in the raw state, with the single exception of the 
quince, which is edible only in the cooked condition. Vegetables in 
the ordinary sense include any part of herbaceous plants, as the stem, 
root, leaves, and fruity products used commonly in the cooked state or 
in the form of salads. Thus, in the popular usage of the terms, 
squashes aud melons, which are the fruits of plants of the same family, 
are classed respectively as vegetables and fruits, and the cereals and nuts 
are classified under neither head. 
First in importance of vegetable foods are the farinaceous seeds ; 
they are of very high nutritive value and easily digested. 
1. Farinaceous Seeds. 
(a) Cereals.-The cereals include wheat, rye, barley, oats, corn, 
buckwheat, and rice. They are very largely starchy and agree in gen- 
eral composition, but they differ in the proportions in which their sev- 
eral constituents are present. These include proteids, carbohydrates, 
ether extractives, mineral matter, and moisture. 
The proteids include a large number of closely related compounds, as 
yet only imperfectly studied, which will be mentioned in the consider- 
ation of each member of the group. The carbohydrates include those 
which are soluble, sugar and dextrin, and those which are insoluble, 
starch, cellulose, pentosans, and gelactans. (H. W. Wiley.) The other 
extractives include fats, resins, chlorophyll, and volatile oil " which 
constitutes the source of the odorous quality possessed by the grain." 
(Wiley.) The mineral matters are chiefly phosphates of calcium and 
magnesium, silica, and salts of sodium and potassium. 
The cereals contain also certain ferments, the most important of 
which, and the only one which has been studied with any thorough- 
ness, is diastase. This acts upon starch, converting it into sugar. The 
others include some which act upon the proteids. 
WHEAT. 
Wheat is very properly classed as the most useful of the vegetable 
foods. The grain consists of a hard outside layer which is quite in- 
digestible and useless as food, and the cortex, softer and more friable, 
which yields flour of high nutritive value. The hard outside layer, 
which constitutes the greater part of the bran, irritates the alimentary 
canal, and while useful to some extent in conditions of habitual con- 
stipation, must be avoided in all irritable conditions of the bowel. It 
causes waste by unduly promoting peristalsis so that much of the 
nutritive portions are hurried along in an undigested condition. 
The proteids of wheat include, according to Osborne and Voorhees,1 
a globulin, an albumin, a proteose, gliadin, and glutenin. The two last- 
mentioned constitute between 80 and 90 per cent, of the whole ; in the 
presence of water they unite to form the very important substance 
gluten, so essential in the conversion of flour into bread. According 
1 American Chemical Journal, XV., p. 392. PLATE VII. 
Fig. 1. 
Wheat Starch, (x 285.) 
Fig. 2 
Rye Starch, (x 285.) WHEAT FLOUR. 
125 
to Wiley, they unite in almost equal proportions, but in the opinion of 
E. Fleurent,1 the closer the composition of gluten approaches the rela- 
tion of 25 parts of glutenin to 75 of gliadin, the more valuable the 
flour. 
The carbohydrates constitute the greater part of wheat as well as of 
the other cereals. They include starch, by far the most important, 
cellulose, sugars, dextrin, and a number of other compounds of com- 
parative unimportance. The starch granules are exceedingly variable 
in size, ranging from about .002 to 0.05 mm. in diameter. They are 
circular and flat, and many of them show a central hilum and con- 
centric rings. The latter appear with greater distinctness in flour that 
has been subjected to heat as, for instance, in the baking of crackers. 
The wide variations in size are illustrated in Plate VII., Fig. 1. The 
other carbohydrates exist in but very small proportions. 
Composition of Wheat.-The vast number of analyses of wheat 
show important variations in the percentage of its several constituents, 
for its quality is considerably influenced by climate, character of the 
soil and other conditions. According to H. W. Wiley,2 a typical 
American wheat of the best quality should yield approximately the 
following results : 
Moisture 10.60 
Proteids 12.25 
Ether extract 1.75 
Crude fiber 2.40 
Starch, etc 71.25 
Ash 1.75 
100.00 
These figures do not vary materially from the averages of a large 
number of analyses of samples of miscellaneous origin compiled by 
Kbnig, excepting in the proportions of moisture and starch, in which 
respects Wiley's typical specimen shows superior value, being less rich 
in the one and richer in the other constituent. 
In the manufacture of flour the wheat kernels are first subjected to 
a process of thorough cleaning, and are then cracked, crushed, and 
ground finer and finer until the required state of fineness is attained, 
the bran and other undesirable portions being removed by bolting. 
All flour is by no means the same in composition and quality; in fact, 
several grades of flour may be made from the same wheat by the em- 
ployment of different processes of manufacture. Flours are graded 
according to color and appearance, those which make the whitest bread 
ranking highest, although not equal in nutritive value to those classed 
as low grade. The flours of the several grades are known commer- 
cially as " patent," " family," 11 bakers'," and by other names which to 
the public have no special significance. Typical flours of the grades 
Wheat Flour. 
1 Comptes rendus, 1898, p. 126. 
2U. S. Department of Agriculture, Division of Chemistry, Bull. 13, Part 9, p. 
1189. 126 
FOODS. 
known as 11 high-grade patent " and " bakers' " should have, according 
to Wiley, approximately the following composition : 
Moisture. 
Proteids. 
Ether extract. 
Carbohydrates. 
Ash. 
Patent 
12.75 
10.50 
1.00 
75.25 
0.50 
Bakers' 
11.75 
12.30 
1.30 
74.05 
0.60 
The average composition of 210 samples of wheat flour of high and 
medium grades and of grades not indicated is, as given by Atwater 
and Bryant, as follows : 
Moisture 12.00 
Proteids 11.40 
Ether extract 1.00 
Carbohydrates 75.10 
Ash . 0.50 
100.00 
Thirteen samples of low grade averaged as follows : 
Moisture 12.00 
Proteids 14.00 
Ether extract 1.90 
Carbohydrates 71.20 
Ash 0.90 
100.00 
It will be noticed that the high grade flours are poorer in proteids 
and fat, and correspondingly richer in starch. Other grades of flour 
include those known as graham and entire wheat. Graham flour is 
generally understood to be a product containing all of the constituents 
of the original grain in their same proportions. When it came first 
into use such, indeed, it was, but at the present time it is an unbolted 
or partially bolted product of thoroughly cleaned and dusted wheat. 
Entire wheat flour is also understood to contain all of the original 
constituents of the grain, but is, in fact, made from wheat deprived of 
its outer coverings. It makes a somewhat dark colored bread which 
is very palatable. 
Parenthetically it may not be out of place to comment here upon the 
absurd views maintained by a large part of the community as to the 
superiority, from a hygienic standpoint, of foods containing all of the 
constituents of the cereals from which they are prepared. It is diffi- 
cult to understand how the nutritive value of any food can be increased 
by the retention of matters which are completely indigestible and to a 
certain extent irritating to the digestive tract. It is argued that an 
all-wise Creator made wheat, for example, in the form in which we 
see it, and that it is not for us to attempt to improve it, as we think, 
by discarding the outer layers. But this sort of reasoning might be 
extended so as to favor the consumption of the peel of oranges, the 
bones of fish, the feathers of birds, and other innutritions and undesir- 
able waste products. 
Preparations of Wheat Flour. Bread.-First in importance of 
the preparations of wheat flour is bread. In the broad sense, bread 
includes all forms of baked flour, whether leavened or unleavened ; PREPARATIONS OF WHEAT FLOUR. 
127 
iii the common use of the term, it includes only those in which 
leavening agents are used, the other forms being designated as pilot 
bread, crackers, biscuits, etc. 
The adaptability of wheat flour for bread-making is due to its gluten 
content. This substance, by reason of its tenacity, is capable of en- 
tangling the gas generated in the process, and by reason of its solidifi- 
cation by heat, furnishes a porous or spongy product easily penetrated 
and acted upon by the gastric juice. Not all cereals are capable of 
being made into bread, since, as will be seen, in most of them this 
very essential agent is lacking. 
For the preparation of bread of good quality the flour should con- 
tain not much in excess of the average amount of moisture, and should 
be so cohesive that after being compressed in the hand it will keep its 
shape on being released. 
In the making of bread the flour is mixed with warm water or milk, 
salt, and yeast, kneaded into a stiff dough and placed in a warm sit- 
uation. The yeast attacks the sugar and splits it into alcohol and car- 
bonic acid gas; the latter by its evolution and expansion causes the 
dough to become porous and to " rise." The fermentative process 
gives rise also to variable amounts of lactic and acetic acids. The 
raised dough is then baked in suitable pans, and its porous character 
is increased by the further expansion of the gas by heat and is made 
permanent by the solidification of the gluten by the same influence. 
If the fermentation is not allowed to proceed far enough, the resulting 
bread will be soggy or " heavy "; if too far, it will be sour. 
In place of yeast as a leavening agent, bicarbonate of sodium, com- 
monly known in the household as saleratus, and baking powders are 
very extensively employed. For the evolution of carbonic acid gas 
from sodium bicarbonate, the presence of an acid is necessary, and this 
is secured by the use of sour milk. The flour is first thoroughly 
mixed with the bicarbonate and then made into a dough with the 
milk. Bread made by this process is rarely of good quality, since 
it is difficult to hit upon the proper amounts of the two agents for the 
best results and any excess of the bicarbonate causes discoloration and 
disagreeable flavor. A better plan is to employ baking powder, which 
consists of sodium bicarbonate and an acid salt combined in such pro- 
portions that all of the available gas is set free from the alkaline salt 
and no unpleasant tasting residue is left. The only advantage pos- 
sessed by baking powders is the saving of time and labor ; the result- 
ing bread is distinctly inferior to that made with yeast. The com- 
position of the various classes of baking powders will be stated 
further on. 
Another process of securing leavening is that of spontaneous fer- 
mentation brought about by the enzymes present normally in flour. 
This process, known as " salt rising," is not in common use, requires 
much more manipulation than any other, possesses no advantages, and, 
therefore, deserves no further mention. 
Freshly baked bread is much less digestible than that which has 128 
FOODS. 
been kept a day or two. Its softness favors its clogging together dur- 
ing mastication into a close mass which is less easily attacked by the 
gastric juice. In this country, however, it is the almost universal 
custom to eat bread, particularly in the form of breakfast rolls, not 
only in the fresh condition, but hot from the oven. When bread is 
kept for a day, it loses part of its moisture and acquires increased 
firmness and friability which help maintain its porosity during masti- 
cation. 
It may acquire unwholesome properties on keeping, due to changes 
brought about in the presence of moisture by micro-organisms. Good 
bread is only slightly acid, but if kept in a moist state is likely to be 
markedly so, and then may cause in those not habituated to its use 
gastric derangement and diarrhoea. The bread in this condition is 
undergoing fermentative changes that are hastened by the body tem- 
perature, with consequent evolution of gaseous products which cause 
flatulence and discomfort, and of irritating compounds which induce 
abdominal pain and diarrhoea. Bread made from old and partially 
spoiled flour is likely to have a distinctly sour taste and to be un- 
wholesome in the manner above described. Mouldy bread also is 
likely to be a cause of digestive derangement. 
Composition of Wheat Bread.-Since wheat flour itself is of vari- 
able composition, and since in the domestic manufacture of any article 
of food the processes employed are subject to slight or considerable 
variations, analyses of wheat bread must necessarily show great differ- 
ences in the proportions of the several constituents. Averages ob- 
tained from examinations of samples of all sorts and of miscellaneous 
origin can hardly represent the composition of bread of good average 
or high quality. Wiley gives the following as the approximate com- 
position of a " typical American high-grade yeast bread made with the 
best flour and in the most approved manner." 
Moisture 35.00 
Proteids 8.00 
Ether extract 75 
Ash 1.50, 
Fiber 30 
Carbohydrates, other than fiber < 54.45 
ioOb 
Toast.-In the process of toasting, a large part of the moisture is 
driven off, the surfaces are scorched, greater firmness is acquired, and 
the product is more easily digestible. Good toast cannot be made from 
perfectly fresh bread on account of the moisture present which causes 
sogginess; it can be made only from bread at least a day old. The 
slices should not be thick, since then, while the surface is scorched, the 
interior acquires increased softness under the action of heat and becomes 
less digestible than the original bread. 
Rusks are much like toast. Instead of being subjected to the direct 
action of hot coals, the bread slices are baked for a time in a moderately 
hot oven. ADULTERATIONS OF FLOUR. 
129 
Pulled bread is the crumb of freshly baked loaves pulled out in small 
masses and baked again like rusks. 
Crackers, or biscuits, are preparations made from unleavened dough 
and baked so dry as to be brittle. They keep well for a long time 
without losing their palatability. If not properly stored and cared for, 
they may, of course, become damp, musty, and mouldy. In composi- 
tion they vary but little from the flour of which they are made; they 
are drier, and what they lack in moisture, they make up in fat, which, 
in the form of butter or lard, is added to prevent them from becoming 
too hard and dry. 
Macaroni, spaghetti, and vermicelli are preparations made with hard 
wheat rich in gluten. The flour is made into a stiff paste with hot 
water, and the compound is then pressed through holes or moulds in a 
metal plate and dried. They are exceedingly nutritious, but they are 
not as easy of digestion as other preparations of wheat on account of 
their closeness. They were first made on a small scale in Sicily, but 
now are produced in enormous amounts in Italy, France, Germany, and 
other countries. In their manufacture, American wheats are not held 
in high esteem, containing not sufficient gluten and too much starch. 
The best wheat for the purpose comes from a particular district in 
Russia and from Algeria. Formerly, a grain from southern Italy was 
regarded as the most suitable. 
Other preparations of wheat flour include cakes, which on account 
of the contained butter, eggs, and sugar, are richer than bread ; pastry, 
which, on account of its content of lard, is more difficult of digestion ; 
and flour puddings, which, being very close, require much time for di- 
gestion and often cause sensation of weight and oppression. 
Adulterations of Flour.-Up to within comparatively recent years, 
flour has not been much subject to adulteration. Occasionally, certain 
mineral substances, as magnesium carbonate, gypsum, and ground 
chalk have been reported in European samples, but such have been 
employed as adulterants very rarely, if, indeed, at all in American 
flours. Alum has been added sometimes to flour of inferior quality 
to improve its color or to check beginning decomposition. Whether 
this addition is objectionable from a hygienic standpoint is a subject 
over which there is a decided disagreement. It is believed by some 
that the amount of alum added is sufficient to exert an injurious effect 
on the digestive tract on account of its astringent action, and bring 
about constipation and dyspepsia. Others believe that it can do no 
harm whatever either to the consumer or to the nutritive value of the 
food, and still others hold that while it is not injurious to health, it 
lessens the nutritive value of the flour by forming insoluble aluminum 
phosphate and thus depriving the system of the phosphates which 
otherwise would be absorbed. 
It is a fact that flour treated with alum on account of beginning 
deterioration has caused untoward effects, but it would be impossible 
to determine how much influence should be ascribed to the alum and 
how much to the products formed by the fermentative processes in 130 
FOODS. 
operation before the addition. The weight of evidence, however, is in 
favor of the view that alum is not incapable of producing injury when 
taken into the system habitually in small amounts, and that it should 
be excluded from all articles of food intended for man. 
On account of the growing tendency to mix other mill products of 
inferior value with wheat flour, such, for instance, as rye and corn flour, 
a law was passed by Congress in June, 1898, to meet the evil and inci- 
dentally to make it a source of revenue. All adulterated flour is by 
the act referred to designated as 11 mixed flour," which term u shall be 
understood to mean the food product made from wheat mixed or 
blended in whole or in part with any other grain or other material, or 
the manufactured product of any other grain or other material than 
wheat." Under the provisions of the law, all persons engaged in the 
business of making mixed flour are required to pay a special annual tax, 
every package must be plainly labelled, the names of the ingredients 
being set forth, and upon every package of 196 pounds a tax of 4 
cents shall be paid. Under the regulations of the Treasury, the term 
" mixed flour " is held not to include " the milling product from corn, 
rye, buckwheat, rice, or other cereals than wheat put upon the market 
as the flour or meal derived from such cereals, although the product 
may contain a percentage of wheat flour." 
The detection of other cereals and starches in wheat flour is best 
accomplished by means of the microscope, since, as will appear, each 
has its characteristic appearance. 
According to Vogel, 70-per-cent. alcohol containing 5 per cent, of 
hydrochloric acid remains colorless after being used to extract pure 
wheat or rye, pale yellow if barley or oats be present, and orange 
yellow if mixed with pea flour. 
RYE. 
In external appearance rye presents a close resemblance to wheat, 
but the kernels are darker in color and smaller in size. It is by no 
means so important as wheat as an article of food in this country, but in 
some parts of Europe it constitutes the main food supply of the peasantry. 
According to Wiley, a typical American wheat should have approx- 
imately the following composition. 
Moisture 10.50 
Proteids 12.25 
Ether extract 1.50 
Crude fiber * 2.10 
Starch, etc 71.75 
Ash 1.90 
100.00 
American rye is smaller than that grown abroad, and contains less 
moisture. The proteids of rye are more like those of wheat than those 
of any other cereal, and in consequence rye stands next to wheat in 
adaptability for bread-making. The yield of gluten is inferior in 
amount to that obtainable from wheat. PLATE VIII. 
Fig. 1. 
Barley Starch, (x 285.) 
Fig. 2. 
Oats Starch, (x 285.) 131 
OA TS. 
The starch of rye is much like that of wheat. The granules are 
rather more variable in size, the smallest of each kind being about 
equal, but the largest of rye somewhat surpassing those of wheat. 
There is but one point of difference in microscopic appearance of 
value in detecting the admixture of rye with wheat, namely, that a 
certain fair proportion of the larger sized granules of rye present 
irregular crosses or fractures. This is illustrated in Plate VII., 
Fig. 2. 
Bread made from rye flour is but little inferior in nutritive value to 
that from wheat, but it is less pleasing to the eye, being of a brownish 
tint, and has a peculiar sour taste not altogether agreeable on first 
acquaintance. Not uncommonly its use by one not habituated to it 
causes a tendency to diarrhoea, which, however, is soon overcome. 
BARLEY. 
This important cereal is used mainly in the manufacture of beer 
and but to a limited extent as a food. Deprived of its husk and 
rounded and polished by attrition, it is known as " pearl barley," and 
in this form is more or less used in the preparation of barley water, 
a drink for invalids. In its composition, barley is quite similar to 
wheat and rye, but as it is devoid of gluten it cannot be made into 
bread. It is sometimes mixed with wheat flour for purposes of bread- 
making, but the product is less palatable and less digestible than 
ordinary bread. 
Wiley gives the following as the approximate composition of a 
typical American unhulled barley. 
Moisture 10.85 
Proteids 11.00 
Ether extract 2.25 
Crude fiber 3.85 
Starch, etc 69.55 
Ash 2.50 
100.00 
The proteids include, as in all cereals, a number of complex sub- 
stances, chief of which is hordein. The starch granules are like those 
of wheat, but are less variable in size. (See Plate VIII., Fig. 1.) In 
the manufacture of malt from barley for brewing, a peculiar nitroge- 
nous product, diastase, is formed, which has the property of converting 
starch to sugar. 
OATS. 
Oats are much used as human food in the form of oatmeal, which is 
the product of grinding the kiln-dried seeds deprived of the husk. It 
has a peculiar taste which is both sweet and bitter. 
The composition of unhulled American oats, as given by Wiley, is 
as follows : 132 
FOODS. 
Moisture 10.00 
Proteids 12.00 
Ether extract 4.50 
Crude fiber 12.00 
Starch, etc 58.00 
Ash 3.50 
100.00 
The mean composition of oatmeal, according to Blyth,1 is as fol- 
lows : 
Moisture 12.92 
Proteids 11.73 
Fat 6.04 
Sugar 2.22 
Dextrin and gum 2.04 
Starch 51.17 
Fiber 10.83 
Ash 3.05 
fooTooo 
The proteids of oats yield no gluten and hence this article of diet 
cannot be made into bread, though with water it can be made into thin 
cakes which are most palatable. Fat is present in greater abundance 
than in any other cereal. The starch granules are very small poly- 
hedra which show no hilum or concentric rings. They tend to adhere 
together in masses of variable size which are easily disintegrated by 
trituration in a mortar. The single granules are shown in Plate VIII., 
Fig. 2. 
Oatmeal is a very nutritious article of diet used largely as a break- 
fast food in the form of porridge. It exerts a somewhat laxative 
action and, therefore, cannot be eaten in irritable conditions of the 
bowel. It is also likely to disagree with some dyspeptics because of 
its tendency to cause acidity and heartburn. 
CORN. 
In the American usage of the word, corn includes the several vari- 
eties of Indian corn or maize. In England, the term is applied gener- 
ally to wheat, rye, oats, and barley, and more specifically to wheat; in 
Scotland, it commonly means oats. 
In this country, corn is in many ways the most important of the 
cereals, constituting in some parts the chief bread food, and being the 
main source of starch and glucose. 
The chief varieties are dent corn, showing a depression in the outer 
end of the kernel; flint corn, having a hard smooth exterior; sweet corn, 
rich in sugar and shrivelling when ripe; and pop corn, a very flinty 
variety with small kernels which contain a considerable amount of oil 
which, in the process of roasting, explodes and causes the extrusion of 
the starchy interior in the form so universally familiar. The variety 
in most common use from which the several kinds of meal, hominy, and 
samp are derived, is the flint corn. Hominy is the product obtained 
by grinding loosely the kernels deprived of the hull by soaking. Samp 
1 Foods : Their Composition and Analysis, London, 1896, p. 210. PLATE IX. 
Fig. 1. 
Corn Starch, (x 285.) 
Fig. 2. 
Rice Starch, (x 285.) CORN. 
133 
is the whole, or practically the whole, of the kernel minus the germ 
and hull. Indian meal, or corn meal, is the product obtained by grind- 
ing the kernels between stones or by other processes of milling, and 
removing more or less of the bran by sifting or bolting. According to 
the process employed, we have coarse and fine, and white and yellow 
meal. Prepared without removal of the germ, which is rich in oil, the 
product is prone to become rancid and mouldy on keeping. 
From a large number of analyses, Wiley deduces the following as 
the approximate composition of typical Indian corn. 
Moisture 10.75 
Proteids 10.00 
Ether extract 4.25 
Crude fiber 1.75 
Starch, etc 71.75 
Ash 1.50 
100.06 
The average of 19 analyses of samples of sweet corn by Mr. Clifford 
Richardson, quoted by Wiley, shows 
Moisture , 8.44 
Proteids 11.48 
Ether extract 8.57 
Crude fiber 2.82 
Starch, etc 66.72 
Ash 4 1.97 
100.00 
The composition of fine meal is given by Wiley as follows: 
Moisture 12.57 
Proteids 7.13 
Ether extract 1.33 
Total carbohydrates 78.36 
Ash 0.61 
100.00 
The lowered percentages of proteids and fats here shown are due to 
the removal of the germ, rich in fat, and of the finer envelopes, rich in 
proteids. 
The proteids of corn, as determined by Chittenden and Osborne, are 
made up of several globulins, including myosine and vitelline, two 
classes of albumins, and two of zeins. The starch granules are poly- 
hedral with rounded angles, and have a punctiform, sometimes stellated, 
hilum. They are much larger than those of oats, which they resemble 
somewhat in form. They are shown in Plate IX., Fig. 1. 
On account of its deficiency in gluten, corn meal is not well adapted 
to the making of leavened bread, but it is used in many forms of sub- 
stitutes therefor. It is mixed with salt and water, sometimes with the 
addition of milk or eggs, and baked into not over thick cakes, which, 
according to the method of preparation and baking, are known as 
johnnycake, corn dodger, corn pone, and corn bread. Sometimes, yeast 
and baking powder are employed. Corn meal is used extensively in 
the form of hasty pudding, or corn mush, and of Indian pudding. In 
whatever form used, corn meal is a most nutritious and wholesome food. 134 
FOODS. 
RICE. 
Rice is the principal food of a very large part, estimated at about a 
third, of the human race. Being, as will be seen, too poor in proteids, 
fat, and mineral matter to satisfy alone the needs of the body, the de- 
ficiencies are met by other vegetable products, as beans and peas, which 
are rich in these constituents. 
The form in which rice is seen in the household is the result of a 
polishing process which removes the reddish cuticle which the grain 
shows on the removal of the husk. Wiley's figures representing the 
composition of typical polished rice are as follows : 
Moisture 12.40 
Proteids 7.50 
Ether extract 0.40 
Crude fiber 0.40 
Starch, etc 78.80 
Ash 0.50 
100.00 
Rice is the richest of the cereals in starch and the poorest in all 
other respects. The proteids have not yet been systematically studied. 
Its starch is very easily digestible and is very useful in all disordered 
conditions of the digestive tract when other solid foods cannot be 
borne. Under the microscope, the starch granules are seen to be much 
like those of corn, but are considerably smaller and have sharper 
angles. They are less easily separated from one another and are com- 
monly in groups of variable size. They are shown in Plate IX., 
Fig-2. 
Rice cannot be made into bread, but is sometimes mixed with wheat 
flour in order to give whiteness to the bread. It is most commonly 
used in the freshly boiled condition or in the form of puddings. The 
most approved method of cooking it is steaming. This has the ad- 
vantage of not taking away any of the already deficient proteids and 
salts, which are to some extent extracted in boiling, and also that it 
leaves each kernel distinct in itself and not aggregated in the form of 
a soggy mush such as is often produced by improper boiling. 
BUCKWHEAT. 
This valuable cereal is very extensively used in this country as a 
breakfast food in the form of pancakes eaten hot with syrup or with 
butter and sugar. As it is devoid of gluten it cannot be made into 
bread. 
The composition of typical American buckwheat is given as fol- 
lows : 
Moisture 12.00 
Proteids 10.75 
Ether extract 2.00 
Crude fiber 10.75 
Starch, etc 62.75 
Ash 1.75 
"100.00 PLATE X. 
Fig 1. 
Buckwheat Starch, (x 285.) 
Fig. 2. 
Pea Starch, (x 285.) LEG UMES. 
135 
The crude fiber is very largely removed in the milling and is almost 
wholly absent from the white flour, a sample of which, analyzed by 
Wiley, had the following composition : 
Moisture 11.89 
Proteids 8.75 
Ether extract 1.58 
Crude fiber 52 
Starch, etc 75.41 
Ash 1.85 
100.00 
Buckwheat is the most expensive of the cereals and consequently is 
the most subject to adulteration with the cheaper members of the class. 
The admixture is readily detected by the microscope since the starch 
granules have a very characteristic appearance. They are small and 
angular, and of fairly uniform size. Ordinarily they are seen in fairly 
large masses which are not disintegrated in the process of milling. 
The starch is shown in Plate X., Fig. 1. 
(6) Legumes.-This group comprises peas, beans, and lentils. It 
is characterized by richness in proteids which may be present in more 
than double the amount found in wheat. The chief proteid is legumin, 
which much resembles casein and is commonly known as vegetable 
casein. According to E. Fleurent,1 the proteids of this group consist 
of vegetable casein composed of legumin and glutenin, and vegetable 
fibrin composed of albumin and gliadin. Thus : 
vegetable casein {S 
Vegetable fibrin ^64 
100.00 
Their high content of proteids makes them more satisfying than 
other vegetable foods and enables them to act as a fair substitute for 
animal food. The millions of rice eaters who, by reason of poverty or 
religious scruples, are denied the use of animal food, depend upon the 
legumes to supply the demands of the body for nitrogen. The East 
Indian, for instance, has no difficulty in satisfying his bodily needs 
with a handful of beans added to his daily ration of rice. 
While they are of a very high nutritive value, they must be ranked 
as much more difficult of digestion than the cereals. They require 
prolonged boiling when cooked whole, but are more quickly prepared 
and more completely digested when ground into meal and cooked with 
milk. Even under the most favorable conditions a large part of the 
proteids is lost in the excreta. Rubner has shown that a fifth to a 
third is not digested and absorbed, whereas in the case of bread the 
proteid loss is less than a seventh. 
Some individuals are obliged to forego the use of peas and beans on 
account of their aptness to cause flatulence through the formation of 
sulphuretted hydrogen from the sulphur in the legumin. This objec- 
tion does not apply to lentils since they contain no sulphur. 
1 Foods: Their Composition and Analysis, London, 1896, p. 210. 136 
FOODS. 
PEAS. 
The average of 61 analyses of peas compiled by Konig is as follows: 
Moisture 14.99 
Proteids 22.85 
Fat 1.79 
Crude fiber 5.43 
Starch, etc 52.36 
Ash 2.58 
100.00 
When dried peas become old, no amount of boiling will make them 
soft, and they must be soaked and crushed and then cooked in some 
other way. The immature pea, so highly prized as a spring and sum- 
mer vegetable, has a very different composition. Five analyses com- 
piled by Atwater and Bryant1 yielded the following average results : 
Moisture 74.6 
Proteids 7.0 
Fat 0.5 
Carbohydrates, including fiber 16.9 
Ash 1.0 
100.0 
The canned pea appears to contain considerably less nutriment. Of 
88 samples reported by the same authorities, none contained less than 
77.5 per cent, of water, and some contained as much as 92.7. Their 
average composition was as follows : 
Moisture 85.3 
Proteids 3.6 
Fat 0.2 
Carbohydrates 9.8 
Ash 1.1 
16(H) 
The starch granules of peas are represented in Plate X., Fig. 2. 
There are many varieties of beans belonging to the two large groups, 
the broad beans and the kidney beans, but their composition is in gen- 
eral quite similar. Forty-one analyses of broad beans and 10 of kid- 
ney beans compiled by Konig give the following averages : 
BEANS. 
Broad. 
Kidney. 
Moisture 
14.76 
13.74 
Proteids 
24.27 
23.21 
Fat 
1.61 
2.14 
Crude fiber 
7.09 
3.69 
Starch, etc 
49.01 
53.67 
Ash 
3.26 
3.55 
100.00 
100.00 
Eleven analyses compiled from American sources by Atwater and 
Bryant yield averages not materially different. 
1 Foods : Their Composition and Analysis, London, 1896, p. 210. PLATE XI. 
Fig. 1. 
Bean Starch, (x 285.) 
Fig. 2. 
Arrowroot Starch, (x 286.) SAGO. 
137 
Five analyses of string beans in the fresh state and 29 of canned 
samples yield the following averages showing, as in the case of peas, 
that the canned are less nutritious. 
Fresh. 
Canned. 
Moisture 
89.2 
93.7 
Proteids 
2.3 
1.1 
Fat 
0.3 
0.1 
Total carbohydrates 
7.4 
3.8 
Ash 
0.8 
1.3 
100.0 
100.0 
The Soja bean, which has been highly recommended in some quarters 
as a suitable food for diabetics, is remarkable for its high content of 
fat, and contains, besides, so large an amount of starch as to make it 
quite unsuited to the dietary of the diabetic. Kbnig has compiled 21 
analyses from all sources, and Jenkins and Winton 1 have collected 10 
more from American sources. The two groups give the following 
averages : 
Jenkins 
Konig. 
and Winton. 
Moisture 
9.51 
10.80 
Proteids 
33.41 
33.98 
Fat 
17.19 
16.85 
Crude fiber 
4.71 
4.79 
Starch, etc 
29.99 
28.89 
Ash 
5.19 
4.69 
100.00 
100.00 
Bean starch is shown in Plate XI., Fig. 1. 
LENTILS. 
Lentils are the most nutritious of the legumes, but are not a pop- 
ular food in this country excepting among certain of the foreign-born. 
Their use is, however, on the increase. The averages of 14 analyses 
compiled by Kbnig are as follows : 
Moisture 12.34 
Proteids 25.70 
Fat 1.89 
Crude fiber 3.57 
Starch, etc 53.46 
Ash 3.04 
100.00 
2. Farinaceous Preparations. 
Under this head are included sago, tapioca, and arrowroot. 
SAGO. 
Sago is derived from the pith of the stems of a number of species of 
palms. The pith is extracted and ground to a powder which is then 
mixed with water and strained. The starch granules pass through 
1 Experiment Station Bulletin, No. 11, Washington, 1892. 138 
FOODS. 
with the water and are deposited as a sediment which constitutes the 
sago flour. From the flour made into a paste, the various forms of gran- 
ulated sago are prepared. 
Sago is quite an important starch preparation and serves as a light 
and digestible food for invalids and dyspeptics, but its use is not re- 
stricted to these alone. It absorbs the liquid in which it is cooked and 
becomes soft and transparent, but retains its original form. 
Tapioca is derived from a thick fleshy tuberous root called " manihot." 
The starch, which is extracted by a method quite similar to that em- 
ployed in the preparation of sago, is heated in a moist state on hot plates 
and stirred about with iron rods, and thus forms irregular masses of 
transparent granules. In the process of heating, many of the starch 
granules become ruptured and are then partially soluble in cold water. 
Tapioca, like sago, is useful for both sick and well. 
TAPIOCA. 
ARROWROOT. 
Arrowroot is a pure form of starch from the tuberous root of the 
maranta. Its name is derived from the fact that the maranta root is 
believed to counteract the effects of arrow poison. It is used chiefly 
as a bland article of food in the sick-room in the form of light pudding 
or other desserts, but may be combined with other starch foods and 
made into bread. There are several varieties, the best of which come 
from Bermuda and Jamaica. Corn starch is frequently employed as a 
fair substitute. Arrowroot starch is shown in Plate XI., Fig. 2. 
3. Fatty Seeds (Nuts). 
Nuts are rich in fat and proteids, but contain no starch. They are 
of high nutritive value, but on account of their richness in fat they are 
not easily digested even when reduced to a finely divided state. 
ALMONDS. 
In the countries where they are produced, the almond is eaten both 
in the green and dry conditions. The ripe kernel has a skin with a 
bitter disagreeable taste. When this is removed by soaking for a 
time in warm water, the almond is known as " blanched." 
There are two varieties of almond, the sweet and the bitter, both of 
which contain over 50 per cent, of oil, about half as much proteid 
material, gum, sugar, and crude fiber. Both contain emulsin, a sub- 
stance which, in the presence of water, acts upon the glucoside amyg- 
dalin, present only in the bitter variety, to form hydrocyanic acid, glucose, 
and benzoic aldehyde. On account of this reaction, the bitter almond 
is not always safe, and fatal results have occurred from its ingestion. 
When almonds are baked, they are made more brittle and are more 
easily reduced to a powder. OLIVE OIL. 
139 
The fleshy white kernel of the cocoanut contains about 70 per cent, 
of fat. The milky interior is chiefly water, but contains nearly 7 per 
cent, of sugar. 
COCOANUTS. 
WALNUTS. 
All of the trees of the genus Juglans yield nuts classed as walnuts; 
the different varieties, though differing in outward appearance and in 
taste, have practically the same composition. They contain about 60 
per cent, of fat, about 16 per cent, of proteids, and about 7 per cent, 
of sugar and gum. The hazel nut, which belongs to the oak family, 
has about the same composition. 
The peanut, known also as ground nut and goober, is less rich in fat, 
but richer in proteids than other nuts. It contains about 45 per cent, 
of the former and about 30 per cent, of the latter. 
PEANUTS. 
CHESTNUTS. 
The chestnut is not of this class, but for convenience will be con- 
sidered here rather than with the farinaceous seeds, in which class it 
properly belongs. It contains but little fat and proteids, about 15 per 
cent, of sugar, about 25 per cent, of starch, and about 50 per cent, of 
moisture. It is very indigestible in the raw state, and even when 
cooked is very trying to the digestion of those with weak stomachs. 
It is very extensively used as a food by the French, Spanish, and Ital- 
ian peasantry in various cooked forms and largely in the form of bread. 
4. Vegetable Fats. 
The vegetable fats include the oils derived from the olive, cotton 
seed, peanut, and other seeds. They are used in the preparation of 
salads and for frying. The most important are the two first mentioned. 
OLIVE OIL. 
Olive oil is a bland fixed oil derived from the fruit of the many 
varieties of the olive tree. It is known by various names which des- 
ignate the grade, but is sold for the most part as virgin oil, which is 
the choicest grade of all and not extensively marketed. Virgin oil is 
made from the choicest olives, about three-fourths ripe, which are only 
slightly bruised in the mill so that only the olive pulp, and not the 
stone, is crushed. The crushed mass is then gathered in a heap, and 
the oil is allowed to drain away without pressure or outside assistance 
of any kind. The product has a greenish tint and a far more delicate 
taste than that made in the manner to be described. 
In the manufacture of the grades ordinarily seen in the market, the 
olives, both pulp and stones, are ground into an oily paste which is 140 
FOODS. 
packed into bags made of woven grass. These are placed in piles 
and subjected to pressure. As the oil drains away, boiling water is 
applied to the bags to keep up the flow, and that which is thus ob- 
tained constitutes the lower grade. Sometimes the pressed pulp is 
thrown into water and separated from the broken kernels which sink 
to the bottom. The pulp is then gathered up and pressed again. 
On account of the cost of pure olive oil, adulteration with other 
cheaper oils is very extensively practiced. The principal adulterant 
is cotton-seed oil which is exported from this country in very large 
shipments for this and other purposes. Much of the oil sold in this 
country as olive oil is cotton-seed oil put up in the cheapest kinds of 
bottles, adorned with gaudy labels bearing inscriptions often not re- 
markable for accuracy in the use of the French language. The author 
has seen, for example, labels which indicated that the contents of the 
bottles had been " virginated." 
Adulteration of olive oil to only a slight extent with the cheaper 
oils is by no means easy of detection, but when the fraud is fairly ex- 
tensive it can be shown by chemical tests and by the use of the re- 
fractometer, the refractive index of olive oil being less than that of 
the cheaper substitutes. The iodine number and saponification equiv- 
alent of olive oil are both less than those of its adulterants. The be- 
havior of olive oil in contact with nitric acid or with alcoholic solu- 
tion of nitrate of silver is markedly different from that of the cheaper 
oils. Thus, equal volumes of strong nitric acid and olive oil mixed 
together and agitated in a flask give a product which has either a 
greenish tinge or at most one inclining to orange, and no marked 
change is perceptible on standing for five or ten minutes, whereas cot- 
ton-seed oil similarly treated yields almost immediately a reddish color 
which shortly darkens and becomes dark brown or almost black. 
Again, if 12 cc. of a suspected sample are mixed in a test-tube with 
5 cc. of a 2.5-per-cent. solution of nitrate of silver in 95 per cent, 
alcohol and placed in a beaker of boiling water, the resulting change 
of color gives indications as follows : if olive oil, the color is greenish ; 
if cotton-seed oil it becomes black; if sesame oil, it is dark reddish 
brown; if peanut oil, it is at first reddish brown, then greenish and 
turbid; if poppy oil, it is greenish yellow. For further details of 
chemical tests the reader is referred to the standard works on the 
adulteration of foods. 
COTTON-SEED OIL. 
This very important and cheap vegetable fat is a perfectly whole- 
some and desirable article of food. It is much used under its own 
name as a substitute for lard and olive oil for frying, and in place of 
the latter as an ingredient of dressings for salads. It lacks the fine 
flavor of olive oil, but its substitution in dressings can be detected only 
by the educated palate. From a hygienic standpoint there is abso- 
lutely no objection to its use in the preparation of foods. The same 
can be said of the other cheap vegetable oils. PLATE XII. 
Potato Starch, (x 286.) POTATOES. 
141 
5. Tubers and Roots. 
In the cooking of tubers, roots, and other vegetables, the albumins 
and globulins are coagulated, the fibrous matters in the cell walls are 
softened and ruptured, the starch granules swell up and burst, the 
starch itself becomes somewhat changed in character, and the whole 
mass is made more digestible. When boiling is the process employed, 
part of the mineral matter and more or less of the other soluble sub- 
stances, including certain proteid material, are extracted and lost. 
POTATOES. 
The potato is the most important of this group. It was intro- 
duced into Spain from Peru about the middle of the sixteenth 
century, and later, in 1585, into Ireland from Virginia by Sir Walter 
Raleigh who, in the following year, introduced it also into England. 
Prior to that time and even later, what was known in England as 
the potato and the " common potato " mentioned by Gerard in his 
Herbal, published in 1597, were sweet potatoes, "batata," introduced 
from Spain. 
The averages of 136 analyses (American samples) compiled by At- 
water and Bryant are as follows : 
Moisture 78.3 
Proteids 2.2 
Fat 0.1 
Total carbohydrates 18.4 
Ash 1.0 
ToEo 
These figures differ but slightly from the averages of 178 analyses of 
European samples. 
The proteids of the potato are chiefly in the albuminous juice be- 
tween and in the cells. Most of the mineral matter is salts of potash, 
and this, too, is almost wholly in the juice. The starch was discov- 
ered by Lenbert and Georgiewsky to be much more readily acted upon 
by the salivary enzyme than any of the cereal starches. The starch 
granules are much larger and more irregular in shape than any of 
those thus far shown. The hilum and concentric rings are quite dis- 
tinct. (See Plate XII.) 
In the process of cooking, the albuminous juice is coagulated and its 
watery part is absorbed by the starch granules, which swell and con- 
sequently distend the cells in which they are lodged. The coherence 
of the cells is reduced and they are then easily separated into a mealy 
mass. If the watery part of the juice is not wholly absorbed, the cells 
are separated with more or less difficulty, the potato remains firm in- 
stead of becoming mealy, and is then spoken of as close, waxy, or 
watery. In this state it is much less easily digested and may, indeed, 
be very trying to the stomach. The same condition is noticed in the 
case of potatoes which have been frozen; they are very watery and of 
inferior flavor however they are cooked. 142 
FOODS. 
According to Balland,1 the mealy condition is due not, as supposed, 
to an especially high content of starch, but to a low percentage of al- 
bumin, for a potato rich in this substance keeps its shape and neither 
cracks nor falls apart. He also points out that beneath the skin there 
are three well-defined layers which can be seen readily by holding a 
thin cross section against a strong light. The outermost is richest in 
starch and poorest in proteids, and in the innermost these conditions are 
reversed; the middle layer 
represents the mean compo- 
sition of the whole. 
The loss which occurs on 
boiling is much less when 
the skins are left intact than 
when removed ; the greatest 
loss occurs when the potatoes 
are first peeled and then 
soaked in cold water. When 
cooked by steaming, there 
is no loss whatever. The 
material lost in boiling has 
been determined by H. Snyder2 as follows : Skins removed, soaked 3 
hours; total nitrogen, 46 per cent., ash, 45.6 per cent. Skins re- 
moved, not soaked; total nitrogen, 16.9 per cent., ash, 17.9 per cent. 
Skins not removed; total nitrogen, 1 per cent., ash, 3.4 per cent. 
The composition of the potato and the loss of nutrients when boiled 
with the skin removed are shown by Snyder by a drawing which is 
here reproduced. (See Fig. 5.) 
Potatoes are so deficient in nitrogen that alone they cannot consti- 
tute a proper ration, but with foods rich in proteids, such as meats, 
beans, or peas, they are valuable and economical. 
The juice of the potato contains citric acid and citrates of potassium, 
sodium, and calcium, which fact accounts for the antiscorbutic value 
of this vegetable. 
Fig. 5. 
a, fiber, pectose,fat,etc.; 6, non-albuminoidnitrogenous 
matter; c, albuminoid nitrogenous matter; d, mineral 
matter. The hatched portion represents the loss. (After 
Snyder.) 
SWEET POTATOES. 
The average composition of sweet potatoes (95 analyses) is given by 
Atwater and Bryant as follows : 
Moisture 69.0 
Proteids 1.8 
Fat 0.7 
Total carbohydrates 27.4 
Ash 1.1 
lOO 
Starch constitutes much the greater part of the carbohydrates; the 
balance is mainly sugar. 
1 Journal de Pharmacie et de Chemie, 1897, VI. 
2 Department of Agriculture, Office of Experiment Stations, Bulletin No. 43, 1897. HERBACEOUS ARTICLES. 
143 
ARTICHOKES. 
The Jerusalem artichoke is so named not after the City of Jeru- 
salem, but from a corruption of the Italian word girasole, meaning 
sunflower, to which family the plant belongs. This tuber is quiet 
sweet to the taste, but it is not so agreeable as the 
potato. It contains no starch, but yields about 15 
per cent, of sugar. It is about twice as rich in 
proteids as the potato. When cooked it becomes 
quite soft and watery. 
Fig. 6. 
ROOTS. 
The carrot, beet, parsnip, turnip, oyster plant, and 
radish agree in a general way in composition and may 
be considered together. They are quite poor in 
proteids, and contain but a small amount of other 
nutriments. All of them are valuable on account 
of their antiscorbutic properties, for providing 
variety in the diet, and for flavoring other foods. 
Their average composition according to Atwater 
and Bryant is set forth in the following table. 
No. of 
Analyses. 
Water. 
Proteids. 
Fat. 
Carbo- 
hydrates 
including 
fiber. 
Ash. 
Beets 
24 
87.5 
1.6 
0.1 
9.7 
1.1 
Carrots 
18 
88.2 
1.1 
0.4 
9.3 
1.0 
Oyster plant'. 
1 
80.4 
1.0 
0.5 
17.1 
1.0 
Parsnips 
3 
83.0 
1.6 
0.5 
13.5 
1.4 
Radishes 
4 
91.8 
1.3 
0.1 
5.8 
1.0 
Turnips 
19 
89.6 
1.3 
0.2 
8.1 
0.8 
a, fiber, starch, fat, 
etc.; 6, sugar; c, non- 
albuminoia nitrogenous 
matter; d, albuminoid 
nitrogenous matter; e, 
mineral matter. The 
hatched portion repre- 
sents the loss when me- 
dium sized pieces were 
boiled. (AfterSnyder. ) 
Snyder represents diagrammatically the compo- 
sition of the carrot and the loss of nutrients when 
boiled. (See Fig. 6.) 
On account of the general resemblance in compo- 
sition, this diagram may be taken fairly to represent the whole group. 
6. Herbaceous Articles. 
These include various leaves, stems, and shoots. They contain but 
little nutriment, but are valuable for their salts and for the variety 
which they give to the diet. It is to be noted, however, that in 
proteids they are, as a class, equal or superior to the tubers and 
roots. They contain unimportant amounts of fat and sugar. The cab- 
bage and allied plants are not easily digested, and on account of con- 
taining more or less sulphur, may give rise to disagreeable flatulence 
and are not suited to weak digestions. Spinach is regarded as slightly 
1 The figures for oyster plant are taken from Konig. 144 
FOODS. 
laxative. Celery is not easily digested in the raw state, but is easily 
borne when stewed. Lettuce, cresses, and similar articles for salads 
are wholesome, digestible, and agreeable to the system. Asparagus, 
while containing but little nutriment, is particularly prized for its deli- 
cate flavor. Onions and leeks, being modified stems, belong in this 
group. They contain volatile oils which act as gentle stimulants.' ' 
The following table compiled from Atwater and Bryant gives the 
composition of the members of this group : 
No. of 
Analyses. 
Water. 
Proteids. 
Fat. 
Total 
carbo- 
hydrates. 
Ash. 
Asparagus 
3 
91.6 
2.1 
3.3 
2.2 
0.8 
Cabbage 
16 
91.5 
1.6 
0.3 
5.6 
1.0 
Cauliflower 
2 
92.3 
1.8 
0.5 
4.7 
0.7 
Sprouts 
1 
88.2 
4.7 
1.1 
4.3 
1.7 
Celery 
5 
94.5 
1.1 
0.1 
3.3 
1.0 
Lettuce 
8 
94.7 
1.2 
0.3 
2.9 
0.9 
Spinach 
3 
92.3 
2.1 
0.3 
3.2 
2.1 
Beet tops 
1 
89.5 
2.2 
3.4 
3.2 
1.7 
Dandelions 
1 
81.4 
2.4 
1.0 
10.6 
4.6 
Leeks 
1 
91.8 
1.2 
0.5 
5.8 
0.7 
Onions 
15 
87.6 
1.6 
0.3 
9.9 
0.6 
The composition of the cabbage and the loss incurred through boil- 
ing are shown in the accompanying figure (Fig. 7), by Snyder. In a 
general way it may be accepted as 
representing the entire group. 
Fig. 7. 
7. Fruit Products Used as 
Vegetables. 
These include the tomato, cu- 
cumber, squash, pumpkin, egg 
plant, and vegetable marrow. The 
tomato is largely consumed in the 
raw state as a salad, and in several 
cooked forms. It contains less 
than 6 per cent, of solid matter and 
in this respect has about the same 
nutritive value as celery and lettuce. 
Its chief solid matter is sugar. Its 
mineral constituents are free from 
earthy salts. 
The cucumber in the raw state, in which condition it is most com- 
monly eaten, is not easy of digestion, but when stewed is light, whole- 
some, and agreeable. As a nutriment it stands even lower than the 
preceding, containing less than 5 per cent, of solid matter. The 
squash, pumpkin, vegetable marrow, and egg-plant have about equal 
nutritive value. They contain about 90 per cent, of water, are very 
a, starch, sugar, fiber, fat, etc.; b, non- 
albuminoid nitrogenous matter; c, albuminoid 
nitrogenous matter ; d, mineral matter. The 
hatched portion represents the loss. (After 
Snyder.) PLUMS. 
145 
poor in proteids-less than 1 per cent.-but are fairly rich in carbo- 
hydrates. 
As stated above, the word fruits is here used in its narrower sense 
to designate those products which, being of an agreeable taste in the 
raw state, are suitable for use as a dessert. The agreeable taste de- 
pends upon the relative proportions of pectin, sugar, gum, acids, and 
other constituents. Some fruits with but a small percentage of sugar 
and considerable acid have a sweeter taste than others richer in sugar 
and with no more acid, because of the masking of the free acid by 
the gum and pectin. Thus the peach, for instance, is comparatively 
poor in sugar, but its content of acid is prevented from being prominent 
by the large content of gum and pectin. Some fruits contain usually 
but little of these constituents. 
Fruits contain but little proteid matter, and their chief food value 
lies in the sugar, salts, and vegetable acids which they contain. Eaten 
in moderation, they exert a favorable influence on the system, but when 
taken in undue proportion to other foods, and especially in unripe or 
too ripe states, may cause digestive derangements. On account of their 
richness in vegetable acids and their salts, which in the system are de- 
composed and converted to carbonates, they tend to diminish the 
acidity of the urine. 
8. Fruits. 
APPLES. 
In the raw state apples are not very easy of digestion, but when 
cooked they are much more so, and when baked are reputed to be 
slightly laxative and, therefore, useful in habitual constipation, but not 
suitable in the reverse condition. From the many analyses which 
have been compiled by various authorities it may be stated that this 
fruit contains about 85 per cent, of water, 7.5 per cent, of sugar, 1 of 
malic acid, 0.4 of ash, besides variable amounts of pectin, pectose, 
fiber, and other matters. 
PEARS. 
Pears are somewhat richer than apples in sugar and poorer in malic 
acid. They are fairly rich in pectin. 
In this fruit the sugar is comparatively low, but the pectous matter 
is exceptionally high and covers the acidity. They contain nearly 1 
per cent, of malic acid. 
PEACHES. 
APRICOTS. 
The sugar content of apricots is about equal to that of peaches. 
The pectous matter is also about the same in amount, but the acidity 
is ihgher. 
PLUMS. 
Plums contain as a rule less sugar and pectin and more malic acid 
than are found in peaches and apricots. They are much more apt 146 
FOODS. 
than most other fruits to disagree and produce derangement of diges- 
tion. 
CHERRIES. 
Cherries are notable for their large content of sugar, over 10 per 
cent., surpassing in this respect all of the foregoing. They contain 
somewhat less than 1 per cent, of malic acid and are low in pectin. 
The popular idea that even in ripe sound condition they are a danger- 
ous article of food if eaten in conjunction with milk has no foundation 
in fact, but when unripe or unsound they have a tendency to cause 
disorder of the bowels. 
The average composition of the foregoing fruits is shown in the fol- 
lowing table compiled from Konig. 
Water. 
Sugar. 
Acid. 
Proteids. 
Pectin, etc. 
Fiber. 
Ash. 
Apples 
83.79 
7.22 
0.82 
0.36 
5.81 
1.51 
0.49 
Pears 
83.03 
8.26 
0.20 
0.36 
3.54 
4.30 
0.31 
Peaches 
80.03 
4.48 
0.92 
0.65 
7.17 
6.06 
0.69 
Apricots 
81.22 
4.69 
1.16 
0.49 
6.35 
5.27 
0.82 
Plums 
84.86 
3.56 
1.50 
0.40 
4.68 
4.34 
0.66 
Cherries 
79.82 
10.24 
0.91 
0.67 
1.56 
6.07 
-0.73 
ORANGES. 
The orange contains nearly 2.5 per cent, of citric acid and about 
4.5 of sugar. The juice is particularly agreeable in almost any con- 
dition of health or sickness and is extremely unlikely to cause any dis- 
turbance of the system. 
The average composition of oranges (23 analyses) according to At- 
water and Bryant is as follows : 
Water 86.9 
Proteids 0.8 
Fat 0.2 
Total carbohydrates, including fiber 11.6 
Ash ... 0.5 
100.0 
The juicy pulp of the grape is wholesome and refrigerant and when 
eaten in large amounts exerts a gentle laxative action. Since the 
number of varieties reaches into the thousands, it follows that wide 
variation in composition must occur. 
Twelve analyses compiled by Kbnig yield the following averages : 
Water 78.17 
Sugar 14.36 
Free acid 79 
Proteids 59 
Pectous matter 1.96 
Fiber 3.60 
Ash ^53 
100.00 
Five analyses compiled by Atwater and Bryant yield averages which 
are somewhat differently expressed, as follows : 
GRAPES. FIGS. 
147 
Water 77.4 
Proteids 1.3 
Fat 1.6 
Total carbohydrates, including fiber 19.2 
Ash 5 
"100.0 
When dried in the sun or in ovens, the product is raisins. Those 
dried in the sun are the better. Raisins are less digestible than grapes and 
are not infrequently the cause of derangement of the intestinal canal. 
What are commonly known as dried currants are small raisins made 
from small seedless grapes. They come from the Levant and are 
shipped from Corinth, whence their name in a corrupted form. - They 
are exceedingly indigestible and are quite likely to traverse the entire 
digestive tract without undergoing any change. 
MELONS. 
The edible portion of melons is very watery, but the small amount 
of nutriment contained is not unlikely to cause in many persons di- 
gestive disturbances accompanied by annoying eructations. Not many 
analyses have been recorded. Storer,1 quoted by Konig, has reported 
three analyses which give the following averages : 
Water 88.09 
Proteids 92 
Fat 18 
Sugar, etc 9.05 
Fiber 1.04 
Ash .72 
100.00 
Two analyses of watermelons noted by Atwater and Bryant give the 
following averages : 
Water 92.4 
Proteids 4 
Fat 2 
Total carbohydrates, including fiber 6.7 
Ash 3 , 
100.0 
Bananas and plantains are among the most nutritious of fruits; in 
many parts of the tropics, they constitute the chief food of those who 
are too lazy to perform any kind of manual labor. The edible part 
yields about 20 per cent, of sugar (cane and invert), about 2 of pro- 
teids, 0.5 of starch, and rather more of fat. 
BANANAS. 
FIGS. 
The fig in the fresh state is about equal to the banana in nutritive 
properties. In both the fresh and dried forms it is highly esteemed as a 
mild laxative. The dried fig contains about 30 per cent, of water, 50 of 
sugar, 4 of proteids, and 3 of ash ; the balance is chiefly seeds and fiber. 
1 Report of Connecticut Experiment Station, 1879, p. 159. 148 
FOODS. 
BERRIES. 
The various berries are notable for their content of free acids and 
sugar. Two kinds, the cranberry and the barberry, are too sour to be 
eaten raw and must be cooked with sugar in order to be made palata- 
ble. The composition of the several members of this group is set forth 
in the following table compiled from Kbnig. 
Water. 
Sugar. 
Free 
Acid. 
Proteids. 
Fiber, 
pectin, etc. 
Ash. 
Blackberries 
86.41 
4.44 
1.19 
0.51 
6.97 
0.48 
Cranberries 
89.59 
1.53 
2.34 
0.12 
6.27 
0.15 
Currants 
84.77 
6.38 
2.15 
0.51 
5.47 
0.72 
Gooseberries 
85.74 
7.03 
1.42 
0.47 
4.92 
0.42 
11 uckleberries 
78.36 
5.02 
1.66 
0.78 
13.16 
1.02 
Mulberries 
84.71 
9.19 
1.86 
0.36 
3.22 
0.66 
Raspberries 
85.74 
3.86 
1.42 
0.40 
8.10 
0.48 
Strawberries 
87.66 
6.28 
0.93 
1.07 
3.25 
0.81 
9. Edible Fungi. 
Mushrooms are reputed to be extremely rich in nitrogen and other 
nutrients and they are accordingly recommended as a valuable food 
material. It is true that they are somewhat rich in nitrogen, but it 
must be said that a large proportion of this element present is in com- 
binations (amido compounds) which are useless as food. As a matter 
of fact, the total solid matter of mushrooms averages about 12 per cent, 
and is largely woody matter. Mushrooms are rather difficult of di- 
gestion and are not at all adapted to weak stomachs. They have been 
called " the poor man's meat " and much has been done to encourage 
the poor to seek for them in the fields and woods in order to add to the 
larder. Inasmuch as the market price of mushrooms for the tables of 
the rich is generally high, and since their food value is decidedly 
over-rated, it would appear that where there is a market for them the 
poor can do much better for their nutrition by disposing of their find- 
ings and converting the proceeds into cheaper, more digestible, more 
nutritious, and less cloying articles of food. 
Truffles contain more nitrogen than mushrooms, but they are very 
much more woody and can hardly be looked upon as valuable from 
the point of view of nutrition. 
MUSHROOMS. 
10. Saccharine Preparations. 
Sugar was known to the ancient Greeks and Romans, and its manu- 
facture has been conducted by the Chinese since the earliest times. It 
is very soluble and diffusible and, therefore, is easily digested. Dex- 
trose is ready for assimilation, but sucrose, maltose, and lactose must 
first undergo a splitting process within the digestive tract. MAPLE SUGAR. 
149 
CANE SUGAR. 
Cane sugar is obtained from the sugar cane, sugar beets, sorghum, 
and sugar maple. It is very soluble in water, but quite insoluble in 
absolute alcohol. Heated with dilute mineral acids or with citric acid, 
it splits into dextrose and laevulose and is then known as invert sugar 
from the fact that the polarization becomes inverted. Cane sugar 
rotates the plane of polarized light to the right; the two substances 
into which it is split, dextrose and laevulose, rotate respectively to the 
right and left, but the action of Isevulose is so much the stronger that 
the mixture gives left polarization. 
Heated above 180° C., sugar yields caramel, which is not a simple 
substance, but a complex mixture of brown products of dehydration. 
It is used as a coloring for low grade milk and other articles of food 
and somewhat as a flavoring. 
Cane sugar is sold in various forms : cut or loaf sugar, granulated, 
and powdered. The cheaper grades, known from their color as " brown 
sugars," contain variable amounts of invert sugar, gummy matters, 
and other impurities. 
Sugar is not much subject to adulteration, though there is a popular 
idea that glucose and sand are common admixtures. It is probable 
that sand is as rare an adulterant of sugar as chalk is of milk. Glu- 
cose is rarely mixed with sugar, but is considerably used as a cheap 
substitute for it in the manufacture of cheap jellies, jams, and candies. 
Sugars that are somewhat " off color " are treated sometimes with 
ultramarine in the final processes of manufacture. This corrects the 
fault and makes the product white. Occasionally, the amount added 
is sufficient to cause great alarm in the household when large quanti- 
ties of sugar are made into syrup with hot water in the preparation of 
preserves and jellies. The blue material comes to the surface as a scum, 
and its unlooked-for appearance gives rise to suspicion of poison. 
MAPLE SUGAR. 
This form of cane sugar is highly prized for its agreeable flavor. It 
is a much more expensive article than ordinary sugar and is used 
more as a confection. In the form of syrup it is very extensively used 
on buckwheat cakes and with other cereal breakfast foods. It is much 
subject to adulteration and substitution. A large part of the syrup in 
the market is wholly artificial, being made from ordinary sugar or 
glucose, appropriately colored, and correctly flavored by means of ex- 
tract of hickory bark. The sugar itself is imitated in the same way, 
but one not infrequently sees specimens which are absolutely devoid 
of any flavor save that of brown sugar. The substitution by flavored 
cane sugar is practically impossible to prove by chemical means, though 
the soluble portion of the ash of the genuine article is almost wholly 
potassium carbonate, while that of crude cane sugar is largely sodium salts. 
The presence of ordinary brown sugar or molasses can be detected 
by the yield of reducing sugar, since pure maple sugar contains but 150 
FOODS. 
very little of this substance. The detection of glucose is very simply 
brought about by the behavior of the specimen under polariscopic 
analysis. 
GLUCOSE. DEXTROSE. 
Dextrose, or grape sugar, is inferior in sweetening power to cane 
sugar and is not crystallizable to the same extent. It is much less 
soluble in water, but is soluble in glycerin and in alcohol of ordinary 
strength. It is found in grapes and in many other fruits and vege- 
tables, but always associated with laevulose. By fermentation with 
yeast it splits into carbonic acid and alcohol ; in the presence of fer- 
ments which disorganize proteids it yields lactic acid. It exerts a 
strong reducing power on Fehling's solution. 
Commercial glucose is obtained by heating starch, usually corn 
starch, with diastase or dilute sulphuric acid. Before the final process 
of concentration of the solution, the acid is completely neutralized by 
the application of marble dust, and the resulting sulphate of calcium 
and the excess of the neutralizing agent are removed. The product 
always contains considerable proportions of maltose and dextrin and its 
rotatory power is, therefore, very much greater than that of pure glu- 
cose such as is obtainable from diabetic urine. 
Glucose is produced in enormous quantities both in the solid form 
and as a very thick colorless syrup. It is used in the manufacture of 
cheap candies, jams, and preserves, in the brewing of beer, and as an 
adulterant of molasses and honey. The popular idea that it is inju- 
rious to health is absolutely without foundation and is the result of a 
senseless agitation against its use, set on foot for commercial reasons 
and by pseudoscientists and amateur hygienists. 
MOLASSES. 
Molasses is a thick, viscid, dark-colored liquid which drains away in 
the process of the manufacture of sugar. It contains from 65 to 72 
per cent, of sugar, part of which is sucrose and part fruit sugar, vari- 
ous salts, gummy matters, extractives, and water. It is graded ac- 
cording to color from the cheapest, almost black article known as 
" black strap," to the finest, which is light yellowish brown. When 
refined, it is brilliant and transparent and known as syrup. 
All grades, but especially the higher, are extensively adulterated 
with glucose syrup. This reduces the sweetening power, but gives 
body and a finer appearance. The fraud is readily detected by the 
use of the polariscope, since the adulterated article gives a much 
higher reading, and on inversion instead of giving left polarization, 
continues to give a reading to the right almost as high as before. 
Another, and from a sanitary point of view, a more important adul- 
terant of molasses, is the protochloride of tin, known also as " tin crys- 
tal " and " salts of tin." This is added for the purpose of reducing the 
amount of color, thus giving a fictitious added value. It combines 
with part of the coloring matters, and the resulting compound separates HONEY. 
151 
and tends to deposit. Thus a large proportion of the amount added to 
a hogshead may be found in the "foot," or sugar sediment, which is 
quite commonly used in the making of cheap candies such as cocoanut 
taffy. Only a part, however, is deposited, and hence a specimen thus 
adulterated will yield notable traces of the salt on incineration and 
analysis. It is useless to attempt to separate the tin in the ordinary 
way without previous incineration, since the organic matters present 
prevent the precipitation of the sulphide. 
Inasmuch as the protochloride of tin is an irritant poison, and since 
its addition can serve no legitimate useful purpose, this form of adul- 
teration should be prohibited and punished. Sometimes tin is present 
in molasses not as an adulterant, but because of a practice followed by 
some makers of crude sugar of treating their product with this agent to 
improve its yellow color before it leaves the centrifugal machines, and 
thus it finds its way into the by-product. 
HONEY. 
Honey is sometimes classed as an animal food since it is a product 
stored up by bees, but it can hardly be so considered since it is obtained 
from the nectaries of flowers, although during its storage in the bee's 
crop it undergoes some change. After this alteration by the secretions 
of the crop, it is disgorged and deposited in the cell of the honey-comb. 
Honey is a concentrated solution of sugars, chiefly dextrose and 
laevulose with small amounts of sucrose and maunite, containing also 
small amounts of wax, organic acids, proteids, mineral matter, pollen, 
and odorous and other principles. The flavor, color, and odor vary ac- 
cording to the nature of the flowers from which the honey is obtained. 
Sometimes when derived from poisonous plants, it has poisonous prop- 
erties ; this fact has been noted by both ancient and modern writers. 
Xenophon, for example, has recorded most serious symptoms of intoxi- 
cation due to its ingestion, and a number of small outbreaks resembling 
ptomain poisoning have been reported by recent writers in this country. 
Honey from the flowers of the yellow jasmine has been known to pro- 
duce serious and even fatal results, and that derived from a species of 
rhododendron growing in the neighborhood of the Black Sea has long 
been recognized as poisonous. 
The power of honey to exert a medicinal influence is sometimes 
turned to good account. Thus, in Abyssinia, where the flowers of 
the cusso tree are the universal remedy for tapeworm and ascarides 
with which a large proportion of the population is afflicted, swarms of 
bees are kept by order of King Menelek in gardens where no other 
plant is cultivated, and the honey which they store has been found to 
have all the good qualities of the drug with none of its unpalatability 
or unpleasant effects, such as nausea and vomiting. 
By microscopic examination, which will show numerous pollen 
grains, one can often easily determine from what kind of flower the 
honey has been gathered. 152 
FOODS. 
Honey contains about 73 per cent, of sugar. In consequence of 
the preponderant influence of the laevulose in the mixture on the ro- 
tation of the plane of polarized light, the polariscopic reading of a pure 
sample is almost always to the left; when not to the left, the reading 
is not over a few degrees to the right. The percentage of water averages 
about 18 or 19 ; occasional specimens are found to contain as high as 25. 
Honey is a very important sugar food; it is very agreeable to the 
taste and easily assimilated. On account of its comparatively high 
price, it is very subject to adulteration with glucose and cane sugar. 
That which is sold in the comb, the comb still in its frame, is almost 
invariably genuine. The extracted honeys sold in bottles and tumblers 
are very commonly mixtures of the genuine article with glucose or 
cane sugar, and often contain no honey whatever. In order to convey 
the idea of genuineness, it is a common practice to insert a small piece 
of comb. At least one ingenious fabricator of glucose-honey has been 
known to add to each tumbler of his product a dead bee to serve as a 
silent false witness of its origin. 
The detection of adulteration with glucose or cane sugar is an easy 
matter, since all samples so made give a strong reading to the right on 
polariscopic examination. On inversion of the sample, the right- 
handed reading persists if the adulterant is glucose, and is changed to 
the left if cane sugar. It is said that inverted cane sugar is sometimes 
mixed in proper proportion to make an artificial honey which will give 
the normal polariscopic test of the genuine article, and that to imitate 
the latter still further, so that microscopical examination may also 
attest its genuineness, pollen grains are added in sufficient amounts. 
The ash of such a product would alone reveal the fraud, since it would 
contain no phosphoric acid, while genuine honey contains about 0.03 
per cent, of that substance. 
CONFECTIONERY. 
Candies are preparations made of sugars or substances containing 
them, such as molasses and honey, with or without the admixture 
of other food materials, such as nuts, fruits and chocolate, starches 
and fats to give body and consistence, and flavoring and coloring 
agents. The addition of substances which serve no legitimate useful 
purpose, such as terra alba, which is said to be added sometimes to 
lend weight, and of injurious colors and flavors, may properly be re- 
garded as adulteration; but the use of glucose sugar, cocoa butter and 
other substances of a harmless nature and possessing value as nutri- 
ment cannot be so regarded. Many, some say most, of the cheaper 
candies, contain variable amounts of glucose and starch, but nothing 
can be said against the use of these substances on the score of whole- 
someness. The use of terra alba is popularly supposed to be very 
common, but numerous analyses by many chemists throughout the 
country show that this substance is an exceedingly uncommon ingredient 
of even the very cheapest candies. TEA. 
153 
The flavoring agents commonly employed are, as a rule, quite harm- 
less in character. The colors used, however, are not infrequently of 
a poisonous nature, especially in those states which have no laws against 
food adulteration, or which, having them, make no provision for 
their enforcement. These injurious coloring agents include the chro- 
mates of potassium and lead, tin lakes, and certain of the coal-tar 
products, such as Martius yellow, dinitrocresol, and dinitroso-resor- 
cinol. The employment of chromate of lead and of chromate of po- 
tassium is frequently scouted, but these substances are, nevertheless, 
not uncommonly used, and have been detected by the author in many 
specimens of yellow sugars used for decorating cakes, and in yellow 
candies made in the shape of beans. Most of the colors used are, how- 
ever, of a harmless nature. 
JELLIES AND JAMS. 
Jellies are semi-solid glutinous preparations made by boiling fruit 
juices with sugar and allowing to cool; jams are somewhat similar 
preparations which include the pulp of the fruit as well as the juice. 
Many of the jellies found in the shops are made with glucose syrup, 
cane sugar, gelatin, artificial flavorings and colors, and extracts made 
by boiling the refuse of canning establishments. Jams, likewise, are 
largely factitious, being made with glucose syrup, flavorings, color- 
ings, various kinds of seeds, and tasteless vegetable tissues such as 
summer squash and boiled white turnips. 
Section 5. BEVERAGES. 
Stimulant Beverages Containing Alkaloids 
These include tea, coffee, and cocoa, and certain others not used to 
any large extent in this country. The alkaloids of these products are 
known respectively as theine and caffeine, which are chemically iden- 
tical, and theobromine, which is very closely related. 
TEA. 
The virtues of tea were discovered, according to Chinese tradition, 
over 2,700 years before the Christian era. It was first used in Eng- 
land in the seventeenth century (about 1657), and came there into 
general use about 1675. It was introduced into America in 1711. 
Tea is the dried leaf of a shrub, Thea Chinensis, indigenous to China 
and other parts of Asia and cultivated in India, Japan, and Ceylon. 
The varieties of the plant produced by different methods of long cul- 
tivation were formerly believed to be distinct species, and were known 
as T. Bohea, T. viridis, etc. The differences in the varieties found in 
commerce depend upon the age of the leaves when gathered and their 
position on the stem, and upon special methods of drying and prepar- 154 
FOODS. 
ing them for the market. The choicest varieties, for example, are 
those which include only the terminal leaves, and the poorest those 
made up of the largest and coarsest leaves from the lower end of 
the twig. 
Tea is commonly classed as green or black. Both kinds come from 
the same shrub, but are different in point of age, and are cured in dif- 
ferent ways. Green tea is made from young leaves, which are roasted 
quickly shortly after being gathered, and then rolled and again roasted. 
Black tea is from older leaves, which are allowed to wilt and are then 
gathered into heaps and allowed to stand without further manipulation 
for about a half day, during which time they undergo a fermentative 
process and change color. They are next rolled by hand and then 
heated, and these processes may be repeated several times alternately. 
Finally, they are dried slowly over burning charcoal. 
The composition of tea is very variable, and it is impossible to give 
figures which may be accepted as indicating the approximate constitu- 
tion of a typical specimen. Kbnig has collected 16 analyses which 
give the following averages : 
Moisture 11.49 
Nitrogenous matters 21.22 
Thein 1.35 
Volatile oil 0.67 
Fat, resin, etc 3.62 
Gum, dextrin, etc 7.13 
Tannin 12.36 
Other extractives 16.75 
Fiber 20.30 
Ash 5.11 
100.00 
But it must be said that the variations in the amounts of individual 
constituents of these sixteen specimens are very wide; for instance, 
water, 4.59 to 16.06 ; them, 0.40 to 4.94; tannin, 4.10 to 20.88; 
fiber, 15.11 to 25.06. Dragendorff found in twenty-three specimens 
from 1.36 to 3.09 per cent, of thein, 7.10 to 12.66 of moisture, and 
from 24.80 to 44.50 per cent, of total soluble constituents. The ash 
of pure tea is fairly constant in amount and almost never reaches as 
high as 7 per cent.; usually between 5 and 6 per cent. 
Tea should be used only in the form of an infusion made by pour- 
ing boiling water upon the requisite amount of leaves and allowing it 
to stand a short while to " draw." It is not uncommonly used in the 
form of a decoction ; that is, by boiling. This process is objectionable in 
two ways ; first, the delicate aroma is lost by the expulsion of the very 
volatile essential oil, and second, the leaves are made to yield all their 
tannin and other extractives, which matters tend to bring about, sooner 
or later, derangement of the digestive function and a catarrhal condi- 
tion of the stomach. The finest and most delicate portion of an infu- 
sion is that which is poured off within three or four minutes, for in 
this will be found a maximum of flavor with a minimum of bitterness 
and astringency. The excellence of an infusion is considerably influ- ADULTERATIONS OF TEA. 
155 
enced by the character of the water, which, if very hard, is slow in ex- 
tracting the desirable soluble constituents, while, if very soft, it ex- 
tracts not only these, but far too rapidly the less desirable principles. 
When properly made, tea in moderation is a wholesome, agreeable, 
and refreshing stimulant beverage, particularly grateful in conditions 
of mental or physical weariness. Used in excess, it exerts a harmful 
influence upon the nervous system, and in a too strong form injures the 
digestive tract and function. 
The abuse of tea as a beverage leads, according to Bullard,1 to ring- 
ing in the ears, tremor, nervousness, headache, neuralgia, hysteria, ir- 
regularity of the heart, dyspnoea, dyspepsia, and constipation. 
Dr. Hayes, the Arctic explorer, has testified to the value of tea and 
coffee in enabling men to endure hardship of all sorts and cold, tea 
being especially soothing at the end of a hard day's work. 
While tea by itself can hardly be looked upon as an article afford- 
ing any important amount of nutriment, as commonly consumed it 
serves as a vehicle for other substances, as sugar, milk, and cream, 
having high nutritive value. 
Adulterations of Tea.-It is commonly stated and generally be- 
lieved that tea is extensively adulterated with other kinds of leaves, 
including those of the beech, sloe, willow, and hawthorn; but at the 
present time, it is extremely improbable that such adulterants are ever 
mixed with tea known to be intended for export to this country. 
Whatever the conditions may have been prior to the enactment of the 
national law governing tea importation, the fact now is that our tea 
supply is practically free from this form of adulteration. The detec- 
tion of spurious tea leaves would be an easy matter, since the genuine 
have a very characteristic appearance which can hardly be confused 
with that of any of the possible substitutes; and even when broken 
into small bits, the characteristic differences in venation and serration, 
and in the stomata as well, are plainly discernible. 
More probable forms of adulteration include the admixture of 
wholly or partially exhausted leaves, the addition of astringent mat- 
ters, such as catechu, to lend color and apparent strength to the infusion, 
the presence of foreign mineral matter, and the practice of " facing." 
The presence of any large proportion of exhausted leaves can be 
detected by the low amount of total soluble extract and by the small 
amount of soluble ash, which should not be less than 3 per cent, of the 
weight of the leaves. The presence of important amounts of accidental 
or added mineral matters is shown in the total ash, which in a genuine 
specimen rarely amounts to 7 and never to 8 per cent. The substances 
most often found are sand and soapstone ; the first named is sometimes 
found in amounts exceeding 25 per cent. 
Catechu is occasionally applied to exhausted tea leaves with the aid 
of solutions of gummy matters, for the purpose of adding astringency 
and color to the infusion. Teas so treated have but little, if any, of 
'Boston Medical and Surgical Journal, April 8, 1886, and September 8, 1887. FOODS. 
the true aroma, and their infusions yield a sediment in which the par- 
ticles of catechu can be readily seen. 
The object of " facing " is to make the product appear to be of 
greater value, and the practice is, therefore, properly speaking, one 
which comes within the definition of fraudulent adulteration. Damaged 
or otherwise inferior leaves are treated with Prussian blue, plumbago, 
indigo, and other substances, and the small amount which adheres im- 
proves their color and general appearance. This amount is too small 
to be of any sanitary significance. The presence of facing materials 
may be detected by the use of the microscope and by chemical analysis. 
COFFEE. 
Coffee is the seeds of the Coffea Arabica, dried and deprived of their 
fleshy covering. The fruit is a small pulpy berry containing usually 
two seeds. The tree is said to have originated in Abyssinia, where, 
however, in the seventeenth century there were few, if any, specimens, 
and to have been introduced into Arabia in the fifteenth century. It 
is now very extensively grown in Brazil, Java, Peru, Ceylon, West 
Indies, and other hot countries. The first European to mention it was 
Prosper Alpinus of Padua, who included it in an account of Egyptian 
plants, published in 1592. The first work devoted wholly to coffee 
was a small Latin treatise, De saluberrima potione cahue, by Faustus 
Nairo, Rome, 1671. Coffee was first sold in London by a Levantine 
in 1650, and some years afterward was introduced into France. The 
first whole cargo introduced into this country arrived in 1809, but 
coffee houses were licensed in Massachusetts as early as 1715. 
The world's production of coffee for the year ended June 30, 1900, 
has been estimated at almost 900,000 tons.1 This country alone con- 
sumes more than the whole of Europe : in 1897 we consumed 318,170 
tons against 305,150. The total consumption by Germany was 136,- 
390; by France, 77,310; by England, 12,420; and by Italy, 12,500 
tons. 
As is the case with tea, coffee must undergo a process of roasting 
before it is fit for use, although it is said that the Arabians and other 
Eastern peoples make a decoction of the raw article and swallow the 
grounds as well as the liquid. The roasting is conducted at about 
200° C. until the natural color, which is greenish, grayish, or drab, is 
changed to a rich dark brown. During the process, certain volatile 
aromatic principles are developed, the alkaloid caffeine is dissociated 
from its union with tannin, the moisture is very largely expelled, the 
sugar is caramelized, gases are formed (largely carbonic dioxide) which 
cause the berry to swell, and much rupturing of the cell layers occurs. 
The berry thus loses in weight and gains in bulk. The process must 
be carefully conducted, else the quality will not be what is desired since 
if the roasting is not pushed far enough, there will be an insufficient 
'Consular Reports, Vol. LX., p. 258. COFFEE. 
157 
development of aroma, and if it is carried too far, the volatile matters 
are expelled and the product takes on an unpleasant taste. 
On account of the volatile nature of the aromatic principles de- 
veloped, coffee should be roasted only as the demands of commerce 
make it necessary. On long keeping, except in hermetically sealed 
containers, it undergoes extensive deterioration. For the same reason, 
the roasted berries should be ground only as needed. 
Coffee contains less caffeine (thein) than is found in tea ; thus, Drag- 
endorff found the amount in 25 samples to vary between 0.64 and 2.21 
per cent., whereas in about the same number (23) of samples of tea, 
the range was 1.36 to 3.09. It contains considerable amounts of fat, 
generally over 12 per cent., about the same amount of nitrogenous 
matters, small, quite unimportant amounts of sugars, gummy matters 
and other substances, and about 40 per cent, of fiber. 
Coffee is used in infusion and as a decoction. Like tea, it loses its 
pleasant aroma when boiled, but its decoction is less bitter and astrin- 
gent than that of tea. In order to enjoy both the fragrance of an in- 
fusion and the strength and body of a decoction, it is not an uncommon 
practice to make first the one and pour it off, and then with a fresh 
portion of water, to boil the grounds for a few minutes, and then to 
add the two liquids together. 
Coffee acts as a decided stimulant to the nervous system, enables one 
better to perform arduous work, and diminishes the sense of fatigue. 
In small amounts it increases the force and frequency of the pulse, but 
taken in excessive quantities it causes palpitation and intermission, be- 
sides general nervousness and derangement of digestion. It has a 
marked inhibitory influence on gastric digestion and is more oppressive 
to the stomach than tea and, hence, must be used with caution by dys- 
peptics. With some persons it stimulates peristalsis and thus acts as a 
gentle cathartic. It increases the secretions of the skin and kidneys. 
Coffee is very extensively adulterated with a variety of substances 
of widely different nature, including chicory, dandelion, and other roots, 
roasted cereals and legumes, sawdust, date stones, red slate, acorns, and 
other cheap articles. It is not alone in the ground form that it is fal- 
sified, for even the beans are imitated with mixtures of flour and other 
materials moulded to the correct shape and carefully roasted and colored. 
The detection of adulterations in coffee requires but little time. Of 
great assistance is the fact that coffee contains absolutely no starch, 
while most of the commoner adulterants contain it in abundance. 
Therefore, if a specimen under examination is boiled and filtered, and 
the filtrate gives a dirty blue reaction with test solution of iodine, one 
may be sure that adulteration has been practiced. But not all of the 
adulterants are starchy in their nature and, therefore, other examina- 
tion is necessary. Microscopical examination will detect not only the 
starchy, but the non-starchy matters as well. Under the microscope, 
ground coffee has a characteristic appearance which cannot be mistaken 
for anything else. Chicory and other roots, date stones, and all other 
berries and seeds have their own characteristics. For the mere de- 158 
FOODS. 
termination of the question of purity, only a knowledge of the micro- 
scopical appearance of coffee itself is required, and this is easily and 
quickly acquired by direct study. For the identification of the adul- 
terants present, one necessarily must be familiar with the appearance 
of all of the substances used. 
Chicory is the root of the Cichorium intybus, a perennial herb grow- 
ing wild and extensively cultivated in this country and in Europe. 
The roots are cleaned, cut into pieces, dried in kilns, roasted in iron 
cylinders, and ground into a coarse powder. Like coffee, chicory when 
roasted contains a volatile principle and a bitter. It is used both as 
an adulterant and as a substitute for coffee. Mixed with coffee, it 
lends both color and flavor to the infusion, and by many is regarded 
as a desirable addition. It is itself subject to adulteration by cheaper 
roots, such as mangelwurzel and dandelion. 
Coffee and chicory behave very differently when thrown into cold 
water; the former floats and retains its firm consistence, while the lat- 
ter absorbs water very quickly and sinks to the bottom of the vessel, 
and in its descent leaves streaks of color. Coffee which has been 
roasted too much will, however, sometimes sink, and chicory which 
has been treated with fatty substances will float. Mixtures of the two 
can often be detected by the difference in resistance when placed be- 
tween the teeth. The particles of coffee are much harder than those 
of chicory, which yield very readily to pressure and also have a sweet- 
ish taste. 
Inferior and damaged raw coffees are not infrequently colored and 
faced in order that they may be improved in appearance or be made 
to imitate better grades. The facing agents used are mixtures con- 
taining variable amounts of ultramarine, indigo, clay, gypsum, chro- 
mate of lead, and coal dust. 
According to G. Wirtz,1 inferior grades of coffee are largely treated 
at Antwerp, Rotterdam, Hamburg, Bremen and elsewhere by washing, 
coloring, and finally drying by centrifugation with sawdust, the result 
being a fine white product of an apparently greater value. 
Package coffees sold under various names such as " French Break- 
fast Coffee," " Vienna Coffee," and " Eureka Breakfast Coffee," are 
rarely anything more than roasted and ground cereals and peas. It is 
to be said, however, that their character is commonly indicated in the 
directions for use printed on the labels, which commonly begin by ad- 
vising the use of "a third more than you would use of genuine coffee." 
Microscopical examination and the iodine test will very quickly reveal 
their composition. 
COCOA. 
Cocoa, a corruption of Cacao and in no way related to the cocoanut, 
is derived from the seeds of the Theobroma cacao, a native of tropical 
America. It is estimated that the annual production of the seeds 
1Zeitschrift fur Untersuchung der Nahrungs- und Genussmittel, 1898, p. 248. COCOA 
159 
amounts to about 150,000,000 pounds, more than a fifth of which is 
exported by Ecuador alone. Nearly a fifth of the annual crop is con- 
sumed within the United States. 
The fruit of the cocoa tree is a large pod, about a foot long and half 
as wide, filled with " beans," or " chocolate nuts," about as large as 
almonds, imbedded in five rows of from four to ten each in a pulpy 
matrix. When ripe, they are gathered and collected into heaps and 
left for a day or more; they are then cut open and deprived of the 
seeds, which are allowed to undergo a process of fermentation either 
in earthen vessels or in holes in the ground. This process, which must 
be very carefully regulated, has for its object the removal of an acrid 
bitter taste and consequent improvement in flavor. Sometimes the 
seeds are dried in the sun as soon as removed, but the product is then 
of much less value ; sometimes the entire pod is buried until the pulp 
becomes rotten and softened. 
When the fermentation process is completed, the seeds are carefully 
dried in the sun, and then become hard, brittle, and reddish or reddish- 
brown in color. 
In the preparation of cocoa for the market, the seeds are first cleaned 
and carefully roasted. As is the case with coffee, the roasting must 
be carried to a certain point to ensure the development of the desired 
flavor, and not so far beyond as to impair it. During this process, the 
thin husks of the seeds become more detachable, and before the next 
operation they are removed. The seeds are next lightly crushed and 
freed from their hardened germs, and in this form are known as " nibs." 
These are ground in a special form of mill into a paste (" flake cocoa") 
which is then moulded into cakes and allowed to harden. In this 
form the product is known as plain chocolate. The sweet and flavored 
chocolates are made with the addition of sugar, vanilla beans, cinna- 
mon and other spices. Inferior vanilla chocolate is made with artifi- 
cial vanillin and cumarin in place of the far more expensive and better 
flavored vanilla bean. 
For the preparation of powdered cocoa, it is necessary to remove a 
part of the oil, which when present in its normal amount favors cak- 
ing. This removal is accomplished by hydraulic pressure, and the 
paste is then passed through sieves of exceedingly fine mesh. 
The so-called soluble cocoas are prepared with sugar and starches, 
particularly arrowroot, but the cocoa itself is not soluble in water. The 
apparent solubility is due to the fineness of the powder and to the in- 
crease in the specific gravity of the liquid due to the sugar in solution, 
both these conditions favoring long suspension without sedimentation. 
Some of the Dutch soluble cocoas are treated with alkalies for the re- 
moval of the crude fiber and for their effect upon the coloring matters. 
These cocoas thereby lose part of their natural flavor, but the loss is 
covered somewhat by the addition of fragrant foreign matter. 
Cocoa was introduced into Europe by the Spaniards after their in- 
vasion of Mexico under Cortez in 1519. It was not known in En- 
gland until 1657, when it was first sold in London by a Frenchman. 160 
FOODS. 
In this country, it was first prepared and sold at Danvers, Massachu- 
setts, in 1771, from raw material brought from the West Indies by 
the fishermen of Gloucester. 
Unlike tea and coffee, which in themselves can hardly be regarded 
as adding any nutriment to the diet, cocoa is an exceedingly valuable 
food which possesses the advantage of much nutriment in small bulk, 
which makes it particularly suited to the needs of those engaged in 
expeditions removed from civilized centers. It makes a wholesome, 
agreeable, stimulant beverage, and is eaten in the form of chocolate 
and as an addition to cakes, puddings, and other compounds. The 
cocoa nibs and plain chocolate contain about 50 per cent, of a whitish 
solid fat of agreeable taste and smell, commonly known as cocoa butter. 
It contains variable amounts of the alkaloid theobromine (dimethyl- 
xanthine), which is very closely related to caffeine and theine (trimethyl- 
xanthine) and has nearly the same physiological action, though some- 
what less stimulant and rather more diuretic. The amount is said to 
average about 1.50 per cent. It is rich in nitrogenous matter, con- 
tains over 10 per cent, of a starch with small round granules, and 
about 3.50 per cent, of ash which is largely phosphate of potassium. 
Sixteen analyses of the kernels, compiled by Konig, give the follow- 
ing averages : 
Water 3.63 
Proteids 13.49 
Fat 49.32 
Starch 13.25 
Extractives 13.18 
Fiber 3.65 
Ash 3.48 
100.00 
The husks, commonly known as " shells," are used in the prepara- 
tion of a cheap and wholesome beverage. They contain but little fat, 
but are about equal in nitrogenous matter, and contain over 40 per 
cent, of nitrogen-free extractives. 
Cocoa and chocolate are subject to extensive adulteration with sub- 
stances having much less commercial value, though perhaps equally 
nutritious. Among those used are starches of various kinds, as wheat, 
rye, potato, arrowroot and rice, sugar, vegetable oils, mutton tallow 
and other fats, Venetian red, clay and brick dust. Various flavor- 
ings are employed, such as vanillin, coumarin, clove, mace, cardamom 
and nutmeg ; but unless these are used under the name of vanilla or of 
other flavorings than themselves, they cannot be regarded as adul- 
terations. 
Fermented Alcoholic Beverages. 
Beer is the generic term which includes all fermented drinks made 
from malt, thus covering lager beer, ale, porter, and stout. As com- 
BEER. BEER. 
161 
monly understood, beer is an infusion of malted barley, flavored with 
hops and fermented with yeast; but on account of the fact that whole- 
some substitutes for malt and hops may be employed in its manufacture, 
it is also defined as a 11 fermented saccharine infusion to which some 
wholesome bitter has been added." In this country, the term beer is 
commonly restricted to the product generally known as lager beer. 
Porter is a beer with a high percentage of alcohol and made from malt 
dried at a high temperature. Stout contains less alcohol and hops, 
but more malt extract. Ale is a pale beer containing more hop ex- 
tract and less malt extract than porter or stout, and brewed by " top 
fermentation." 
Beer was made by the Egyptians many centuries before the Chris- 
tian era. It is related that for public reasons the suppression of beer- 
shops was attempted by their government more than forty centuries 
ago. The art of brewing was taught by them to the ancient Greeks 
and Romans; thus, beer was a common drink in Greece prior to 700 
B. C., and one of the principal beverages of the soldiers of Csesar. 
In the time of Tacitus, it was in common use in Germany; and Pliny 
speaks of its use in Spain. The ancient Britons at the time of the 
Roman conquest made it from barley. At the time of the Norman 
conquest, the words beer and ale meant in England the same thing, a 
drink made of malt without hops. Later, the word beer fell into 
disuse, but in the fifteenth and sixteenth centuries, after the introduc- 
tion by the Flemish of beer made with hops, the term was revived and 
then meant hopped ale. The use of hops was forbidden in 1530 by 
Henry VIII., who regarded them as an adulteration, and in the first year 
of the reign of Richard III. the authorities of London laid a fine of 
6s 8d on every barrel of beer containing them. Later this was re- 
duced one-half. 
The prejudice against the use of hops in brewing is voiced by one of 
the earliest English writers on dietetics, Andrew Boorde,1 who says, 
" Ale is made of malte and water; and they the which do put any 
other thynge to ale than is rehersed, except yest, bar me, or godesgood, 
doth sofysticat theyr ale. Ale for an Englysshe man is a natural 
drynke. Ale must haue these propertyes : it must be fresshe and 
cleare, it muste not be ropy nor smoky, nor it must haue no weft nor 
tayle. Ale shuld not be drunk under v. dayes olde. Newe ale is 
vnholsome for all men. And sowre ale, and deade ale the which doth 
stande a tylt, is good for no man. Barley malte maketh better ale 
than oten malte or any other corne doth : it doth engendre grose hu- 
moures; but yette it maketh a man stronge. Bere is made of malte, 
of hoppes, and water: it is the naturall drynk for a Dutche man. 
And nowe of late dayes it is moche vsed in Englande to the detryment 
of many Englysshe men; specyally it kylleth them the which be 
troubled with the colycke, and the stone, & the strangulion; for the 
drynke is a colde drynke ; yet it doth make a man fat, and doth inflate 
1 A Compendyous Regyment, or A Dyetary of Helth, made in Mountpylier, com- 
pyled by Andrewe Boorde of Physyche Doctour, London, 1542. 162 
FOODS. 
the bely, as it doth appere by the Dutche mens faces & belyes. If the 
here be well serued, and be fyned, & not newe, it doth qualyfy the heat 
of the lyuer." 
The ancient Germans made beer from all kinds of grains, and for 
flavoring used oak bark, sage, and leaves of the laurel, ash, and tama- 
risk. Hops were used more or less from the ninth century and came 
into general use in the eleventh. 
Beer being the common drink of most European peoples before the 
establishment of colonies in America, it followed naturally that the 
early settlers of this country brought the art of brewing with them. 
In 1629, the cultivation of hops was already carried on in New Am- 
sterdam, and hop roots were sent for from England by the authorities 
of Massachusetts. In nearly all the colonies, the brewing of beer was 
regarded as quite as essential an accomplishment of women as the 
ability to make good bread. 
The first law regulating the sale of alcoholic beverages in Massa- 
chusetts was made in 1633 ; it prescribed that no person should sell 
wine or spirits without a permit, but made no reference to beer. In 
the following year, it was ordered that no one should charge more than 
a penny for a quart of beer, and in 1637, that no inn-keeper or vic- 
tualler should sell any intoxicating drink but beer; and this they were 
prohibited from brewing themselves, but must obtain from a licensed 
brewer. In the following year, owing to the fact that the only one of 
this class was unable to meet the demand, they were allowed to con- 
duct the process themselves. In 1649, it was further ordered that 
every inn-keeper and victualler should always keep on hand a supply 
of good wholesome beer. In 1651, the court undertook to stimulate 
the production of a better grade of beer in the belief that thereby the 
growing tendency to the use of wine and spirits and the increasing 
habit of drunkenness would be checked, and permission was granted to 
charge one, two, and three pence per quart, according to the amount 
of malt used per barrel. 
A duty of a shilling per bushel of imported malt imposed in 1654 
called forth a protest from Boston merchants on account of the very 
great importance of beer as a beverage of the people. In the following 
year, in order to promote home production of malt, importation was 
prohibited, but this order was repealed in 1660. In 1667, the use of 
molasses as an adulterant of beer was punishable by a fine of five 
pounds. Similar laws relating to beer were passed from time to time 
by the authorities of all the original colonies. 
Process of Manufacture of Beer.-The first step in the brewing 
of beer is the preparation of the malt. The barley is first steeped in 
water for several days and is then removed and arranged in heaps, 
which, after a time, are spread out and turned repeatedly until germi- 
nation has proceeded to the requisite extent. It is next dried in kilns 
at a temperature below or about 90° F., and then is heated further to 
from 125° to 180° according to the color desired. This process 
develops flavor, completely checks germination, and determines the SUBSTITUTES FOR BARLEY HALT. 
163 
commercial character of the product. The steeping of the malt is best 
done in water containing considerable of the mineral salts that cause 
hardness; a soft water exerts too much solvent action on the proteid 
matters, which, soon after extraction, are quite likely to undergo 
decomposition. During the progress of germination, the ferment 
diastase is developed and proceeds to convert the starch into dextrin 
and maltose. 
After the germs and rootlets have been removed by proper screen- 
ing and sifting, the malt is crushed, and then an infusion, the " wort/' 
is made with water at about 160° F. This is drawn off* from the ex- 
hausted malt and then boiled for an hour or two with hops, which, be- 
sides giving a characteristic bitter flavor, assist in clarification by the 
action of their contained tannin on some of the proteid matters. The 
boiled bitter wort is next rapidly cooled, run into vats, mixed with 
yeast and allowed to ferment for several days, during which time alco- 
hol and carbonic acid are formed from the maltose. The nature of the 
product is very largely influenced by the purity of the yeast and by the 
method of fermentation followed. Top fermentation is carried on rapidly 
and at a comparatively high temperature, the yeast growing at the sur- 
face ; in bottom, or sedimentary, fermentation, the yeast grows at the 
bottom, the process is slower, and is carried on at a lower temperature. 
The chief advantage of the employment of yeast which grows at a 
low temperature is that other perhaps undesirable growths may be un- 
able to proceed. Whatever the process of fermentation followed, not 
all the sugar should be allowed to be converted, for then the flavor 
would be not what it should and the keeping qualities would be im- 
paired. On the completion of fermentation, the beer is separated from 
the yeast and transferred to vats where it is clarified. As clarifying 
agents, a variety of materials are used, the chief of which are chips or 
shavings of certain woods, as hazel or beech, which attract and hold 
the particles which cause turbidity. These materials affect in no way 
the taste of the beer. Other substances used include gelatin, isinglass, 
flax-seed, and carrageen. After clarification is accomplished, the 
product is stored for a time in storage casks, where it undergoes a 
further slow fermentation at a low temperature, after which it is ready 
for use. 
Substitutes for Barley Malt.-While barley is universally recog- 
nized as the grain best suited to the brewing of wholesome beer, any 
other cereal can be used. Sometimes, unmalted grains are added to 
the malt before the infusion is made, for the diastase of the malt is 
capable of converting not only the starch with which it is naturally 
associated, but a large amount of other starches, and so, rice, corn, 
and other cereals may be employed. Glucose and cane-sugar are some- 
what used, but the product is decidedly inferior in quality, since these 
substances are lacking in some of the elements, as proteids and min- 
eral matters, which contribute to the desirable character of the best 
beers. 
Concerning the use of glucose, which adds strength to the wort, there 164 
FOODS. 
can be no objection on the score of being in any way deleterious to 
health. The popular belief in the unwholesomeness of glucose made 
from corn starch led the Treasury Department, in 1882, to request an 
investigation of the subject by the National Academy of Science. 
This was conducted by a committee of eminent scientists, including 
Professors Gibbs of Harvard, Brewer of Yale, Remsen of Johns 
Hopkins, Barker of Pennsylvania, and Chandler of Columbia, whose 
conclusions were that the processes employed in the manufacture are 
unobjectionable, that the product is of exceptional purity and in no 
way inferior in healthfulness to cane sugar, and that there was no evi- 
dence adduced to show that even when taken in large quantities, either 
in its natural condition or fermented, it has any injurious effects upon 
the system. 
Substitutes for Hops.-Various substances have from time to time 
been reported as being used in place of hops to give bitterness to beer. 
These include nearly everything having a bitter taste, such as strych- 
nine, chirata, calumba, cocculus indicus, aloes, and picric acid. Coc- 
culus indicus was mentioned in Holland as early as 1620 as an adul- 
terant. This and its active principle picrotoxine, and picric acid have 
been occasionally employed in England and elsewhere, but at the 
present time, it is safe to say, none of these substances are used. Of 
476 samples of beer examined for the State Board of Health of New 
York in 1885, not one was found to contain any hop substitutes what- 
ever. 
No objections can be alleged against such wholesome bitters as 
quassia, gentian, calumba, and chirata. Evidence that they are ever 
employed is exceedingly slight. As a matter of fact, there is no satis- 
factory substitute for hops, which give not alone bitterness, but other 
flavors and a peculiar aroma due to the peculiar resinous matter which 
they contain. In the sixteenth and seventeenth centuries, various 
other flavorings were used, such as sage, coriander, laurel leaves, pep- 
per, grains of Paradise, orris, and essential oils. 
Physical Properties and Chemical Composition of Beer.-Beer 
should be perfectly clear and bright. The presence of any turbidity 
denotes either imperfect brewing or the occurrence of undesirable 
decomposition processes. The latter are generally accompanied by 
disagreeable odors. The taste should be pleasantly bitter and inclining 
to sweetness rather than to acidity. There should be a sufficient 
amount of carbonic acid to make a pleasant impression in the mouth, 
such as is not produced by flat beer. The specific gravity ranges from 
about 1.005 to 1.025, averaging below 1.020. In bock beer, which 
is a special brew containing a considerable increase in malt extractives, 
the specific gravity is notably higher, running as high as 1.035 and 
averaging over 1.021. 
The most important constituents of beer are the extract and alcohol. 
The extract includes all of the non-volatile matters in solution, and 
consists of proteid matters, dextrin, sugar, hop resin, and other sub- 
stances left as a residue on full evaporation. The amount is quite ANALYSIS OF BEER. 
165 
variable; it is highest in porter, stout, and bock beer, and lowest in 
the light-colored lager beers. In the former, it averages about 7.50, 
and in the latter, about 5.50 per cent. Twenty-eight specimens of 
American beers, ales, and porter collected in Washington and analyzed 
by Mr. C. A. Crampton 1 averaged 5.53 per cent. 
The average extract of 182 analyses of specimens of beers of the 
lighter kinds, compiled by Konig, is stated at 5.49 (range, 1.98-9.23) ; 
of 211 lager beers of all kinds, at 5.78 ; of 50 export beers, at 6.48 ; 
and of 56 bock beers, at 7.20. 
The amount of alcohol is also quite variable. The specimens ex- 
amined by Crampton averaged 4.63 per cent, by weight and 5.79 by 
volume. The light beers above mentioned (Kbnig) averaged 3.46 per 
cent, by weight; the second group, 3.95; the third, 4.31 ; and the 
fourth, 4.74. 
Adulteration of Beer.-Beer is commonly supposed to be exten- 
sively adulterated, and the substances alleged to be in common use 
make up a list remarkable for length and variety, including such poi- 
sonous drugs as opium, belladonna, henbane, and strychnine, many of 
the aromatics and aromatic bitters, corrosive acids, drastic cathartics, 
and many other substances. The actual adulteration of beer is, how- 
ever, practically restricted to the use of preservatives, such as sodium 
fluoride and salicylic acid, of sodium bicarbonate to correct acidity and 
to increase the " bead," and of salt to correct bad taste and to inspire 
thirst for more. 
The use of preservatives is the only form of adulteration which is of 
any practical hygienic importance, and in several countries is punish- 
able by heavy penalties. In Germany, preservatives are very strictly 
interdicted, except in beer intended for export; and the permission ex- 
tended is so freely accepted that it is rare to find in this country a 
specimen of German bottled beer which does not contain a liberal dose 
of salicylic acid. Many of our American brewers use this agent with 
a liberal hand, under the benevolent plea that it is a prophylactic 
against rheumatism. By the same process of reasoning, one might just 
as well contend that opium in food and drink would prevent pain, and 
biniodide of mercury keep the system free from syphilitic infection. 
Analysis of Beer. 
In the analysis of beer, the most important items are the determina- 
tion of the percentage of alcohol and of extract, and the detection of 
preservatives. 
Determination of Alcohol.-For the determination of the percent- 
age of alcohol, a sufficiently large portion of beer should be well shaken 
in a capacious flask until the carbonic acid is expelled, and then a 
measured volume should be subjected either to distillation or to partial 
evaporation in an open vessel. 
1U. S. Department of Agriculture, Division of Chemistry, Bulletin 13, p. 282. 166 
FOODS. 
(a) Determination by Distillation.-Introduce into a flask connected 
with a Liebig's condenser 100 cc. of the well-shaken beer at 60° F., 
and distill into another flask connected with the discharging end of the 
condenser by means of a bent glass tube. Carry the distillation until 
somewhat more than 50 cc. of distillate have been collected, when all 
of the contained alcohol will have been expelled and condensed. Add 
sufficient water to the distillate to make 100 cc. at 60° F., determine 
its specific gravity by means of a picnometer or Westphal balance (a 
specific gravity spindle is not sufficiently accurate), and ascertain from 
this by reference to the appended table the percentage of alcohol by 
weight or volume. 
(6) Determination by Open Evaporation.-This method involves less 
manipulation and gives equally accurate results. The specific gravity 
of the beer is first determined in the manner above mentioned. Then 
place 100 cc. at 60° F. in a glass or porcelain evaporating dish, and 
by the application of heat drive off rather more than half the amount. 
Remove, cool, make up with water to the original volume at the orig- 
inal temperature, and again determine the specific gravity. Divide 
the original gravity by the latter, and the result equals that of the 
alcohol which has been expelled. Refer to the table and obtain there- 
from the percentage of alcohol in the original beer. 
The following table by Mr. Edgar Richards is the one used by the 
Association of Official Agricultural Chemists.1 
TABLES SHOWING PERCENTAGE OF ALCOHOL BY WEIGHT 
AND BY VOLUME. 
^Recalculated from the determinations of Gilpin, Drinkwater, and Squibb, 
by Edgar Richards.) 
Specific 
gravity at 
60 3 F. 
Per cent. Per cent, 
alcohol by alcohol by 
Specific 
gravity at 
60° F. 
Per cent. Per cent, 
alcohol by [alcohol by 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
volume. 
weight. 
volume. 
weight. 
1.00000 
0.00 
0.00 
0.99849 
1.00 
0.79 
0.99701 
2.00 
1.59 
0.99992 
.05 
.04 
842 
.05 
.83 
694 
.05 
.63 
984 
.10 
.08 
834 
.10 
.87 
687 
.10 
.67 
976 
.15 
.12 
827 
.15 
.91 
679 
.15 
.71 
968 
.20 
.16 
819 
.20 
.95 
672 
.20 
.75 
961 
.25 
.20 
812 
.25 
.99 
665 
.25 
.79 
953 
.30 
.24 
805 
.30 
1.03 
658 
.30 
.83 
945 
.35 
.28 
797 
.35 
.07 
651 
.35 
.87 
937 
.40 
.32 
790 
.40 
.11 
643 
.40 
.91 
930 
.45 
.36 
782 
.45 
.15 
636 
.45 
.95 
.99923 
0.50 
0.40 
.99775 
1.50 
1.19 
.99629 
2.50 
1.99 
915 
.55 
.44 
768 
.55 
.23 
622 
.55 
2.03 
907 
.60 
.48 
760 
.60 
.27 
615 
.60 
.07 
900 
.65 
.52 
753 
.65 
.31 
607 
.65 
.11 
892 
.70 
.56 
745 
.70 
.35 
600 
.70 
.15 
884 
.75 
.60 
738 
.75 
.39 
593 
.75 
.19 
877 
.80 
.64 
731 
.80 
.43 
586 
.80 
.23 
869 
.85 
.67 
723 
.85 
.47 
579 
.85 
.27 
861 
.90 
.71 
716 
.90 
.51 
571 
.90 
.31 
854 
.95 
.75 
708 
.95 
.55 
564 
.95 
.35 
1U. S. Department of Agriculture, Division of Chemistry, Bulletin No. 46, Wash- 
ington, Government Printing Office, 1899. PERCENTAGE OF ALCOHOL. 
167 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent. | Per cent, 
alcohol by alcohol by 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
volume. 
weight. 
0.99557 
3.00 
2.39 
0.99149 
6.00 
4.80 
0.98777 
9.00 
7.23 
550 
.05 
.43 
143 
.05 
.84 
771 
.05 
.27 
543 
.10 
.47 
136 
.10 
.88 
765 
.10 
.31 
536 
.15 
.51 
130 
.15 
.92 
759 
.15 
.35 
529 
.20 
.55 
123 
.20 
.96 
754 
.20 
.39 
522 
.25 
.59 
117 
.25 
5.00 
748 
.25 
.43 
515 
.30 
.64 
111 
.30 
.05 
742 
.30 
.48 
508 
.35 
.68 
104 
.35 
.09 
736 
.35 
.52 
501 
.40 
.72 
098 
.40 
.13 
730 
.40 
.56 
494 
.45 
.76 
091 
.45 
.17 
724 
.45 
.60 
.99487 
3.50 
2.80 
.99085 
6.50 
5.21 
.98719 
9.50 
7.64 
480 
.55 
.84 
079 
.55 
.25 
713 
.55 
.68 
473 
.60 
.88 
072 
.60 
.29 
707 
.60 
.72 
466 
.65 
.92 
066 
.65 
.33 
701 
.65 
.76 
459 
.70 
.96 
059 
.70 
.37 
695 
.70 
.80 
452 
.75 
3.00 
053 
.75 
.41 
689 
.75 
.84 
445 
.80 
.04 
047 
.80 
.45 
683 
.80 
.88 
438 
.85 
.08 
040 
.85 
.49 
678 
.85 
.92 
431 
.90 
.12 
034 
.90 
.53 
672 
.90 
.96 
424 
.95 
.16 
027 
.95 
.57 
666 
.95 
8.00 
.99417 
4.00 
3.20 
.99021 
7.00 
5.61 
.98660 
10.00 
8.04 
410 
.05 
.24 
015 
.05 
.65 
654 
.05 
.08 
403 
.10 
.28 
009 
.10 
.69 
649 
.10 
.12 
397 
.15 
.32 
002 
.15 
.73 
643 
.15 
.16 
390 
.20 
.36 
.98996 
.20 
.77 
637 
.20 
.20 
383 
.25 
.40 
990 
.25 
.81 
632 
.25 
.24 
376 
.30 
.44 
984 
.30 
.86 
626 
.30 
.29 
369 
.35 
.48 
978 
.35 
.90 
620 
.35 
.33 
363 
.40 
.52 
971 
.40 
.94 
614 
.40 
.37 
356 
.45 
.56 
965 
.45 
.98 
609 
.45 
.41 
.99349 
4.50 
3.60 
.98959 
7.50 
6.02 
.98603 
10.50 
8.45 
342 
.55 
.64 
953 
.55 
.06 
597 
.55 
.49 
335 
.60 
.68 
947 
.60 
.10 
592 
.60 
.53 
329 
.65 
.72 
940 
.65 
.14 
586 
.65 
.57 
322 
.70 
.76 
934 
.70 
.18 
580 
.70 
.61 
315 
.75 
.80 
928 
.75 
.22 
575 
.75 
.65 
308 
.80 
.84 
922 
.80 
.26 
569 
.80 
.70 
301 
.85 
.88 
916 
.85 
.30 
563 
.85 
.74 
295 
.90 
.92 
909 
.90 
.34 
557 
.90 
.78 
288 
.95 
.96 
903 
.95 
.38 
552 
.95 
.82 
.99281 
5.00 
4.00 
.98897 
8.00 
6.42 
.98546 
11.00 
8.86 
274 
.05 
.04 
891 
.05 
.46 
540 
.05 
.90 
268 
.10 
.08 
885 
.10 
.50 
535 
.10 
.94 
261 
.15 
.12 
879 
.15 
.54 
529 
.15 
.98 
255 
.20 
.16 
873 
.20 
.58 
524 
.20 
9.02 
248 
.25 
.20 
867 
.25 
.62 
518 
.25 
.07 
241 
.30 
.24 
861 
.30 
.67 
513 
.30 
.11 
235 
.35 
.28 
855 
.35 
.71 
507 
.35 
.15 
228 
.40 
.32 
849 
.40 
.75 
502 
.40 
.19 
222 
.45 
.36 
843 
.45 
.79 
496 
.45 
.23 
.99215 
5.50 
4.40 
.98837 
8.50 
6.83 
.98491 
11.50 
9.27 
208 
.55 
.44 
831 
.55 
.87 
485 
.55 
.31 
202 
.60 
.48 
825 
.60 
.91 
479 
.60 
.35 
195 
.65 
.52 
819 
.65 
.95 
474 
.65 
.39 
189 
.70 
.56 
813 
.70 
.99 
468 
.70 
.43 
182 
.75 
.60 
807 
.75 
7.03 
463 
.75 
.47 
175 
.80 
.64 
801 
.80 
.07 
457 
.80 
.51 
169 
.85 
.68 
795 
.85 
.11 
452 
.85 
.55 
162 
.90 
.72 
789 
.90 
.15 
446 
.90 
.59 
156 
.95 
.76 
783 
.95 
.19 
441 
.95 
.63 168 
FOODS. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
0.98435 
12.00 
9.67 
0.98114 
15.00 
12.13 
0.97808 
18.00 
14.60 
430 
.05 
.71 
108 
.05 
.17 
803 
.05 
.64 
424 
.10 
.75 
104 
.10 
.21 
798 
.10 
.68 
419 
.15 
.79 
099 
.15 
.25 
793 
.15 
.73 
413 
.20 
.83 
093 
.20 
.29 
788 
.20 
.77 
408 
.25 
.87 
088 
.25 
.33 
783 
.25 
.81 
402 
.30 
.92 
083 
.30 
.38 
778 
.30 
.85 
397 
.35 
.96 
078 
.35 
.42 
773 
.35 
.89 
391 
.40 
10.00 
073 
.40 
.46 
768 
.40 
.94 
386 
.45 
.04 
068 
.45 
.50 
763 
.45 
.98 
.98381 
12.50 
10.08 
.98063 
15.50 
12.54 
.97758 
18.50 
15.02 
375 
.55 
.12 
057 
.55 
.58 
753 
.55 
.06 
370 
.60 
.16 
052 
.60 
.62 
748 
.60 
.10 
364 
.65 
.20 
047 
.65 
.66 
743 
.65 
.14 
359 
.70 
.24 
042 
.70 
.70 
738 
.70 
.18 
353 
.75 
.28 
037 
.75 
.75 
733 
.75 
.22 
348 
.80 
.33 
032 
.80 
.79 
728 
.80 
.27 
342 
.85 
.37 
026 
.85 
.83 
723 
.85 
.31 
337 
.90 
.41 
021 
.90 
.87 
718 
.90 
.38 
331 
.95 
.45 
016 
.95 
.91 
713 
.95 
.39 
.98326 
13.00 
10.49 
.98011 
16.00 
12.95 
.97708 
19.00 
15.43 
321 
.05 
.53 
005 
.05 
.99 
703 
.05 
.47 
315 
.10 
.57 
001 
.10 
13.03 
698 
.10 
.51 
310 
.15 
.61 
.97996 
.15 
.08 
693 
.15 
.55 
305 
.20 
.65 
991 
.20 
.12 
688 
.20 
.59 
299 
.25 
.69 
986 
.25 
.16 
683 
.25 
.63 
294 
.30 
.74 
980 
.30 
.20 
678 
.30 
.68 
289 
.35 
.78 
975 
.35 
.24 
673 
.35 
.72 
283 
.40 
.82 
970 
.40 
.29 
668 
.40 
.76 
278 
.45 
.86 
965 
.45 
.33 
663 
.45 
.80 
.98273 
13.50 
10.90 
.97960 
16.50 
13.37 
.97658 
19.50 
15.84 
267 
.55 
.94 
955 
.55 
.41 
653 
.55 
.88 
262 
.60 
.98 
950 
.60 
.45 
648 
.60 
.93 
256 
.65 
11.02 
945 
.65 
.49 
643 
.65 
.97 
251 
.70 
.06 
940 
.70 
.53 
638 
.70 
16.01 
246 
.75 
.11 
935 
.75 
.57 
633 
.75 
.05 
240 
.80 
.15 
929 
.80 
.62 
628 
.80 
.09 
235 
.85 
.19 
924 
.85 
.66 
623 
.85 
.14 
230 
.90 
.23 
919 
.90 
.70 
618 
.90 
.18 
224 
.95 
.27 
914 
.95 
.74 
613 
.95 
.22 
.98219 
14.00 
11.31 
.97909 
17.00 
13.78 
.97608 
20.00 
16.26 
214 
.05 
.35 
904 
.05 
.82 
603 
.05 
.30 
200 
.10 
.39 
899 
.10 
.86 
598 
.10 
.34 
203 
.15 
.43 
894 
.15 
.90 
593 
.15 
.38 
198 
.20 
.47 
889 
.20 
.94 
588 
.20 
.42 
193 
.25 
.52 
884 
.25 
.98 
583 
.25 
.46 
188 
.30 
.56 
879 
.30 
14.03 
578 
.30 
.51 
182 
.35 
.60 
874 
.35 
.07 
573 
.35 
.55 
177 
.40 
.64 
869 
.40 
.11 
568 
.40 
.59 
172 
.45 
.68 
864 
.45 
.15 
563 
.45 
.63 
.98167 
14.50 
11.72 
.97859 
17.50 
14.19 
.97558 
20.50 
16.67 
161 
.55 
.76 
853 
.55 
.23 
552 
.55 
.71 
156 
.60 
.80 
848 
.60 
.27 
547 
.60 
.75 
151 
.65 
.84 
843 
.65 
.31 
542 
.65 
.80 
146 
.70 
.88 
838 
.70 
.35 
537 
.70 
.84 
140 
.75 
.93 
833 
.75 
.40 
532 
.75 
.88 
135 
.80 
.97 
828 
.80 
.44 
527 
.80 
.92 
130 
.85 
12.01 
823 
.85 
.48 
522 
.85 
.96 
125 
.90 
.05 
818 
.90 
.52 
517 
.90 
17.01 
119 
.95 
.09 
813 
.95 
.56 
512 
.95 
.05 PERCENTAGE OF ALCOHOL. 
169 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, j Per cent, 
alcohol by:alcohol by 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
volume. 
weight. 
0.97507 
21.00 
17.09 
0.97201 
24.00 
19.59 
0.96883 
27.00 
22.11 
502 
.05 
.13 
196 
.05 
.63 
877 
.05 
.15 
497 
.10 
.17 
191 
.10 
.67 
872 
.10 
.20 
492 
.15 
.22 
185 
.15 
.72 
866 
.15 
.24 
487 
.20 
.26 
180 
.20 
.76 i 
861 
.20 
.28 
482 
.25 
.30 
175 
.25 
.80 
855 
.25 
.33 
477 
.30 
.34 
170 
.30 
.84 
850 
.30 
.37 
472 
.35 
.38 
165 
.35 
.88 
844 
.35 
.41 
467 
.40 
.43 
159 
.40 
.93 
839 
.40 
.45 
462 
.45 
.47 
154 
.45 
.97 
833 
.45 
.50 
.97457 
21.50 
17.51 
.97149 
24.50 
20.01 
.96828 
27.50 
22.54 
451 
.55 
.55 
144 
.55 
.05 
822 
.55 
.58 
446 
.60 
.59 
139 
.60 
.09 
816 
.60 
.62 
441 
.65 
.63 
133 
.65 
.14 
811 
.65 
.67 
436 
.70 
.67 
128 
.70 
.18 
805 
.70 
.71 
431 
.75 
.71 
123 
.75 
.22 
800 
.75 
.75 
426 
.80 
.76 
118 
.80 
.26 
794 
.80 
.79 
421 
.85 
.80 
113 
.85 
.30 
789 
.85 
.83 
416 
.90 
.84 
107 
.90 
.35 
783 
.90 
.88 
411 
.95 
.88 
102 
.95 
.39 
778 
.95 
.92 
.97406 
22.00 
17.92 
.97097 
25.00 
20-43 
.96772 
28.00 
22.96 
401 
.05 
.96 
092 
.05 
•47 
766 
.05 
23.00 
396 
.10 
18.00 
086 
.10 
.51 
761 
.10 
.04 
391 
.15 
.05 
081 
.15 
.56 
755 
.15 
.09 
386 
.20 
.09 
076 
.20 
.60 
749 
.20 
.13 
381 
.25 
.13 
071 
.25 
.64 
711 
.25 
.17 
375 
.30 
.17 
065 
.30 
.68 
738 
.30 
.21 
370 
.35 
.21 
060 
.35 
.72 
732 
.35 
.25 
365 
.40 
.26 
055 
.40 
.77 
726 
.40 
.30 
360 
.45 
.30 
049 
.45 
.81 
721 
.45 
.34 
.97355 
22.50 
18.34 
.97044 
25.50 
20.85 
.96715 
28.50 
23.38 
350 
.55 
.38 
039 
.55 
.89 
709 
.55 
.42 
345 
.60 
.42 
033 
.60 
.93 
704 
.60 
.47 
340 
.65 
.47 
028 
.65 
.98 
698 
.65 
.51 
335 
.70 
.51 
023 
.70 
21.02 
692 
.70 
.55 
330 
.75 
.55 
018 
.75 
.06 
687 
.75 
.60 
324 
.80 
.59 
012 
.80 
.10 
681 
.80 
.64 
319 
.85 
.63 
007 
.85 
.14 
675 
.85 
.68 
314 
.90 
.68 
001 
.90 
.19 
669 
.90 
.72 
309 
.95 
.72 
.96996 
.95 
.23 
664 
.95 
.77 
.97304 
23.00 
18.76 
.96991 
26.00 
21.27 
.96658 
29.00 
23.81 
299 
.05 
.80 
986 
.05 
.31 
652 
.05 
.85 
294 
.10 
.84 
980 
.10 
.35 
646 
.10 
.89 
289 
.15 
.88 
975 
.15 
.40 
640 
.15 
.94 
283 
.20 
.92 
969 
.20 
.44 
635 
.20 
.98 
278 
.25 
.96 
964 
.25 
.48 
629 
.25 
24.02 
273 
.30 
19.01 
959 
.30 
.52 
623 
.30 
.06 
268 • 
.35 
.05 
953 
.35 
.56 
617 
.35 
.10 
263 
.40 
.09 
949 
.40 
.61 
611 
.40 
.15 
258 
.45 
.13 
942 
.45 
.65 
605 
.45 
.19 
.97253 
23.50 
19.17 
.96937 
26.50 
21.69 
.96600 
29.50 
24.23 
247 
.55 
.21 
932 
.55 
.73 
594 
.55 
.27 
242 
.60 
.25 
926 
.60 
.77 
587 
.60 
.32 
237 
.65 
.30 
921 
.65 
.82 
582 
.65 
.36 
232 
.70 
.34 
915 
.70 
.86 
576 
.70 
.40 
227 
.75 
.38 
910 
.75 
.90 
570 
.75 
.45 
222 
.80 
.42 
905 
.80 
.94 
564 
.80 
.49 
216 
.85 
.46 
899 
.85 
.98 
559 
.85 
.53 
211 
.90 
.51 
894 
.90 
22.03 
553 
.90 
.57 
206 
.95 
.55 
888 
.95 
.07 
547 
.95 
.62 170 
FOODS. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume.' 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
- 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
0.96541 
30.00 
24.66 
0.96172 
33.00 
27.23 
0.95773 
36.00 
29.83 
535 
.05 
.70 
166 
.05 
.27 
766 
.05 
.87 
• 529 
.10 
.74 
159 
.10 
.32 
759 
.10 
.92 
523 
.15 
.79 
153 
.15 
.36 
752 
.15 
.96 
517 
.20 
.83 
146 
.20 
.40 
745 
.20 
30.00 
511 
.25 
.87 
140 
.25 
.45 
738 
.25 
.05 
505 
.30 
.91 
133 
.30 
.49 
731 
.30 
.09 
499 
.35 
.95 
127 
.35 
.53 
724 
.35 
.13 
493 
.40 
25.00 
120 
.40 
.57 
717 
.40 
.17 
487 
.45 
.04 
114 
.45 
.62 
710 
.45 
.22 
.96481 
30.50 
25.08 
.96108 
33.50 
27.66 
.95703 
36.50 
30.26 
47-5 
.55 
.12 
101 
.55 
.70 
695 
.55 
.30 
469 
.60 
.17 
095 
.60 
.75 
688 
.60 
.35 
463 
.65 
.21 
088 
.65 
.79 
681 
.65 
.39 
457 
.70 
.25 
082 
.70 
.83 
674 
.70 
.44 
451 
.75 
.30 
075 
.75 
.88 
667 
.75 
.48 
445 
.80 
.34 
069 
.80 
.92 
660 
.80 
.52 
439 
.85 
.38 
062 
.85 
.96 
653 
.85 
.57 
433 
.90 
.42 
056 
.90 
28.00 
646 
.90 
.61 
427 
.95 
.47 
049 
.95 
.05 
639 
.95 
.66 
.96421 
31.00 
25.51 
.96043 
34.00 
28.09 
.95632 
37.00 
30.70 
415 
.05 
.55 
036 
.05 
.13 
625 
.05 
.74 
409 
.10 
.60 
030 
.10 
.18 
618 
.10 
.79 
403 
.15 
.64 
023 
.15 
.22 
610 
.15 
.83 
396 
.20 
.68 
016 
.20 
.26 
603 
.20 
.88 
390 
.25 
.73 
010 
.25 
.31 
596 
.25 
.92 
384 
.30 
.77 
003 
.30 
.35 
589 
.30 
.96 
378 
.35 
.81 
.95996 
.35 
.39 
581 
.35 
31.01 
372 
.40 
.85 
990 
.40 
.43 
574 
.40 
.05 
366 
.45 
.90 
983 
.45 
.48 
567 
.45 
.10 
.96360 
31.50 
25.94 
.95977 
34.50 
28.52 
.95560 
37.50 
31.14 
353 
.55 
.98 
970 
.55 
.56 
552 
.55 
.18 
347 
.60 
26.03 
963 
.60 
.61 
545 
.60 
.23 
341 
.65 
.07 
957 
.65 
.65 
538 
.65 
.27 
335 
.70 
.11 
950 
.70 
.70 
531 
.70 
.32 
329 
.75 
.16 
943 
.75 
.74 
523 
.75 
.36 
323 
.80 
.20 
937 
.80 
.78 
516 
.80 
.40 
316 
.85 
.24 
930 
.85 
.83 
509 
.85 
.45 
310 
.90 
.28 
923 
.90 
.87 
502 
.90 
.49 
304 
.95 
.33 
917 
.95 
.92 
494 
.95 
.54 
.96298 
32.00 
26.37 
.95910 
35.00 
28.96 
.95487 
38.00 
31.58 
292 
.05 
.41 
903 
.05 
29.00 
480 
.05 
.63 
285 
.10 
.46 
896 
.10 
.05 
472 
.10 
.67 
279 
.15 
.50 
889 
.15 
.09 
465 
.15 
.72 
273 
.20 
.54 
883 
.20 
.13 
457 
.20 
.76 
267 
.25 
.59 
876 
.25 
.18 
450 
.25 
.81 
260 
.30 
.63 
869 
.30 
.22 
442 
.30 
.85 
254 
.35 
.67 
862 
.35 
.26 
435 
.35 
.90 
248 
.40 
.71 
855 
.40 
.30 
427 
.40 
.94 
241 
.45 
.76 
848 
.45 
.35 
420 
.45 
.99 
.96235 
32.50 
26.80 
.95842 
35.50 
29.39 
.95413 
38.50 
32.03 
229 
.55 
.84 
835 
.55 
.43 
405 
.55 
.07 
222 
.60 
.89 
828 
.60 
.48 
398 
.60 
.12 
216 
.65 
.93 
821 
.65 
.52 
390 
.65 
.16 
210 
.70 
.97 
814 
.70 
.57 
383 
.70 
.20 
204 
.75 
27.02 
807 
.75 
.61 
375 
.75 
.25 
197 
.80 
.06 
800 
.80 
.65 
368 
.80 
.29 
191 
.85 
.10 
794 
.85 
.70 
360 
.85 
.33 
185 
.90 
.14 
787 
.90 
.74 
353 
.90 
.37 
178 
.95 
.19 
780 
.95 
.79 
345 
.95 
.42 PERCENTAGE OF ALCOHOL. 
171 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume.' 
Per cent. 1 
alcohol by| 
weight. ■ 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
0.95338 
39.00 
32.46 
0.94868 
42.00 
35.13 
0.94364 
45.00 
37.84 
330 
.05 
.50 
860 
.05 
.18 
355 
.05 
.89 
323 
.10 
.55 
852 
.10 
.22 
346 
.10 
.93 
315 
.15 
.59 
843 
.15 
.27 
338 
.15 
.98 
307 
.20 
.64 
835 
.20 
.31 
329 
.20 
38.02 
300 
.25 
.68 
827 
.25 
.36 
320 
.25 
.07 
292 
.30 
.72 
820 
.30 
.40 
311 
.30 
.12 
284 
.35 
.77 
811 
.35 
.45 
302 
.35 
.16 
277 
.40 
.81 
802 
.40 
.49 
294 
.40 
.21 
269 
.45 
.86 
794 
.45 
.54 
285 
.45 
.25 
.95262 
39.50 
32.90 
.94786 
42.50 
35.58 
.94276 
45.50 
38.30 
254 
.55 
.95 
778 
.55 
.63 
267 
.55 
.35 
246 
.60 
.99 
770 
.60 
.67 
258 
.60 
.39 
239 
.65 
33.04 
761 
.65 
.72 
250 
.65 
.44 
231 
.70 
.08 
753 
.70 
.76 
241 
.70 
.48 
223 
.75 
.13 
745 
.75 
.81 
232 
.75 
.53 
216 
.80 
.17 
737 
.80 
.85 
223 
.80 
.57 
208 
.85 
.22 
729 
.85 
.90 
214 
.85 
.62 
200 
.90 
.27 
720 
.90 
.94 
206 
.90 
.66 
193 
.95 
.31 
712 
.95 
.99 
197 
.95 
.71 
.95185 
40.00 
33.35 
.94704 
43.00 
36.03 
.94188 
46.00 
38.75 
177 
.05 
.39 
696 
.05 
.08 
179 
.05 
.80 
169 
.10 
.44 
687 
.10 
.12 
170 
.10 
.84 
161 
.15 
.48 
679 
.15 
.17 
161 
.15 
.89 
154 
.20 
.53 
670 
.20 
.21 
152 
.20 
.93 
146 
.25 
.57 
662 
.25 
.23 
143 
.25 
.98 
138 
.30 
.61 
654 
.30 
.30 
134 
.30 
39.03 
130 
.35 
.66 
645 
.35 
.35 
125 
.35 
.07 
122 
.40 
.70 
637 
.40 
.39 
116 
.40 
.12 
114 
.45 
.75 
628 
.45 
.44 
107 
.45 
.16 
.95107 
40.50 
33.79 
.94620 
43.50 
36.48 
.94098 
46.50 
39.21 
099 
.55 
.84 
612 
.55 
.53 
089 
.55 
.26 
091 
.60 
.88 
603 
.60 
.57 
080 
.60 
.30 
083 
.65 
.93 
595 
.65 
.62 
071 
.65 
.35 
075 
.70 
.97 
586 
.70 
.66 
062 
.70 
.39 
067 
.75 
34.02 
578 
.75 
.71 
053 
.75 
.44 
059 
.80 
.06 
570 
.80 
.75 
044 
.80 
.49 
052 
.85 
.11 
561 
.85 
.80 
035 
.85 
.53 
044 
.90 
.15 
553 
.90 
.84 
026 
.90 
.58 
036 
.95 
.20 
544 
.95 
.89 
017 
.95 
.62 
.95028 
41.00 
34.24 
.94536 
44.00 
36.93 
.94008 
47.00 
39.67 
020 
.05 
.28 
527 
.05 
.98 
.93999 
.05 
.72 
012 
.10 
.33 
519 
.10 
37.02 
990 
.10 
.76 
004 
.15 
.37 
510 
.15 
.07 
980 
.15 
.81 
.94996 
.20 
.42 
502 
.20 
.11 
971 
.20 
.85 
988 
.25 
.46 
493 
.25 
.16 
962 
.25 
.90 
980 
.30 
.50 
484 
.30 
.21 
953 
.30 
.95 
972 
.35 
.55 
476 
.35 
.25 
944 
.35 
.99 
964 
.40 
.59 
467 
.40 
.30 
934 
.40 
40.04 
956 
.45 
.64 
459 
.45 
.34 
925 
.45 
.08 
.94948 
41.50 
34.68 
.94450 
44.50 
37.39 
.93916 
47.50 
40.13 
940 
.55 
.73 
441 
.55 
.44 
906 
.55 
.18 
932 
.60 
.77 
433 
.60 
.48 
898 
.60 
.22 
924 
.65 
.82 
424 
.65 
.53 
888 
.65 
.27 
916 
.70 
.86 
416 
.70 
.57 
879 
.70 
.32 
908 
.75 
.91 
407 
.75 
.62 
870 
.75 
.37 
900 
.80 
.95 
398 
.80 
.66 
861 
.80 
.41 
892 
.85 
35.00 
390 
.85 
.71 
852 
.85 
.46 
884 
.90 
.04 
381 
.90 
.76 
842 
.90 
.51 
876 
.95 
.09 
373 
.95 
.80 
833 
.95 
.55 172 
FOODS. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight.' 
Specific 
gravity at 
60° F. 
Per cent, 
alcohol by 
volume. 
Per cent, 
alcohol by 
weight. 
0.93824 
48.00 
40.60 
0.93636 
49.00 
41.52 
0.93540 
49.50 
41.99 
815 
.05 
.65 
626 
.05 
.57 
530 
.55 
42.04 
805 
.10 
.69 
617 
.10 
.61 
521 
.60 
.08 
796 
.15 
.74 
607 
.15 
.66 
511 
.65 
.13 
786 
.20 
.78 
598 
.20 
• 71 
502 
.70 
.18 
777 
.25 
.83 
588 
.25 
.76 
492 
.75 
.23 
768 
.30 
.88 
578 
.30 
.80 
482 
.80 
.27 
758 
.35 
.92 
569 
.35 
.85 
473 
.85 
.32 
749 
.40 
.97 
559 
.40 
.90 
463 
.90 
.37 
739 
.45 
41.01 
550 
.45 
.94 
454 
.95 
.41 
.93730 
48.50 
41.06 
721 
.55 
.11 
711 
.60 
.15 
702 
.65 
.20 
692 
.70 
.24 
683 
.75 
.29 
679 
.80 
.34 
664 
.85 
.38 
655 
.90 
.43 
645 
.95 
.47 
Determination of Extract.-The extract may be determined di- 
rectly or, with the aid of a table, from the specific gravity of the de- 
alcoholized beer. The direct method is the more accurate and is 
carried out as follows : Into an accurately weighed platinum dish, such 
as is used in the analysis of milk, weigh 5 grams of beer ; evaporate to 
complete dryness, and multiply the weight of the residue by 20. 
Approximately accurate results are obtained by reference to the fol- 
lowing table after Schultze-Ostermann. 
Specific 
Gravity. 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
1.011 
2.S7 
2.90 
2.92 
2.95 
2.97 
3.00 
3.03 
3.06 
3.08 
3.11 
2 
3.13 
3.16 
3.18 
3.21 
3.24 
3.26 
3.29 
3.31 
3.34 
3.37 
3 
3.39 
3.42 
3.44 
3.47 
3.49 
3.52 
3.55 
3.57 
3.60 
3.62 
4 
3.65 
3.67 
3.70 
3.73 
3.75 
3.78 
3.80 
3.83 
3.86 
3.88 
5 
3.91 
3.93 
3.96 
3.98 
4.01 
4.04 
4.06 
4.09 
4.11 
4.14 
6 
4.16 
4.19 
4.21 
4.24 
4.27 
4.29 
4.32 
4.34 
4.37 
4.39 
7 
4.42 
4.44 
4.47 
4.50 
4.52 
4.55 
4.57 
4.60 
4.62 
4.65 
8 
4.67 
4.70 
4.73 
4.75 
4.78 
4.80 
4.83 
4.85 
4.88 
4.90 
9 
4.93 
4.96 
4.98 
5.01 
5.03 
5.06 
5.08 
5.11 
5.13 
5.16 
1.020 
5.19 
5.21 
5.24 
5.26 
5.29 
5.31 
5.34 
5.36 
5.39 
5.41 
1 
5.44 
5.47 
5.49 
5.52 
5.54 
5.57 
5.59 
5.62 
5.64 
5.67 
2 
5.69 
5.72 
5.74 
5.77 
5.80 
5.82 
5.85 
5.87 
5.90 
5.92 
3 
5.95 
5.97 
6.00 
6.02 
6.05 
6.08 
6.10 
6.13 
6.15 
6.18 
4 
6.20 
6.23 
6.25 
6.28 
6.30 
6.33 
6.35 
6.38 
6.40 
6.43 
5 
6.45 
6.48 
6.50 
6.53 
6.55 
6.58 
6.61 
6.63 
6.66 
6.68 
6 
6.71 
6.73 
6.76 
6.78 
6.81 
6.83 
6.86 
6.88 
6.91 
6.93 
7 
6.96 
6.98 
7.01 
7.03 
7.06 
7.08 
7.11 
7.13 
7.16 
7.18 
8 
7.21 
7.24 
7.26 
7.29 
7.31 
7.34 
7.36 
7.39 
7.41 
7.44 
9 
7.46 
7.49 
7.51 
7.54 
7.56 
7.59 
7.61 
7.64 
7.66 
7.69 
1.030 
7.71 
7.74 
7.76 
7.79 
7.81 
7.84 
7.86 
7.89 
7.91 
7.94 
1 
7.99 
8.01 
8.04 
8.06 
8.09 
8.11 
8.14 
8.16 
8.19 
8.21 
BEER EXTRACT TABLE. 173 
DETECTION OF PRESERVATIVES. 
The figures at the head of the several columns represent the fourth 
decimal place of the specific gravity. Example : Specific gravity, 
1.0187 ; referring to 1.018 in the left-hand column and running out 
to the column headed by the figure 7, we find 4.85 as the percentage 
of extract for that gravity. 
Detection of Preservatives.-The principal preservative used in 
beer is salicylic acid ; next in importance is fluoride of sodium which, 
however, is not used to any considerable extent as yet in this country. 
Salicylic Acid.-The ordinary method of extracting by means of 
ether and testing the residue left on evaporation of the latter with 
ferric chloride cannot be used in the examination of beer, since kiln- 
dried malt contains a principle which gives the same violet reaction 
as salicylic acid. The following methods are, however, reliable and 
satisfactory. 
1. Jorissen's method. Add to a sample of the liquid a few drops 
of a 10-per-cent. solution of potassium nitrite, an equal amount of 
acetic acid, and a drop of a 10-per-cent. solution of copper sulphate. 
If salicylic acid is present, a blood-red coloration appears. This re- 
action does not occur with the principle which is developed in kiln- 
dried malt. 
2. Spica's method. Acidify 100 cc. with sulphuric acid, extract 
with ether, allow the separated ether to evaporate spontaneously, and 
warm the residue gently with a drop of strong nitric acid whereby, if 
salicylic acid is present, picric acid is formed. The addition of a few 
drops of ammonia or of sodium hydroxide produces the corresponding 
picrate with its bright yellow color, which can be imparted to a woolen 
thread immersed in the liquid. 
Fluorides.-Several methods are recommended and among them the 
following : 
Method of Hefelmann and Mann.-Expel the carbonic acid from 500 
cc. of beer and then add 1 cc. of a solution containing 5 per cent, each 
of calcium and barium chlorides, and follow it with 0.5 cc. of 20-per- 
cent. acetic acid and 50 cc. of 90-per-cent. alcohol. Let stand 24 
hours and filter. Dry the filter and precipitate collected thereon with- 
out washing, and transfer to a platinum crucible. Add strong sul- 
phuric acid and cover the crucible with a waxed watch glass with some 
lines scratched through the wax coating, then heat at 100° C. for two 
hours and observe the effect on the exposed glass. This method is said 
to be of sufficient delicacy to detect the presence of 7 milligrams in a liter. 
Brand's Method.-To 100 cc. of beer made slightly alkaline with 
ammonium carbonate and heated, add 2 or 3 cc. of a 10-per-cent. so- 
lution of calcium chloride. Boil for a few minutes, filter, and dry the 
filter and contents. Then proceed as in the method just described. 
In either process it is best to place a lump of ice in the concavity of 
the watch glass to keep the latter cool; the water must be removed 
from time to time by means of a pipette so that it shall not overflow. 
Other Determinations.-Of minor interest are the determinations 
of acidity and ash. 174 
FOODS. 
Total Acidity.-To 10 cc. of beer freed from carbonic acid by shak- 
ing, add a few drops of neutral litmus solution, and then add decinor- 
mal sodium hydroxide until the end reaction is observed. Express the 
results in parts of acetic acid. One cc. of decinormal sodium hydroxide 
solution equals 0.006 gram of acetic acid. 
Fixed and Volatile Acidity.-Concentrate 10 cc. of beer to a third 
of its bulk by evaporation, add water up to the original volume, and 
proceed as before. The difference is due to the acetic acid which has 
been driven off. The fixed acidity is due chiefly to lactic a»cid, and, if 
desired, may be so expressed. One cc. of the decinormal solution is 
equivalent to .009 gram of lactic acid. The other acids present in- 
clude succinic, malic, and tannic. 
Ash.-The residue obtained in the direct determination of the ex- 
tract may be utilized for the estimation of the ash. It must be ignited 
very cautiously and at as low a temperature as possible until the ash 
is white. 
WINES. 
Properly speaking, wine is the fermented juice of grapes, though the 
term is applied also to other products of fermentation of saccharine 
liquids and fruit juices. It has been in use as a drink from the very 
earliest periods of civilization. At the present time, wines are pro- 
duced in infinite variety and of many qualities. The character and 
properties depend upon a great number of factors including the variety 
of the grape, the nature of the soil upon which the vine is cultivated, 
the climate in general and the state of the weather in particular when 
the grapes are ripening, the degree of ripeness when gathered, the 
method followed in the preparation of the must, and the care with 
which the other steps in the making of the final product are conducted. 
Of very great influence is the extent to which the seeds, skins, and 
stems of the fruit are allowed to be acted upon. The seeds yield con- 
siderable amounts of tannic acid, and the skins lend color, flavor, and 
to some extent astringency. 
The most important constituent of the juice of the grape is the sugar, 
and this is present in greatest abundance when the fruit is fully ripe. 
In the making of wine, the first step is the preparation of the must. 
The grapes with or without preliminary careful examination and sort- 
ing, usually without, are crushed by machinery or by the naked feet 
of men so that the juice is set free. Sometimes, the stems are first care- 
fully eliminated, and particularly good individual grapes are cut out and 
set aside for special use. In the crushing of the fruit, the method of 
treading has in its favor the fact that the seeds are not thereby affected 
and so do not give up so much of their astringent principle. If a 
white wine is to be made, the must is freed at once from the skins and 
stalks ; but if the product is to be red, these are left in during the proc- 
ess of fermentation. The juice of both the white and the black varieties 
of grapes is practically without color, but when the dark skins are left WINES. 
175 
in contact with the fermenting mass, the alcohol formed extracts the 
yellow and blue coloring matters, which become red under the action 
of the free acids formed at the same time. 
The constituents of the must are water, sugar, proteid matters, 
gummy substances, pectous matter, organic acids and their salts, and 
mineral matters. 
The must, with or without the skins and seeds, is fermented in vats 
of wood, marble, or stone, the process starting very quickly, being in- 
duced by organisms which grow on the skin itself. The temperature 
at which this is allowed to proceed exerts an important influence in de- 
termining the character of the wine; conducted between 5° and 15° 
C., the process is comparatively slow and the aroma of the wine is rich, 
while at higher temperatures, the rate is more rapid and the bouquet is 
less marked. The termination of the process is made evident by the 
cessation of the evolution of carbonic acid, the diminution in specific 
gravity, and the sinking of matters which before had formed part of 
the scum. 
Whether all of the sugar is used up, depends somewhat upon the 
amount of proteid nutrient material for the growth of the organisms 
by which the conversion is carried on. If this is exhausted first, there 
will be a residue of sugar, and the product will be correspondingly 
sweet; if there is an abundance of proteid matter, the sugar will be the 
first to be exhausted, and the wine will be " dry." It is sometimes 
necessary to add nitrogenous matter such as egg albumin or gelatin in 
order to keep the process from ceasing too early. 
As the percentage of alcohol in the fermenting must rises, the bitar- 
trate of potassium present is gradually deposited, owing to its insolu- 
bility in alcohol. The deposit is known commercially as argol and is 
the source of cream of tartar. 
When the first fermentation is completed, the alcoholic liquid is drawn 
off into casks in which it is kept for a number of months, the vessels 
being kept constantly filled. It now undergoes a second slow fermen- 
tation which brings about a group of changes which are not understood 
excepting in their gross result, which is the production of the " bou- 
quet" or flavor. In this second process, there is a further deposition 
of argol and also an oxidation of aldehyde to acetic acid. The bouquet 
is due to a combination of ethers, the chief of which is oenanthic ether, 
supposed to be produced from the alcohol through the agency of the 
organic acids normally present. 
The wine is next racked off into fresh casks, and in some cases this 
has to be done several times. Sometimes, the appearance of the wine 
is such that the operation of fining is necessary. This consists in the 
addition of egg albumin, isinglass or other gelatinous matter, which in 
its descent attracts and enmeshes the fine particles of matter which 
not only prevent brilliancy but later on may detract from the keeping 
quality of the wine. 
Classification of Wines.-Wines are variously classified according 
to color, strength, sweetness, and content of carbonic acid. Accord- 176 
FOODS. 
ing to color, they are classed as red or white, the latter term applying 
not only to the very light, almost colorless kinds, but also to those hav- 
ing a decided yellowish or even yellowish-brown color such as is pos- 
sessed by " white port." The red wines include those generally known 
as Clarets and Burgundies, though both these kinds exist in the 
white forms. The white wines include the white Clarets commonly 
designated as Sauternes, white Burgundies of which Chablis is a type, 
the Rhine and Moselle wines, and others. 
According to strength, wines are classed as natural and fortified. 
The natural wines contain of alcohol only that which is formed in the 
natural process of fermentation ; the fortified wines, such as Sherry, 
Port, and Madeira contain, besides, a considerable amount in the form 
of added spirits. 
According to their content of sugar, they are classed as sweet or 
dry. Some of the sweet wines contain added sugar and that which 
has escaped the action of the yeast plant. In the dry wines, all or 
nearly all of the sugar has been converted into alcohol. Not all of 
the sugar, however, in any wine is converted into alcohol and carbonic 
acid, small amounts going to form glycerin and succinic acid. 
According to their content of carbonic acid, wines are classed as still 
or sparkling (effervescent). The natural wines contain practically 
no carbonic acid; the sparkling, or effervescent, wines, as Champagne 
and sparkling Moselle, are in a sense artificial in that they are sub- 
jected to a process of fermentation in the bottle, sugar being added for 
the purpose. They are also flavored with liqueurs. 
Composition of Wines. Alcohol.-The most important constitu- 
ent, the active principle, of wine is ethylic alcohol. The higher alcohols, 
propylic, butylic, and amylic, are always present in traces. The amount 
of alcohol is quite variable, ranging in natural wines from 6 to 15 per 
cent, by weight, but ordinarily present between the limits of 9 and 12 
per cent. In fortified wines, the amount ranges from 12 to about 22 
per cent., but is usually about 17 per cent. 
Sugar.-While the amount of sugar in the original must ranges be- 
tween 12 and 35 per cent., in the natural finished product it is as a 
rule quite low, ordinarily considerably under a half of one per cent., 
and often none at all. The sweet Tokays contain exceedingly variable 
amounts, ranging from 3 to 26 per cent., Ports and Madeiras about 
4, and Sherries somewhat less. Champagnes, even those ordinarily 
classed as sweet, contain but small amounts, the impression of sweet- 
ness being largely due to the flavorings of the liqueurs added. Four 
specimens analyzed by the author, one of which (No. 4) is well known 
as an extra sweet wine, yielded the following results : 
Brand. 
Sugar. 
Extract. 
Alcohol by 
Weight. 
1. 
Brut Imperial (Moet & Chand on) 
1.35 
3.27 
11.15 
2. 
St. Marceaux 
1.52 
3.21 
10.38 
3. 
Dry Imperial (Moet & Chandon) 
1.56 
3.18 
10.85 
4. 
White Seal (Moet & Chandon) 
4.76 
6.88 
10.23 177 
ADULTERATION OF WINES. 
Extract.-The extract, or residue, represents the sum of the non- 
volatile constituents including sugar, nitrogenous matters, tartaric and 
other acids, mineral and organic salts, coloring and astringent princi- 
ples, glycerin, etc., all of which are present in but small quantities. 
In sweet wines, the principal constituent of the residue is sugar. The 
actual food value of the residue is, apart from the sugar, practically nil. 
Adulteration of Wines.-Wines have been subject to a wide vari- 
ety of adulterations from the earliest times, and measures against the 
practice of their sophistication were taken long before those against the 
adulteration of bread and other foods were thought of. The ancient 
Greeks and Romans, for example, enacted stringent laws and appointed 
officials whose duty was to detect and punish those who offended. 
At the present time, adulteration of wines is practiced very exten- 
sively and includes the addition of water, of coloring agents, of pre- 
servatives, of glycerin to impart sweetness and body, of alum to 
heighten color and of decolorizing agents to remove it, the substitution 
of wholly artificial compounds, and processes for the " improvement " 
of the natural product. The flavoring and coloring agents are as a 
rule quite harmless in their nature. They are employed chiefly in the 
manufacture of factitious wines, and not uncommonly the same agent 
serves in both capacities. Prunes, raisins, dried apples and peaches, 
and dates are quite commonly so employed. Various berries, logwood, 
alkanet, red beets, coal-tar products and a wide variety of other sub- 
stances are said to be used for imparting color. 
The addition of alcohol is recognized as a legitimate practice in the 
case of the fortified wines ; that of glycerin has no sanitary significance. 
The amount of alum used for heightening color is so small as to be 
productive of no harm. The employment of decolorizing agents is, 
like the substitution of artificial products, a fraud pure and simple; 
but the use of preservatives such as salicylic acid, formaldehyde, and 
sulphites, is objectionable on account of danger to health. 
For the improvement of wines, a number of processes are in vogue. 
Chief of these is " plastering," which consists in the addition of gyp- 
sum to the must for the purpose of conferring a more brilliant appear- 
ance and increasing the keeping qualities. This agent decomposes the 
potassium bitartrate, forming tartrate of calcium and acid sulphate of 
potassium, which is eventually converted to the neutral sulphate. 
Chaptalizing consists in the neutralization of* the acidity of the must 
by the use of marble dust, and the addition of cane sugar or glucose. 
This process diminishes the natural acidity and increases the yield of 
alcohol. Gallizing consists in diluting the must so as to reduce its 
acidity to a given standard, and adding a sufficient amount of cane sugar 
or glucose to ensure the production of the proper alcoholic strength. 
The Pasteur treatment of wines is sometimes resorted to as soon as 
evidence of untoward fermentations producing the so-called " wine dis- 
eases " appears. The wine, best in the bottle, is heated to from 55 to 
65° C. according as the alcoholic strength is high or low, whereby the 
existing germs are killed and the preservation of the wine is permanent. 178 
FOODS. 
The manufacture of artificial wines is carried on quite extensively 
in this country and abroad, in spite of the fact that fair grades of the 
genuine product are obtainable at very low prices. A number of hand- 
books and guides to the " art of blending and compounding " are pub- 
lished for the use of wholesalers and retailers of wines and liquors, and 
from several of these the following are selected as examples of the 
methods given: (1) Port. Cider, 30 gallons; alcohol, 5 gallons; 
syrup, 4 gallons ; kino, one-half pound ; tartaric acid, one-quarter 
pound ; port wine flavor, 6 ounces. (2) Claret. California hock, 40 
gallons ; extract of kino, 8 ounces ; essence of malvey flower, 8 ounces. 
(3) Sherry. Equal parts of Spanish sherry and California hock. (4) 
White wine. Dissolve 25 pounds of grape sugar and one of tartaric 
acid in 25 quarts of hot water, add 75 quarts of cold water and 50 
pounds of grape pulp, stir, cover, let ferment for four or five days, 
and strain. 
In France, an artificial substitute for wine, known as ° piquette," is 
very extensively manufactured from raisins and dried apples. It is 
estimated that in 1898 no less than 50,000,000 gallons were made and 
consumed. The process is exceedingly simple. To each gallon of 
water used are added one pound of raisins and one of dried apples; 
the mixture is placed in an open vessel and allowed to stand three 
days. It is then bottled with a half teaspoonful of sugar and a small 
piece of cinnamon in each bottle. It is said to be a pleasant and 
harmless beverage. 
Analysis of Wines. 
Determination of Alcohol.-The process for the determination of 
alcohol is the same as that followed in the analysis of beer, except that 
the distillation or evaporation is carried further along. At least 60, 
and better, 75 cc. are collected by distillation or driven off by open 
evaporation. 
Determination of Extract.-The specific gravity of the de-alcohol- 
ized wine gives, as with beer, an approximate estimate of the amount 
of extract, and the same table may be used. The direct determination 
is made by evaporating 50 cc. of the wine in a weighed platinum dish 
on the water-bath and drying to constant weight in an air-bath. With 
sweet wines a smaller amount is preferable. 
Determination of Acidity.-The total acidity due to bitartrate of 
potassium, tartaric acid, malic and other acids is reckoned as tartaric 
acid. Twenty-five cc. of the wine are titrated in the usual way with 
decinormal sodium hydroxide, one cc. of which equals 0.0075 gram of 
tartaric acid. 
The volatile acids are reckoned as acetic acid. Fifty cc. of the wine 
are placed in a distilling flask connected by means of its outlet tube 
with a Liebig's condenser and by means of a bent tube passing through 
its stopper and projecting well below the surface of the wine, with a 
flask containing 250 cc. of water. The contents of both flasks are DETECTION OF COAL-TAR COLORS. 
179 
brought to the boiling point, and then the flame beneath the wine is 
turned down and the current of steam passed through until 200 cc. of 
distillate are collected. This is titrated with decinormal sodium hy- 
droxide, and the result is expressed as acetic acid. The determination 
of the amounts of the individual acids is of no hygienic interest. 
Determination of Sugar.-The amount of sugar in wine is deter- 
mined by reduction of Fehling's solution, by the method of Allihn, and 
by polariscopy. For the details of these methods the reader is referred 
to any of the standard works on wine analysis, for the small amount 
of sugar ordinarily present is of but little hygienic interest, and the de- 
scription of the processes would involve an amount of space vastly out 
of proportion to the importance of the subject. 
Determination of Ash.-The residue obtained in the determination 
of extract can be utilized for the determination of the ash. It must 
be ignited at as low a temperature as possible. 
Detection of Coal-tar Colors.-While the presence of coal-tar 
colors is not difficult of detection, the identification of the individual 
members of the group is by no means easy. The following tests give 
reliable indications of the presence of this class of colors. Equal 
volumes of wine and ether, agitated in a flask and let stand and sepa- 
rate, will show in the ether layer a red coloration, if anilin colors are 
present. In place of ether, nitro-benzene may be used ; this removes 
fuchsin, eosin, and methylen blue, but does not take up any of the 
vegetable colors, safranin, or indigo-carmine. Amyl alcohol, also, will 
become reddened when agitated with wine containing anilins, but the 
wine must first be made slightly alkaline. If white woolen threads 
are immersed for some time in the colored liquids, they will take up 
the colors and become dyed. 
Cazeneuve's test is performed as follows: To 10 cc. of wine add 
0.200 gm. of mercuric oxide, then shake for one minute, boil, let stand, 
and filter. The filtrate should be quite clear, and in the absence of anilins 
should be colorless; if it is red, an anilin color is present. Absence 
of color is, however, not conclusive evidence of purity, since a number 
of the anilin colors, as eosin, methylen blue, and others, are wholly 
precipitated, and so do not appear in the filtrate. Safranin, methyl- 
eosin, Ponceau red and a number of other colors are partially or com- 
pletely precipitated. 
A number of these, including safranin, Bordeaux red and Ponceau 
red, may be separated by the following process : To 200 cc. of wine 
from which the alcohol has been expelled, add 4 cc. of 10-per-cent. 
hydrochloric acid and some white woolen threads, and boil for five min- 
utes. Withdraw the threads and wash them with cold water acidu- 
lated with hydrochloric acid, next with hot water similarly acidulated, 
and lastly with distilled water alone. Boil the threads in 50 cc. of 
distilled water containing 2 cc. of strong ammonia water, remove them, 
and immerse new ones. Make acid with hydrochloric acid and boil 
for five minutes. Varying shades of rose-red will be imparted to the 
threads if any of these colors are present. 180 
FOODS. 
Fuchsin may be detected by the following methods : (1) To 100 cc. 
of wine add 5 cc. of ammonia water and 30 cc. of ether, and shake. 
Remove the ether, which will have no color, place it in a watch glass 
with a white woolen thread, and let it evaporate to dryness. If even 
a'trace of fuchsin is present, the thread will show a distinct rose col- 
oration. (2) Mix two volumes of wine and one of solution of basic 
acetate of lead, warm gently, and shake. Filter, add to the filtrate a 
small amount of amyl alcohol, shake again, and remove the amyl alco- 
hol. If this has a red color, it may be due to fuchsin or to orseille. 
To a portion of the colored liquid add hydrochloric acid ; if the color 
is discharged, it was due to fuchsin. To another portion add ammonia 
water ; if the color is changed to purple violet, it was due to orseille. 
Detection of Preservatives. Salicylic Acid.-Spica's method for 
detecting salicylic acid in wine is as follows : Acidify 10 cc. of wine 
with a few drops of hydrochloric acid and shake with an equal volume 
of ether. Remove the ether, filter it if necessary, and evaporate it to 
dryness. Add a drop of nitric acid, warm gently, and add an excess 
of ammonia and 1 cc. of water. Immerse a white woolen thread, 
apply gentle heat, and then withdraw the thread, wash it, and dry it 
between pieces of blotting paper. A yellow color indicates that sali- 
cylic acid was present in the wine. 
Another method for which great delicacy is claimed, even to a tenth 
of a milligram in a liter, is the following. Acidify 50 cc. of wine, 
beer, or other liquid with sulphuric acid, and shake it with an equal 
volume of a mixture of equal parts of ether and naphtha. Separate 
the ether, filter, and evaporate down to 5 cc. ; then add 3 cc. of water 
and a few drops of very dilute solution of ferric chloride, and filter 
through a wet filter. In the presence of salicylic acid, the watery por- 
tion will have a violet color. A modification of this method consists 
in extracting with ether alone and then extracting the ether residue 
with naphtha; the residue on evaporation of the naphtha is treated 
with water and very dilute ferric chloride. 
Formaldehyde.-To 10 cc. of wine, add a few drops of milk known 
to be free from formaldehyde, and shake in a test tube. Next pour 
down the side of the tube about 4-5 cc. of strong commercial sul- 
phuric acid, and note the color at the line of contact of the two liquids. 
(See under milk.) 
Sulphites.-To 200 cc. of wine (or beer) add 5 cc. of phosphoric 
acid ; distill 100 cc., using a Liebig's condenser with a bent delivery 
tube which dips below the surface of 20 cc. of deci normal solution of 
iodine. By distilling in a current of washed CO2 the danger of back 
suction is avoided. The reaction which is brought about is as follows : 
SO., + 2H2O 4- I2 = H2SO4 + 2HI. The amount of SO2 may be de- 
termined by estimating the excess of iodine by means of standard so- 
dium thiosulphate, or the distillate may be acidified with hydrochloric 
acid and the contained sulphuric acid precipitated as barium sulphate 
by the addition of barium chloride. One milligram of barium sul- 
phate is equivalent to 0.2748 milligram of SO2. DISTILLED ALCOHOLIC BEVERAGES. 
181 
CIDER. 
Cider, or apple wine, is the fermented juice of the apple. It is very 
extensively made wherever apples are grown, and is a very important 
product, viewed either as a beverage or as the basis of what is generally 
regarded as the best kind of vinegar. 
A very large if not the greater part of the cider produced is made 
without special care by a very simple process. The apples used are 
ordinarily those not marketable on account of small size, greenness, 
over-ripeness, or bruises, but often perfect fruit is used when the crop 
is so abundant that there is more profit in converting it into cidei* and 
vinegar than in sending it in barrels to market. 
The fruit is ground to a pulp and pressed, and the juice drawn into 
barrels and allowed to ferment. If the same amount of care is taken 
as is given to the making of wine from, grapes, the product is of a 
superior grade and has great keeping qualities, but as ordinarily made 
in the country, its life is short unless treated with salicylic acid or other 
preservative to check fermentation. In France, where the yearly yield 
is very great, the best grades are made with due regard to the temper- 
ature at which the fermentation proceeds and to the importance of 
racking off and fining. 
Cider of good quality contains usually from 3 to 5 per cent, and 
sometimes as much as 8 per cent, by weight of alcohol. Very new 
sweet cider may contain less than 1 per cent. The total extract, which 
is largely sugar, is in inverse proportion to the amount of alcohol; in 
average samples it amounts to from 4 to 6 per cent., while in new 
sweet cider it is commonly nearer 9 per cent. The free acids, chiefly 
malic, amount to less than three-fourths of 1 per cent, and average 
about 0.40. 
The adulterations of cider are water and salicylic acid. The latter 
is very commonly found in that which reaches the city markets. 
PERRY. 
Perry, or " pear cider," is the fermented juice of pears. It is made 
in the same way as cider. Pear juice being richer in sugar than apple 
juice, it follows that the average content of alcohol is somewhat higher 
than in cider. 
Distilled Alcoholic Beverages. 
Spirits, or distilled liquors, are the product of distillation of fermented 
sugar solutions. Their most important constituent is ethylic alcohol 
which is ordinarily present to the extent of about 45 per cent. When 
freshly made, they contain variable small quantities of higher alcohols, 
furfurol, fatty acids, and other volatile principles, which together con- 
stitute what is known as fusel oil, the chief constituent of which is 
amylic alcohol. 
Each kind of grain or other raw material from which the ferment- 
able sugar solution is obtained yields a different kind of fusel oil; dif- 182 
FOODS. 
ferent because of the changing relative proportions of its constituents, 
which include butylic, propylic and amylic alcohol and their corre- 
sponding acids, butyric, propylic, and valerianic, and other matters. 
That which is found in potato spirits is richest in amylic alcohol and 
is the most toxic, while that from grapes contains much the least and 
produces the least harm. During the process of aging, the constituents 
of the fusel oil undergo chemical changes which result in the formation 
of oenanthic, acetic, and butyric ethers, acetate and valerianate of amyl, 
and other compounds, which together constitute the aroma or "bou- 
quet." Thus, a spirit is improved in two directions by long storage; 
it loses in toxicity and gains in flavor. 
The relative toxicity of the several alcohols and of other constituents 
of fusel oil has been determined by Dujardin-Beaumetz and others, 
who show that the poisonous properties increase with the boiling point 
and molecular weight. Jeffrey and Serveaux 1 determined the amounts 
in grams necessary per kilogram to kill a rabbit, as follows: Ethylic 
alcohol 11.70; propylic alcohol 3.40; butylic alcohol 1.45; amylic 
alcohol 0.63 ; furfurol 0.24. Daremberg 2 found by experiment that 
artificial spirits and wines made with pure rectified alcohol are less 
toxic than the genuine products by reason of the absence of the con- 
stituents of fusel oil. Roubinowitch,3 speaking of the greater toxicity 
of the higher alcohols, calls attention to the fact that the distillates from 
cider, perry, and fermented grains, potatoes, and molasses are much 
more toxic than brandy. 
Most spirits are artificially colored by the addition of harmless col- 
oring agents, the most widely used of which is caramel. As the prac- 
tice of coloring is in response to the demand of the consumer for a 
darker color than can be obtained otherwise, it can hardly be regarded 
as an adulteration. 
BRANDY. 
Brandy is obtained by distilling wines of the poorer qualities, often 
mixed with the " lees," or dregs from the wine casks, and the " marc," 
or solid refuse left after pressing the grapes. The lees and marc are 
also used alone for the production of a highly odorous brandy which is 
much used for improving the flavor of other brandies and for giving 
flavor to the artificial brandies made from pure alcohol and water. 
From this marc brandy, is obtained the oily substance, oenanthic ether, 
which is known commercially as " oil of wine." 
Brandy is produced very largely in France, and much less exten- 
sively in Spain, Portugal, and Germany; in California and in the wine- 
growing region of the Ohio and Mississippi Valley, it is produced in 
large quantities and of most excellent quality. 
The colorless distillate is stored for some time in oaken casks from 
'Archives de Medicine Experimentale et d'Anatomie Pathologique, 1895, p. 569. 
2 Ibidem, p. 719. 
'Gazette des Hopitaux, 1895, p. 237. WHISKEY. 
183 
which a small trace of tannin and a varying depth of amber color are 
acquired. The flavor, which in general depends upon the kind of 
grapes, their condition when pressed, and the care observed in the 
making of the wine, becomes improved during storage. The liquor is 
then colored and bottled for the market. 
Good brandy should contain from 39 to 47 per cent, of alcohol by 
weight, should have an agreeable odor and taste, and should be free 
from substances added to impart sharp taste and apparent strength. 
The nearly dry residue from 100 cc. very slowly evaporated on a 
water-bath should have a pleasant odor, and its taste should be neither 
sweet nor sharp ; a harsh odor points to the presence of fusel oil de- 
rived from potato or cereals ; a sweet taste is indicative of added sugar 
or glycerin; and a sharp taste is suggestive of cayenne or other spice. 
Much of the brandy of commerce is a purely artificial product made 
from alcohol or potato spirits, water, and flavorings. The formulae 
for making brandy are very numerous, and not a few require what is 
known as brandy essence, an article made with ethers and other sub- 
stances in varying proportions. By one formula, it is made with 5 
parts of cenanthic ether, 4 of acetic ether, 3 of tincture of galls, 1 of 
tincture of pimenta, and 100 of alcohol; by another, it consists of 15 
parts of acetic ether, 12 of sweet spirits of nitre, and 1 of rectified 
wood spirit. One part of either of these mixtures is sufficient to flavor 
a mixture of 1,000 parts of alcohol and 600 of water. 
As examples of the way in which factitious brandy is made, the fol- 
lowing will serve. (1) Boil 5 ounces of raisins and 6 of St. John's 
bread in water, filter and make up to 10 quarts ; mix this with 20 
quarts of alcohol, 10 ounces of brandy essence and a half-ounce of 
essence of violet flowers. (2) Dissolve 1 pound of argols and 3 of 
sugar in a gallon of water, add 40 gallons of alcohol, a quarter-pound 
of acetic ether, 2 ounces of tincture of kino, 6 pounds of bruised 
raisins, and a sufficient amount of caramel, and let stand 14 days ; 
strain and bottle. 
WHISKEY. 
Whiskey is the product of distillation of the fermented mash of 
grain or potatoes. The raw materials from which the mash is made 
include malt, wheat, rye, corn, oats, and potato. In the process of 
mashing, the starch of the grain is changed to sugar by the diastase of 
the malt; and since this ferment is capable of converting other starch 
than that with which it is associated, it is customary to mix malt and 
raw grain in the proportion of one to from five to nine parts. A 
bushel of grain makes about 2.5 gallons of spirits. In this country, 
the grains employed are chiefly corn, wheat, and rye ; in Great Britain, 
barley, oats, and rye are used together ; potatoes are used to a greater 
or less extent on the continent. The mash for Scotch whiskey is very 
commonly prepared from 2 parts of malt, 7 of barley, and 1 each of 
oats and rye ; that for Irish whiskey is the same with the exception of 
the rye. 184 
FOODS. 
As soon as the fermentation of the mash through the agency of 
yeast is complete, the distillation is begun. The first distillate, known 
as " low wine," is re-distilled. The second distillate is stronger and 
less rich in fusel oil, which, being less volatile than ethylic alcohol, 
comes over chiefly in the later portions. The new whiskey is stored 
for several years in order that it may acquire the flavor due to the for- 
mation of new compounds from the constituents of the fusel oil. Dur- 
ing storage, it takes up a trace of tannin from the oak of the casks. 
The flavor of whiskey depends upon the nature of the raw material, 
and largely upon the aging process. The disagreeable flavor and 
odor of new whiskey are due to fusel oil; the smoky taste of Scotch 
and Irish whiskies is due to the smoke of the peat and turf fires over 
which the malt is dried. Indian corn whiskey has a much different 
flavor from that of rye whiskey; this flavor is highly regarded by 
many to whom rye whiskey is unpalatable and insipid, and at the 
same time it is so full that to others it is rank and nauseating. The 
peculiar flavor of Bourbon whiskey, so-called because originally pro- 
duced in Bourbon County, Kentucky, is due to the corn from which, 
with rye, the mash is prepared. 
Whiskey of good quality should contain about 45 per cent, of alco- 
hol, and should yield not more than 0.25 per cent, of residue, which 
should have a slightly aromatic odor and but little taste. 
Whiskey is very largely manufactured from alcohol, water, and 
various flavoring compounds, some of which can hardly be looked upon 
as wholly innocuous. The following directions are taken from a small 
work, the object of which is, according to the preface,11 to give the dis- 
penser of liquors thorough and practical information by which he will 
be enabled to compound, and blend liquors for his own purposes, and 
thus secure the additional profit." 
1. Bourbon Oil.-Take of fusel oil 64 ounces, acetate of potassium 
and sulphuric acid each 4 ounces, and black oxide of manganese 1 
ounce. Dissolve a half ounce each of sulphate of copper and oxalate 
of ammonium in 4 ounces of water, mix all in a glass percolator, and 
let rest for 12 hours. Then percolate and put into a glass still, and 
distill 64 ounces. 
2. Bye Oil.-Mix 64 ounces of fusel oil, 8 each of oenanthic ether, 
chloroform, and sulphuric acid, and 2 of chlorate of potassium in 8 of 
water, place in a glass still and distill 64 ounces. 
3. Beading Oil.-Mix together 48 ounces of oil of sweet almonds 
and 12 of sulphuric acid, and when cool neutralize with ammonia and 
dilute with double the volume of proof spirits. " This is used to put 
an artificial bead on inferior liquors." For making the lowest grade 
of whiskey one is directed to mix 32 gallons of alcohol and 16 of 
water, 4 ounces of caramel and 1 of beading oil. By adding oil of 
rye or oil of Bourbon, " making the result rye whiskey or Bourbon as 
the case may be," the value is said to be increased. 
From another similar source the following recipes for factitious 
whiskey are taken : LIQUEURS. 
185 
1. Bourbon Whiskey.-Proof spirit,1100 gallons; pear oil, 4 ounces; 
pelargonic ether, 2 ounces; oil of wintergreen, 13 drachms in ether; 
wine vinegar, 1 gallon; caramel color, a sufficient quantity. 
2. Old Bourbon.-.Alcohol, 40 gallons; Bourbon whiskey, 5 gal- 
lons ; sweet spirits of nitre, 2 ounces; fusel oil, 2 ounces. Mix and 
let stand four days. 
3. Old Rye.-Soak a half peck of roasted dried peaches, put them 
into a woolen bag and leach them with common whiskey enough for a 
barrel, and add 12 drops of strong ammonia. 
4. Scotch Whiskey.-Alcohol, 46 gallons ; genuine Scotch, 8 gal- 
lons ; water, 18 gallons; ale, 1 gallon ; creasote, 5 drops in 2 ounces 
of acetic acid ; pelargonic ether, 1 ounce; honey, 3 pounds. 
5. Irish Whiskey.-Same as above, substituting Irish for Scotch, 
and omitting the honey. 
RUM. 
Rum is made by distilling fermented molasses or the skimmings of 
sugar boilers, with, not uncommonly, other substances, as pineapples 
and guavas, to give flavor. The characteristic flavor of rum is due to 
butyric ether. The alcoholic content of rum is very variable, ranging 
from 30 to over 60 per cent, by weight. Like other spirits, rum is 
very largely an artificial product of alcohol, water, and flavorings 
known as rum essence. One of these consists of 15 parts of butyric 
ether, 2 each of acetic ether, essence of vanilla, and essence of violet, 
and 90 of alcohol. Another consists of 32 parts each of rum ether 
and acetic ether, 8 of butyric ether, 16 of extract of saffron and one- 
eighth of oil of birch cut in strong alcohol. The rum ether required 
is a product of distillation of alcohol, sulphuric acid, pyroligneous 
acid and black oxide of manganese. Prune juice is also a common ad- 
dition to factitious rum for its flavor and color. 
GIN. 
Gin is an alcoholic liquor flavored with juniper berries and a wide 
variety of other substances including cardamom, coriander, cassia buds, 
calamus, orris, angelica root, orange peel, licorice powder, and sugar. 
It should contain about 40 per cent, of alcohol and not over 6 per 
cent, of total residue including sugar. 
Liqueurs. 
Liqueurs, or cordials, are manufactured compounds of alcohol, essen- 
1 Proof spirit is defined by an act of Parliament as a diluted spirit which at 51° F. 
shall weigh exactly twelve-thirteenths as much as an equal measure of distilled water. 
It contains half its volume of alcohol of sp. gr. 0.7939 at 60° F., or 49.5 per cent, by 
weight, or 57.27 per cent, by volume of absolute alcohol. Its sp. gr. is 0.91984. 
Over and under proof mean that a spirit is stronger or weaker than proof spirit, and 
the excess or deficiency is expressed as so many degrees over or under proof. The ex- 
pression, for example, 25 under proof, means that the specimen consists of 25 parts of 
water and 75 of proof spirit; 25 over proof means that 100 parts may be diluted with 
25 of water to bring it to the strength of proof spirit. 186 
FOODS. 
tial oils, cane sugar, and coloring matter. They contain usually about 
40 per cent, of alcohol by weight, and from 25 to 50 per cent, of cane 
sugar. The colorings are, as a rule, of vegetable origin, but sometimes 
the coal-tar colors are employed. In the small amounts in which they 
are consumed at any one time, they can hardly be looked upon as espe- 
cially harmful outside of their alcoholic content. There is one, how- 
ever, very largely consumed diluted with water as a " long drink," 
that appears to exert a decidedly deleterious effect upon the nervous 
system ; namely, pbsinthe. The evil effects of this drink are by some 
attributed to the oil of wormwood (Artemisia absinthium) and by others 
to the star anise (lUwium) both of which are among the numerous in- 
gredients used in its manufacture. 
Where the blame lies is of no great consequence, the drink being 
one which should be shunned above all others as a poison without re- 
gard to the innocuousness of most of its constituents ; but it is unlikely 
that its disastrous effects are due to wormwood, which as a drug has 
little or no action, and which enters into the composition of another 
drink, vermuth, which enjoys a good reputation. This is in no sense 
a cordial, but for convenience may be here described. Vermuth is a 
fortified white wine in which certain herbs and other vegetable matters 
have been infused. The ordinary French vermuth is made from worm- 
wood, bitter-orange peel, water germander, orris root, chamomile, Peru- 
vian bark, aloes, cinnamon, nutmeg, centaury and raspberry, but very 
many other substances are used by different makers. The fresh prod- 
uct has a very pronounced flavor which is mellowed by age. 
The wines most used in making French vermuth are from the Rhone 
Valley, Picpoul, and from the southernmost parts of France. The 
Italian vermuth differs materially from the French; it is a much 
weaker infusion with a far more bitter taste. The materials used are 
in the main the same, but they are employed in very different propor- 
tions. Vermuth contains about 17 per cent, of alcohol. 
Section 6. CONDIMENTS, SPICES AND BAKERS' 
CHEMICALS. 
The condiments include a large number of food accessories which, 
while they are themselves of no nutritive value in the amounts which 
it is possible to eat, serve a very useful purpose in imparting flavor, 
and in stimulating appetite and digestion. Among them are some 
which act through free acids, some through volatile oils, some through 
resinous matters, and one, perhaps the most important of all, common 
salt, through itself alone. Some are simple substances ; as vinegar, salt, 
and the spices ; while others are combinations of a number of ingredi- 
ents blended according to definite and, as a rule, secret formulas; as 
sauces, chutneys, catsups, and curries. Only when these compounded 
articles contain substances injurious to health can they be regarded as 
adulterated. The tomato catsups are very commonly preserved with 
salicylic acid or other preservatives, and colored with anilin dyes. 187 
VINEGAR. 
Thus, of 25 samples of different makes examined in 1897 by the health 
authorities of San Francisco, 20 contained salicylic acid, 2 contained 
this agent together with borax, and 1 contained formalin ; 16 were arti- 
ficially colored, mostly with coal-tar colors. 
VINEGAR. 
Vinegar is a weak solution of acetic acid resulting from the acetous 
fermentation of saccharine solutions which have already undergone 
alcoholic fermentation. It contains in addition to acetic acid, small 
and unimportant amounts of alcohol and aldehyde, and extractive 
matters in varying amounts according to the nature of the original 
liquid. The acetic acid contained is the product of oxidation of 
alcohol through the agency of mycoderma aceti, a fungus which forms 
what is known as the "mother of vinegar." Thus, the change from 
sugar to acetic acid involves two separate fermentative changes through 
the agency of two different organisms, saccharomyces cerevisice and 
mycoderma aceti. 
There are several kinds of vinegar in common use, as follows : 
Cider Vinegar.-In this country, cider vinegar is very generally 
regarded as the most desirable kind. It contains no aldehyde, about 
4.50 to 5.50 per cent, of acetic acid, marked traces of malic acid, and 
about 2 per cent, of total residue, or " cider-vinegar solids." 
Wine Vinegar.-In wine-producing countries, the vinegar in com- 
mon use is made from the cheaper kinds of wine. It has color or not, 
according to the kind of wine from which it is made. The so-called 
white wine vinegar in common use in this country among our foreign- 
born population is a quite colorless product of the oxidation of dilute 
spirits. Wine vinegar contains rather more acetic acid than cider 
vinegar, but far less residue. 
Malt Vinegar.-In England, which is neither a cider-producing 
nor a wine-producing country, the vinegar in commonest use is made 
from a wort prepared from malt and unmalted grain. It is less strong 
in acetic acid than the vinegars already described, but commonly con- 
tains sulphuric acid which, under the English law, is a permissible 
admixture to the extent of not exceeding 0.10 per cent. 
Molasses Vinegar.-A very large part of the domestic supply of 
vinegar is manufactured from fermented molasses. It is made to imi- 
tate cider vinegar in color, and is very commonly sold under the name 
of that article. It yields about the same amount of acid, but is very 
deficient in residue. The latter has a very bitter taste, and after com- 
plete ignition yields an ash containing no potassium salts, while that 
from cider vinegar gives a decided indication. 
Spirit Vinegar.-Spirit vinegar, also known as " Quick Process " 
vinegar, is made from diluted alcohol. The process used is the same 
as that employed in the making of malt vinegar and molasses vinegar. 
A series of suitable vats is constructed and filled with beech or birch 
shavings or twigs, which by appropriate treatment become coated with 188 
FOODS. 
mycoderma aceti. The alcoholic liquid is allowed to percolate through, 
and in its passage the alcohol is transformed. The temperature of the 
room is maintained at about 70° F. 
Adulterations of Vinegar.-The principal adulterations of vinegar 
are the addition of water and the coloring of inferior grades so that 
they may be sold as cider vinegar. Where laws are in force establish- 
ing standards of acidity and residue for cider vinegar, a very common 
fraud is the addition of cider jelly or of a preparation made from apple 
pomace to a cheap vinegar of the proper strength, colored, if necessary, 
with caramel. Such compounds always show but slight or no reac- 
tion when tested for malic acid. The addition of mineral acids is not 
a common practice in this country. 
Examination of Vinegar. Acidity.-To 6 cc. of the specimen in 
a porcelain casserole, add a few drops of phenolphthalein solution and 
about 20 cc. of distilled water. Titrate with decinormal sodium hy- 
droxide solution, adding little by little until the appearance of a faint 
pink coloration. The number of cc.'s of the reagent used, divided by 
10, equals the percentage of absolute acetic acid. 
Residue.-Evaporate 5 grams in an accurately weighed platinum 
dish to complete dryness over boiling water. After the residue is 
weighed, it may be ignited for its yield of ash. 
Genuine cider vinegar should give no more than a faint cloudiness 
on being tested with nitrate of silver and chloride of barium (absence 
of more than traces of chlorides and sulphates) and should yield a 
fairly copious precipitate with solution of subacetate of lead (presence 
of malic acid). The residue should not taste bitter (absence of cara- 
mel). 
Cider vinegar to which water has been added is likely, according to 
the nature of the water, to show more than the usual results on testing 
for chlorides and sulphates, and to yield notable traces of lime. Mo- 
lasses vinegar generally yields marked indications of lime salts and a 
more or less pronounced odor of rum. 
LEMON JUICE AND LIME JUICE. 
Lemon juice is the expressed juice of the ripe fruit of Citrus limonum. 
It is a somewhat turbid yellowish liquid with a very acid taste and a 
slight agreeable odor due in part to the presence of a small trace of 
volatile oil from the rind. It should contain about 7 to 10 per cent, 
of citric acid and should yield from 0.50 to 1.00 per cent, of ash. 
Its specific gravity should be not less than 1.030, and is usually above 
1.040. As it is quick to undergo decomposition in its natural con- 
dition, a number of methods have been proposed for its preservation, 
the best of which appears to be first to clarify it by means of strong 
alcohol, next to filter or decant from the precipitated matters, and then 
to expel the alcohol by heat. The clear juice can then be bottled and 
sterilized. 
Lime juice is the expressed juice of the sour lime, Citrus acida, and MUSTARD. 
189 
of the sweet lime, C. limetta. It contains usually somewhat less acid 
than lemon juice, and has a lower specific gravity. It is preserved by 
the same method. 
As antiscorbutics, lemon juice and lime juice are of about equal 
value, and far superior to vinegar. 
Adulterations.-Lemon juice is much more subject to adulteration 
than lime juice, but both are extensively falsified and imitated. In 
fact, it would not be overstating the case to say that by far the larger 
part of the lemon juice sold in this country is wholly factitious. Com- 
monly, it is nothing more than an aqueous solution of citric acid; 
sometimes, it is flavored with oil of lemon. Its taste is much sharper 
and less agreeable than that of the genuine article. The residue is 
very different in character and appearance, and leaves practically no 
ash on ignition. 
Other acids are sometimes used in place of or in addition to citric 
acid. The most commonly employed is said to be tartaric; this is 
readily detected by the gradual formation of bitartrate of potassium on 
addition of the acetate. The mineral acids are said to be not infre- 
quently added; they are detected without difficulty by the common 
tests. 
SALT. 
The best grades of common salt are white, dry, free from dirt, and 
completely soluble in water. Many specimens of good quality contain 
traces of chloride of magnesium, which causes caking. In humid 
weather, the best of salt absorbs moisture sufficient in amount to cause 
it to lose its dry powdery nature. The addition of about 10 per cent, 
of corn starch serves to keep it dry and powdered. 
MUSTARD. 
Mustard is the flour of the seed of the black and the white mustard, 
Sinapis niger and 8. alba. The first mentioned is much the more pun- 
gent of the two; on being wet with water a volatile oil is developed 
from two of its constituents. The white mustard yields no volatile 
oil by this treatment, but develops an acrid principle. Both varieties 
of seeds contain a bland fixed oil to the extent of 20-25 per cent. As 
this adds nothing to the flavor, makes grinding more difficult, and ex- 
erts an injurious influence on the keeping qualities, it is best removed 
from the whole seeds by pressure. 
Mustard is very subject to adulteration with wheat, rice, and corn 
flour, with the further addition of turmeric to restore the color lost by 
dilution. These substances are very easily detected by means of the 
microscope. Furthermore, since starch is wholly absent from pure 
mustard flour, if a small portion of a suspected sample, boiled in a 
little water in a test tube and cooled, gives a blue or bluish black 
color on the addition of compound iodine solution, it is unquestionably 
adulterated. 190 
FOODS. 
PEPPER. 
Pepper is the fruit of Piper nigrum, a perennial climbing shrub. 
The unripe berries, dried for several days after being picked, are known 
as Black Pepper. The ripened berries, dried and decorticated, are 
known as White Pepper. In the powdered form, in which they are 
most commonly retailed, both are very extensively adulterated with 
substances of a harmless nature. These include ground shipbread, 
cornmeal, cocoanut shells, rice, buckwheat, oatmeal, mustard hulls, 
charcoal, olive stones, and a variety of other substances of little or no 
value capable of being reduced to powder. 
The simplest method of determining the purity of this or any other 
form of spice is to reduce a specimen of the genuine unground sub- 
stance to powdered form and study its appearance under the microscope, 
and then to compare it with the sample in question. Each kind has its 
characteristic appearance, and so with a little practice one is enabled to 
determine very quickly the question of purity. By a similar study of 
the microscopic appearances of the common adulterants, these can be 
readily identified in the mixture. The chemical analysis is intricate 
and tedious and not always conclusive. 
CLOVES. 
Cloves are the flower buds of Eugenia caryophyllata, picked while 
red and dried in the sun. They contain about 16 per cent, of volatile 
oil easily removed and of considerable value. In the powdered form, 
cloves are commonly adulterated with allspice, clove stems, spent 
cloves, cocoanut shells, and other worthless matter. The presence of 
spent cloves can be determined only by estimation of the amount of 
volatile oil present. Clove stems show microscopically a very large 
proportion of the so-called stone cells. Other substances are detected 
in the manner already described under Pepper. 
CINNAMON AND CASSIA. 
Cinnamon is the inner bark of Cinnamomum zeylanicum. Cassia is 
the bark of several species of Cinnamomum. In the unground state, 
cinnamon is thin and delicate; cassia is thick and comparatively 
coarse. Cinnamon is the richer in volatile oil, and for this reason and 
because it is much less abundantly found, is considerably more expen- 
sive than cassia. Ground cinnamon is practically never found in the 
market, the substance sold under that name being almost invariably 
cassia. The common adulterants of cassia include ground shipbread, 
nut shells, and cedar sawdust. 
ALLSPICE OR PIMENTO. 
Allspice is the dried unripe berries of Pimenta officinalis. Although 
one of the cheapest of spices, it is extensively adulterated with ground 
shipbread, charcoal, nut shells, clove steins, and mustard hulls. BAKING POWDERS. 
191 
Ginger is the rhizome of Zingiber officinale. It is one of the most 
commonly adulterated of condiments. The substances used include 
ground shipbread, rice, mustard hulls, cayenne, turmeric, cornmeal, 
clove stems, and exhausted ginger from the manufacture of the tincture. 
It is very rich in starch which is very easily differentiated from other 
starches. 
GINGER. 
NUTMEG. 
Nutmeg is the inner kernel of the fruit of Myristica fragrans. It is 
not commonly sold in the powdered condition, but when so sold is 
generally adulterated with the substances used as admixtures of other 
spices. 
Mace is the dried membranous covering, the arillode, of the nutmeg. 
It is adulterated with wild mace, cornmeal, and other cheap materials. 
MACE. 
CAYENNE PEPPER. 
Cayenne is not a true pepper, but the powdered pods of several 
species of Capsicum, including C. annuum and C. fastigiatum. Its 
appearance under the microscope is very characteristic. The common- 
est adulterant is cornmeal. Among others are rice, mustard hulls, 
turmeric, and ground shipbread. 
BAKING POWDERS. 
Baking powders, like condiments, are in no sense foods, but being 
employed in the preparation of bread in which are retained the ulti- 
mate products of the reactions of their component parts upon each 
other, they are of some hygienic interest. They are employed for the 
production, within a short time, of a result, which, when caused by the 
action of yeast, is only slowly brought about; namely, the leavening of 
bread. Yeast produces the leavening gas, carbon dioxide, through 
slow fermentation of a part of the carbohydrates ; while with the use 
of baking powders, this gas is disengaged as a result of chemical action 
of one of the constituents upon another in the presence of moisture, 
and chemical substances foreign to yeast-leavened bread are left as a 
residuum in the bread. Whether this residuum is objectionable on the 
score of its influence upon the system, depends upon the nature of the 
ingredients of the powder ; but aside from the question of disadvantage 
or inferiority on this account, it is a fact generally acknowledged that 
bread made with baking powder is lacking in a certain agreeable flavor 
developed by the action of yeast. 
Baking powders are combinations of an acid or acid salt with sodium 
bicarbonate in about the proper proportions for chemical union, to- 
gether with an amount of starch sufficient to keep the ingredients in a 
dry state and hence mutually inactive. When the combination is in- 
troduced directly into the flour and water is added to make the dough, 192 
FOODS. 
the reaction occurs and carbon dioxide is set free. They are known 
according to the nature of the acid salt as tartrate, phosphate, and alum 
powders. Tartrate powders are usually made with " cream of tartar " 
(potassium bitartrate), but occasionally with tartaric acid, which is not 
only more expensive, but objectionable from a practical standpoint on 
account of its readier solubility, which causes a too rapid evolution of 
gas. The reaction which occurs between potassium bitartrate and so- 
dium bicarbonate has as results carbon dioxide, water, and potassium 
sodium tartrate, or " Rochelle salt as follows : 
KHC4H4Ofi 4- NaHCO3 = KNaC4H4O6 4- CO2 4- H2O. 
The commercial advocates of other kinds of powders dwell upon the 
undesirability of aperient substances in bread, but the residuum of 
Rochelle salt in the amount of bread which one can eat in a day would 
be very much under the minimum dose from which any results could 
be expected. 
Cream of tartar as retailed is very commonly adulterated with gyp- 
sum, chalk, alum, and starch, but as furnished to the manufacturer by 
the refiners it contains but a very small percentage of a normal im- 
purity, tartrate of calcium. The usual chemical tests and microscopic 
examination reveal fraudulent adulteration very quickly. Good speci- 
mens contain at least 94 per cent, of bitartrate, and two decigrams 
dissolved in hot water and titrated with decinormal sodium hydroxide 
require for complete neutralization not less than 10 nor more than 10.6 
cc. The presence of a small amount of tartrate of calcium is of no 
sanitary importance whatever, statements to the contrary in advertising 
matter notwithstanding. 
The phosphate powders are made with acid phosphate of calcium, 
which contains ordinarily more or less sulphate as a natural impurity. 
The reaction with sodium bicarbonate is expressed as follows : 
CaH4(POJ2 4- 2NaHCO3 = CaIIPO4 4- Na,HPO4 4- 2CO2 4- 2H2O. 
There is no well-grounded objection to the use of this class of 
powders. 
Alum powders are made usually with burnt ammonia alum and a 
very large amount, frequently as high as 50 per cent., of starch " fill- 
ing." Their leavening power is almost invariably far below that of 
tartrate and phosphate powders of good quality. The cheapest class 
of powders, the sale of which is promoted by accompanying gifts or 
" premiums " of cheap crockery and glass, are made with alum and 
the maximum amount of filling. 
The reaction between burnt alum and sodium bicarbonate is ex- 
pressed as follows: 
(NHJ2A12(SO4)4 4- 6NaHCOs = A12O6H6 4- 3Na2SO4 + (NHJ2SO4 4- 6CO2. 
Whether the alum exerts any injurious effect upon the bread itself 
and whether the resulting hydrate or any excess of alum has any sani- 
tary importance, are questions which have been the subject of extensive 193 
FOOD PRESERVATION. 
controversy. Without reproducing the arguments and claims of both 
sides, it must be said that the weight of scientific evidence is decidedly 
against the employment of alum in the making of bread. Some of 
those who believe alumina to be harmless in the amounts consumed re- 
gard powders containing both alum and potassium bitartrate as highly 
objectionable, the complete precipitation of alumina being prevented. 
Powders containing alum and acid phosphate are also held to be objec- 
tionable on account of the formation of aluminum phosphate, which is 
supposed to inhibit gastric digestion. 
In addition to sodium bicarbonate, ammonium carbonate is more 
or less used as a source of leavening gas. While this agent when ad- 
ministered therapeutically may exert a marked temporary influence, 
the amount used is quite too small to be in any way hurtful to the 
system. 
The amount of starch filling used in making baking powders is 
very variable. The best grades contain considerably under 20 per 
cent., and anything over that amount may rightly be regarded as in the 
nature of unnecessary and fraudulent dilution. 
Section 7. FOOD PRESERVATION. 
Foods of a perishable nature are preserved in many different ways, 
but not all methods are equally applicable to all foods. Thus, freezing 
and salting, while well suited to meats and fish, can hardly be employed 
with fruit and vegetables ; and preservation in sugar syrup, while well 
adapted to fruits, is not suited to meats. The methods in general use 
include the employment of low temperatures, desiccation, salting, smok- 
ing, canning, and chemical treatment. 
Cold.-For the best results of preservation by cold it is not always 
essential that the food shall be frozen; but unless the temperature to 
which it is exposed is near or below the freezing point, the advantage 
is only temporary. Packing in ice serves very well for short periods of 
time sufficient to enable one to ship meats and fish through long dis- 
tances, and to keep them in satisfactory condition for reasonable periods 
in the homes of the consumers. There are several methods of apply- 
ing cold on a large scale in cold-storage warehouses, ocean steamers, 
and public markets, the principal one being known as the ammonia 
process by means of which any desired temperature down to 0° F. can 
be obtained with but slight fluctuation, provided the walls, floor, and 
roof of the space occupied are rendered non-conducting by hair-felt, 
air spaces, and other means. Meats and fish are preserved indefinitely 
and without deterioration when frozen, but must not be allowed to thaw 
and freeze; eggs and fruits may be kept many months in dry air at 
just above the freezing point. 
The advantages of cold as a preserving agent are that unlike any 
other it involves neither the abstraction of any constituent of the food 
nor the addition of any foreign matter; it neither imparts a new taste 
nor alters the natural flavor; it causes neither a loss of nutriment nor 194 
FOODS. 
diminished digestibility ; and on the withdrawal of its influence the ma- 
terial is left in its original condition. It must be said, however, that 
after restoration to the natural condition, the keeping qualities appear 
to be somewhat impaired, and in consequence the material must be 
used within a shorter time than is the case with similar fresh food that 
has not been frozen. 
Drying.-Drying is efficient according to the thoroughness of the 
process. The method is not so well adapted to meats as to vegetables, 
since it leads to more or less loss of the natural flavors which are likely 
to be replaced by others less agreeable in character. Dried meats are, 
moreover, considerably less digestible. When thoroughly dried and 
properly stored, both meats and vegetable products can be kept with- 
out limit of time. Drying does not insure safety against parasites. 
Salting.-In the process of salting, the soluble organic constituents 
of meat and fish are in large part removed, and the fibers become 
hardened. The nutritive value and digestibility are, therefore, cor- 
respondingly diminished. Brine salting of fish is one of the oldest 
processes of preservation known. 
Smoking.-Smoking consists in exposing the meat or fish to the 
action of the smoke of wood fires after, as a rule, a preliminary salt- 
ing. The exposed material, already deprived of part of its natural 
moisture, becomes still further dried and is partly penetrated by 
acetic acid, creosote, and other preservative elements of smoke. In 
the quick smoking process, the meat is brushed over with or dipped into 
pyroligneous acid at definite intervals, and finally dried in the air. 
Canning.-In 1804, M. Appert of Paris discovered that meats and 
other foods in sealed vessels would keep indefinitely, if, after being 
sealed, they were kept for an hour in boiling water. In 1810, he 
introduced the method of sealing the vessel after the heating process 
has driven out the air and replaced it with steam so that when cooled 
a vacuum is formed. At the present time, the chief method followed 
is to pack the cans full and close them completely excepting a small 
hole, then to subject them to the temperature of boiling water, or 
higher, and close the hole with solder. They are then reheated and 
finally allowed to cool. 
Much has been said for and against this method of preserving foods. 
The chief objections have been that the natural acids of the foods may 
corrode the inner surface of the cans and form metallic salts, and that 
terne plates, that is to say, sheet iron or steel coated with an alloy of 
two parts of lead to one of tin, may be used instead of the best quality 
of tin plates. As to the latter objection, while there is in this country 
no legal restriction as to the character of the tin employed, it is a fact 
that terne plates are never used. With regard to the possibility of 
corrosion of the metallic surface, it must be admitted that not only the 
very acid foods, but even those which are neutral and even alkaline in 
reaction, will almost invariably yield traces of tin ; but there is, at the 
same time, absolutely no evidence that the small amount present in the 
entire contents of a can is capable of causing the slightest injury. FOOD PRESERVATION. 
195 
. There are, it is true, numerous cases of poisoning reported as due to 
metallic contamination of canned foods, but not one of those which 
have fallen under the view of the author will stand the test of exclu- 
sion of other possible and more probable causes. Of the small amounts 
of tin found in canned foods, Professor Attfield says that they are un- 
deserving of serious notice, and questions that they represent the 
amount regularly worn off of tin sauce pans and kettles. Furthermore, 
it is the nearly unanimous opinion of writers of works on toxicology 
that the only compounds of tin that are in any way poisonous are the 
chlorides, and even these are completely ignored by most of the lead- 
ing authorities. 
On the other hand, there is no limit to the testimony regarding the 
very great value of canned foods, especially in military operations on a 
large scale and expeditions of various kinds away from market centers 
and other sources of supply. Lieutenant Greely, Dr. Nansen, and 
other Arctic explorers are unanimous in their praise. Greely, for ex- 
ample, says, " No illness of any kind occurred prior to our retreat, and 
those most inclined to canned fruits and vegetables were the healthiest 
and strongest of the party." Lord Wolesley, in speaking of their use- 
fulness in hot climates, says that " tinned provisions, meat or vegetables 
put up separately or combined in the form of soups are practically un- 
damageable by any climatic heat " provided they are of the best quality 
and have been properly cooked and enclosed in perfectly sound air- 
tight tins. " Given these conditions, nothing can be more admirable ; 
failing them, nothing more deleterious." In military operations in the 
tropics, where beef cattle cannot be taken along on the hoof and re- 
frigerated beef cannot be transported overland on account of speedy 
decomposition, canned meats are quite indispensable. 
How long properly canned foods will remain in good condition can 
hardly be determined, but the evidence at hand points to indefinite 
preservation. In 1824, according to Letheby, a number of tins of 
mutton were cast ashore from the wreck of a ship at Prince's Inlet; 
eight years later they were found by Sir John Ross, and those which 
he opened were found to be in good condition, although exposed dur- 
ing this time to alternate freezing and thawing. Sixteen years after- 
ward, they were again found by men from the ship Investigator, and 
in 1868, forty-four years from the time they were cast ashore, the re- 
maining tins, opened by Dr. Letheby, were found to be in a perfectly 
sound state. Tyndall1 makes mention of tins in the Royal Institution 
that had remained in good condition sixty-three years. 
Professor A. H. Chester of Hamilton College relates that in the 
summer of 1875 he hid a number of cans of corned beef under a 
stump in some woods in the northern part of Minnesota, and five years 
later found them to be perfectly sweet and good, although they had 
been exposed to alternate heat and cold of five successive summers and 
winters. Again, a number of cans of meat and fruit, washed into the 
Genessee River in 1865, were dug out of the mud sixteen years ater 
and found to be unaltered. 
1 Floating Matters in the A.ir, New York, 1882, p. 293. 196 
FOODS. 
It is an unfortunate fact that the cupidity of some of our largest 
packing-houses has led to the canning of what is practically refuse 
meat from which the constituents to which the desirable flavors are 
due have been extracted, and that in consequence the public mind has 
become largely imbued with a prejudice against canned meats in gen- 
eral. But it is not alone in this country that canned meats are some- 
times not what they purport to be. It is related that in France, in 
1899, a packer of meats was sentenced to pay a fine and to serve 
eight months in prison for putting upon the market an immense amount 
of canned game and poultry, all of which had been made from the flesh 
of broken-down cab horses. 
Chemical Treatment.-Chemical preservatives are substances or 
combinations added to foods with the object of delaying or preventing 
their decomposition. They are used on the assumption that while 
they accomplish the desired object, they are incapable of exerting any 
harmful influence upon the system of the consumer-an assumption 
that has not been demonstrated as capable of proof. It is assumed 
that bad effects cannot be caused, because they are not manifested at 
once after the ingestion of small doses by persons in good health ; but 
this is no proof that continued use may not result in serious trouble 
which may be referred to some other possible cause. 
It is said that the preparations employed are in common use as 
valuable remedies in the treatment of the sick ; but it must be taken 
into consideration that when used as remedies in morbid conditions, 
they are given only for a limited time for the purpose of counter- 
acting abnormal influences, and that the doses are carefully regulated 
under proper professional supervision. Their action in conditions of 
health and disease may be very different; but whether so or not, one 
can hardly find any excuse for the ingestion of curative remedies 
by a person in a state of health, whose system needs no such aid, for 
indefinite periods and with no regulation of the size of the dose. 
Salicylic acid, for example, is a remedy holding a high position in 
the treatment of rheumatism, but its value in this condition is no 
valid excuse for its administration day in and day out to those who 
have never felt the twinges and pain of this affliction. It is much 
more fair to assume that drugs which exert a powerful influence for 
good in morbid states will exert an equal degree of influence for harm 
in conditions of health. Moreover, it is to be considered that the object 
of chemical treatment of foods is not to benefit the unconscious con- 
sumer, but to bring the largest possible financial return to the manu- 
facturer and purveyor, to whom the health of the consumer is a matter 
of little concern. In all fairness to the consumer, chemically pre- 
served foods should be so labelled that the purchaser may be informed 
of the nature and amount of the added substance, so that those who 
object to the dietetic use of drugs may not have them forced upon 
them without their knowledge. 
The addition of preservatives to foods offered for sale is forbidden 
in most civilized countries, and several governments have enacted laws FOOD PRESERVATION 
197 
specially directed against individual drugs. Thus, France names boric 
acid, borax, salicylic acid, and sodium bisulphite; Austria names sali- 
cylic acid ; Germany prohibits all antiseptics and especially boric acid 
and borates, and imposes additional penalties for the sale of chemically 
preserved foods to the navy. 
The substances used as chemical preservatives include boric acid 
and borax, salicylic acid, sulphurous acid, sulphites and sulphates, 
benzoic acid, formaldehyde, hydrogen peroxide, sodium fluoride, and 
others of minor importance. Many of the commercial preparations 
in common use are combinations of two or more of these and other 
substances. Thus, Venzke and Schorer1 report the ingredients of 38 
meat preservatives analyzed by them as follows: Salt, sugar and 
saltpeter (1), salt and sodium sulphite and sulphate (4), sodium sul- 
phite and sulphate (4), the same, plus sugar and salt (1), salt and 
sodium bicarbonate and nitrate (1), salt, boric acid, saltpeter and sodium 
sulphate (3), salt, boric acid and sodium sulphate (1), salt, boric acid, 
gypsum and sodium sulphate (1), salt and boric acid (6), salt, saltpeter, 
sodium and calcium sulphates, and cochineal (1), salt and borax (1), 
salt, borax, and saltpeter (2), salt, borax and sodium nitrate (2), salt, 
borax, sodium and calcium sulphates, and salicylic acid (1), borax and 
sugar (2). The balance consisted of single substances. 
A large proportion of 24 meat preservatives examined by Kammerer 
were found to be mixtures of borax and boric acid, and borax and so- 
dium sulphite ; 31 others examined by Kionka were, as a rule, sodium 
sulphite and sulphate, but 14 liquid preparations consisted chiefly of 
calcium sulphite and sulphate, and sodium sulphite, bisulphite and sul- 
phate. Kirchmaier has reported one as consisting of salicylic acid 
and sodium salicylate and phosphate. Polenske found boric acid 
(about 60 per cent.), saltpeter (about 12-14 per cent.), sugar, salt, and 
sodium salicylate (about 7.50 per cent.) in a specimen of sausage salt 
and in a number of other preparations sold under fancy names. Of 
seven other meat preservatives examined by him,2 one contained salt, 
sodium sulphite and sulphate, iron chloride, and vanillin, and the rest 
were combinations already described. 
A. C. Chapman3 has reported a most extraordinary combination of 
aluminum sulphate, salt, sodium nitrate, benzoic acid, iodic acid, sul- 
phurous acid, and chloral. 
Another, examined by Tbllner, proved to be ammonium bromide, 
boric acid, borax and sugar. Another, known as " Mayol," contained 
wood alcohol, ethylic alcohol, boric acid, ammonium fluoride, and gly- 
cerin. Meats preserved by means of it are said to show no trace of 
boric acid or ammonium fluoride beneath the brown coating: which 
forms to a depth of a millimeter. 
In this country, the favorite mixture is one of borax and boric acid, 
and this is sold under many different names. 
Deutsche Fleischerzeitung, 1893, XXI., Nos. 20, 21 and 24. 
2Arbeiten aus dem kaiserlichen Gesundheitsamte, VIII., p. 686. 
'Analyst, Dec., 1898. 198 
FOODS. 
Boric Acid and Borax.-These substances are generally used together 
for the reason that though the acid has greater power as an antiseptic 
than the salt, the combination of the two is still more efficient. It is 
used quite extensively in butter to the extent of about a tenth of an 
ounce to the pound, and is dispensed with a generous hand in oysters, 
clams, and other fish, in sausages and other meat products, and in 
milk. 
With regard to the effects of boric acid and borax on the system, 
there is a decided difference of opinion among those who have investi- 
gated the subject, but it must be said that a number of the reports 
favorable to the use of these agents, published by commercial houses, 
suggest that the conclusions arrived at were somewhat inspired by 
financial considerations. Our knowledge of possible ill effects is de- 
rived chiefly from the clinical experience of those who have used the 
drugs internally and as washes and injections. It is a fact that many 
patients can take large doses of both substances for long periods with 
no apparent harm, but it is equally true that small doses and local 
applications have been a frequent cause of serious and even fatal re- 
sults. Deaths have been reported from the use of 5-per-cent. solutions 
in washing out the pleural cavity and lumbar abscesses, and from wash- 
ing out a stomach with a solution of half that strength. 
Very numerous cases of troublesome cutaneous eruptions and of 
serious gastro-intestinal disturbances following internal and external use 
have been reported within recent years. Plaut1 has shown that the in- 
ternal use may be followed by acute parenchymatous nephritis, and his 
conclusions have been endorsed by the experience of Fere, mentioned 
below. 
In 1876, the admixture of borax to butter was officially sanctioned 
in France, but seven years later a committee of scientists, who inves- 
tigated the matter with great care, concluded that continued ingestion 
is likely to cause deterioration of the blood corpuscles ; and when some- 
what later this was confirmed by the investigations of Pouchet, the use 
of borax was prohibited by the government not only in butter, but in 
all articles of food. In 1891, the subject was presented by the Ken- 
sington Vestry to Sir Andrew Clark, Sir Henry Thompson, and Pro- 
fessor Lauder Brunton, who concurred in pronouncing boric acid in 
large doses, or in small doses taken for long periods, as dangerous to 
health. The Local Government Board, in 1891, reported that while 
large doses are undoubtedly injurious, they had not sufficient evidence 
to hold that minute amounts added to foods can affect the system 
harmfully. 
As is well known, borax has been extensively used in the treatment 
of epilepsy and other diseases of the nervous system. Professor H. 
C. Wood states that in his experience the most marked result from its 
use in this direction was severe gastro-intestinal irritation. Dr. F6r€,2 
of Paris, has given a valuable report of his results- in the treatment of 
1 Inaugural dissertation, Wurzburg, 1889. 
2 Revue de Medicine, September, 1895. FOOD PRESERVATION. 
199 
122 cases of epilepsy by this drug, which was given in beginning 
doses of 30 grains increased to as much as five drachms a day. 
In over 70 per cent, of the cases, the treatment had no beneficial re- 
sult ; in about 20 per cent., some temporary or doubtful improvement 
was seen; and, in 9 per cent., there was distinct gain. But the great 
drawback was the frequency of toxic effects and the danger of pro- 
ducing or aggravating lesions of the kidneys even when given in small 
doses. Among the most common results were loss of appetite and 
burning pain, followed by nausea and vomiting. Cutaneous affections 
were very common, and complete baldness was not infrequently caused. 
(This result has been noted by many other practitioners.) In some 
cases, a cachectic condition, characterized by wasting, a waxy tint of 
the skin, puffiness of the face, and even general oedema, was observed. 
In a number of cases of general oedema, uraemia developed with some 
suddenness. 
Dr. Grumpelt1 has reported a case in which headache, nausea, and 
intense dryness of the skin followed the use of an injection containing 
a tablespoonful of boric acid to the pint. The effects disappeared 
with cessation of the treatment, and came on again with its renewal. 
Dr. J. J. Evans 2 has found as a common result of continued use of 
boric acid in cystitis and urethritis, an erythema followed by desqua- 
mation. Internal doses of 10 to 20 grains twice daily for five weeks 
caused in one instance total baldness. 
Experiments on man and animals by Professors Mattern, Forster, 
Chittenden, and Schlenker have demonstrated that boric acid and 
borax interfere with digestion and nutrition. Mattern reported pro- 
found disturbance in dogs after a few daily doses of 8 grains ; diarrhoea 
and other signs of gastro-intestinal irritation, and in some instances 
even fatal results were caused. He himself took 30 grains and suf- 
fered violent abdominal pain and diarrhoea. Forster and Schlenker 
have shown that doses of 8 grains have a decided effect in preventing 
absorption of nutriment and causing intestinal irritation. 
Dr. Annett, of Liverpool, fed a number of kittens with milk con- 
taining 20 grains of boric acid to the quart, and all of them died in 
an emaciated condition at the end of the third or fourth week. 
As to the effect of these agents on the different processes of diges- 
tion, there is no agreement. Chittenden, for example, believes that 
boric acid increases the digestion of proteids, and that even 25 per 
cent, will not check gastric digestion of egg albumin. He has noted 
also a marked stimulant effect on pancreatic digestion of proteids fol- 
lowing the use of borax. Leffmann and Beam and others, however, 
have observed effects directly contrary to those reported by Chittenden. 
Chittenden's first experiments were made to determine their possible 
influence upon the processes of salivary, gastric, and pancreatic diges- 
tion. He calls attention to the fact that his results throw no light 
upon the influence of the agents upon the secretion of the digestive 
1 British Medical Journal, Jan. 7, 1899. 
2 Ibidem, Jan. 28, 1899. 200 
FOODS. 
fluids. He shows that borax inhibits the action of saliva on starch, 
and boric acid in small amounts increases it and also the power of the 
gastric juice to digest proteids. Later experiments by Chittenden 
and Gies1 lead them to the conclusion that the two substances have no 
peculiar action on nutrition, and that since elimination is complete 
within 36 hours, the possibility of cumulative action must be very 
small even when moderate amounts are ingested daily. 
Considering the many reports of untoward results of large and small 
medicinal doses and from absorption of both agents from local appli- 
cations, and the positive evidence of injury through feeding experi- 
ments on the lower animals, it seems not unreasonable to conclude that 
the daily ingestion of variable amounts in foods and drinks for all ages 
cannot be wholly free from objection. A very common practice is 
the addition of the combination or either of its constituents to milk to 
the extent of one part in 500 or 1,000; a pint will therefore contain a 
fair-sized adult dose, an amount which, taken twice or more times dur- 
ing each day by a bottle-fed child, can hardly fail to have some effect 
not wholly for its well-being. 
Salicylic Acid.-Salicylic acid is more efficient than borax and boric 
acid as a preservative, but cannot be so generally used, because of its 
tendency to cause unpleasant flavors in foods having a bland taste. It 
is extensively used in jams, jellies, tomato catsups, bottled beers (es- 
pecially those from Germany), the heavy beers innocently consumed by 
total abstainers under the name of " malt extracts," fruit juices, soda- 
water syrups, cider, wines, and other saccharine preparations, and pre- 
served vegetables. Concerning its objectionable nature as an addition 
to foods, there is practical unanimity. It not only exerts an inhibitory 
action on digestion, but acts also as an irritant, especially to the kid- 
neys, by which organs it is excreted. Its addition in any quantity to 
articles of food or drink is expressly forbidden in many European and 
South American countries. Its addition to beer and other articles in- 
tended for export is permitted in Germany. 
Sulphites.-Sodium sulphite and bisulphite and sulphurous acid are 
used more or less extensively for preserving meat, beer, wine, and 
vegetables and fruits put up in cans and glass jars. The latter should 
need no preservative if properly put up, but they are, nevertheless, often 
treated with these and other agents. Sendtner has found from 26.4 to 
482.6 milligrams of sulphurous acid in 32 specimens of vegetables in 
glass. Kammerer and others have reported various amounts, ranging 
from 3 to 250 milligrams per liter, in red and white wines. In this 
country, it is not uncommonly present in canned corn which has been 
bleached thereby and hence improved in appearance. 
The most extensive investigation of the effects of the sulphites on 
the system is that of Kionka,2 who has shown that in practical doses 
they have an injurious effect on the heart and central nervous system 
of cold-blooded animals. With warm-blooded animals, he found that 
'New York Medical Journal, Feb. 26, 1898. 
2Zeitschrift fiir Hygiene und Infectionskrankheiten, XXII., p. 351. FOOD PRESERVATION. 
201 
large doses exert a marked and sometimes fatal poisonous action, and 
that small doses, long continued, affect seriously the circulation, lungs, 
and kidneys. Dogs, fed upon meat treated with amounts recommended 
for preservative purposes, were very seriously affected. 
Sodium sulphite is very commonly used in sausages and chopped 
meat (Hamburg steak) both as a preservative and to cause the bright 
red color of the fresh meat to be retained unaltered. Chopped meat 
keeps its color but a very short time, and as the purchaser will not 
accept it when not bright red, the vendor is driven to make its appear- 
ance acceptable. Thus, the purchaser, insisting upon having what to 
his eye is freshly chopped wholesome meat, may be served with stale 
meat containing a most undesirable chemical preservative. In 1898, 
the Imperial Board of Health of Germany forbade the use of sodium 
sulphite in foods, because of its dangerous properties. 
Formaldehyde.-On account of its property of hardening tissues, 
formaldehyde does not lend itself to general use as a food preservative. 
Fish and meats are rendered so hard by very dilute solutions, even 1 
to 5,000, as to be quite worthless commercially. It is most commonly 
used in milk and other liquids, and acts most efficiently in delaying and 
preventing decomposition. Its use in milk is, however, far from 
commendable, for though efficient as a preservative, it alters the charac- 
ter of the proteids, which are thereby made less digestible. 
The casein, when precipitated, does not separate in fine clots, but in 
tough heavy curds, which yield only with much resistance to pepsin 
and hydrochloric acid. Weigle and Merkel1 have shown that the 
proteids are made much less digestible, and their conclusions are in 
agreement with those of most investigators of the subject. Bliss and 
Novy,2 after a most careful and exhaustive inquiry into the effects of 
formaldehyde on the digestive ferments, found that pepsin and trypsin 
have diminished action upon fibrin which has been altered by it in 
very weak solution; that casein is rapidly altered, and, as a result, is 
not coagulated by rennet or, at best, very slowly, and is not readily 
digested by the proteolytic ferments; and that pepsin and rennet are 
themselves not affected by fairly strong (4- and 5-per-cent.) solutions 
acting several weeks. Pepsin was found to be very quickly affected 
by very dilute solutions, trypsin to be affected according to the amount 
of organic matter present, and amylopsin and ptyalin to be not de- 
stroyed by very dilute solutions. The latter were, however, found to 
be destroyed by strong solutions. Feeding experiments, conducted by 
Dr. Annett with kittens, demonstrated that as the amount mixed with 
the milk was increased, the retarding action on their development was 
more marked. 
Formaldehyde is said to favor the conversion of starch to sugar and 
to obstruct alcoholic fermentation. It is not a poison in the ordinary 
sense of the term, biff it is very irritating to mucous membranes. It 
is doubtless the most powerful of all the antiseptics. 
1 Forschungsberichte uber Lebensmittel, etc., 1895, II., p. 91. 
2 Journal of Experimental Medicine, 1899, p. 47. 202 
FOODS. 
Hydrogen Peroxide.-This agent is recommended as the least danger- 
ous of all chemical preservatives, and is thought by some to exert no 
deleterious effect whatever. It is well adapted for use in wine, beer, 
and fruit juices. One part in a thousand is said to prevent entirely 
the alcoholic fermentation of glucose solutions, and in somewhat larger 
amounts to prevent the formation of lactic acid in milk. 
Sodium Fluoride.-So far as is known, sodium fluoride exerts no poi- 
sonous action, but its effect on digestion has not been thoroughly studied. 
Perret1 asserts that it has a decided influence in inhibiting the develop- 
ment of lactic and butyric ferments. Using himself and a number of 
dogs, he undertook a series of feeding experiments, and concluded there- 
from that the salt is in no way poisonous and may be used without 
danger as a food preservative. Specimens of milk containing 3 parts 
in 1,000 and kept at 38° C. remained unchanged long after the controls 
had become coagulated. A dozen tubes of milk containing it and 
planted with butyric ferment, and another dozen containing untreated 
milk similarly planted were kept side by side at 38° C.; on the day 
following, the latter were coagulated, but the former were unchanged. 
Subcutaneous injections of the salt to the extent of 0.08 gram per 
kilogram of weight caused in a dog some salivation and diuresis; but 
larger doses caused marked salivation, diuresis, thirst, and refusal of 
food. Intravenous injections of 0.10 per kilogram caused immediate 
rise of pulse and respiration, followed by abundant salivations, nausea, 
convulsions, and death in 35 minutes. Leffmann and Beam2 have noted 
that sodium fluoride interferes but little with the digestion of starch. 
Sodium fluoride appears to be weak as a general preservative, but 
prevents alcoholic fermentation completely when present to the extent 
of 1 part in 2,000. The fluorides and hydrochloric acid are used by 
some brewers for the prevention of undesired fermentations. 
Sodium Bicarbonate.-This agent seems to be as little objectionable 
as any, but it is very weak in its preservative action and is too ineffective 
for general use. It is somewhat used in Sweden in conjunction with 
sugar for meat and fish. A more common use is to overcome begin- 
ning acidity of milk ; against this is urged the possibility of purgative 
effects in infants, through the sodium lactate produced. 
Section 8. CONTAMINATION OF FOODS BY METALS. 
Not infrequently, small amounts of metallic salts are present in foods, 
either through accident or by reason of intentional admixture for some 
definite end. The most common are compounds of copper and of lead, 
and these are regarded as of greater hygienic importance than the salts 
of zinc, tin, and nickel occasionally present. 
Copper.-Copper gains entrance through the improper use of cook- 
ing utensils of brass and copper, and through the use of its salts for 
greening peas and other vegetables reverdissage "), and for improv- 
1 Annales d'Hygiene et de Medicine Legale, June, 1898, p. 497. 
2 Journal of the Franklin Institute, 1899. CONTAMINATION OF FOODS BY METALS. 
203 
ing flour of inferior grade. Copper and brass kettles yield small 
amounts to acid, fatty, and other foods allowed to stand in them, espe- 
cially if the contents are exposed to the air. Their yield is much greater 
if they are not kept thoroughly clean and well polished. Lehmann 1 
found 36.8 milligrams of copper in a liter of broth made in a brass 
vessel and allowed to stand 24 hours, 8.7 mgr. in 100 cc. of rancid fat 
allowed to stand two weeks, 21 mgr. in a liter of sour wine, and 61 in 
the same volume of vinegar after 24 hours. Mair has reported 24 
mgr. in a liter of rice soup after 24 hours. 
The use of copper for greening vegetables is exceedingly common. 
It serves no useful purpose other than to please the eye. The peas or 
other vegetables are boiled in a very dilute solution of copper sulphate, 
drained, washed, and, finally, put up in cans or glass jars. The arti- 
ficial color, which is often much more intensely green than the natural, 
is due to an organic compound of copper which is insoluble in water. 
The claim sometimes urged that the copper serves to fix the chlorophyll 
and is not itself retained is preposterous, for if a solution of chlorophyll 
is heated with dilute copper sulphate, the color is destroyed and a 
brown precipitate is produced, while if perfectly white beans are boiled 
for a short time in the same weak solution, they take on a deep green 
color through the formation of a new compound with the contained 
legumin or some other proteid. Rice and potatoes, being very poor in 
proteids, are hardly affected by similar treatment, but eggs may be 
colored intensely green. 
The liquor of canned greened vegetables is commonly quite free 
from copper, and the testing of specimens by adding ammonia to a 
portion of the liquor in the expectation of producing a blue color in 
case the vegetable has been so treated is, therefore, quite worthless. 
In order to determine the presence of copper, a few grams of the sub- 
stance may be incinerated in a porcelain capsule, the residue therefrom 
treated with dilute hydrochloric acid, and the filtrate subjected to the 
usual tests. 
The question of the hygienic importance of small amounts of copper 
has been the subject of a number of extensive investigations on the 
part of individuals and foreign governments, and while it can hardly 
be said to be proven that any danger can arise therefrom, nevertheless 
no good reason can be advanced in favor of the practice of greening. 
Two students in Lehmann's laboratory took daily doses of copper salts 
with no perceptible disturbance; one took 39 milligrams of copper 
sulphate daily for 50 days, and then double that amount for 30 more; 
the other took the acetate for 51 days in doses ranging from 16 to 96 
milligrams. These amounts are larger than an average eater would 
be likely to take into his system from canned vegetables in the course 
of a day, for the entire contents of an ordinary tin-somewhat less 
than half a pound-commonly yield less than 50 milligrams of copper. 
According to Baum and Seelinger,2 whose numerous experiments 
1 Seventh International Congress of Hygiene, 1891. 
2 Zeitschrift fiir offentliche Chemie, 1898, p. 181. 204 
FOODS. 
extended over a period of three years, small daily doses are, as a rule, 
completely absorbed and again eliminated; larger doses are not com- 
pletely absorbed. Complete elimination may require as much as five 
months from the date of the last dose. Long-continued ingestion of 
small doses may bring about a true condition of chronic poisoning. 
Copper appears to be a normal constituent of some articles of food. 
The assertion, made originally by Meyer of Copenhagen, that wheat 
and oats often contain minute traces, especially in their husks, has been 
repeatedly proven. According to Lehmann,1 the species of plants has 
far less influence on the amount taken up than the amount of copper 
present in the soil. He found the metal in a great variety of plants 
growing in a copper soil; rye, oats, hops, potatoes, dandelion, juniper, 
violets, cherries, etc., etc. In woody plants, the greatest amount of 
copper is in the bark. According to Karsten,2 the spraying of grape- 
vines with copper solutions is not wholly free from objection, since 
that which adheres to the fruit may be sufficient to make their yield of 
wine toxic. He instances a number of cases of diarrhoea and vomiting 
due to wine which yielded traces of copper. 
Lead.-Traces of lead are of common occurrence in various articles 
of food, especially those wrapped in foil or enclosed in cans having ex- 
posed seams of lead solder. A number of specimens of wrapping foil 
analyzed by Dr. Charles P. Worcester3 yielded lead in amounts rang- 
ing from traces to 89 per cent. They are used largely for wrapping 
cream cheeses, chocolate, and other foods. The metallic caps for clos- 
ing glass jars of preserved fruits and vegetables are also sources of 
danger. One specimen examined by Worcester contained 93.5 per 
cent, of lead. Patent stoppers, consisting of a metallic disc with a 
border of rubber, used in bottles for summer beverages known to the 
trade as u soft drinks," commonly contain lead, as is shown by 
Worcester's examination of 28 specimens which yielded from 3.5 to 
50.7 per cent. The contents of the several bottles yielded lead with- 
out exception ; the largest amount was 1.05 milligrams. 
Dr. William R. Smith 4 has drawn attention to the common occur- 
rence of lead in citric and tartaric acids. The former is considerably 
used in making summer drinks, and the latter in effervescing powders 
and baking powders. Of a dozen specimens examined by him, only 
one was uncontaminated ; the highest amount found was 0.037 per 
cent. At the present time, canned foods are less likely to show traces 
of lead than formerly, when the cans were made with less care. In 
1893, Wiley5 reported traces in 132 out of 248 samples examined. 
Concerning the hygienic importance of small daily doses of lead, 
there is but one opinion. It is quite improbable that the occasional 
use of canned vegetables containing but a fraction of a milligram in an 
entire can will lead to any serious injury, but the constant daily inges- 
1 Archiv fur Hygiene, XXVII., p. 1. 
2 Chemiker-Zeitung, 1896, p. 37. 
3 29th Annual Report of the State Board of Health of Massachusetts, p. 570. 
4 Journal of State Medicine, October, 1892. 
5 Department of Agriculture, Division of Chemistry, Bulletin No. 13, Part VIII. 205 
CONTAMINATION OF FOODS BY METALS. 
tion of appreciable amounts of lead is likely to lead to serious conse- 
quences in at least a fair proportion of cases. 
Especially to be avoided are the acid drinks contained in bottles 
with lead stoppers. The amount of lead present is small, and an occa- 
sional indulgence is unlikely to cause harm; but cases of serious injury 
have occurred. In one, in which the cause of the trouble was investi- 
gated by the author, the patient, a temperance lecturer, had for some 
weeks been passionately addicted to the use of a particular brand of 
effervescent drink known as " strawberry tonic," a carbonated, acidu- 
lated solution of sugar, flavored with an artificial compound ether, and 
colored with an anilin dye. Evidence of chronic lead poisoning de- 
veloped with some suddenness, and in a short time not only wrist-drop, 
but toe-drop appeared. Specimens of the beverage were obtained and 
examined. The stoppers were almost pure lead, and the contents of 
each bottle yielded notable traces of the metal. 
Zinc.-Zinc sometimes occurs in small traces in canned foods from 
the use of the chloride in soldering. With improved methods in which 
another flux is employed, this contamination is becoming uncommon in 
this class of foods. It appears to be quite a common accidental im- 
purity in dried apples from contact with galvanized iron wire racks on 
which they are cured. Kammerer 1 found it in 4 out of 9 specimens 
of American dried apples ; the average amount, reckoned as malate, was 
0.0656 per cent. Bujard 2 found it in 37 out of 54; in 20, the amount 
present ranged from 0.030 to 0.490 gram to the kilogram, reckoned 
as oxide; in 17 it was present only in traces. We have no evidence 
that these small amounts are of the slightest sanitary importance. 
Nickel.-Nickel is sometimes employed in place of copper for green- 
ing peas. About a quarter of a gram of the sulphate suffices for a 
kilogram of peas. It is dissolved in boiled water to which 10 cc. of 
a 2-per-cent. solution of ammonia are added, and then it is diluted 
with boiled water in sufficient amount to cover the peas, which are then 
boiled for a few minutes, drained, and washed. According to E. Lud- 
wig,3 nickel is given off in small amounts to all sorts of foods cooked 
in nickel dishes. He found from traces to 12.9 milligrams per 100 
grams of the food examined. 
Tin.-Contamination with compounds of tin is exceedingly common, 
and, so far as is known, quite harmless and unimportant, the compounds, 
other than the chloride, being apparently incapable of producing any 
physiological or local action. 
1 Chemiker-Zeitung, 1897, p. 721. 
2 Forschungsbericht uber Lebensmittel, etc., 1897, IV., p. 218. 
3 Oesterreiche Chemische Zeitung, 1898, I. CHAPTER II. 
AIR. 
Air is a mixture of gases and not a chemical compound. Until the 
latter part of the seventeenth century (1669), it was supposed to be an 
element, but Jean Mayow then proved it to be a mixture of gases, and 
later, Lavoisier discovered the two gases, oxygen and nitrogen, which, 
a hundred years later, were separated by Priestley and by Scheele. 
It is a colorless and apparently odorless mixture of oxygen, nitrogen, 
argon, carbonic acid, aqueous vapor, and traces of other substances. It 
is not, however, under ordinary conditions odorless, but, on the con- 
trary, quite full of various scents to which we are so accustomed that 
unless present in unusual degree, owing to local conditions, they are 
not perceived. This is noticed on returning to an ordinary atmosphere 
from one where the causes of the usual odors are absent or nearly so; 
as, for instance, from deep subterranean caves, or from a room where 
the air is foul and oppressive; as, for instance, from a heated, over- 
crowded hall or street car into the pure outdoor air. The air of the 
Arctic regions contains but little odor, on account of the absence of 
bodies which give rise to odors, and the proximity of any source of 
smell is quickly noticed. The explorer Nansen 1 speaks of the pervad- 
ing smell of soap which he noticed when, after months of wandering, 
he met Jackson, who had been comfortably housed with all the com- 
mon necessities of man. 
While air is a mixture of gases, it is one of tolerably constant com- 
position, particularly in the case of its chief constituent, nitrogen. 
Under the conditions of life, the more important but less abundant 
element oxygen is subject to more or less variation. In the presence 
of vegetable life, particularly by day, it is slightly increased ; in the 
presence of animal life, it is more or less diminished. 
OXYGEN. 
The normal amount of oxygen is stated usually at just below 21 per 
cent, by volume. A. Leduc gives it at just 21, with 78.06 of nitrogen 
and 0.94 of argon. Different observers have reported the following as 
averages of large numbers of analyses of pure outdoor air. 
20.99 Scotland. 
20.98 Scotland. 
20.94 Sweden. 
20.92 France. 
•Farthest North, Vol. IL, p. 529. OXYGEN 
207 
20.94 Germany. 
20.92 Norway. 
20.95 England. 
20.95 Ohio. 
The mean of a number of analyses by Bunsen was 20.924 by vol- 
ume, and of a hundred at Paris by Regnault, 20.960. 
For the sake of convenience, we may disregard the very slight dif- 
ference between 21 and the figures obtained by exact analysis, a dif- 
ference in the second place of decimals, and accept 21 as a normal. 
At great heights, the proportion of oxygen is less than at the sur- 
face. For instance, on the Faulhorn in Switzerland, 20.77 has been 
observed as the mean of a number of determinations. Under certain 
conditions, there is very slightly more than 21 parts; for instance, in 
the immediate vicinity of vegetation, especially by day, there may be 
an excess of oxygen, but it is very small; sea air, taken in mid-ocean, 
has yielded 21.59, but ordinarily contains less than 21. It is less, by 
very small fractions, in the streets of cities than in the open country, 
and in towns than at sea. 
Oxygen is the element in air that supports all life. It is constantly 
being withdrawn from the air in the process of respiration, and is re- 
turned to it in chemical union with carbon as carbonic acid. This is 
absorbed by vegetation and split up, the carbon being retained and the 
oxygen for the most part released and returned to the air. Thus, the 
processes of animal and vegetable life combine to maintain the equilib- 
rium. 
All animals do not breathe in the same degree ; birds have the 
most active respiration, and next come mammals; and all consume 
more oxygen when active than when asleep. 
Oxygen is essential to the germination of seeds and to the growth 
of plants. Although plants take up carbonic acid and exhale oxygen, 
they also breathe as do animals, absorbing the latter and exhaling the 
former. Even the anaerobic organisms consume oxygen, although liv- 
ing where air is wanting, for they split up combinations of oxygen and 
other elements. Thus, in dilute sugar solutions they withdraw some 
of the oxygen and split up the sugar into carbonic acid and alcohol. 
For sustaining animal life, it is essential that the air shall contain not 
far from the normal amount of oxygen ; that is, that it shall be neither 
much diminished nor yet over-rich in that element. Human life is 
impossible in air which contains but four-fifths of the normal amount, 
and equally so in an artificial atmosphere containing materially more 
than the normal. 
In man and animals, the tissues do not receive oxygen in the free 
condition, for when the air is inspired, the oxygen is taken up by the 
red blood corpuscles and unites with the haemoglobin to form an un- 
stable compound, oxyhaemoglobin, which, as the blood circulates through 
the tissues, is decomposed; the oxygen is then taken up by the cells, 
and eventually returned to the blood in the form of carbonic acid, and 
eliminated as such from the body. In an artificial atmosphere con- 208 
AIR. 
taining an excessive amount of oxygen, the haemoglobin becomes sat- 
urated with the gas, part of which becomes dissolved in the blood 
serum, and then acts as a poison to the tissues and kills them. 
Inspired air loses about a fourth of its oxygen and is returned to 
the atmosphere rich in impurity, but diffusion occurs so rapidly that 
the atmosphere of a thickly settled city shows no very material varia- 
tion from that of the open country. 
The lungs are never filled with pure air after the first respiration 
at birth, since they are never wholly emptied, and they consequently 
contain an impure residue of air after each expiration. The upper 
part of the respiratory tract is the only part that receives strictly pure 
air. Professor Richet has demonstrated that if the respiratory tract be 
artificially lengthened by means of a rubber tube, the pure air will never 
reach even the upper air passages and the animal will die of asphyxia. 
The amount of oxygen absorbed varies with age, condition of health, 
and activity. According to Professor Foster, an average person inhales 
in 24 hours about 34 pounds of air, which corresponds to a little over 
7 pounds of oxygen; and as the lungs absorb about a fourth of the 
oxygen inhaled, it appears that the average amount of oxygen absorbed 
daily is nearly two pounds. 
The principal constituent of the air, nitrogen, is quite inert. It 
takes no part in respiration, and is not increased in expired air. But 
though it is indifferent and inert, it is, nevertheless, by no means un- 
important. In the first place, it serves to dilute the oxygen so that 
the latter is respirable, and in the second, it plays an important part 
in the growth of plants, the original source of all nitrogenous food, 
for that which we consume in the form of meat is from animals that 
have built up their tissues from vegetable food. 
As a diluent of oxygen it serves to prevent too great activity of 
that element, which cannot be breathed with impunity for any length 
of time when present in an atmosphere above its normal amount. 
How nitrogen is absorbed by plants, we know only in part. Certain 
low forms seem to absorb it directly from the atmosphere when exposed 
freely to light and air. Some of the higher forms (peas, beans, 
clover, etc.) acquire it through the agency of certain micro-organ- 
isms which are present in nodules in their roots, and without which 
they will not thrive. These micro-organisms take the nitrogen from 
the atmosphere and give it in some form to the plants. That this is 
so is proved by the fact that the plants will thrive in a soil quite free 
from nitrogen (in clean sand for instance) and store up in their tissues 
an amount of nitrogen far in excess of that which was originally pres- 
ent in the seeds, provided these micro-organisms are present in the 
nodules of the roots. If these are not present, the plants will not 
thrive, but can be made to do so by the application of water contain- 
ing cultures of the organisms. 
NITROGEN. CARBONIC ACID. 
209 
On the other hand, certain other plants, grown in the open air in soils 
free from nitrogen, and protected from receiving ammonia and nitrates 
from the rain, will show no more nitrogen in their whole organization 
than was present in the seeds from which they sprang. The subject 
is one which has been but partly investigated, and future research will 
doubtless show that under natural conditions, all plant life takes up in 
some way more or less nitrogen from the atmosphere, as well as from 
nitrogenous compounds in the soil. 
Up to the time of its discovery, the element argon was included 
under nitrogen in the tables of composition of the air. How much is 
present, is not yet accurately determined. It was discovered in 1894 
by Lord Rayleigh and Professor Ramsay, by whom it was later esti- 
mated as composing about 0.75 of 1 per cent, of the atmosphere. 
Leduc gives its amount as 0.94, and Schloesing as 0.84. It is quite 
inert and cannot be made to combine with any other element, though 
it has been combined by Berthelot with benzene under the influence of 
electric discharge. 
Other elements, as krypton, neon, and metargon, also discovered by 
Professor Ramsay, coronium, discovered by Nasini, and several others 
are interesting solely from a purely scientific standpoint. 
CARBONIC ACID. 
All air contains carbonic acid as a constant constituent. The nor- 
mal average amount in pure air is but slightly in excess of three parts 
in 10,000, or about 0.03 per cent., and not four parts as is commonly 
stated. As little as 2.03, and even 1.72, has been observed in the air 
on mountain tops, though generally we expect more rather than less 
than the normal amount at high elevations. 
It is a result of oxidation of organic matter, and owes its presence 
in the atmosphere to respiration, fermentation, combustion, and chem- 
ical action in the soil. An average man exhales about twenty liters in 
an hour, and very nearly a kilogram in a day ; women exhale less, and 
children and aged persons still less. The amount exhaled is increased 
by muscular exertion and diminished by rest. Birds send out more in 
proportion to weight than other animals. 
The respiration of millions and millions of human beings and ani- 
mals is constantly throwing into the atmosphere countless tons of the 
gas ; every ton of coal in burning yields over 67,000 cubic feet; every 
cubic foot of coal gas yields about double its volume ; every pound of 
candle nearly three times its weight (2.769) ; every gallon of oil and 
kerosene, and every piece of wood used as fuel, contributes its pro- 
portion. Huge volumes are continually communicated by the soil air, 
which contains it in abundance, and by mineral springs, the waters of 
which contain it under pressure. It has been estimated that from all 
sources 5,000 million tons are discharged annually into the atmosphere. 
It is slightly more abundant in cities than in the country, and at 
night than by day. It is highest in amount at a given location dur- AIR. 
210 
ing autumn, and lowest in winter. It is more abundant inland than 
on the coast. It increases somewhat as we ascend from sea-level-ac- 
cording to Schlagintweit, up to 11,000 feet. 
Its removal from the atmosphere is mostly through the agency of 
growing vegetation, but materially also by absorption by bodies of 
water, which at ordinary temperature and pressure will take up its 
own volume of the gas. It has been calculated that the ocean con- 
tains about ten times as much as the whole atmosphere. 
All green plants absorb it by day, and by means of their chloro- 
phyll break it up into carbon and oxygen, the former being used in 
building tissue, and the latter returned to the air as a waste product. 
This process of nutrition goes on only under the influence of light, and 
consequently by day ; but there is also a respiratory function that is 
active both day and night and has the same effect on air as that of the 
respiration of animals; namely, the consumption of oxygen and dis- 
charge of carbonic acid. But the respiratory process has but a trivial 
influence in comparison with the chlorophyllian function. 
It is estimated that an acre of woodland withdraws in one season 
about four and a-half tons, retains over one and one-fifth tons of carbon, 
and returns over three and a-quarter tons of oxygen to the air. 
The slight increase at night is supposedly due in part to its exhala- 
tion by plants in their respiration, and also to currents of soil air, 
which ascends as soon as the air at the surface becomes colder and con- 
sequently heavier than itself. During the day, the soil air is colder 
and remains stationary. 
Carbon dioxide is a heavy gas incapable of supporting combustion 
or respiration and of no use to animal tissues. It constitutes about 
4 per cent, of expired air, in which it is an excretion of the body. It 
is in itself inert and incapable of exerting any poisonous action, but 
will cause asphyxia when present in sufficient amount to interfere with 
the atmospheric oxygen in the performance of its function. 
An atmosphere of respired air, containing 4 per cent, of carbonic 
acid and about 16 per cent, of oxygen, will not support life more than 
a short time, since the blood cannot get enough oxygen for the needs 
of the cells and tissues, and in addition cannot rid itself of its CO2. 
Gas exchange between the blood and inspired air depends upon the 
tension of the gas in both media, and, therefore, as soon as the tension 
of the CO2 in the atmosphere exceeds that of the CO., of the blood, 
the blood corpuscles cannot excrete it, but must retain it. In conse- 
quence, asphyxia occurs. 
The question as to how much CO2 is permissible in air has been 
variously answered. We assume three parts in 10,000 as the normal 
amount, and all in excess as impurity due to respiration and combus- 
tion. A total of 6 or 7 parts in 10,000 is regarded by the best au- 
thorities as the permissible limit, and 10 in 10,000 as distinctly bad. 
When the amount reaches 10 parts in 10,000, the air begins to be 
"close," and when it reaches 15 in 10,000, it is likely to cause head- 
ache in those unaccustomed to bad air. OZONE. 
211 
In crowded assembly rooms, as churches, theatres and schools, the 
amount may reach 100 parts in 10,000 ; and more than twice as much 
has been found in a Swiss stable crowded with men and animals. The 
air of the hall in which the German Public Health Society (Deutscher 
Verein fur bffentliche Gesundheitswesen) met in Nuremberg in Octo- 
ber, 1890, contained 24.10 in 10,000 at the beginning of one of the 
addresses, and 43.20 at its close. 
A large amount of carbon dioxide may be present in air without 
producing any ill effects, if there is plenty of oxygen present. Thus, 
Regnault and Reiset have proved that animals can live in a mixture 
of 25 per cent, carbonic acid, 30-40 per cent, oxygen, and nitrogen. 
It has been generally held that CO2 up to 20:10,000 is in itself 
harmless ; that the deleterious agents in polluted air are organic matters 
thrown off by the skin and lungs in company with it; and that it serves 
as a convenient index of their amount. It has been the custom to say 
" The more carbonic acid we find, the more organic matter we infer." 
These poisonous organic matters, however, though much sought after, 
have never been isolated, although a number of observers, using faulty 
methods, have from time to time obtained erroneous results. This sub- 
ject will be considered further on. 
OZONE. 
Ozone is a normal but by no means constant constituent of the air. 
It is generally absent from the air of large towns and cities, and is 
almost never present in the air of an inhabited room or near decom- 
posing matter. It is found in minute amounts (maximum 1: 700,000) 
in the open air of the country and sea. It is most abundant at sea 
and near woods, and somewhat more abundant on mountains than in 
valleys and on plains. It is more abundant in the morning in the 
colder months, and in the evening during hot weather; it is more 
abundant in winter than in summer. It is stated that it is most abun- 
dant directly after a thunder storm, but beyond the fact that it is pro- 
duced by the passage of the electric spark, there is nothing to substan- 
tiate this statement. As a matter of fact, the origin of ozone in the 
atmosphere is unknown. 
Ozone is an allotropic form of oxygen, consisting of molecules con- 
taining three atoms of that element. It has been liquefied under great 
pressure (127 atmospheres) and in that condition, and, indeed, in the 
gaseous form, has a deep blue color. It is produced by the passage of 
the electric spark, by slow oxidation of phosphorus, and in the electrol- 
ysis of water; but, as has been said, its origin as a normal constituent 
of the atmosphere has not been satisfactorily explained. It has an odor 
not unlike that of diluted chlorine. It has very strong oxidizing 
powder, much more so than oxygen, which it exercises most actively 
both on metals and on organic matter ; hence its absence from the air of 
inhabited rooms and of densely populated areas, where it is charged 
with organic matter and dust of all sorts, is easily explainable. To 212 
AIR. 
this property, its diminution in autumn, when decomposition products 
are most actively generated, may be properly attributed. Its presence 
in the air of any place is very fair evidence of freedom from oxidizable 
matters. 
It has an exceedingly irritating effect on the respiratory mucous mem- 
branes, and when inhaled with oxygen in the proportion of one part in 
240, is quick to produce death in animals subjected to it. It is be- 
lieved to exert a bad influence in inflammatory conditions of the lungs 
and bronchi even when present in not much more, if any, than the 
ordinary amount in the atmosphere. We actually know little or noth- 
ing of the real effects of ozone on the system in the amounts ordinarily 
present in air, but the absurdity of the expression so often used, that 
one has " gone to breathe the pure ozone " at a health resort is manifest. 
Peroxide of Hydrogen (H.,O.,) is believed to exist in minute traces 
in the atmosphere and to exert some influence in the process of oxida- 
tion. 
AMMONIA. 
Ammonia is constantly present in the air in very slight traces. It 
exists in the free state and in combination as nitrate and carbonate. 
Daily analysis of the air at Montsouris for 5 years gave as a mean 
for ammonia 2.2 milligrams per 100 cubic meters. It proved to be 
highest in amount in summer and lowest in winter. It is diminished 
in rainy weather, because it is absorbed by the rain in its passage 
through the atmosphere; it is increased with rising temperature some 
time after rain has ceased falling. 
As it is one of the products of decomposition of nitrogenous organic 
matter, perhaps nowhere more observable than in stables where it is 
plainly perceptible to the sense of smell, it is hardly necessary to point 
out that its sources are various and innumerable. 
NITROGEN ACIDS. 
Nitrous and nitric acids are also present in small traces, due in part 
to the union of atmospheric oxygen and nitrogen through the agency 
of electrical discharges, and in part to the action of ozone on ammonia. 
Nitric acid is found in comparative abundance in buildings lighted by 
means of the arc light, but it is not probable that the amount present 
can be of any sanitary importance. 
AQUEOUS VAPOR 
Aqueous vapor is a normal constituent which occurs in very variable 
amounts influenced by a number of natural conditions, the chief of 
which is the temperature. It is an invisible gas, lighter than air and 
very unequally diffused. Its sources are numerous ; some comes from 
the evaporation of water, some from the soil moisture, some from the 
lungs and skin of animals and man, some from the leaves of growing AQUEOUS VAPOR. 
213 
plants, some from combustion. Indoors, a considerable amount is 
communicated to the air through the combustion of illuminants. 
According to Professor Foster, an adult man gives off under ordi- 
narily favorable conditions about four pounds of watery vapor from 
his skin and lungs during twenty-four hours; two and a-half pounds 
by the skin, and the balance (Pettenkofer and Voit say 10 oz.) by the 
lungs. An adult healthy tree of fair size gives off an amount which 
is enormous in comparison. The amount of water exhaled by plants 
has been estimated by Hellriegel to vary from 250 to 400 times the 
weight of the dry organic matter formed during the same time, which 
means that during the growth of each ton of green grass or leaves of 
any kind, there have been exhaled therefrom many tons of water, and 
that in the production of each pound of dry matter, an average of 325 
pounds of water has been discharged. 
The evaporation of water from foliage has, among other important 
functions, that of holding down the temperature below the point where 
the vital processes would be interfered with. 
The amount of aqueous vapor which a volume of air will absorb 
and retain depends on the temperature. For each degree of tempera- 
ture, a volume of air can take up a definite amount of vapor and no 
more, and when it has taken up this amount it is said to be " saturated." 
The higher the temperature, the greater the amount it can hold, 
and hence when a volume of air completely saturated is subjected to a 
change in temperature, one of two things will occur : if the tempera- 
ture is increased, it can take up more vapor and hence is no longer 
saturated ; if it is diminished, the aqueous vapor is in excess of the 
amount required for saturation at the new temperature, and the excess 
will be condensed and precipitated as moisture. 
At 0° C., a volume of air can take up 1/160 of its weight of aque- 
ous vapor; at 15°, it can take up twice as much ; at 30°, four times, at 
45°, eight times, and at 60°, sixteen times as much. Thus it appears 
that with each increase of 15° C. in temperature, the capacity for 
aqueous vapor is doubled. 
At 15° C. (59° F.), a cubic foot of air will hold nearly 6 grains of 
water vapor; at 30° C. (86° F.), it will hold twice as much. 
Evaporation cannot go on when the surrounding air is already sat- 
urated ; therefore, the presence of a body of water will add nothing to 
a saturated atmosphere. But plants and animals can continue to give 
off the vapor to an already saturated atmosphere, which, however, con- 
denses and deposits the excess at once, perhaps on the very surface 
where it is originated, as on the leaf of a tree or on the skin of man. 
The difference between evaporation and transpiration, which is the 
proper term for the giving off of vapor by animals and plants, is that 
the one is merely physical, while the other is a vital process due to the 
action of living cells. 
The rate of elimination of water by the body in a state of rest de- 
pends upon the amount of humidity present in the air. Determina- 
tions by Rubner and Von Lewaschew 1 demonstrated the great in- 
1 Archiv fur Hygiene, XXIX., p. 1. 214 
AIR. 
fluence of humidity in this particular. At 15° C. in moist air, the 
daily elimination fell to 216 grams, while in dry air at the same tem- 
perature it rose to 871. The rate rises with the temperature in both 
moist and dry air, and the more promptly, the greater the dryness. 
The outer air commonly contains from 60 to 75 per cent, of the 
amount necessary for saturation. In some places noted for the dryness 
of the air, the amount is much below; in others where the opposite is 
the case, it is above. 
Relative humidity is the degree of approach to saturation at any 
given temperature. Thus, " relative humidity 80 " means that at 
the observed temperature, the air holds but 80 per cent, of the amount 
which it can take up. Absolute humidity is the actual weight of mois- 
ture in a given air space. 
Aqueous vapor exerts a most important influence. By day, it ab- 
sorbs part of the sun's heat and tempers it; by night, it acts as a pro- 
tecting blanket to the earth by preventing too great loss of heat by 
radiation. At night, the earth gives up part of the heat which it has 
absorbed during the day ; and when the air is very dry and the sky 
very clear, the temperature falls much more than when there is more 
vapor present to prevent loss by radiation. In the Sahara, after the 
hottest days, the nights are generally very cool, the temperature 
falling 30 to 40 degrees in a few hours. At high altitudes also, where 
the blanket of vapor is thin, the fall in temperature at night is very 
marked. Absence of aqueous vapor permits the cooling process to be- 
gin as soon as the sun begins to get low, and ice may form in a few 
hours where, during the day, the sun's heat had been intolerable. This 
is seen in the great deserts and at high altitudes. 
It is commonly noticed that the first frosts of autumn and those 
which come occasionally in the middle and latter parts of spring occur 
only on very clear nights with low humidity. 
An amount of watery vapor approaching saturation gives rise to dis- 
comfort, whether the temperature be high or low. The " sticky " days 
of summer and the " raw " ones of winter owe their disagreeableness 
to their high relative humidity. In a hot saturated atmosphere, while 
transpiration can proceed, evaporation cannot, and hence the cooling 
influence of evaporation is missing. The sweat stays on the skin in the 
liquid form instead of passing into the air as a vapor, and the word 
" sticky " becomes singularly appropriate. 
On the other hand, with low humidity and high temperature, the 
sweat does not condense and remain on the skin, but passes into the 
air, and transpiration is not impeded in the lungs. Hence the great 
bearability of dry heat as compared with moist. 
Saturation at low temperature has as great, if not greater, influence 
on bodily comfort. It does not follow that since one feels the heat 
more acutely with high relative humidity, this condition will enable 
one to withstand the opposite discomfort of cold. Indeed, the re- 
verse is true. At low temperatures, saturated air causes a greater 
withdrawal of heat than dry air, and intensifies the sensation of cold; 215 
DUST. 
for moist air is a much better heat conductor. Cold dry air is much 
more comfortable than air some degrees warmer but materially moist. 
In the very cold climate of eastern Siberia, the air is so dry that 50° 
to 60° below zero is no hardship, provided one wears completely dry 
clothing, whilst with moist clothing one would perish in a very short 
time. Some parts of Siberia are both cold and damp, and hence unin- 
habitable. 
Atmospheric moisture has, therefore, directly opposite effects ; it in- 
tensifies the effects of heat and also of cold. 
DUST. 
Another normal constituent of the atmosphere-one of enormous im- 
portance-is dust; normal, because it is everywhere in the atmosphere, 
and because a perfectly dustless air is an artificial product obtained 
only with the observance of great care. 
The individual particles are very small, but at the same time very 
variable in size, ranging from those plainly discernible to the naked 
eye, to those of extreme minuteness. 
Dust is organic and mineral, and has its origin in countless processes. 
It includes particles of animal matter, vegetable substances of every 
kind including bacteria and moulds, sea salt, matters swept from the 
soil by the action of winds, those discharged by volcanoes,1 others from 
manufacturing establishments, from chimneys, and from the millions 
of meteorites which daily fall from interplanetary space. The ordi- 
nary combustion of illuminating gas yields millions and millions of 
particles of carbon for every individual cubic foot. 
Organic dust exists only in the lower strata of the atmosphere, but 
that of mineral origin is everywhere. Micro-organisms are very 
abundant in the air of inhabited rooms, and in general in that of towns 
and cities, less abundant in the country, and least at great heights and 
at sea. 
Experiments have shown that at an elevation above 6,300 feet the 
air is quite free from them. Pasteur exposed a large number of flasks 
of broth at an altitude of 6,000 feet and obtained a growth in but one. 
Tyndall exposed 27 flasks at 8,000 feet and got no growth whatever. 
Dr. Fischer has shown that on the ocean, 120 miles from land, the 
air is usually quite free from organisms, and that at lesser distances, 90 
miles for example, it contains but few. 
The air of cities contains thousands in every cubic meter against 
less than a hundred in the same volume of country air. It has been 
calculated that in densely populated places, such as London and Man- 
chester, an individual inhales in the course of an hour upwards of 4 
millions of germs and spores. But this figure is enormously in excess 
of the figures given by Fliigge,2 who estimates that in 70 years a man 
1 After the great eruption in Java in 1883, a haze of extremely fine particles of 
pumice, estimated to be from seven to over twenty miles above the earth, was visible in 
all parts of the world for several months. 
2 Grundriss der Hygiene, 1897. 216 
AIR. 
may inhale 25,000,000 bacteria, which, he says, is about what one 
swallows in 25 cc. of ordinary milk. 
The number of bacteria in air is influenced very greatly by dry 
winds and aqueous vapor. The former, sweeping them up from the 
surface, increases their number; the latter by condensing on them and 
on the dust particles to which they adhere, causes them to fall to the 
ground. They are washed out of the air by rain, and are killed by 
long exposure to bright sunshine. Moulds, on the other hand, have 
been observed by Miquel to increase rapidly after a rainstorm, and to 
be much less affected by winds. 
The average number of organisms found at Montsouris in an inves- 
tigation which lasted six years was 455 per cubic meter. The lowest 
results were observed in February and the 
highest in July. During the same period, the 
number in the air at the center of Paris was 
3,910; the smallest figures were yielded in 
January and the highest in May. 
All organisms are less numerous in the 
air at night, since then there is less me- 
chanical disturbance of the earth's surface. 
While the number of bacteria in outdoor 
air may be fairly high, it must be borne in 
mind that most of them are of the harmless 
varieties and that the pathogens constitute 
only an infinitesimal proportion. 
Dust, as has been said, is of enormous im- 
portance. Without it there would be no 
rain, no fog, no clouds, and no comfort. The 
air would be saturated with moisture, and 
every object would be continually wet. It 
is largely hygroscopic and, therefore, attracts 
the watery vapor of the atmosphere, thus be- 
coming the nucleus for a drop of rain or 
particle of mist. Were it not for its pres- 
ence in the air, the aqueous vapor would con- 
dense without rain on every tree and plant, 
every rock, every dwelling, every living 
creature, and, in short, on every object to which air has access. 
That atmospheric dust is necessary for the production of rain and fog 
can be demonstrated very simply by condensing moisture from a saturated 
atmosphere through lowering of the temperature, and noting what occurs 
when dust is present or absent. For this purpose a simple piece of 
apparatus such as is shown in Fig. 8 is all that is required. This 
consists of a large flask fitted with a rubber stopper through which 
pass two pieces of glass tubing, to the free ends of which pieces of 
rubber tubing with pinchcocks are attached. The glass tubes project 
beyond the shoulder into the body of the flask. If we pour into the 
flask an amount of water rather more than sufficient to fill the neck 
Fig. 8. 
Apparatus for demonstrating the 
relation of dust to rain and fog. CARBON MONOXIDE. 
217 
when the flask is inverted with the stopper in position, we have 
the conditions necessary for complete saturation of the confined air 
with watery vapor. If now we withdraw by suction through one of 
the rubber tubes a small amount of the contained air, the temperature 
falls at once; and inasmuch as the air within is already saturated, and 
since the lowering of the temperature of a saturated atmosphere is ac- 
companied by the condensation of part of its moisture, such a con- 
densation occurs within the flask and is manifested by the formation 
of a distinct haze which fills the whole air space. If next we restore 
the original pressure by readmitting enough air to abolish the partial 
vacuum, the mist disappears instantly. 
The production and dissipation of the mist cloud may be repeated 
indefinitely so long as nothing is done to remove the dust from the air. 
But if we wash the air thoroughly by shaking the flask vigorously for 
a few minutes, and then repeat the experiment, we shall find that no 
visible mist is produced. 
CARBON MONOXIDE. 
Other matters found in air include under certain conditions traces 
of sulphuretted hydrogen, sulphurous, sulphuric, and hydrochloric 
acids, carbon disulphide from rubber factories, marsh gas, carbon 
monoxide from illuminating gas, fumes of zinc, arsenic, and phos- 
phorus, organic vapors from offensive trades, and other gaseous and 
solid matters too numerous to mention. 
The most important of these is carbon monoxide, a very power- 
ful poison often present in the air of inhabited rooms from leaking gas 
pipes, imperfect combustion of illuminating gas, and defects in heating 
apparatus fed by coal. It is yielded in great abundance by burning 
charcoal and given off in small amounts from stoves of cast iron, which 
material in a red-hot condition absorbs it in considerable amounts from 
burning coal. This was first noticed by Dr. Carret1 of Chambery, 
who described an outbreak of sickness traced by him to this cause. 
This property of cast iron was later established beyond a doubt by 
others. 
Another by no means insignificant source is burning tobacco, one 
gram of which, according to G rehan t,2 yields 82 cc. of the gas. Its 
presence in the air of rooms in which smoking is carried on was illus- 
trated by Kunkel3 in 1888 before a society of scientists, by exposing a 
small amount of blood solution to two puffs of tobacco smoke and 
demonstrating the absorption of the gas by means of the spectroscope. 
The most important source of all is illuminating gas, which contains 
it in varying amounts according to its mode of manufacture. Under 
ordinary conditions, the leakage of gas from the mains into the soil and 
thence into the atmosphere is enormous. Pettenkofer 4 reckons that 
1 Comptes rendus, 1865, p. 793. 
2Annales d'Hygiene Publique, 1879, p. 115. 
3 Sitzungsbericht der physikalisch-medicinische Gesellschaft zu Wurzburg, 1888, 
p. 89. 
4Ueber die Vergiftung mit Leuchtgas. Nord und Sud, January, 1884. AIR. 
218 
in badly jointed systems at least a fifth of the annual output is lost in 
the ground, and Wasserfuhr1 has calculated the annual loss in Paris 
due to leaks as 15,000,000 cubic meters. Leakage occurs from im- 
perfect joints, faulty cocks, and corroded iron pipes. 
Besides that due to leakage, we have to reckon with that due to im- 
perfect combustion. While a good Argand or other burner acting 
normally gives off no trace of carbon monoxide, a certain proportion of 
the poison will escape oxidation and mingle with the air of the room 
in company with other impurities, if the gas supply is not properly 
regulated. The use of gas stoves is responsible for more or less con- 
tamination due to imperfect combustion, for when a cold object is 
put into the flame, the latter is cooled and part of its carbon monoxide 
is given off as such. Imperfect combustion of kerosene is still another 
source which must not be overlooked, for a smoking lamp can exert a 
very decided influence on the respirability of the air of a room aside 
from the discomfort caused by the particles of soot. 
Less than a quarter of one per cent, by volume in the air will cause 
poisoning, and but one per cent, is rapidly fatal to animal life, owing to 
the fact that it unites very readily with the haemoglobin of the blood 
corpuscles, forming a stable chemical compound, carboxyhaemoglobin, 
which will neither take up and carry oxygen to the tissues nor pro- 
mote the elimination of carbonic acid. As a consequence, asphyxia 
occurs. 
In fatal cases of poisoning, it produces a rapid parenchymatous de- 
generation of the liver, kidneys, spleen, and heart. 
It has been proved by L. de Saint Martin 2 to be present in minute 
amounts in the blood of animals living in cities. Nicloux3 has gone 
farther and demonstrated its existence in that of animals in the coun- 
try, and, indeed, in about the same amounts (0.16 volume per cent.). 
Nicloux finds by experiment that it is not derived from the air, but is 
developed directly in the system, and that its amount can be diminished 
by bringing about slight asphyxiation. Potain and Drouin4 have 
shown that at ordinary temperatures it is gradually oxidized to car- 
bonic acid. 
Contamination of the air of dwellings with gas from leaking street 
mains is quite common, and fatal results are not infrequent, the gas 
travelling through the soil for considerable distances and being drawn 
up through cellars by the force of aspiration brought into play by the 
difference between internal and external temperatures. Many cases of 
fatal poisoning have been recorded in which the gas had been aspirated 
through the soil over a hundred feet. Such accidents are naturally 
more likely to occur in streets which, being well paved, oppose an 
obstacle to the escape of the gas upwards. 
The odorous constituents of the gas serve a very useful purpose in 
1 Deutsche Vierteljahrsschrift fur offentliche Gesundheitspflege, XVII., 1885, p. 309. 
2Comptes rendus, CXXVL, p. 1036. 
3 Ibidem, CXXVL, pp. 1526 and 1595. 
4 Ibidem, CXXVL, p. 938. 219 
"SEWER GAS." 
pointingout the danger, but they are sometimes held back by the earth 
and cannot perform that office. Professor Wolffhiigel reported at the 
Sixth Congress of Hygiene a case of poisoning by gas which had thus 
been robbed of its odor by the absorptive power of the soil. Water gas 
has much less odor than ordinary coal gas, and this fact together with 
its much greater richness in the poison has led, as was predicted it would, 
to a notable increase in the number of fatalities due to gas leaks. Since 
its introduction, a very material increase has obtained in New York, 
Baltimore, Brooklyn, and Boston. 
"SEWER GAS." 
Another impurity is what is commonly but improperly called a sewer 
gas." This is simply sewer air which may be more or less foul by 
reason of containing the emanations of sewage matters. Its chemical 
composition depends upon the extent to which the gases of decomposi- 
tion are generated, and upon the rate of ventilation. It may be almost 
as pure as the outside air; it may be as rich in carbonic acid as the 
air of badly ventilated rooms ; and it may be much worse. From 
10 to 30 volumes of CO2 in 10,000 are quite commonly found. Dr. 
W. J. Russell found as high as 51 volumes in 10,000 in the air of 
one of the London sewers, and Letheby as high as 53.2 in that of an- 
other, while in an unventilated sewer in Paris as high as 340 volumes 
have been reported. Sulphuretted hydrogen and ammonium sulphide 
are ordinarily present in small amounts or mere traces, and may be 
wholly absent; but in old unventilated sewers, they may be present in 
quite notable amounts. The highest recorded, 299 volumes in 10,000, 
was found by Parent-Duchatelet in an old choked sewer in Paris. 
Marsh gas, ammonia and compound ammonias, and other gaseous 
products of decomposition of organic matter may be present in variable 
amounts according to circumstances. 
Sewer air contains micro-organisms and animal and vegetable debris 
just as does the outer air, but as a matter of fact, the number of bac- 
teria is invariably small and they are often wholly absent. This was 
first shown in 1883 by Miquel, whose results have been corroborated by 
those of a number of other investigators including Carnelly and Hal- 
dane, Laws and Andrews, and Percy Frankland. The first mentioned 
conducted a most elaborate chemical and bacteriological examination 
of sewer air, and proved that from both points of view it compares 
very favorably with the air of schools and small dwellings, and that 
bacteriologically it is, indeed, far superior. It contains fewer organisms 
than the air of the streets above or of any kind of dwelling, and such 
as are present come entirely or chiefly from the outer air and not from 
the sewage. 
Laws and Andrews arrived at the same conclusions after a similar 
research. In each sample of sewage examined, the bacillus coli com- 
munis was found in numbers varying from 20,000 to 200,000 per cc., 
and closely allied species in even greater abundance; but neither the 220 
AIR. 
one nor any of the others was found in the many samples of air ex- 
amined. They found, further, that the number of organisms existing 
in sewer air depends entirely upon the number present in the outside 
air in the same vicinity, and that while the sewage bacteria are largely 
of the liquefying varieties, such are practically absent in the air. 
The chief importance of "sewer gas" lies not in its power to pro- 
duce disease, but in its capacity for being the vehicle for bad smells 
which make the air disagreeable but not necessarily dangerous to health, 
except that appetite and digestion, and hence general nutrition, may be 
interfered with. 
As a matter of fact, sewer air has served for a long time as a most 
convenient scapegoat to bear the blame for starting and spreading out- 
breaks of typhoid fever and other infectious diseases, and as a most 
useful aid in explaining obscure questions of various sorts. 
Many believers in the sewer-air theory of dissemination of typhoid 
fever hold that the coarser dust particles carry the germs on their sur- 
face and may be blown about through considerable distances before the 
organisms lose their vitality ; but the great objection to this explanation 
is that in sewers and cesspools the typhoid bacillus is speedily destroyed 
by other organisms, and that even though it be present in an active 
state in liquid sewage, it is extremely unlikely that it will be released 
therefrom into the air. No ordinary stirring up of the water will 
throw the germs into the air, though according to the researches of 
Frankland,1 the bursting of gas bubbles generated by decomposition 
will throw into the air traces of chemical salts which have been mixed 
and dissolved in the sewage, and in the same way may throw out bac- 
teria as well. But it has been shown by Niigeli that bacteria cannot 
be given off from moist surfaces. 
Another explanation, offered by Dr. C. R. C. Tichbourne,2 is that the 
disease germs are scattered into the air by the fermenting sewage and 
carried by a mist formed when the warm sewer air, saturated with 
moisture, meets the colder external air at the points where the venti- 
lating outlets are placed. Then each minute droplet of mist, carrying 
one or more microbes, is transported through longer or shorter distances 
in the air, perhaps into dwellings, and eventually by the influence of the 
heat of the sun or by other natural agency, becomes dissipated as vapor 
and leaves the organisms suspended in the atmosphere. 
The majority and the best of the German investigators, as Fliigge, 
Rubner, Gartner, Soyka, Prausnitz and others, maintain that sewer air 
and sewer gases are quite incapable of conveying the germs of typhoid 
fever and other infective diseases. It is true that some of the gases 
given off in the putrefaction processes which go on in sewers are more 
or less poisonous, but whether they are capable of producing any inju- 
rious effects depends very much on the amount inhaled and on the 
degree of concentration. In any event, they are certainly incapable of 
producing any infective disease in the absence of the specific germ. 
'Proceedings of the Royal Society, 1879. 
2 Dublin Journal of Medical Sciences, July, 1897. 221 
"SEWER GAS?' 
In any well constructed and properly ventilated sewer, no great 
amount of putrefaction will go on, since the sewage matters soon pass 
on and are discharged ; consequently, not much gas will be evolved, 
and with proper ventilation, whatever is evolved, is soon dissipated in 
the outer air. Offensive gases and odors are much more likely to be 
given off by unclean unventilated house plumbing than by well built 
sewers. 
It is commonly asserted that the inhalation of small amounts of this 
air will produce a train of symptoms, including headache, anaemia, loss 
of appetite, sore throat, albuminuria, diarrhoea, and others, and that it 
may be the exciting or auxiliary cause of typhoid fever, measles, diph- 
theria, scarlet fever, dysentery and other infective diseases. But in 
the cases which are accepted as proving the causal relation, inference 
has taken the place of proof, no other means of infection being ascer- 
tainable. In not a single case has the supposed relation been bacterio- 
logically demonstrated. 
In answer to the well-known stubborn fact that the workmen em- 
ployed in all the large systems of sewerage-men whose occupation 
involves the daily and constant inhalation not of traces, but of large 
volumes of sewer air-are as a class unusually healthy and strong, with 
a high mean age at death and a low death rate, it is asserted that they 
become immunized by daily contact and thus escape. If we accept 
this theory, however, we must go farther and say that large doses are 
a benefit in that they confer an immunity, and that, therefore, all pre- 
cautions against their admission to the air of dwellings are misdirected 
and should be abandoned. 
The air of properly constructed sewers is in constant motion, brought 
about by differences in temperature and mechanically through influx 
of sewage. During the colder months, the temperature within the 
sewer is higher than that of the air above, and it is materially influenced 
by the fact that the entering sewage is largely warm ; therefore, it tends 
to rise and escape through the openings in the man-hole covers. Dur- 
ing the warm season, the natural interchange is much lessened, since 
then the conditions as to temperature are reversed. At night, however, 
at all seasons, the temperature of the air of the sewer is higher than that 
of the atmosphere above, and thus ventilation goes on by natural laws 
the year round. Much air is displaced by the entering sewage; in 
fact, disregarding the effect produced by the warmth of the sewage, for 
every cubic foot of sewage which enters, a cubic foot of air is forced 
out, and as the sewage is discharged, more air is brought in to take its 
place. 
Owing to the prevailing idea of the noxious character of sewer air, 
it was formerly the custom to place baskets of charcoal in the outlet 
shafts of the man-holes, but as this material loses its absorptive prop- 
erty with access of moisture, the plan was abandoned. It was also re- 
garded as an advantage to connect the sewer with chimneys which 
should act as ventilators, but in the light of further knowledge and 
because of excessive action, that method of ventilation fell into disuse. AIR. 
222 
ORGANIC MATTERS. 
Among other impurities given off to the air, the organic matters 
from the processes of the body are, in a way, of considerable impor- 
tance. These include particles of epithelium, the constituents of sweat 
(butyric, capric, capronic, and caprylic acids, lactate, butyrate, and 
other salts of ammonium), and volatile matters from foul mouths, de- 
caying teeth, the digestive tract, and excrementitious matters deposited 
on unclean clothing. In addition to these, it has been claimed that 
other matters of a poisonous character are given off in the process of 
respiration, which matters will be referred to later on in the discussion 
of the effects of impure air on health. That the air of inhabited con- 
fined spaces may contain organic animal matter, is apparent to the 
senses when one enters such an atmosphere from one not thus contami- 
nated. 
Effects of Bad Air. 
The effects of bad air on the system are of great importance and 
vary in degree within very wide limits. For proper aeration of the 
blood, it is necessary that the oxygen of the air shall be present in the 
normal proportion in the free state and not in chemical union with 
carbon as a waste product. Further, it is necessary for the proper ex- 
cretion of the carbonic acid of the blood that the difference in the ten- 
sion of that gas in the air and in the blood shall be as wide as pos- 
sible ; that is to say, the less the amount of carbonic acid in the 
inspired air, the greater the facility with which the blood can disengage 
that which it carries to the lungs. 
Any interference with this most important function of the body must 
have an injurious effect on the general health, and it is generally ac- 
cepted that impurity of the air is without doubt the most important 
of the predisposing causes of disease. 
It is well known that other conditions being equal, in proportion as 
a people are drawn to employments indoors, the disease rate and death 
rate are increased. This is particularly true as regards phthisis, which 
is preeminently associated with overcrowding. 
Overcrowding means the association of two or more people in a 
space so confined as to preclude the admission of a constant supply of 
fresh air sufficient in amount to maintain a proper dilution of their 
excretory products and a normal supply of free oxygen. It was recog- 
nized long ago as a most important factor in the production of a high 
death rate among occupants of crowded jails, barracks, and hospitals, 
and experience has repeatedly demonstrated that increase in space 
allowance is always followed by decrease in sickness and death rates. 
At one time, for example, the English army averaged 11.9 deaths per 
1,000 men annually from phthisis alone; improvement in barrack 
ventilation and increase of average air space showed immediate im- 
provement, and the phthisis rate fell gradually to 1.2 per 1,000. The 
same general result has been observed in the armies of France, Russia, 
Germany, and Belgium. EFFECTS OF BAD AIR. 
223 
What is true of overcrowding applies not alone to human beings 
but to animals as well, and it is a well-known fact that crowded stables 
show high mortality among cows and horses. It has such a remark- 
able influence on egg production and growth of fowls that practical 
poultrymen are exceedingly careful on this point. 
The immediate effects of inhalation of impure air are discomfort and 
oppression, which may amount to headache, dizziness, faintness, and 
even nausea. Continued exposure is likely to bring about a gradual 
impairment of health shown by pallor, languor, anaemia, skin troubles, 
loss of appetite, and diminished power of resistance to the exciting 
causes of disease, and this is especially true of those whose daily work 
is carried on in crowded spaces. 
It is customary to cite as extreme cases of overcrowding and its 
effects the Black Hole of Calcutta, the ship Londonderry, and the 
prison at Austerlitz, but the conditions that obtained in each of these 
instances were most unusual, and the cases are of historical rather than 
sanitary interest, since the confining of a number of persons in a space 
from which air is practically excluded can have but one outcome. 
The Black Hole of Calcutta is the name applied to the military 
prison of Fort William, where, in June, 1756, Surajah Dowlah con- 
fined 146 persons over night in a space of less than 5,900 cubic feet with 
two small windows in one side. Within an hour, all broke out in a 
profuse sweat and were tortured with thirst and difficult breathing ; in 
three and a-half hours, a majority were delirious, and when the place 
was opened in the morning, 123 of the prisoners were found dead. 
In the case of the Londonderry which, in December, 1848, left Sligo 
for Liverpool and ran into a storm, 200 steerage passengers were con- 
fined over night in a space 18 by 11 by 7 feet with no means of ven- 
tilation. In the morning, when they were released, it was found that 
over seventy had expired. 
In the other extreme case, that at Austerlitz, 300 captured soldiers 
were confined in a small cellar, and within a few hours all but 40 were 
dead. 
To what one or more conditions of impure air are the ordinary 
effects due ? We have seen that CO2 is in itself not an active poison 
and that its action is to interfere with the proper oxygenation of the 
blood within the lungs. The aqueous vapor of respiration and from 
the skin and that produced in the combustion of illuminating material 
constitutes an important part of a vitiated atmosphere and is respon- 
sible for at least a part of the discomfort produced, but it is also true that 
a deficiency in watery vapor in the air of well-ventilated rooms has 
equal or greater disadvantages, as will appear in the consideration of 
ventilation. 
Concerning the effect of ordinary amounts of ordinary dust in in- 
habited rooms, there is little to be said. The micro-organisms, most 
of which are non-pathogenic, vary in number with efficiency of ven- 
tilation. In pure air, the bacteria and moulds approximate each other 
in number; but in vitiated air, the bacteria increase in number, while 224 
AIR. 
the moulds are much less affected. The experiments of Carnelly, 
Haldane and Anderson showed a progressive increase in both bacteria 
and moulds with diminished ventilation. Thus, 
Character of air space. 
Number organisms in 10 L. air. 
Ratio 
Moulds to 
Bacteria. 
Moulds. 
Bacteria. 
External air 
2 
6 
1 : 3 
4-roomed houses 
4 
85 
1 : 21 
2-roomed houses 
22 
430 
1 : 20 
1-roomed houses 
12 
580 
1 : 48 
The increase in bacteria is not due to respiration, though a diminu- 
tion in their number might be thus explained ; for the great majority 
of inhaled bacteria are filtered out by the nose, and the expired air is 
almost completely free from germs, though they may be thrown out in 
the processes of coughing or sneezing. 
Investigation thus far has not proved that the bacteria of infection 
are commonly introduced into the system through the medium of re- 
spired air. 
As has been already mentioned, it is held by many that the effects 
of bad air are not due to carbonic acid, but to the organic matters and 
aqueous vapor given off by the lungs and skin, and that these are con- 
veniently estimated by determining the amount of carbonic acid with 
which they are discharged. It is also said that while considerable car- 
bonic acid escapes even under the most imperfect system of ventila- 
tion, the organic matters and watery vapor do not so readily pass out, 
but are deposited on walls, furniture, hangings, and clothing, where 
they putrefy and become offensive. As proof of this is cited the fact 
that a room in which a person has slept without adequate ventilation 
has an unpleasant smell in the morning, and that this persists even 
after considerable airing. 
Brown-Sequard and d'Arsonval, in 1888, obtained from condensation 
of the aqueous vapor of men and animals a liquid which, injected into 
rabbits, caused death with greater or less rapidity, according to the size 
of the dose. They believed the toxic element to be of the nature of a 
volatile alkaloid and that it was exhaled dissolved in the aqueous va- 
por of the breath. In the same year, Wurtz, reporting a similar re- 
search, claimed to have found a toxic substance. 
Merkel,1 in 1892, claimed to have obtained positive results and con- 
cluded that respired air from persons in health contains a minute quan- 
tity of a volatile organic base, which is poisonous when free, but innoc- 
uous after contact with an acid. Dr. Sivierato2 collected the aqueous 
vapor of the breath of persons suffering from diseases of respiration 
both with and without fever, of persons with no respiratory disease 
but with fever, and of persons in health, and injected it into rabbits. 
That from those with respiratory diseases produced fever and dimin- 
1 Archiv fur Hygiene, XV., p. 1. 
2 Archives Italiennes de Biologie, 1895. EFFECTS OF BAD AIR. 
225 
ished reflexes lasting 3-6 days; that from cases of fever with no res- 
piratory disease caused little or no disturbance; and that from persons 
in health produced no results whatever. 
Many other experimenters, French, German, Italian, American, and 
English, working along the same lines, but with extra precautions to 
exclude matters from the nose and mouth, have failed to obtain any 
toxic effects from the condensed vapor ; others have demonstrated that 
the lungs exhale no organic matter except in minute amounts, and that 
these have no poisonous influence. 
Arloing, however, has pursued the subject further so as to include 
the sweat constituents among the deleterious agents of vitiated air. 
He soaked in distilled water the undershirt of a man who had spent 
a long evening in dancing, and injected the infusion into dogs; they 
became drowsy, suffered from violent diarrhoea, and shortly died. The 
drawers, similarly treated, gave a liquid which, injected into rabbits, 
produced clonic spasms followed by paralysis and death. 
Should these results be confirmed by a more scientific research, in 
which the possible influence of the body bacteria and other agents 
should be elimitated, it will have to be admitted that the sweat pos- 
sesses a high degree of toxicity. Until such confirmation is re- 
ported, however, the weight of evidence leads to the conclusion that 
the injurious action of vitiated air is due to the diminution of oxygen 
and the increase of carbonic acid, both of which factors, alone or to- 
gether, interfere with the intake of oxygen and the excretion of car- 
bonic acid from the lungs. Yet, diminution in oxygen, which even in 
very crowded rooms does not proceed very far, is met by increase in 
the respiratory function which, however, cannot increase the difference 
between the tension of the carbonic acid of the air and of the blood. 
Not even in very badly ventilated mines does the oxygen fall much 
below 20 per cent, by volume, and thus we can see that the whole 
range of fluctuation in the oxygen of good and very bad air is but 
little more than one volume per cent. 
Smith and Haldane 1 have shown that in a leaden chamber contain- 
ing air which had undergone but slight diminution in oxygen, but 
which contained 384 parts of carbonic acid in 10,000, two men suf- 
fered from headache immediately on entering. 
As a rule, bad air is associated with high temperature and saturation 
with aqueous vapor, which latter interferes with evaporation from the 
skin. Less often it is associated with low temperature, and with this 
condition comes an increased demand for oxygen to meet the require- 
ments of the oxidation processes. 
It seems probable that where the carbonic acid is not present in any 
great excess and the oxygen is not markedly deficient, the conclusion 
arrived at by Drs. Weir Mitchell, Billings, and Bergey is true; namely, 
that the discomfort suffered is largely and chiefly due to heat and dis- 
agreeable odors arising from the occupants in various ways; from bad 
breath, unclean skin, unclean clothes, sweat, and gases from the bowels. 
'Journal of Pathology and Bacteriology, L, 1892. 226 
AIR. 
Such may induce very disagreeable sensations, even amounting to 
nausea, in those who are not habituated to such influences, but on the 
other hand, those who are accustomed to such air notice no discomfort. 
Disagreeable smells do not act directly as a cause of specific disease, 
but appear to have an influence on the appetite, and hence on the gen- 
eral well-being of persons not accustomed to them. Much lies also in 
the imagination ; a disagreeable smell from a source known to be clean 
(chemicals, for instance) has not ordinarily as much influence as an- 
other of equally offensive character supposed to be from filth. It 
seems probable also that there is much to learn concerning the real 
effects of disagreeable smells and that they may be more extensive than 
we now commonly believe, but in order to determine this we shall need 
methods which will reveal the nature of the odoriferous substances 
and make their isolation possible. 
Other causes of discomfort may be sought for in the presence of traces 
of carbon monoxide from heating apparatus or incomplete combustion 
of illuminating gas, and in excessive dryness of the air due to furnace 
or steam heat. 
It must not be overlooked that impure air may affect the vitality and 
bactericidal power of the cells of the air passages and of the alimen- 
tary tract, and thus lower the power to resist the action of infective 
material. 
The Air as a Carrier of Infection. 
On the agency of air in spreading infectious matter, much has been 
said and written, and much careful research has been conducted, but 
the conclusions reached are by no means in agreement or conclusive. 
It is generally conceded that pathogenic organisms in the air are ad- 
herent to particles of dust of various kinds, and that their retention of 
virulence depends upon the amount of hygroscopic moisture with which 
they are associated. The conditions favorable to their continuance as 
living organisms are naturally more likely to obtain in indoor air, with 
imperfect ventilation, than in the outer air, where they are diluted 
and blown about and exposed to the disinfectant action of the direct 
rays of the sun. Indoors or outdoors, the more they are protected by 
hygroscopic dust particles, the longer they will retain the moisture 
which is essential to their viability. It appears, too, that conditions 
being equal, certain micro-organisms retain vitality longer than others, 
some being but slightly, others very tenacious of life. 
With regard to the transmission of pulmonary tuberculosis through 
the air, it must be said that while there can be no doubt that this dis- 
ease is preeminently connected with over-crowding and bad air, there 
is a very decided difference of opinion as to the method of conveyance, 
some contending that dust, and others that tuberculous material, thrown 
into the air by coughing and sneezing, is the vehicle. 
Buchner has found the bacillus in an active state in the dust of a 
room a year after the death of its occupant from the disease. G. Cornet1 
1 Zeitschrift fur Hygiene, V., p. 191. THE AIR MS A CARRIER OF INFECTION. 
227 
demonstrated its presence in over a third of 147 samples of dnst col- 
lected in hospitals and other public institutions and in private houses 
inhabited by phthisical persons, and succeeded later in producing the 
disease in 46 out of 48 guinea-pigs exposed to air containing dust from 
dried tuberculous sputum. Some of the animals were placed eight 
inches from a glass vessel containing dried pulverized sputum from an 
advanced case; others were placed on shelves 8 to 28 inches from the 
floor of a room on the carpet of which sputum, mixed with dust, had 
been spread and dried and, at the end of two days, stirred up by 
sweeping; others were allowed to stay in the room without any dis- 
turbance of the dust. 
Klein obtained positive results with guinea-pigs placed in the ven- 
tilating shaft of a consumptives' hospital, but Heron 1 obtained but 
2.7 per cent, of positive results in 74 guinea-pigs inoculated with dust 
from the ventilating shaft of the London Hospital for Diseases of the 
Chest, and Kirchner2 got but one positive result out of 16 pigs inocu- 
lated with the dust from a military hospital. 
Fliigge, on the other hand, was wholly unsuccessful in inducing the 
disease in guinea-pigs exposed to such dust, and concluded that the 
transmission from one person to another is chiefly by means of the 
finest droplets thrown into the air in speaking, coughing, and sneezing. 
From later experiments, conducted under his supervision by Lascht- 
schenko, Heymann, Sticher, and Beninde,3 he concluded that in rooms 
in which tuberculous sputum is dried on the floor or other places, and 
where the air is filled with coarse dust through dry cleaning and air 
currents or, as in railway cars, by continual mechanical jarring, infec- 
tion may arise, and that under these conditions, long-continued expo- 
sure offers a certain degree of probability of infection. Therefore, dry 
cleaning is to be avoided in rooms in which consumptives are employed 
with others, and the rooms should not be occupied so long as the air 
is perceptibly dusty. The great possibility of infection through mat- 
ters thrown off in coughing and sneezing is insisted upon as of para- 
mount importance. This danger is to be prevented by requiring the 
person coughing to hold a handkerchief or the hand before the mouth 
during the act, and by the avoidance on the part of others of approach- 
ing within a meter. 
Answering Fliigge, Cornet4 contends that the number of bacilli 
thrown into the air during the act of coughing must be extremely 
small. He caused 18 consumptives to hold dishes before the mouth 
while coughing, and obtained two positive results therefrom on inocu- 
lation into guinea-pigs; repeating the test with 15 others, he got none. 
Zielgen 5 also disagrees with Fliigge as to the possibility of trans- 
mission of germs in general through the air and believes that it is 
much assisted by evaporation of water from surfaces upon which they 
'The Lancet, Jan. 6, 1894. 
2 Zeitschrift fiir Hygiene und Infectionskrankheiten, XIX., p. 153. 
3 Ibidem, XXX., p. 107. 
4 Berliner klinische Wochenschrift, May 13, 1899. 
5 Tribune Medicale, May 10, 1899. 228 
AIR. 
are deposited. He obtained positive results from inoculation of drop- 
lets condensed on the upper surface of a vessel in which a culture of 
bacillus pyocyaneus had been incubated. 
Experiments conducted at the Adirondack Cottage Sanitarium by 
Dr. I. H. Hance 1 for the purpose of determining the degree of danger 
of infection when all possible sanitary measures for the care and disin- 
fection of sputum are enforced, support the view that dust in the air is 
of secondary importance, but that where carelessness in this regard ob- 
tains, the danger is a real one. A complete examination was made of 
the group of buildings, some of which had been occupied by consump- 
tives for eleven years. Dust was collected from places most likely to 
be infected, and with it 81 guinea-pigs were inoculated. Four inocu- 
lated with dust from the infirmary (a building where all the acutely 
sick are sent), and from the main building in which are a parlor, sit- 
ting-room and library, died of other infections on the third to the 
sixth day. Five of the ten inoculated with dust from the oldest cot- 
tage, which was occupied by a man who had been complained of for 
promiscuous spitting, became tuberculous. Those inoculated with the 
dust from the other buildings gave negative results. During eleven 
years, not one of the 20 to 25 attendants employed had ever developed 
the disease. 
As to typhoid fever, too, opinions are at variance. Dr. John 
Brownlee reported before the Glasgow Philosophical Society an ex- 
periment proving that the specific bacilli can live in ordinary dust. 
Buchner is of the opinion that neither typhoid nor other fevers can 
thus be spread. 
Perhaps the most extensive research on the subject of transmission 
of this and other diseases is that conducted by Dr. Eduardo Germano.2 
In his experiments, he used various kinds of dust and dirt, and from 
his results, he concludes that the typhoid germ is unable to withstand 
complete drying and hence cannot be transmitted to man through dust 
dry enough to be disseminated by air currents. Experiment showed 
that the germ can live for a long time in moist surroundings even in 
an apparently dry condition, that is, when adherent to or encompassed 
by matters which contain a certain amount of moisture, such as cloth- 
ing, particles of dirt, and fecal filth. Most of the bacilli die as drying 
progresses, but some are more or less resistant, though not necessarily 
dangerous on admission to air currents, since then complete drying and 
consequent death occur. They are dangerous only in case of introduction 
into the system through contact with the fingers, food, or eating utensils. 
With regard to diphtheria, he found that the bacillus withstands long 
drying in membranes, tissues, and dust, even when the drying process 
is assisted by sulphuric acid, and that its resistance is greater according 
to the amount of enveloping material which retards oxidation. When 
completely dry, it preserves its full virulence up to the time it dies. 
Hence his belief that this disease can be disseminated by air currents. 
1 Medical Record, December 28, 1895. 
2 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIV., p. 403; XXV., p. 
439 ; XXVI., pp. 66 and 273. 229 
THE AIR AS A CARRIER OF INFECTION. 
With regard to pneumonia, erysipelas and other streptococcus infec- 
tions, he finds that the resistance of the organism to the drying process 
is always high, though it varies with the method followed and the 
nature of the enveloping material, and may last a number of months. 
Transmission through the air is extremely probable. The diplococci 
can, in general, bear drying for a long time ; some varieties last longer 
when dried than if moist, and some have but little resistance ; but the 
rapidity of the drying process with medium temperature does not affect 
the result. He found that the cholera organism retains its virulence 
only so long as it remains moist, and dies quickly on drying, particu- 
larly if the process is hastened. He concluded that dissemination by 
air is most highly improbable. 
His work with the plague bacillus confirms the results announced 
by Kitasato and Wilm. This does not withstand drying, but lives a 
long time in a moist condition. It remains active fairly long when 
dried on cloth, because then complete drying requires a long time, and 
thus may be explained the danger of infection recognized to exist in 
infected clothing. 
His experiments with the diplococcus of epidemic cerebro-spinal 
meningitis agree in results with those of Jager, who found the organ- 
ism in an active condition in a handkerchief six weeks after use by a 
patient sick with the disease. Germano shows that it belongs to the 
class of bacteria which show the greatest possible resistance to drying, 
whether the process is slow or quick, and whether assisted by the action 
of sulphuric acid ; and concludes that it may without difficulty get into 
the air in the form of dust, and thus spread the infection. 
Dr. Max Neisser,1 working in the same line with an apparatus of his 
own design which establishes a constant aspiration current of dusty in- 
fected air, disagrees with Germano as to the pneumococcus, inasmuch 
as while mice, inoculated with infected dust, died from the infection 
without exception, 24 others, inoculated with the same dust after it had 
been sent through the apparatus in a current of air, gave absolutely 
negative results. His experiments with various organisms led him to 
the conclusion that dust infection is impossible with the organisms of 
diphtheria, typhoid fever, cholera, plague and pneumonia, but possible 
with staphylococcus pyogenes aureus, B. pyocyaneus, B. anthracis, B. 
tuberculosis, and meningococcus. 
His conclusions, so far as they relate to diphtheria, are opposed to 
the results obtained by Richardiere and Tollemer,2 who made a series 
of examinations of the air of diphtheria wards of the Hopital Trous- 
seau. In one set of experiments, the wards had not been disinfected 
for several weeks, and in another, the examinations were made after 
disinfection had been carried out. The results showed that active 
diphtheria bacilli were present in the air which had not undergone 
disinfection. The bacteriological tests were controlled by inoculation 
experiments with animals. 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXVI., p. 175. 
2 Gazette des Maladies Infantiles, No. 10, 1899. 230 
AIR. 
With regard to the possibility of spreading cholera germs through 
the agency of moving air, Dr. N. William 1 has reported that while 
that means has been regarded as most favorable, in actual experiment 
it fails. Mixed with dry dust, the germs live but a short time, and 
perish more quickly when a current of air is conducted through the 
dust. When the dust is distributed through large volumes of air, the 
germs die rapidly, and when the impregnated dust is let fall upon a 
suitable culture only a very small proportion of living organisms can 
be found. In other words, cholera germs, adherent to dust particles 
floating in and moved about by air, cannot retain their activity for any 
length of time nor through any considerable distance. 
The experiments of lionsell2 indicate that the cholera organism finds 
no favoring conditions for its passage into the air from its situation 
in privy vaults. 
The matter of danger of cholera infection by dust from baled rags 
was thoroughly considered at the Dresden Cholera Conference, and it 
was then found impossible to quote a single case in which infection 
could be traced to this source. 
According to Dr. E. W. Hope,3 atmospheric dust is largely respon- 
sible for the spread of infantile diarrhoea in cities and large towns 
where, from largely unavoidable causes, the air becomes more or less 
laden with filth. He presents evidence of the association of rainfall 
and its attendant cleansing of the atmosphere with diminished mor- 
tality from choleraic diarrhoea, as follows : 
Period. 
Average rainfall 
June to 
September. 
Conditions. 
Annual average of deaths 
from diarrhoea during 
3d quarter of year. 
6 years 
13.8 inches 
Average wet sum- 
373 
14 " 
10.9 " 
mers. 
Average dry sum- 
573 
Extreme years 
1891 
16.0 " 
mers. 
Wettest summer. 
203 
1895 
7.7 " 
Driest summer. 
819 
Influence of Fog. 
Dust and moisture together in the form of fog affect the health of 
large communities in a marked degree. In a still air nearly or com- 
pletely saturated with aqueous vapor and containing ordinary dust and 
smoke, a fall in temperature causes each particle of dust and soot to 
become the nucleus of a minute droplet of condensed moisture. These 
countless droplets in a state of suspension form a more or less dense 
blanket of fog, which impedes the dispersion of the impurities given 
off by natural processes and as products of combustion. While ordi- 
nary country and seashore fogs are not known to exert any deleterious 
effects, in smoky cities, like London, the case is quite different. 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XV., p. 166. 
2Arbeitem aus den patholog-anatomischen Institut zu Tubingen, 1896. 
3Public Health, July, 1899. EXAMINATION OF AIR. 
231 
It is a well-recognized fact that during periods of heavy fogs in 
manufacturing centers, the morbidity and mortality from respiratory 
diseases are very greatly increased, and that as the atmosphere clears, 
a sharp decline follows. In London, for example, the usual death rate 
from all causes has been known to become almost doubled during a 
fortnight of continued dense smoky fog, and then to return to its normal 
figure with the advent of clear weather, the increase being due par- 
ticularly to bronchitis and other affections of the respiratory tract, at- 
tributed to the irritating influence of the finely divided particles of 
soot and the acids which accompany them. 
During the prevalence of thick fogs, the air being necessarily in a 
stagnant condition, it has been observed that the carbonic acid content 
increases progressively. During one such period following bright 
weather, the air of London acquired in four days three and a-half 
times its normal content of this gas. 
The importance of smoke both as a promoter of disease and on ac- 
count of its corrosive and disfiguring action on buildings, and also on 
account of the obstruction of light, has led to much legislation and to 
the exercise of inventive genius for devising means for the prevention 
of its discharge in objectionable amounts into the atmosphere of cities. 
Many patents have been granted for smoke-consuming devices, most 
of which have been found to work unsatisfactorily. The most effective 
invention, which gives promise of solving the problem most completely, 
is one which has been brought to the attention of the Department of 
State by Consul General Mason.1 This process consists in distributing 
heated and slightly compressed air through hollow grate bars to the 
whole lower surface of the furnace. Not only is practically perfect 
combustion attained, but immense saving of expense is possible, since 
what are ordinarily unsalable low-grade coals can be employed to 
greatest advantage. 
For all practical purposes, the examination of air may be restricted 
to the determination of the amounts of aqueous vapor and carbonic 
acid. The essential element, oxygen, fluctuates within such very nar- 
row limits that its estimation is a matter of purely scientific interest, 
and, moreover, the process is one which demands a much higher de- 
gree of manipulative skill than is possessed by those to whom the 
task of making sanitary examinations ordinarily falls. The chief con- 
stituent, nitrogen, is practically constant in amount and its determina- 
tion would serve no useful purpose. Whatever is the cause of the 
deleterious effects of an atmosphere vitiated by respiration, whether it 
be carbonic acid or the organic matters given off by the body, this at 
least is certain, that the amount of carbonic acid serves as an index of 
impurity, and that the amount of aqueous vapor is of considerable 
sanitary importance. In special cases, it is important to look for that 
most dangerous contamination carbon monoxide, which, coming even in 
Examination of Air. 
1 Consular Reports, 1899, p. 491. 232 
AIR. 
very small amounts from leaking gas pipes and other sources, exerts a 
decidedly deleterious influence. In the minds of many, the test for 
ozone is also of importance. 
In addition to chemical analysis, the determination of the amount of 
dust and the number and varieties of micro-organisms present may be 
of interest and importance. 
Determination of Aqueous Vapor.-As has been stated above, a 
volume of air at a given temperature can hold a definite amount of 
moisture and no more, and when this amount is present the air is said 
to be saturated. The amount which a volume of air contains consti- 
tutes its absolute humidity, and the difference between this and the 
amount which it is possible for it to hold is known as its saturation 
deficiency. The ratio which its absolute humidity bears to its possible 
content is known as its relative humidity. 
Direct Determination of Moisture by Weighing.-Prepare two small 
wide-mouthed flasks of about 150 cc. capacity in the following manner : 
Provide each with a tightly fitting rubber stopper with two perforations 
through which are inserted two pieces of glass tubing bent at a right 
angle. One of these reaches to the bottom of the flask and serves as an 
Fig. 9. 
Apparatus for direct determination of moisture. 
inlet; the other extends only a short distance below the stopper and 
ser ves as an outlet. Fill the flasks with small pieces of pumice which have 
been heated to a high temperature over a Bunsen burner, dropped while 
hot into concentrated sulphuric acid, removed therefrom, and quickly 
drained. The two thus filled and with stoppers tightly inserted are 
then to be connected by means of a short piece of rubber tubing, the 
inlet of one joining the outlet of the other. They are then weighed. 
T he flask with the free outlet tube is now to be connected with an 
aspirator by means of which from 20 to 50 liters of air are drawn 233 
DETERMINATION OF AQUEOUS VAPOR. 
through. As the air comes in contact with the pumice saturated with 
sulphuric acid, the latter deprives it of its moisture and thereby gains 
in weight. At the expiration of the aspirating process, the flasks are 
disconnected from the aspirator and again weighed. The increase in 
weight represents the amount of atmosphere in the volume of air used. 
The apparatus is shown in Fig. 9. 
Knowing the temperature of the air, one can 
then easily determine the relative humidity by 
reference to the table below, which shows the 
maximum humidity possible at different tem- 
peratures. 
Fig. 10. 
TABLE OF MAXIMUM WATER CAPACITY FOR 
TEN LITERS OF AIR. 
Tempera- 
ture Centi- 
grade. 
Corre- 
sponding 
degrees F. 
Grams. 
Tempera- 
ture Centi- 
grade. 
Corre- 
sponding 
degrees F. 
Grams. 
-10 
14.0 
0.021 
13 
55.4 
0.113 
- 8 
17.6 
0.027 
14 
57.2 
0.120 
- 6 
21.2 
0.032 
15 
59.0 
0.128 
- 4 
24.8 
0.038 
16 
60.8 
0.136 
- 2 
28.4 
0.044 
17 
62.6 
0.145 
0 
32.0 
0.049 
18 
64.4 
0.151 
1 
33.8 
0.052 
19 
66.2 
0.162 
2 
35.6 
0.056 
20 
68.0 
0.172 
3 
37.4 
0.060 
21 
69.8 
0.182 
4 
39.2 
0.064 
22 
71.6 
0.193 
5 
41.0 
0.068 
23 
73.4 
0.204 
6 
42.8 
0.073 
24 
75.2 
0.215 
7 
44.6 
0.077 
25 
77.0 
0.229 
8 
46.4 
0.081 
26 
78.8 
0.242 
9 
48.2 
0.088 
27 
80.6 
0.256 
10 
50.0 
0.094 
28 
82.4 
0.270 
11 
51.8 
0.100 
29 
84.2 
0.286 
12 
53.6 
0.106 
30 
86.0 
0.301 
Determination of Relative Humidity by the 
wet and dry Thermometer Bulbs.-This instru- 
ment, which is known also as the psychrom- 
eter, consists of a pair of accurate thermom- 
eters on an upright support. The bulb of one 
is free; that of the other is covered with a 
layer of muslin kept moistened by means of a piece of wicking which 
dips into a small vessel of water beneath. (See Fig. 10.) 
In a saturated atmosphere, no evaporation can occur from the wet 
muslin ; but in one not saturated, the process goes on with varying 
rapidity. Evaporation is a process which requires heat and causes a 
lowering of the temperature of the moist surface; the more rapid its 
rate, the greater the abstraction of heat. The drier the atmosphere, 
the greater the rate of evaporation and, therefore, the greater the fall 
in temperature. 
Psychrometer. 234 
AIR. 
If the instrument is placed in a saturated atmosphere, the two ther- 
mometers will give the same readings; but in one not saturated, the 
wet thermometer will fall gradually until the surface of its bulb 
has reached nearly the temperature of the dew point; that is, to that 
point at which air at that temperature is so saturated that a further 
lowering would be followed by condensation of moisture. As a mat- 
ter of fact, the wet thermometer does not fall so far in a quiet air, since 
its bulb becomes surrounded by a layer of stagnant saturated air and 
receives more or less heat from the surrounding warmer atmosphere. 
Again, in a saturated atmosphere, the wet thermometer may stand 
slightly higher than the dry one, owing to the fact that its covering 
protects it from loss of heat by radiation. 
For the purpose for which it is intended, the instrument is exposed 
until the wet thermometer ceases to fall, and then the reading of both is 
noted. From these data, with the assistance of Glaisher's factors, the 
dew point is easily calculated in the following manner: Multiply the 
difference in the two readings by the factor opposite the figure in the 
table corresponding to the temperature of the dry bulb, and subtract 
the product from this temperature. 
glaisher's table. 
Reading of 
Dry Bulb 
Thermometer. 
Factor. 
Reading of 
Dry Bulb 
Thermometer. 
Factor. 
Reading of 
Dry Bulb 
Thermometer. 
Factor. 
10 
8.78 
41 
2.26 
71 
1.76 
11 
8.78 
42 
2.23 
72 
1.75 
12 
8.78 
43 
2.20 
73 
1.74 
13 
8.77 
44 
2.18 
74 
1.73 
14 
8.76 
45 
2.16 
75 
1.72 
15 
8.75 
46 
2.14 
76 
1.71 
16 
8.70 
47 
2.12 
77 
1.70 
17 
8.62 
48 
2.10 
78 
1.69 
18 
8.50 
49 
2.08 
79 
1.69 
19 
8.34 
50 
2.06 
80 
1.68 
20 
8.14 
51 
2.04 
81 
1.68 
21 
7.88 
52 
2.02 
82 
1.67 
22 
7.60 
53 
2.00 
83 
1.67 
23 
7.28 
54 
1.98 
84 
1.66 
24 
6.92 
55 
1.96 
85 
1.65 
25 
6.53 
56 
1.94 
86 
1.65 
26 
6.08 
57 
1.92 
87 
1.64 
27 
5.61 
58 
1.90 
88 
1.64 
28 
5.12 
59 
1.89 
89 
1.63 
29 
4.63 
60 
1.88 
90 
1.63 
30 
4.15 
61 
1.87 
91 
1.62 
31 
3.60 
62 
1.86 
92 
1.62 
32 
3.32 
63 
1.85 
93 
1.61 
33 
3.01 
64 
1.83 
94 
1.60 
34 
2.77 
65 
1.82 
95 
1.60 
35 
2.60 
66 
1.81 
96 
1.59 
36 
2.50 • 
67 
1.80 
97 
1.59 
37 
2.42 
68 
1.79 
98 
1.58 
38 
2.36 
69 
1.78 
99 
1.58 
39 
2.32 
70 
1.77 
100 
1.57 
40 
2.29 TABLE OF TENSIONS. 
235 
Having now determined the dew point, the next step is to ascertain 
the elastic tension of the vapor present in the air, that is, the tension 
of the dew point, and the tension of that necessary for saturation at the 
temperature of the dry bulb, which data can be obtained by reference 
to the following table : 
TABLE OF TENSIONS. 
Tempera- 
ture. 
Fahrenheit. 
Corre- 
sponding 
degrees C. 
Tension 
in inches of 
Mercury. 
Tension 
in mm. 
Tempera- 
ture. 
Fahrenheit. 
Corre- 
sponding 
degrees C. 
Tension 
in inches of 
Mercury. 
Tension 
in mm. 
1 
-17.2 
0.046 
1.17 
51 
10.6 
0.374 
9.50 
2 
-16.7 
0.048 
1.22 
52 
11.1 
0.388 
9.86 
3 
-16.1 
0.050 
1.27 
53 
11.7 
0.403 
10.24 
4 
-15.6 
0.052 
1.32 
54 
12.2 
0.418 
10.62 
5 
-15.0 
0.054 
1.37 
55 
12.8 
0.433 
11.00 
6 
-14.4 
0.057 
1.45 
56 
13.3 
0.449 
11.40 
7 
-13.9 
0.060 
1.52 
57 
13.9 
0.465 
11.81 
8 
-13.3 
0.062 
1.57 
58 
14.4 
0.482 
12.24 
9 
-12.8 
0.065 
1.65 
59 
15.0 
0.500 
12.70 
10 
-12.2 
0.068 
1.73 
60 
15.6 
0.518 
13.16 
11 
-11.7 
0.071 
1.80 
61 
16.1 
0.537 
13.64 
12 
-11.1 
0.074 
1.88 
62 
16.7 
0.556 
14.12 
13 
-10.6 
0.078 
1.98 
63 
17.2 
0.576 
14.63 
14 
-10.0 
0.082 
2.08 
64 
17.8 
0.596 
15.14 
15 
- 9.4 
0.086 
2.18 
65 
18.3 
0.617 
15.67 
16 
- 8.9 
0.090 
2.28 
66 
18.9 
0.639 
16.23 
17 
- 8.3 
0.094 
2.38 
67 
19.4 
0.661 
16.79 
18 
- 7.8 
0.098 
2.49 
68 
20.0 
0.684 
17.37 
19 
- 7.2 
0.103 
2.62 
69 
20.6 
0.708 
17.98 
20 
- 6.7 
0.108 
2.74 
70 
21.1 
0.733 
18.62 
21 
- 6.1 
0.113 
2.87 
71 
21.7 
0.759 
19.28 
22 
- 5.6 
0.118 
3.00 
72 
22.2 
0.785 
19.94 
23 
- 5.0 
0.123 
3.12 
73 
22.8 
0.812 
20.62 
24 
- 4.4 
0.129 
3.28 
74 
23.3 
0.840 
21.34 
25 
- 3.9 
0.135 
3.43 
75 
23.9 
0.868 
22.05 
26 
- 3.3 
0.141 
3.58 
76 
24.4 
0.897 
22.78 
27 
- 2.8 
0.147 
3.73 
77 
25.0 
0.927 
23.55 
28 
- 2.2 
0.153 
3.89 
78 
25.6 
0.958 
24.33 
29 
- 1.7 
0.160 
4.06 
79 
26.1 
0.990 
25.15 
30 
- 1.1 
0.167 
4.24 
80 
26.7 
1.023 
25.98 
31 
- 0.6 
0.174 
4.41 
81 
27.2 
1.057 
26.85 
32 
- 0.0 
0.181 
4.60 
82 
27.8 
1.092 
27.74 
33 
+ 0.6 
0.188 
4.78 
83 
28.3 
1.128 
28.65 
34 
1.1 
0.196 
4.98 
84 
28.9 
1.165 
29.59 
35 
1.7 
0.204 
5.18 
85 
29.4 
1.203 
30.55 
36 
2.2 
0.212 
5.38 
86 
30.0 
1.242 
31.55 
37 
2.8 
0.220 
5.59 
87 
30.6 
1.282 
32.56 
38 
3.3 
0.229 
5.82 
88 
31.1 
1.323 
33.60 
39 
3.9 
0.238 
6.04 
89 
31.7 
1.366 
34.69 
40 
4.4 
0.247 
6.27 
90 
32.2 
1.410 
35.81 
41 
5.0 
0.257 
6.53 
91 
32.8 
1.455 
36.95 
42 
5.6 
0.267 
6.78 
92 
33.3 
1.501 
38.12 
43 
6.1 
0.277 
7.04 
93 
33.9 
1.548 
39.31 
44 
6.7 
0.288 
7.32 
94 
34.4 
1.596 
40.53 
45 
7.2 
0.299 
7.59 
95 
35.0 
1.646 
41.80 
46 
7.8 
0.311 
7.90 
96 
35.6 
1.697 
43.09 
47 
8.3 
0.323 
8.20 
97 
36.1 
1.749 
44.42 
48 
8.9 
0.335 
8.51 
98 
36.7 
1.802 
45.77 
49 
9.4 
0.348 
8.84 
99 
37.2 
1.856 
47.14 
50 
10.0 
0.361 
9.17 
100 
37.8 
1.911 
48.54 AIR. 
236 
From these several data the relative humidity is calculated as fol- 
lows : Divide the tension of the dew-point by that of saturation at 
the actual temperature and multiply by 100. 
Example. 
Reading of dry bulb = 67° 
Reading of wet bulb = 62° 
Dew point = 67-(5X 1.80) = 67 -9 = 58° 
Relative humidity = X100 - 72.92 per cent. 
More accurate determination may be made by employing the 
" whirled " or " sling " thermometers. These are fastened to a string 
of such a length that the distance from the bulbs to the held end is 
exactly a meter. In use, they are whirled in a horizontal plane 100 
times at the rate of one revolution per second. By their use, the 
errors mentioned as likely to occur when the 
observations are made in still air are elimi- 
nated. For all practical purposes, the use of 
the thermometers in the ordinary way gives 
sufficiently accurate results. 
In making determinations out of doors 
when the temperature is below the freezing 
point, the wick may be dispensed with and 
the bulb is then wetted by dipping it into 
water, the excess being removed by means 
of a bit of filter paper or common blotting 
paper, or water may be applied with a 
camel's-hair pencil. Below the freezing point, 
however, the relative humidity is of little 
hygienic interest, since the amount of mois- 
ture which air can then contain is but slight. 
A very convenient instrument for quick 
approximate determinations without the ne- 
cessity of tables and computation is known 
as the hygrophant of AV inlock and Huddles- 
ton. It consists of a pair of thermometers 
and a cylinder upon which is inscribed a 
series of 22 columns of figures numbered 
from 1 to 22, any one of which can, by a 
turn of a knob, be brought into apposition 
with a fixed scale on the casing. (See Fig. 11.) To ascertain the relative 
humidity, note the difference in the readings of the thermometers, turn 
the cylinder until the column having at its top the number correspond- 
ing to the difference appears opposite the scale, and read the figures 
opposite the number corresponding to the temperature of the wet bulb. 
Example. 
Reading of dry bulb ; = 72° 
Reading of wet bulb = 60° 
Difference = 12° 
Fig. 11. 
Hygrophant. DETERMINATION OF CARBONIC ACID. 
237 
The cylinder is turned until column 12 appears. Opposite 60 of 
the scale, the reading is 46 ; and this is approximately the percentage of 
saturation present. 
Determination of Carbonic Acid.-For the collection of samples 
of air for this determination, it is well to provide a number of bottles 
of about a gallon capacity. These must first of all be very carefully 
measured. This can be done by filling them with ice water and not- 
ing the number of cc. required, or by determining by means of plat- 
form scales sensitive to 5 grams the difference between their weights 
empty and filled. It is well to place a distinguishing number and the 
figures denoting its capacity on each bottle either on a label, or better, 
by means of a writing diamond. When used, the bottle should be 
perfectly clean and dry. 
When it is necessary to employ the same bottle again, time being an 
object, the drying process is very much hastened by washing first with 
water, then with a little alcohol to remove the small amount of water 
which will not drain away, and finally with a little ether for the re- 
moval of the residuum of alcohol. The small amount of adherent ether 
may then be removed by blowing a current of air into the bottle by 
means of a bellows. A number of tightly fitting rubber caps should 
be provided in place of corks or rubber stoppers, though if these are 
not at hand, the latter may be used; but note should be made of the 
volume of air which they displace when they are inserted. 
Solutions Required. 1. Solution of Barium Hydrate.-Dis- 
solve about 4.5 grams of barium hydrate and 0.5 of barium chloride 
in a liter of distilled water which has been pre- 
viously boiled in order to expel any carbonic acid 
which it may contain. It is well to prepare an 
amount sufficient for future needs, say 4 liters, and 
keep it in a bottle such as is shown in Fig. 12. 
This is provided with a rubber stopper with two 
perforations, through one of which a bent tube, 
reaching to the bottom and intended for with- 
drawal of the reagent, is inserted. Through the 
other is carried another tube extending only into 
the neck and communicating at its outer extremity 
with a U-tube filled with pieces of pumice soaked 
while hot in a strong solution of caustic potash. 
The delivery tube carries at its outer end a piece 
of closely fitting rubber tubing which is kept closed 
by means of a pinchcock. ' 
In withdrawing the reagent for use, a 100-cc. 
pipette is inserted into the free end of the rubber 
tube, suction is applied, and the pinchcock is 
opened. When the pipette is filled to the mark, 
the pressure is removed from the pinchcock and 
the pipette released. As the reagent is withdrawn, air flows in 
through the other opening and is robbed of its carbonic acid by 
Fig. 12. 
Bottle for barium hy- 
drate. 238 
AIR. 
contact with the caustic potash with which the pumice has been 
charged. 
This reagent is used for the absorption of the carbonic acid con- 
tained in the sample of air under examination. The reaction is ex- 
pressed by the following formula : 
BaO2H2 -J- CO2 = BaCO3 + H2O. 
The function of the barium chloride is explained below. 
2. Standard Solution of Oxalic Acid.-Dissolve 2.808 grams 
of pure oxalic acid in a liter of distilled water. One cc. of this solu- 
tion is equivalent to 0.5 cc. of carbonic acid; that is to say, will neu- 
tralize the same amount of barium hydrate as will combine with car- 
bonic acid to form barium carbonate. 
3. Solution of Phenolphthalein.-Dissolve 0.5 gram of 
phenolphthalein in 100 cc. of alcohol. This solution is used as an 
a indicator " of alkalinity. 
Process of Analysis.-The process of analysis depends upon the fact 
that when a volume of the barium hydrate solution is brought into 
contact with carbonic acid, its alkalinity is diminished by the forma- 
tion of barium carbonate, which is a neutral body. The greater the 
amount of carbonic acid to which it is exposed, the greater will be the 
reduction of its alkaline strength. A preliminary determination of the 
amount of oxalic acid solution which 100 cc. of the reagent will neu- 
tralize is made by titrating 25 cc. contained in an Erlenmeyer flask and 
colored by means of a few drops of the phenolphthalein solution, and 
multiplying the result by four. After the reagent has been subjected 
to the influence of the gas in the air sample, a similar determination is 
made. The difference between the two results, divided by two, indi- 
cates the number of cc. of carbonic acid present in the amount of air 
employed. 
The sample of air is obtained in the following manner : One of the 
bottles above mentioned is placed in the situation from which the air 
is to be obtained, and its air content is displaced by means of a bellows 
provided at its outlet with a rubber tube of sufficient length to reach 
nearly or quite to the bottom. A half minute's pumping is sufficient 
to insure that the original air is quite replaced by that under observa- 
tion. One is sometimes admonished to be careful not to breathe in 
the direction of the mouth of the bottle, but this is an unnecessary 
precaution, since the current issuing from the bottle is much too power- 
ful to admit of the entrance of any air except that propelled by the 
bellows. A much more and very necessary precaution to be ob- 
served is that the operator shall not allow his breath to reach the inlet 
holes of the bellows. After a half minute's pumping, the rubber cap 
is affixed, and the bottle may then be carried to the laboratory, or 
better, the treatment of the contained air may be proceeded with on 
the spot. 
Another method of collecting the sample is often recommended in 
place of the one described. It consists in filling the bottle with water DETERMINATION OF CARBONIC ACID. 
239 
and emptying it where the air is to be taken. By this process, the 
space originally occupied by water is filled with air, but the method is 
objectionable in that the water cannot drain away completely and that 
that which remains behind serves to dilute, slightly it .is true, the 
charge of barium hydrate next to be introduced, and thus brings in an 
error at the very outset. 
A hundred cc. of the barium hydrate solution are next introduced by 
drawing aside the edge of the rubber cap and inserting into the open- 
ing so made, the point of the filled pipette, and allowing its contents 
to flow unaided into the bottle. The beginner will often incline inad- 
vertently to gain time and assist the emptying of the pipette by 
blowing into it, thereby vitiating his results with the impurities of his 
own respiration. As soon as the pipette is emptied, it is withdrawn 
and the edge of the cap replaced. The bottle is then thoroughly 
shaken for about 10 minutes, care being observed not to wet the cap 
since in that event some of the reagent may escape by capillary attrac- 
tion. At the end of that time it may be assumed that all of the con- 
tained carbonic acid has been brought into contact with and absorbed 
by the barium hydrate, which is then to be poured quickly from the 
bottle through a good-sized funnel into a glass-stoppered bottle of 
rather more than 100 cc. capacity. 
The solution which is now more or less turbid from the presence of 
barium carbonate is allowed to stand until, through settling of this 
substance, the supernatant liquid is quite clear. Three successive por- 
tions of 25 cc. each are next to be withdrawn by means of a pipette of 
the proper size, and, after addition of the indicator, titrated in Erlen- 
meyer flasks with the standard oxalic acid solution until the pink color 
caused by the former is made to disappear. So long as any color 
remains, one knows that barium still exists in the form of hydrate and 
that the contents of the flask are still alkaline, for phenolphthalein 
gives a pink tinge only in the presence of the alkalies. When the 
pink color disappears, the process is finished and the reading of the 
burette is noted. The three portions of 25 cc. each are titrated in 
turn, and the mean of the results is multiplied by four. The differ- 
ence between this product and the figure obtained in the preliminary 
test of the strength of the reagent, divided by 2, indicates the number 
of cc. of carbonic acid in the volume of air taken for analysis. 
In filling the 25-cc.^pipette from the bottle containing the used 
reagent, great care must be observed not to stir up the sediment of 
barium carbonate. To perform the operation properly, it is necessary 
to insert the point of the pipette well below the surface and to fill it 
up to the mark, or just beyond it, by one uninterrupted act of suction. 
If one stops to regain breath, part of the liquid already within the 
pipette will escape downward during the interval with sufficient force 
to stir up the sediment. When the pipette is filled, the point of the 
tongue should be applied to its upper end, and the tip should then be 
withdrawn from the bottle. Then by placing the end of the forefinger 
over the opening of the tip of the pipette, the escape of its contents is 240 
AIR. 
prevented while the forefinger of the other hand is replacing the point 
of the tongue. 
The reason for such careful avoidance of stirring up the sediment is 
that the presence of barium carbonate introduces a slight error in the 
titration. The slight excess of oxalic acid present when the color of 
the phenolphthalein is discharged attacks the suspended barium car- 
bonate, forming barium oxalate and setting free the combined carbonic 
acid. Thus: 
H2C A + BaCO3 = BaC A + H2O + CO2. 
The free carbonic acid then attacks more of the carbonate and forms 
barium bicarbonate, which, being soluble and of alkaline reaction, causes 
the pink color to reappear. 
.OH 
CO2< 
J>Ba = BaH2(CO3)2. 
CO2< 
\OH 
The reason for adding barium chloride in making the barium hy- 
drate solution is that most barium hydrate contains, in addition to 
small amounts of carbonate, traces either of caustic soda or of caustic 
potash. When either of these substances is brought into contact with 
barium chloride, mutual decomposition occurs and we have as results 
barium hydrate and sodium (or potassium) chloride. If the impurity 
were disregarded, it would cause errors as shown below. The barium 
hydrate solution when titrated with oxalic acid would behave accord- 
ing to the following formula : 
BaO2H2 + BaCO3 + 2NaOH + 2H2C2O4 = BaC2O4 + BaCO3 + Na^A + 4H2O 
(Barium (Barium (Sodium (Oxalic (Barium (Sodium 
hydrate) carbonate) hydrate) acid) oxalate) oxalate) 
In practice a very slight excess of oxalic acid is also present, and 
the reaction then proceeds still further. The sodium oxalate attacks 
the barium carbonate, forming barium oxalate and sodium carbonate. 
Thus: 
Na^A 4- BaCO3 = BaCA + NajCQ,- 
Next, the sodium carbonate neutralizes the traces of the free oxalic 
acid, and any surplus causes a reappearance of the pink color and a 
consequent further addition of oxalic acid. This causes the formation 
of more sodium oxalate which in its turn attacks another portion of 
the barium carbonate with the same results as before; and so the cycle 
continues until the last trace of suspended carbonate is decomposed. 
If the hydrate contains no impurities, the addition of chloride is un- 
necessary. 
Corrections.-In figuring the results of the determination, certain 
corrections are necessary. First, the volume of the barium hydrate 
used (100 cc.) must be subtracted from the capacity of the bottle, 
since its introduction displaces an equal volume of air; and next, al- 
lowances must be made for any departure from standard temperature DETERMINATION OF CARBONIC ACID. 
241 
and barometric pressure, since the capacity of the sample bottle is 
reckoned for air at 0° C. and 760 mm. pressure. In order to make 
the necessary corrections for temperature and pressure, the thermom- 
eter and barometer must be noted at the time of taking the sample. 
In determining the amount of correction, we are guided by two 
physical laws : that for each degree of temperature, air expands a con- 
stant fraction of its own volume (Law of Charles), and that the volume 
of a gas is inversely proportionate to the pressure (Law of Boyle). 
For each degree centigrade above or below 0° C., air expands or con- 
tracts 0.0036648 of its volume; and this figure is known as the co- 
efficient of expansion for centigrade degrees. For each degree Fahren- 
heit above or below 32°, air expands or contracts 0.002036 of its 
volume; and this is known as the coefficient of expansion for Fahren- 
heit degrees. Thus, 1 liter of air, heated to 40° C., will expand to 
1 4- (40 x 0.0036648), which equals 1.146592 liters ; or heated to 
104° F. (104° F. = 40° C.), it will expand to 1 + (72 x 0.002036), 
which equals 1.146592 as before. Again, the same volume cooled to 
- 15° C., will contract to 1 - (15 x 0.0036648), or 945 cc.; or cooled 
to 5° F. (5° F. = 15° C.), it will become 1 - (27 x 0.002036) or 945 
cc. as before. 
So an apparent volume of 1,000 cc. at any temperature above freez- 
ing is in reality a smaller volume expanded to that size; and at any 
temperature below, is a larger volume brought to that size by con- 
traction. 
To correct volume for temperature, we must divide the apparent 
volume by 1 plus the product of .0036648 times the number of de- 
grees away from 0° C., or in case of temperatures below freezing, by 1 
minus that amount. If the Fahrenheit scale is used, the appropriate 
coefficient and factors must be substituted. 
Thus we may employ a set of formulae as follows: 
V' 
For temperatures above 0° C x + 0 oq36648 t° C 
V' 
For temperature, below 0» C V = ^0 0036648^ & 
V' 
For temperatures above 32° F V= 1 + 0002036 (to F._32) 
V' 
For temperatures below 32' F V = p _ 0.002036 (32 -4° F.) 
In the above, V = correct volume. 
V = apparent volume. 
Inasmuch as volume is inversely proportionate to pressure, the true 
volume at any observed pressure is obtained by multiplying the 
apparent volume by the barometric pressure expressed in millimeters 
or inches, and dividing the product by 760 or by 29.92 as the case 
may be. We may use, then, this formula: 
760 ' 242 
AIR. 
Applying it, we find that an apparent volume of 1,000 cc. at 750 
mm. becomes 
1,000 X 750 _ 
760 "yb7CC' 
or using the other scale, the barometer standing at 29.53 inches (29.53 
in., 750 mm.) it becomes 
1,000X29.53 uQ7 
"29.92- = 987 
If the barometer reads higher than the standard pressure, the true 
volume will be greater than the apparent. Thus, suppose the pres- 
sure to be 30.22 inches, then 1,000 cc. will represent 
1,000X 30.22 1 
29.92 = 1'O1(|CC- 
Instead of going through two separate calculations, we may make 
both corrections at once by means of one formula which is a combina- 
tion of the two kinds already used. For temperatures above 0° C. the 
correct volume is obtained by means of the following: 
F_ 
(1 + 0.0036648.i°) 760' 
By changing the plus sign to minus, the formula is adapted to tem- 
peratures below freezing. If the Fahrenheit thermometer is used and 
the barometric pressure is expressed in inches, the formula is as 
follows : 
-F= 
[1 + 0.002036 (<° F. - 32)] 29.92 
and if the temperature is below 32°, it must be changed to 
F_ 
[1-0.002036 (32 -1° F.)] 29.92' 
In these formulae : 
V = correct volume. 
V - apparent volume. 
B = barometric pressure. 
t° = temperature. 
In order to avoid the tedious process of multiplication and division 
which the working of these formulae involves recourse may be had to 
the admirable tables of Dr. Walter Hesse1 wherein can be found the 
correction to be made for all temperatures between - 2 and 30° C. 
and all pressures between 680 and 770 mm. by simple reference to 
the proper column. 
For all practical purposes, the coefficients of expansion may be 
shortened to 0.00366 and 0.002, thus avoiding much figuring which 
has but very little influence on the end results. 
1 Tabellen zur Reduction eines Gasvolumens auf 0° und 760 mm. Brunswick, 1879. DETERMINATION OF CARBONIC ACID. 
243 
Example of Method of Reckoning CO2.-Capacity of sample bottle, 
3,885 cc. 25 co. barium hydrate solution require 21 cc. standard 
solution of oxalic acid, hence 100 cc. = 84 cc. After contact, 25 cc. 
require 17.2 cc. ; 100 cc. require 68.8 cc. 
Difference in oxalic acid required = 84 - 68.8 = 15.2 cc. 
One cc. oxalic acid solution = 0.5 cc. CO2; hence, 15.2 cc. = 7.6 
cc. CO2. 
The air in the bottle contained, therefore, 7.6 cc. CO2. 
Determination of volume of air taken : 
Capacity of bottle = 3,885 
Amount of barium solution = 100 
Apparent volume of air = 3,785 
Observed barometric pressure = 29.60 inches. 
Observed temperature = 65° F. 
„ 3,785X 29.60 _ 112,036 112,036 
" [1 + (0.002036 X 33)] X 29.92 ~ 1.067188 X 29?92 ~ 31.93 ~ 
3,509 cc. = actual air volume examined. 
Then 3,509 cc. of air contain 7.6 cc. of CO2. It being customary to 
express results in parts per 10,000, this rate is determined as follows : 
3509 : 7.6 = 10,000 :x. x = 21.66. 
Hence the air contains 21.66 volumes of CO2 in 10,000. 
Determination of CO., by Wolpert's Method.-This process is designed 
for what may be called roughly approximate work in testing the air 
of school rooms and similarly crowded spaces. It requires no chemical 
training on the part of the operator, and for practical purposes gives 
fairly satisfactory results, indicating that the air is good, fair, poor, or 
very bad. The apparatus consists of a graduated glass cylinder with a 
movable piston reaching to the bottom and kept in proper position by 
a metallic cap, through the center of which the shaft protrudes. The 
shaft is a glass tube of narrow calibre, open at both ends. The reagent 
used is a standard solution of alkali, colored with phenolphthalein. 
In making a test, the piston is removed and 2 cc. of the solution are 
introduced by means of a pipette into the cylinder. The piston is then 
replaced and pressed down until all air is expelled through the shaft 
and the liquid appears within the bore. The piston is then drawn up 
until its lower edge is opposite the first mark, and in the process the 
space so made is filled with air which enters through the shaft. The 
apparatus is now shaken vigorously for one minute. If the liquid be- 
comes colorless, it is proof that the air of the room is bad. If on the 
other hand the color persists, the piston is raised to the next graduation, 
and the shaking is renewed for another minute. If the reagent still 
retains color, the piston is raised further and more air is admitted. 
The process is continued until repeated additions of air and renewed 
shakings cause the color to be discharged. At this point the reading 
of the scale indicates the character of the air. The greater the amount 244 
AIR. 
of air required for complete decolorization, the less the relative amount 
of impurity. The apparatus is shown in Fig. 13. 
Determination by Fitz's Method.-A modification of this process giv- 
ing results which are in close agreement with parallel analyses by 
the Pettenkofer method above described has been devised by Dr. G. 
W. Fitz.1 The apparatus is very simple and consists of a small cylin- 
der of glass with a rounded bottom, and a smaller open 
one which slips into the other through a collar of rubber 
tubing which makes a tight joint. As the inner cylinder 
is drawn out, air enters through its upper end, and its 
amount can be measured by the graduations on the outer 
tube, the lower margin of the inner tube serving as an 
index. (See Fig. 14.) 
The reagent used is a 1-per-cent, solution of lime 
water made in the following manner. About 95 cc. of 
water containing a few drops of phenolphthalein solution 
are neutralized by the addition, drop by drop, of lime 
water, which causes a pink color that at first disappears 
on shaking. As soon as a faint tinge persists, the com- 
plete neutralization of the carbonic acid of the water is 
evident. One cc. of saturated lime water is next added 
and the whole is then made up to 100 cc. 
The solution must be made as needed, 
since it retains its full strength but 
about 12 hours. In making a test, 10 
cc. are introduced into the outer cylin- 
der ; the inner one is inserted as far as 
it will go and then raised to the 10-cc. 
mark on the scale, which means the pres- 
ence of 20 cc. of air, since the tube itself 
contains 10 cc. The apparatus is then 
closed by applying the end of the fore- 
finger, and shaken vigorously 30 times. 
If the pink color persists, the inner 
cylinder is pushed to the bottom and 
then drawn up again, and the operation 
is repeated until the color disappears. 
At this point, the amount of air used is 
noted, and by reference to a table, the 
number of parts per 10,000 is ascer- 
tained.2 Dr. Fitz asserts that in the 
hands of an ordinarily careful man the 
process is accurate within one part of CO2 in 10,000. This is sub- 
stantiated by Professor L. P. Kinnicutt3 of the Worcester Polytechnic 
Fig. 13. 
Fig. 14. 
Wolpert's air 
tester. 
Fitz's air tester. 
1 Journal of the Massachusetts Association of Boards of Health, IX., p. 5. 
2 The apparatus and complete directions for use are obtainable of the Knott Appa- 
ratus Company, Boston. 
3 Loco citato, p. 8. DETERMINATION OF CARBON MONOXIDE. 
245 
Institute, who has employed the process himself and controlled its 
use by others with parallel analyses by the Pettenkofer method. 
Determination of Carbon Monoxide.-While a number of proc- 
esses have been devised for the detection and determination of carbon 
monoxide, none has been discovered as yet that is wholly satisfactory 
for other than qualitative work. The gas can be detected qualitatively 
by exposing water containing a small amount of fresh normal blood to 
the air under examination, and then examining the same with the 
spectroscope. If no carbon monoxide is present in the air, the char- 
acteristic absorption bands of oxyhaemoglobin, shown by the spectro- 
scope, are changed to a single band in the space between on the addi- 
tion of a reducing agent such as ammonium sulphide. If, however, 
the gas is present no change occurs. 
The test is applied in the following manner : A few drops of blood 
well diluted with water are exposed to the air in a jar and brought 
into intimate contact by vigorous shaking. A few drops of ammonium 
sulphide are next added, and the mixture is again well shaken. If on 
spectroscopic examination but a single band is observed, the absence 
of the gas in amount equal to three parts per 10,000 may be inferred, 
for this is the limit of delicacy claimed. If, however, the character- 
istic two bands of oxyhaemoglobin appear, the presence of the im- 
purity to that extent is proved, since otherwise the reagent would have 
exerted its normal effect. 
The following process, devised by Fodor,1 is said to be of sufficient 
delicacy to detect one part in 20,000. Fresh defibrinated blood is 
mixed with 10 volumes of water and introduced into a large jar con- 
taining the suspected air. After being allowed to stand for about an 
hour without shaking, it is transferred to a small flask provided with 
a rubber stopper carrying two glass tubes, one of which dips beneath 
the surface and connects at its outer end with a potash bulb con- 
taining palladium chloride solution. The other tube serves as an out- 
let, and is connected with a series of three potash bulbs containing 
respectively lead acetate solution, dilute sulphuric acid, and palladium 
chloride so diluted that it has a bright yellow color. The terminal 
bulb is connected with an aspirator, which, when set in action, draws 
a current of air through the five different pieces. 
The flask containing the blood is heated on a water-bath for fifteen 
to thirty minutes with occasional shaking, and meanwhile a slow cur- 
rent of air is drawn through the apparatus. When the blood begins 
to change color, the carboxyhaemoglobin decomposes and yields its CO, 
which reduces the palladium contained in the terminal bulb. The 
chloride of palladium in the first bulb is for the purpose of removing 
any traces of the gas and of other reducing agents in the aspirated 
air. At the close of the operation, if the blood contained CO, the 
palladium chloride in the terminal bulb shows a precipitate of reduced 
palladium and the liquid has a somewhat darker tint. The lead ace- 
tate and dilute sulphuric acid serve to remove any traces of sulphuretted 
1 Deutsche Vierteljahrsschrift fur offentliche Gesundheitspflege, Vol. 12. 246 
AIR. 
hydrogen and ammonia, both of which substances will cause precipita- 
tion of the palladium. 
Other qualitative tests of greater or less delicacy include the following: 
1. Mix 5 cc. of exposed blood solution and 15 cc. of a one-per-cent, 
solution of tannic acid. The resulting precipitate, which settles very 
slowly, has a brownish-red color, if CO was present in the air; other- 
wise it is grayish-brown. 
2. Mix 10 cc. of the blood solution with 5 cc. of a 20-per-cent. 
solution of potassium ferrocyanide and 1 cc. of acetic acid (1 part 
glacial acetic acid to 2 of wrater). A reddish-brown precipitate is in- 
dicative of the presence of the gas, and one of grayish-brown shows 
its absence. 
3. Bring together on a porcelain plate one drop each of exposed 
defibrinated blood and sodium hydrate solution of a specific gravity of 
1.300. With CO blood the color is bright-red, while with normal 
blood it is brownish or blackish. 
4. In place of the above reagent, use a mixture of one part of the 
same with three of calcium chloride solution. CO blood gives a car- 
mine, and normal blood a light-brown or brownish-red color. 
5. Draw air through a tube containing a solution of cuprous chlo- 
ride, which, in the presence of CO, deposits a characteristic precipitate, 
which, according to Berthelot, is Cu2C12CO.2H2O. 
Quantitative Determination.-Nicloux 1 has devised a colorimetric 
method for which he claims great accuracy. It is based upon the fact 
that by the action of the gas on iodic acid, definite amounts of iodine 
are set free. He combines this with an alkali, acidulates and shakes 
out with chloroform or carbon disulphide, and then compares the color 
with solutions containing known amounts of iodine. From the amount 
of iodine, the amount of CO which caused its liberation can be reckoned. 
Gautier2 allows the liberated iodine to act upon copper foil, and de- 
termines the amount of CO from the increase in weight. He also de- 
termines the CO2 produced by the action of iodine pentoxide on CO ; 
the result indicates volume for volume. Potain and Drouin 3 recom- 
mend a colorimetric method by means of dilute palladium chloride so- 
lution. 
Determination of Ozone.-The allotropic form of oxygen acts upon 
potassium iodide in the presence of moisture and converts it to hydrate, 
with liberation of iodine, according to the following formula: 
2KI + H2O + O3 = 2K0H + O2 + I2. 
This reaction is the basis of most of the processes which have been 
proposed for qualitative and quantitative determination, none of which 
can be regarded as of any great value, since there are many sources of 
error to be taken into account, sources impossible to eliminate and of 
importance impossible to compute. 
1 Comptes rendus, CXXVL, p. 746. 
2 Ibidem, CXXVL, pp. 871, 931, 973. 
'Ibidem, CXXVL, p. 938. DETERMINATION OF DUST. 
247 
The presence of ozone in the air is supposed to be demonstrated 
when on exposure of paper saturated with starch paste containing po- 
tassium iodide, a blue color gradually develops, owing to the action of 
the liberated iodine on the starch. Quantitative determinations are 
made by comparing the tint with a standard scale, the depth of color 
being dependent upon the amount of iodine liberated, and this upon 
the amount of ozone present. The papers are prepared in the follow- 
ing manner. From 2.50 to 10 grams of starch are taken, according 
to the recommendations followed, and after trituration with a small 
amount of cold water, are boiled for about 10 minutes in about 200 
cc. of water, and filtered. One gram of potassium iodide in solution is 
next added gradually with constant stirring. Strips of stout filter 
paper, wet with distilled water, are soaked in the starch preparation 
until they are thoroughly impregnated (about 2 to 4 hours), then re- 
moved with the aid of forceps, spread flat, and dried in the dark. 
When used, they are hung up out of the direct sunlight and exposed 
for a definite time, then removed, moistened with water and compared 
with the scale. 
The objections to the process are that a number of other substances 
which may be in the air, as certain volatile organic acids, chlorine ni- 
trous acid, and hydrogen peroxide, cause this same chemical reaction ; 
that the blue color is destroyed by other substances, as sulphuretted 
hydrogen and sulphurous acid, and that light, moisture, heat, and wind 
exert very decided modifying influences. Thus, wind brings more air 
into contact, sunlight bleaches the color, moisture hastens the bluing, 
and heat dissipates the free iodine. 
In order to differentiate between ozone and nitrous acid it has been 
proposed to use neutral litmus (violet) paper instead of ordinary filter 
paper in making the strips. The KOH formed in the reaction will 
change the violet to blue, while nitrous acid, chlorine and organic acids 
will convert it to red, or bleach it, or leave it unchanged. 
In spite of the fallacies mentioned, the weight of evidence thus far 
obtained in ozonimetry shows that the reaction with starch is most 
marked in pure air at the sea-shore and at great heights, and that but 
little is shown indoors. 
Determination of Dust.-Dust is determined quantitatively in two 
ways, and the results are expressed in terms of w'eight or of number. 
In order to ascertain the weight of the dust contained in a given vol- 
ume of air, a chloride of calcium tube, containing perfectly dry ab- 
sorbent cotton or glass wool, is accurately weighed, and then attached 
to a water suction pump with an air meter between. A large amount 
of air, say 500 liters, is then drawn through as quickly as possible. 
When a sufficient amount has passed, the tube is detached and placed 
either in a drying oven or in a desiccator over sulphuric acid, and kept 
until it ceases to lose weight (moisture). The net increase in weight 
represents the amount of dust in the volume of air aspirated. 
To determine the number of dust particles in a given volume, the 
method of Aitkin is employed. The apparatus includes a shallow 248 
AIR. 
metallic box with glass top and bottom etched in squares. Into this 
box, containing air which has been freed from dust by filtration through 
cotton and is kept saturated with moisture by means of wet filter 
paper, a small measured amount of the air under examination is in- 
troduced. By causing the formation of a partial vacuum, each par- 
ticle of dust becomes coated with condensed moisture and hence tends 
to fall upon the etched squares of the bottom. The number deposited 
is counted with the aid of a magnifying glass. The number of par- 
ticles varies, according to Aitkin's observations, from 8,000 to 100,000 
per cubic inch in the country, and from 1,000,000 to 50,000,000 in 
cities. 
Bacteriological Examination.-The method which involves the 
least trouble and requires a minimum of apparatus, and which for all 
practical purposes gives greatest satisfaction, consists in exposing 
gelatin plates or Petri dishes for a definite period of time, and then 
covering them and letting the colonies develop. After the proper in- 
terval, the number of growths may be counted and the individual 
species isolated and studied. This method is very useful for compara- 
tive work, the results being given as the number of colonies which de- 
velop after a given exposure. 
Formore accurate quantitative work, Petri1 devised a process of 
sand filtration. A glass tube, 9 by 1.6 cm., serves to carry two small 
filters which are arranged in the following manner. Two small 
tightly fitting diaphragms of fine wire gauze are inserted into the 
tube to a point midway between the ends. Into one side, a quantity 
of fine quartz sand is packed, and upon it, to keep it in place, another 
diaphragm is driven. Above this, the space is filled with a cotton 
plug. The tube is now reversed and a second filter of sand is made 
in the same way. After complete sterilization, the cotton plug in one 
end gives way to a rubber stopper with a single perforation, through 
which passes a glass tube connected with an aspirating pump. The 
other cotton plug is removed and the process of suction begun. When 
a sufficient amount has been drawn through, the two filters are removed, 
each by itself, and mixed with the nutrient gelatin from which plates 
are next to be made. The first filter should contain all of the organ- 
isms, the second serving as a control. 
Ficker suggested an improvement in the construction of the filters, 
substituting for sand, which, to a certain extent, masks the colonies, 
powdered glass which has not this disadvantage. A still better ma- 
terial is fine sugar, the use of which was first suggested by Sedgwick. 
The advantage of this is that it is dissolved in the liquefied gelatin and 
thus disappears from view and, therefore, neither masks the colonies 
nor can be mistaken for them in counting. 
Sedgwick's method of collecting organisms and obtaining cultures is 
one which, on the whole, is preferable to any other thus far suggested. 
His apparatus, known as the aerobioscope, is a glass tube about 14 
inches in length, shaped like a hydrometer and open at both ends. 
1 Zeitschrift fiir Hygiene, III., p. 1. BACTERIOLOGICAL EXAMINATION. 
249 
The narrow portion, which makes rather less than half the length of 
the tube, has an internal diameter of 0.2 inch ; the broader portion has 
an internal diameter of 1.8 inches and at its free end is constricted for 
an inch to about half its size. Into the outer end of the narrow por- 
tion, a diaphragm consisting of a roll of fine wire gauze is inserted to 
act as a plug for the sugar filter. The two open ends are stopped 
with cotton and the apparatus is then sterilized. The plug at the larger 
end is next removed and the sugar, sufficient in amount to fill the 
small tube above its contained diaphragm, is introduced. The plug is 
replaced and then the whole is sterilized at 120° for several hours. 
In use, the apparatus is held in a vertical position with the narrow 
portion down, the plugs are removed, and a measured volume of air is 
drawn through by means of an aspirating apparatus connected by a 
rubber tube to the lower end. When the desired amount of air has 
been aspirated, the sugar with the bacteria which it has arrested is 
brought, by proper manipulation, into the broad part into which, by 
means of a bent funnel, a sufficient amount of liquefied nutrient gelatin 
is introduced. The plug is replaced and the tube is then rolled and 
chilled on ice and set aside for the development of colonies. After the 
proper interval, the count is made in the usual manner. 
The methods above given have generally superseded that of Hesse, 
who was a pioneer in this branch of investigation. His apparatus con- 
sists of a glass tube, 28 inches long and about 1| wide, supported in a 
horizontal position upon a wooden tripod. One end is covered with 
two rubber caps, the inner of which has a single perforation; the other 
is closed with a rubber stopper with an outlet tube of glass plugged at 
each end with cotton and connected with a pair of aspirating flasks of 
a liter capacity. The tube is sterilized and charged with 50 cc. of 
gelatin, which is allowed to solidify before use. 
In conducting the operation, the outer cap is removed, thus exposing 
the inner perforated one, and a current of air is drawn slowly through 
by the action of the aspirating flask, which, filled with water, empties 
itself into the other. By reversing the flasks, any number of liters 
of air may be drawn through. In its passage, the air deposits its bac- 
teria on the gelatin. The process has many disadvantages and can 
make no great claim to accuracy. CHAPTER III. 
THE SOIL. 
Notwithstanding the constant and necessarily intimate relation of 
all life to the soil upon which we build our habitations, from which 
we derive in such great part our supply of drinking water, into which 
we cast vast quantities of organic filth, and to which we consign our 
dead, the subject of the sanitary importance of the soil has not until 
within comparatively recent years received the attention which it 
merits. That the soil exerts important influences on the public health 
was recognized long before the time of Hippocrates, and extensive 
researches on the subject figure among the earliest investigations of 
the modern hygienist, but by far the greatest part of the attention that 
has been paid to the study of the soil has been due to considerations 
of public wealth rather than of public health. With the gradual de- 
velopment, however, of a more accurate knowledge of the causes of 
disease has come an increasing interest in the relations of the soil to 
those causes, and what has hitherto been a rather neglected field of 
exploration now bids fair to be well and thoroughly tilled. 
That portion of the earth's crust in which we as hygienists are 
interested includes the superficial layer, known as tilth or arable soil, 
which is the result of disintegration of rocks and decay of animal 
and vegetable life, and the subsoil which lies directly beneath. The 
former varies from a few inches to several feet in depth; the latter 
extends few or many feet downward to the hardpan or other imper- 
meable stratum. 
Soil is a mixture of sand, clay, and other mineral substances, with 
humus, or organic matter, and living organisms, and it is classified ac- 
cording as one or another of its constituents predominates. The usual 
classification of soils includes sands, clays, loams, marls, humus, and 
peats. Sandy soils consist almost wholly, or at least above four-fifths, 
of pure sand of any kind. Clays are stiff soils consisting chiefly of 
silicate of aluminum and other very finely divided mineral matters. 
Clay exists in particles of the smallest possible size, is very cohesive, 
possesses a high degree of plasticity and plays a very important part 
in determining the fertility of soils, their texture and their capacity for 
holding water. Its plasticity is due to the presence of a small pro- 
portion of hydrated silicate, and is very greatly modified by the addi- 
tion of less than a hundredth part of caustic lime. It is exceedingly 
impermeable to water, and when wet dries with great slowness. 
Loams are mixtures of sand, clay and humus ; hence their properties 
partake of the characteristics of these substances according to the ex- THE SOIL. 
251 
tent to which each is present. When sand predominates they are 
designated as light, and when clay prevails they are known as heavy. 
These terms, however, have no reference to weight, but to the ease or 
difficulty with which they are worked in the processes of agriculture, 
and, indeed, those soils which are the lightest in this sense are the 
heaviest in actual weight. Since loams consist of varying proportions 
of the chief constituents, it is obvious that the word loam may have 
but little significance without some qualifying term, and they are, there- 
fore, divided into five classes, as follows : 
1. Heavy clay loam, containing 10-25 per cent, of sand. 
2. Clay loam, containing 25-40 " " 
3. Loam, containing 40-60 " " 
4. Sandy loam, containing 60-75 " " 
5. Light sandy loam, containing 75-90 " " 
Mixtures containing less than 10 or more than 90 per cent, of sand 
are classed respectively as clay or sand. 
Marls are mixtures of clay, sand, and amorphous calcium carbonate 
in various proportions, and contain, often, potash or phosphates from 
the fauna and flora of the sea. From their content of carbonate of 
calcium they are often known as lime soils, and according as one or 
another constituent predominates they are designated as clay marl, 
sand marl, and shell marl. All contain varying amounts of humus. 
Humus is a term used to designate the entire product of vegetable 
decomposition in the various intermediate stages of the process. It is 
the essential element of vegetable mould, and is necessarily of most 
complex composition, so complex, indeed, that it cannot be definitely de- 
termined. It is composed of a great number of closely related definite 
chemical compounds, chief among which are ulmin and ulmic acid, which 
are supposed to characterize brown humus; humin, and humic acid, 
which dominate dark, or black, humus ; and crenic and apocrenic acids. 
Its principal characteristic is its high percentage of nitrogen, especially 
marked in some of our prairie soils and in the " black soil " found in 
the provinces of the Ural Mountains, which, according to Von Hensen 1 
contains as much as from five to twelve per cent, of organic matter. 
Its complete decay is most rapid in warm well-drained soils permeable 
to air, and in such soils the amount of humus present at any one time 
will be relatively small, while in soils which are damp, not well venti- 
lated, and, for months at a time, frozen, its accumulation is favored. 
While its ultimate products of decay are of the greatest importance 
to vegetable growth, it does not follow that its complete absence ren- 
ders a soil necessarily sterile or even poor, provided that the necessary 
nitrogen is supplied in the form of nitrates. But its presence is neces- 
sary to the growth and life processes of the soil bacteria, without whose 
assistance many plants would fail to thrive. 
Peat, muck and humus soils contain large amounts of humus, but differ 
according to the conditions under which they are formed. Peat and 
muck result from the incomplete decay of vegetable matter under water ; 
1 Zeitschrift fiir wissenschaftliche Zoologie, XXVIIL, p. 360. 252 
THE SOIL. 
the former term applies to that which is compact and fibrous ; the latter 
is less compact, not fibrous, and, when dry, easily reduced to powder. 
They contain but a small amount of mineral matter. Humus soils are 
soils which contain large percentages of vegetable mold with ordinary 
soil constituents. 
The expression rocky soil applies to any kind of soil containing 
masses of rock. Gravelly soils are those which contain notable amounts 
of gravel, which consists of small fragments of rock more or less worn 
by the action of water, and larger and coarser than sand. Alkaline or 
salt soils are soils which contain considerable amounts of soluble salts, 
especially carbonate and sulphate of sodium and salts of calcium. 
Constituents of the Soil.-The chief constituent of the soil is silica, 
which, it is estimated, forms about two-thirds of the entire earth's crust. 
Next in abundance is aluminum, chiefly in the form of clay (silicate of 
aluminum). Lime and magnesia are large constituents, existing chiefly 
as carbonates in the form of limestone. Both are indispensable to the 
growth of plants and lime exerts a marked influence on the physical 
condition of the soil and upon the processes of nitrification. Although 
its principal combination is carbonate, it exists also largely as phos- 
phate and sulphate. 
Iron is universally present and is of very great importance to vege- 
tation, although but a small amount is needed. The red and yellow 
colors of soils are due to the presence of iron compounds. Manganese 
stands second to iron in abundance among the heavy metals, but is of 
much less importance. It is a constituent of many plants, notably of 
tea. Chlorine is not a large constituent; it occurs chiefly in combina- 
tion with sodium, potassium, and magnesium. Its total amount in 
ordinary unpolluted soil seldom exceeds one ten-thousandth part of the 
whole. Sulphur occurs as sulphides and sulphates, the latter usually 
in combination with lime. It is very necessary to vegetable growth, 
as it is an essential element of vegetable albumin. Phosphorus in the 
form of phosphates of lime, magnesia, iron and alumina, is another 
essential element, widely distributed in small amounts. Sodium and 
potassium are present, chiefly in the form of insoluble silicates and 
partly as chlorides. Their total in combination seldom exceeds four 
per cent. 
Nitrogen exists in soils in three distinct forms : proteids, ammonia 
and its salts, and nitric acid and nitrates. In average soils the total 
nitrogen is not large in amount, considerably less than one per cent., 
but in some exceptionally rich humus soils four, five, and even six per 
cent, are found. In the organic combinations (proteids) it is not avail- 
able as plant food, consequently these must be broken up into simpler 
forms in order to be of direct use. In their decomposition the second 
form, ammonia, is produced, but not all the ammonia of the soil is from 
this source, for some is brought into it from the air by rain. And in 
the second form, also, it appears to be not available as plant food, but 
even, according to Bouchardat and Cloez,1 seems to act as an energetic 
' Deutsche medicinische Wochenschrift, 1886. PHYSICAL PROPERTIES OF SOILS. 
253 
poison when absorbed by plant roots from solutions of a tenth to a 
hundredth of one per cent, strength. So it is probable that complete 
oxidation to the third form is necessary for the absorption of any form 
of nitrogen. As soon as the ammonia is oxidized in its turn to nitric 
acid, this latter combines with sodium, potassium or calcium, and the 
resulting nitrates are then ready for absorption. 
All of these changes from the complex proteid to the simple nitrate 
are carried along by different groups of micro-organisms, but no great 
accumulation of the end products occurs because, while vegetation is 
flourishing, they are removed as fast as formed, and when it has ceased, 
they are washed down into the subsoil by the rain and melting snow. 
The amount of organic matter in soils varies widely according to 
circumstances, but the amount necessary for vegetation is quite small, 
although certain crops, as tobacco and wheat, require much more than 
others, as oats and rye. The soils richest in organic matter are the 
peats and mucks; next come the very rich humus soils which may 
yield over a fourth of their weight. From ten to fifteen per cent, de- 
notes unusual richness, and about six per cent, may be regarded as a 
fair amount for a productive soil. 
Physical Properties of Soils. Pore-volume.-In all soils, no mat- 
ter how closely the individual particles are packed, there must exist a 
greater or less amount of interstitial space, which may be filled with 
water or air or both together. The sum total of these interstitial 
spaces is known as the porosity or pore-volume and is expressed in per- 
centage of the volume of the soil. Its amount depends not upon the 
size of the soil particles, but upon their uniformity or lack of uniform- 
ity of size and upon their arrangement. 
If we have, for instance, a very coarse soil, consisting of particles of 
uniform size as large as peas, and another of uniform particles, the size 
of small shot, we will find, on determining their pore-volume, that it 
Fig. 15. 
Fig. 16. 
is practically the same in each case and probably not far from a third 
of the whole. Packed in the most solid manner possible, which is that 
in which each sphere rests on three beneath it (arranged like the fa- 
miliar pyramid of marbles), helps support three in the layer above it, 
and comes in contact with others at six equi-distant points along its 
equator, as in Fig. 15, the volume of interstitial space will equal 25.95 
per cent, of the whole. Packed as loosely as possible, so that each 
rests upon but one, supports another and comes in contact with but 
four of its neighbors in the same layer as itself, as in Fig. 16, the vol- 254 
THE SOIL. 
ume of the interstices will be 47.64 per cent.1 Thus a soil composed 
of spherical grains of uniform size would have, regardless of the coarse- 
ness of the grains, a pore-volume of not less than 25.95 per cent. 
That the size of the individual grains makes no difference can be 
easily demonstrated in a practical manner. If we take two cylindrical 
glass vessels of the same size, fill them to the same height with water, 
and then add to the one a measure of large shot and to the other an 
equal measure of much finer shot, and secure as solid packing as pos- 
sible by gentle tapping, it will be found that the water in each cylin- 
der has risen to practically the same height; that is, that the actual 
volume of each is about the same. There will be, perhaps, some slight 
difference one way or the other, owing to the impossibility of securing 
absolute uniformity of packing, and to the error due to the inequality 
of the spaces along the circumference of the cylinders. 
But in nature we do not deal with perfect spheres or with soils made 
up of particles all of the same size, but with soils composed of angular 
pieces of varying size. The greater the variation in size of the parti- 
cles, the greater the possibility of variation from the limits of pore- 
volume as given above. With varying size, the small particles may 
fall into the spaces made by the larger ones, and the spaces between the 
new comers may be trespassed upon by still smaller grains, and so on 
until the interstitial space has been reduced to a minimum. 
To illustrate this diminution in a practical way, fill a large beaker 
with marbles, then pour into it, from a graduate, sufficient water to dis- 
place all of the air in the interstices, and note the amount of water re- 
quired, which is the pore-volume of the mass. Next, pour out the 
water as completely as possible and run on to the surface of the marbles 
a quantity of coarse sand or shot, and shake the vessel gently in all di- 
rections so as to favor their descent into the spaces below. When all 
have penetrated that can, pour in water again until it appears at the 
surface, and note the amount required; this is smaller than before, on 
account of diminished air spaces. Now pour off the water a second time, 
add still finer shot, and repeat the operation as before. So long as new 
matter can be added, so long will the pore-volume show a diminution. 
Irregularity of size and shape of the particles may also have an in- 
fluence in the other direction and cause the formation of large spaces 
and increased pore-volume. 
All soils, even the most compact rocks, have a certain amount of 
pore-volume, and some apparently compact masses, such as sandstone, 
have as much as 30 per cent. In soils which are cemented into homo- 
geneous masses, the pore-volume sinks to a minimum, but in ordinary 
soils it amounts to about 40 per cent. 
Permeability of Soils.-The permeability of a soil to air depends not, 
as it might appear, upon the amount of its pore-volume, but upon the 
size of the individual spaces. In fact, a soil of high pore-volume may 
be almost impermeable to air in comparison with one of less pore- 
volume, as will be shown ; and the pore-volume is of itself no measure 
1 Soyka, Der Boden, Leipzig, 1887. PERMEABILITY OF SOILS. 
255 
whatever of permeability, which diminishes in an extraordinary degree 
with diminution in the size of the soil particles. The greater the num- 
ber of the individual spaces, the greater the number of angles and the 
greater the friction of the entering air; and conversely, the less the 
number, and consequently the larger the size of the spaces, the less the 
number of angles and the less the obstruction. A series of experiments 
very carefully conducted by Renk1 with different kinds of soil in 
cylinders of equal height, through which air was forced under the same 
degree of pressure, yielded the following interesting results. 
Nature of soil. 
Diameter of grains. 
Pore- 
volume 
Pressure 
in mm. o 
water. 
Amount of 
air in 
1 iters per 
minute. 
Ratio. 
Fine sand 
less than J mm. 
55.5 
20 
.00133 
1 
Medium sand 
to 1 mm. 
55.5 
20 
.112 
84 
Coarse sand 
1 to 2 mm. 
37.9 
20 
1.280 
961 
Fine gravel 
2 to 4 mm. 
37.9 
20 
6.910 
5,195 
Medium gravel 
4 to 7 mm. 
37.9 
20 
15.540 
11,684 
Thus it is seen that a fine sand with a pore-volume of 55.5 per 
cent, permitted the passage of but one volume of air, while a gravel 
of medium coarseness with much lower porosity permitted the passage 
of 11,684 times as much in the same unit of time. 
Renk showed, further, that with soils of the finer textures, permea- 
bility to air is directly proportionate to pressure, but that this is not 
true of those of coarser grain. 
Nature of soil. 
Size of grain. 
Height 
of 
column. 
Units 
of 
pressure. 
Ratio of 
volume of air 
passed. 
Fine sand 
Less than J mm. 
J to 1 mm. 
1 to 2 mm. 
0.50 M. 
1 
1 
Medium sand 
0.50 M. 
1.5 
1 
1.5 
1 
Coarse sand 
2.00 M. 
0.50 M. 
2 
3 
1 
2 
3.6 
1 
2 
3 
1 
2 
3.6 
1 
Fine gravel 
2 to 4 mm. 
2.00 M. 
(NCOHNMr- 
1.91 
2.78 
1 
2 
2.9 
1 
1.67 
2.30 
1 
1.77 
2.42 
1 
1.65 
2.19 
Medium gravel 
4 to 7 mm. 
2.00 M. 
2.00 M. 
2 
4 
1 
2 
3 
1 
2 
3 
1 Zeitschrift fur Biologie, XV., p. 205. 256 
THE SOIL. 
The absence of any connection between pore-volume and permea- 
bility has been shown also by Von Welitschkowsky,1 from whose re- 
sults the following table has been constructed : 
Nature of soil. 
.Pore-volume 
Pressure 
in mm. 
of water. 
Amount of air 
in liters 
per minute. 
Ratio. 
Fine sand 
41.87 
50 
.0058 
1 
Medium sand 
40.64 
50 
.8990 
155 
Coarse sand 
37.38 
50 
7.399 
1,276 
Fine gravel 
35.47 
50 
33.6512 
5,802 
Since permeability diminishes with fineness of texture, it follows 
that clay and similar soils possess this property in the smallest degree, 
and that when these are mixed with sandy soils they must necessarily 
lessen it to a very marked extent. But clays and loams may occur in 
very open crumbly form, that is, in loose fragments of varying size, 
each consisting of myriads of small particles held together by the aid 
of moisture ; and such soils show a high permeability due to their 
large interstitial spaces. 
The degree of permeability to air is very greatly influenced by the 
amount of contained moisture, the maximum influence being exerted 
by decided wetness. This is due to the fact that the greater the 
amount of water present in the interstices, the greater the diminu- 
tion in the space available for the passage of air and the greater the 
obstruction to its movement. Thus the complete occlusion of the in- 
terstices by water is equivalent to absolute impermeability, except 
when the pressure of air is sufficient to displace the water and move 
it along. 
In the case of soils that are only partially wet, the diminution in 
permeability varies according as the moisture enters from above by 
rain or from below by capillary attraction from the water in the sub- 
soil. This is owing to the fact that when the soil is wetted from 
above by the rain, the superficial interstices are more or less completely 
occluded, and the air in those below is restrained in its movement; 
while when the moisture is derived by capillary attraction, the air is 
displaced upward, and the superficial interstices are more or less com- 
pletely open. The action of downward and upward moistening has 
been investigated by Renk3 whose results, in part, are given in the 
following table : 
1 Beitrag zur Kenntnis der Permeabilitat des Bodens fur Luft: Archiv fur Hygiene, 
II., p. 483. 
2 The height of the column of material in this experiment was three-fourths of a 
meter instead of a half as in the case of the other three. With an equal height the 
result would have been much larger. 
3 Loco citato. PERMEABILITY OF SOILS. 
257 
Nature of soil. 
Pore- 
volume 
Moisture. 
Pressure. 
Ratio of air 
passed. 
Medium gravel 
37.9 
absent 
20 
15.54 
14.63 
from above 
20 
from below 
20 
13.70 
Fine gravel 
37.9 
absent 
40 
14.04 
13.16 
from above 
40 
from below 
40 
12.55 
Coarse sand 
37.9 
absent 
40 
2.33 
1.91 
from above 
40 
from below 
40 
1.71 
Medium sand 
41.5 
absent 
150 
0.57 
0.11 
from above 
150 
from below 
150 
0.00 
55.5 
absent 
150 
0.04 
from above 
150 
0.03 
from below 
150 
0.00 
Fine sand 
55.5 
absent 
150 
0.01 
0.00 
from above 
150 
from below 
150 
0.00 
Permeability is also lessened by freezing temperatures by reason of 
the fact that the contained moisture expands one-tenth of its volume 
as it freezes and so occupies that much more space in the interstices. 
Moreover, when frozen, the moisture is in a fixed rather than a mov- 
able condition, and causes the production of a compact mass more or 
less resembling stone. The finer the grain, the more solid the prod- 
uct, and the greater the diminution of permeability. Renk1 deter- 
mined the diminution in the permeability of soils of different grain 
size due to freezing, as follows : 
Nature of soil. 
Source 
of moisture. 
Permeability. 
Diminution. 
Moist. 
Frozen. 
Medium gravel 
from above 
14.63 
13.87 
5 2°Z 
u u 
" below 
13.70 
12.20 
10.9 
Fine gravel 
4 ' above 
13.16 
12.54 
5.4 
b " " 
'1 below 
12.55 
10.18 
19 0 
Coarse sand 
4 4 above 
1.91 
1.64 
14.1 
cc u 
11 below 
1.71 
1.27 
25 7 
Medium sand 
" above 
0.11 
0.07 
36.4 
U Ci 
44 below 
0.00 
0.00 
cc cc 
4 4 above 
0.23 
0.00 
100. 
cc cc 
" below 
0.00 
0.00 
The degree of permeability of soil to water is, like that of permea- 
bility to air, governed by the texture rather than by pore-volume as 
is shown by the following results obtained by von Welitschkowsky2 
who determined the rates at which water would pass through columns 
of soil of differing fineness packed in cylinders of equal diameter. 
Each specimen was first completely saturated and then kept so during 
each experiment, the water supplied being kept at constant level. 
1 Beitrag zur Kenntnis der Parmeabilitat des Bodens fur Luft: Archiv fur Hygiene, 
IL, p. 483. 
2 Experimentelle Untersuchung uber die Permeabilitat des Bodens fur Wasser, 
Archiv fur Hygiene, II., p. 499. 258 
THE SOIL. 
Height of column of soil. 
25 cm. 
50 cm. 
Height of water column above soil surface. 
20 cm. 
50 cm. 
20 cm. | 
50 cm. 
Nature of soil and size of grain. 
Amount of water discharged in liters per min. 
Fine sand, less than J mm 
Medium sand, J to 1 mm 
Coarse sand, 1 to 2 mm 
Fine gravel, 2 to 4 mm 
Medium gravel, 4 to 7 mm 
0.00024 
0.175 
1.767 
8.570 
14.909 
0.00059 
0.435 
4.014 
16.190 
0.00014 
0.123 
1.351 
7.465 
12.872 
0.00028 
0.237 
2.422 
11.705 
Comparing these results with those obtained by the same investi- 
gator in his experiments on permeability to air, it will be noticed that 
the total pore-volume has here even less significance. 
Nature of soil. 
Height. 
Pressure. 
Pore- 
volume 
Ratio of permeability. 
To air. 
To water. 
Fine sand 
50 cm. 
50 cm. 
41.87 
1 
1 
Medium sand 
50 cm. 
50 cm. 
40.64 
155 
846 
Coarse sand 
50 cm. 
50 cm. 
37.38 
1276 
8650 
If to a volume of any soil packed into a cylinder of glass or metal 
we add water in such a way that all of the air in the interstices is dis- 
placed, the soil is then saturated and the amount of the contained 
water represents the total 11 water capacity " which, it is seen, equals 
the pore-volume. The " water-retaining capacity " is quite another 
thing, and depends upon the structure and composition of the soil, 
and, in a minor degree, upon other considerations. If for the imper- 
vious bottom we substitute one of wire gauze or coarse cloth, the con- 
tained water will begin to drain away, owing to the force of gravity, 
and the flow will by degrees become less and less, and finally cease 
altogether. Then the interstices, which originally were filled with 
air alone and next with water, are filled in part with the one and in 
part with the other. 
By comparing the original weight of the volume of soil with its 
weight in its now wet condition, its power to retain water is easily de- 
termined. This power is the result of two forces acting in opposition 
to the force of gravity; namely, surface attraction of solids for liquids, 
and capillary attraction. The water which is simply adherent to the 
surfaces of the soil grains is known as hygroscopic water, while that 
which is held in the capillary spaces is called capillary water ; and it is 
the latter which, in any but the coarsest soils, constitutes by far the 
larger part of the retained moisture. 
Not all of the interstices of a soil form capillary spaces, but only 
those of which the boundary walls are separated only by intervals 
which come within the limits of capillary magnitude. Thus, a coarse 
soil may contain comparatively few such spaces, while one of a fine 
texture may have its particles so closely approximated that all of its 
Capacity for Water, and Water-retaining Capacity. 259 
CAPACITY FOR WATER, AND WATER-RETAINING CAPACITY. 
interstitial spaces are capillary. It follows, therefore, that compact 
soils must possess greater retaining power than those with large inter- 
stices which permit rapid percolation, and that when the texture is so 
fine that all the spaces are capillary, the maximum retaining power is 
attained. 
The influence of soil texture on capacity for holding water may be 
seen in the following table of some of the results obtained by Hof- 
mann.1 
Diameter of grain 
in mm. 
Pore-volume per 
1,000 ec. 
Amount of con- 
tained water in cc. 
Amount of con- 
tained air in cc. 
Per cent, of pore- 
volume filled with 
water. 
5 
434 
55 
379 
12.7 
3 
418 
77 
341 
18.4 
2 
410 
98 
312 
23.9 
1 
400 
150 
250 
37.5 
0.5 
413 
270 
143 
65.4 
less than 0.5 
413 
347 
66 
84.0 
The water-retaining capacity of soils is very largely determined also 
by the amounts of organic matter present; a soil rich in organic matter 
will, other conditions being the same, show more water than another of 
less richness. The. extreme influence is observed in the case of humus, 
which can hold ten times its weight of water. In view of this influ- 
ence of organic matter, it is very clear that one way to help keep a 
soil dry is to avoid discharging filth into it and thus keep it clean. 
For the purpose of illustrating the influence of very fine soil par- 
ticles (clay) and of organic matter (humus), the following results of an 
investigation by Wolff2 may be quoted. He packed soils of varying 
clay and humus content into a metallic vessel with a permeable bot- 
tom, saturated them completely with water, then superimposed a col- 
umn of water of equal cross section and 8 cm. high, and observed the 
time required for the added water to be delivered below. 
Nature of soil. 
Percentage of clay. 
Percentage 
of 
humus. 
Time required. 
Per cent. 
Ratio. 
Hours. 
Ratio. 
Very fine sandy loam 
15.74 
1. 
0.88 
20.3 
1. 
Very fine sandy loam 
15.96 
1- + 
1.15 
1.40 
25.8 
1.27 
Black, rich, chalky loam 
18.17 
6.87 
31.0 
1.52 
Very fine sandy loam 
25.93 
1.64 
0.92 
75.8 
3.73 
Very clayey soil 
42.56 
2.70 
0.66 
133.0 
6.55 
Soil with considerable clay 
29.76 
1.89 
2.19 
188.0 
9.26 
It will be observed that the soil which permitted the passage of the 
water in the shortest time was poorest in clay and almost so in humus, 
and that the one which required the longest time combined a consid- 
erable amount of clay, not the highest, with a high percentage of humus, 
also not the highest. The highest percentage of clay was associated 
1 Archiv fur Hygiene, L, p. 273. 
2 Anleitung zur chemischen Untersucliung landwirthschaftlich wich tiger Stoffe, 1875. 260 
THE SOIL. 
with the lowest amount of humus, and the highest of humus with a 
low content of clay; but these two soils (Nos. 5 and 3) were both less 
impermeable than that (No. 6) which contained less clay than the 
one and less humus than the other. 
It is to be noted, however, in the case of the soil with the highest 
proportion of clay and lowest of humus, that it contained 12.8 per cent, 
of chalk as against 2.28 per cent, in the most impermeable, and that this 
substance has, as has been already mentioned, a very great influence 
in diminishing the degree of plasticity of clays. 
Soil Temperature. 
The sources of heat in the soil are three in number; namely, the 
sun's rays, chemical changes, and the original heat of the earth's inter- 
ior. The principal source is the sun. The heat derived from chemical 
changes is not great, and, indeed, is not even worthy of consideration 
except in soils very rich in organic matter; and here the changes 
occur only in the presence of comparatively high temperature due 
to the action of the sun. The third source is constant and of much 
importance. 
The soil temperature is influenced by a number of conditions in- 
cluding exposure, atmospheric temperature, color, compactness, com- 
position and moisture. Naturally, the surfaces exposed to the greatest 
amount of sunshine get more heat than others. The nearer the angle 
of incidence of the sun's rays approaches a right angle, that is, the 
more perpendicularly the rays strike, the greater the amount of heat 
received. 
The rapidity with which soils are affected in either direction by 
changes in atmospheric temperature varies quite widely, but with any 
soil it is only in the very uppermost layers, the very surface in fact, 
that any immediate corresponding rise or fall is observed. Great sud- 
den changes affect the soil below the surface very slowly, and in the 
deeper layers the maximum and minimum temperatures occur much 
later than in the atmosphere above. The annual variation diminishes 
as the distance from the surface increases ; at fifteen feet the amplitude 
is, as a rule, less than 10° F., and between fifty and eighty feet the 
temperature is constant the year round. 
The color of a soil exerts an important influence in the determina- 
tion of its temperature. As is well known, a black surface exposed to 
the sun absorbs the heat rays more than a white one. A common il- 
lustration of this fact is the greater rapidity with which snow melts 
when its surface is dotted over with dirt and soot than when it is clean 
and white, owing to the absorption of heat by the dark particles and 
its communication by conduction to the snow beneath and about. In 
the same way, soot and cinders work their way downward into the ice 
on a pond. Another illustration is the greater feeling of warmth con- 
ferred by black clothes than by white in the bright sunshine. 
So, other conditions being the same, a dark soil is warmer than a 261 
SOIL TEMPERATURE. 
light one which reflects the heat rays instead of absorbing them. Ob- 
servation has shown a difference of over 25° F. in the temperature of 
black and white sands exposed side by side to the direct rays of the 
sun, but the white sand by reason of reflecting the heat rays will ap- 
pear to be much hotter than it really is. 
The influence of compactness on soil temperature varies with the 
season. According to King,1 the general tendency of rolling the land 
is to make it warmer during bright sunny weather, but in cloudy or 
cold weather it tends to promote cooling. He has observed that at the 
depth of 1.5 inches below the surface, a rolled field may have a tem- 
perature 10° F. higher than a similar soil not rolled, and at double the 
distance he has noted a difference of 6.5°. This is due chiefly to the 
fact that a compact soil is a better conductor of heat than one contain- 
ing large interstices filled with air. 
The character of the mineral and organic constituents of the soil and 
the amount of its content of water exert the very greatest influence 
upon its temperature. Rocks, sands, and mineral substances in gen- 
eral are better heat conductors than water, organic matter and air, and 
they differ also one from another in conductivity. Organic matter is 
a particularly poor conductor of heat, and hence the greater the 
amount of humus a soil contains, the slower its response to the action 
of the sun. 
The great influence of moisture on soil temperature is due to the 
high specific heat of water and to the loss of heat which accompanies 
the process of evaporation. The specific heat of ordinary dry soils 
varies from a fifth to a fourth of that of water, though in exceptional 
cases it may amount to nearly a half; and the wetter the soil is, the 
higher will be the specific heat of the mass, that is, the greater the 
number of heat units necessary to warm a given weight one degree. 
Thus it happens that a light-colored dry soil may, in spite of the 
great influence of color, attain a much greater degree of warmth than a 
dark one which is damp. The different soil constituents have different 
specific heats, ranging from about 0.16 for certain sands and clays, to 
about 0.44 for dry humus, that of water being unity. Thus, to raise 
the temperature of 100 pounds of water one degree will require 100 
units of heat, while to perform the same office for equal weights^of dry 
sand, weathered porphyry, weathered granite, and humus will require 
respectively 16, 20, 30, and 44 units. Therefore, the same amount of 
heat necessary to raise a given weight of water one degree will raise 
the equivalent weights of these substances respectively 6.67, 5.00, 
3.33, and 2.27 degrees. 
But though the high specific heat of water is of importance in de- 
termining soil temperatures, the chief influence of moisture in this di- 
rection is due to the great loss of heat which accompanies the process 
of evaporation, for the change from the liquid to the gaseous form is 
accomplished only at the expense of heat. The greater the amount of 
water evaporated from a given soil, therefore, the greater the expendi- 
1The Soil, New York, 1898. 262 
THE SOIL. 
ture of heat and the greater the lowering of the soil temperature. 
Conversely, the drier the soil, the less the evaporation, and the greater 
its warmth. 
Water does not, however, always tend to produce lowering of the 
temperature, for, in point of fact, it may and does often have the oppo- 
site effect. In the spring, for instance, when the frost is not yet out 
of the ground and when the interstices are filled with cold water de- 
rived from the melting ice and snow, the warmer rain hastens the re- 
moval of frost, and, as it sinks into the soil, displaces downward the 
colder water and consequently raises the temperature. 
Changes in the Character of Soils Due to Chemical and 
Biological Agencies. 
Chemical action is constantly at work in the soil, not alone on the 
organic constituents, but upon the mineral matters as well. The 
changes which occur in the latter are of importance to the hygienist 
almost solely in so far as they affect the quality of the drinking water. 
Complicated processes involving the decomposition of organic matters 
give rise to quantities of carbon dioxide which, being taken into solu- 
tion by the water in the interstices, assists in the production of still 
more complicated processes which engage the mineral constituents. 
The changes which, from a public health point of view, are of the 
greatest interest are those which are in progress in the process known 
as the " self purification " of soils, in which the complex organic mat- 
ters are broken up and reduced to simple chemical substances through 
the intervention of bacterial life. In the end, the carbon is oxidized 
to CO2, and the nitrogen is either set free or combined with hydrogen 
in the form of ammonia, or oxidized to nitric acid and nitrates. 
The process requires the presence of atmospheric air and of moist- 
ure not in excess, and is favored by temperatures between 53 and 131° 
F., the most favorable being 98°. It proceeds most vigorously and 
perfectly nearest the surface, and virtually ceases at a depth of more 
than three feet, little or no action occurring in the subsoil beyond that 
depth. If too much organic filth and its attendant moisture are pres- 
ent, the soil becomes boggy and the changes cannot proceed. 
An influence of very great importance in its effects on the physical 
and chemical characteristics of soils is that exerted by earth worms, 
which live chiefly on half decayed leaves which they drag into their 
burrows to be used as food and as linings and plugs for the burrows 
as well. 
According to Charles Darwin,1 their castings contain 0.018 per 
cent, of ammonia, and the humus acids, which have been proved to 
play a very important part in the disintegration of various kinds of 
rocks, appear to be generated within their bodies. They swallow 
earth both in the process of excavating their burrows and for the nu- 
1 The Formation of Vegetable Mould through the Action of Worms. SOIL AIR. 
263 
triment which it may contain, and exert an important mechanical 
action on the soil grains, reducing their size by attrition within their 
gizzards. After filling themselves with earth, they soon come to the 
surface for the purpose of emptying themselves. 
" In many parts of England a weight of more than 10 tons of dry 
earth annually passes through the bodies of worms, and is brought to 
the surface on each acre of land, so that the whole superficial bed of 
vegetable mould passes through their bodies in the course of every few 
years." From various data, Darwin calculated that the castings, 
spread out uniformly, would form, in the course of ten years, a layer 
varying from 0.83, in the case of a very poor soil, to 2.2 inches in 
ordinarily rich soils. Their mechanical action and that of ants, moles, 
and other burrowing animals has much to do with keeping soils open 
and friable. 
Soil Air. 
The air in the interstices of the soil differs from that of the atmos- 
phere mainly in its richness in carbon dioxide, which arises from the 
decomposition of organic matters. It is also poorer in oxygen, but by 
no means always in a corresponding degree, and it is usually quite 
humid by reason of the presence of soil moisture. 
The amount of carbon dioxide varies very widely in different soils 
and at different depths of the same soil, and it fluctuates very consider- 
ably also under differing conditions at any given point in the same soil. 
Other conditions being the same, the amount is most marked in soils 
rich in organic matter undergoing decomposition changes. In soils 
poor in this respect, the amount may be no greater than in the atmos- 
phere. Pettenkofer, for instance, found in the air of desert sand, 
which was devoid of organic matter, the same amount as was present in 
the air immediately above it. 
In ordinary soils, the amount increases with the distance from the 
surface, as has been shown by Fodor,1 who made a great number of 
analyses of air at different depths at a number of places, the observa- 
tions extending over several years. The average amounts found at 
depths of 1, 2, 3, and 4 meters, expressed in parts per thousand, were 
as follows : 
Depth in meters. 
1 
2 
3 
4 
Station 1 
4.8 
6.6 
28.7 
Station 2 
13.7 
14.3 
20.1 
Station 3 
18.1 
28.4 
36.5 
The influence of season was also shown by him to be very consider- 
able, the highest amounts occurring during the hot months, and the 
lowest in winter. The averages by months are presented in the fol- 
lowing table : 
1 Boden und Wasser, Braunschweig, 1882. 264 
THE SOIL. 
Month. 
Depth in meters. 
1 
2 
4 
Januai'y 
6.5 
12.6 
25.0 
February 
6.8 
12.2 
24.8 
March 
7.0 
11.8 
24.7 
April 
9.9 
14.9 
25.2 
May 
11.5 
16.1 
27.2 
June 
14.5 
21.5 
29.2 
July 
15.8 
22.8 
35.9 
w • •• 
August 
12.8 
20.7 
32.6 
September 
10.9 
19.3 
31.4 
October 
9.8 
15.0 
29.4 
November 
8.4 
13.8 
26.5 
December 
8.1 
12.6 
25.8 
These results are only such as might be expected when we consider 
that decomposition of organic matters proceeds most vigorously within 
certain limits of high temperature. 
Fluctuations in the amount present at any given 
point are due to a number of conditions which in- 
clude rainfall, the action of the wind, the rise and 
fall of the subsoil water, and differences in atmos- 
pheric pressure and temperature. 
Rainfall, by filling the superficial interstices of 
the soil with water, interferes with the natural proc- 
ess of soil ventilation and causes an immediate ac- 
cumulation of carbon dioxide, which, however, is 
shortly followed by a diminution due to the ab- 
sorption of the gas by the water which thus acquires 
an increase in its power of attacking and dissolv- 
ing the mineral constituents of the soil. Inasmuch 
as the bulk of the absorbed rainfall is held by the 
upper strata of the soil, its influence is more marked 
there than at greater depths. As it sinks down- 
ward, however, in very wet weather, it drives the 
air before it and causes its escape at points where 
its egress is not obstructed. 
The action of the wind is exerted in two ways: by 
perflation and by aspiration. By blowing strongly 
across the surface of the soil, it aspirates the air in 
the upper layers and causes an upward movement in the air below, or 
it may suck it out at one moment and take its place the next. Again, 
it may blow with such force against the surface as to drive the con- 
tained air downward before it so that the interstices become filled 
with ordinary atmospheric air. The action is more marked with soils 
of ordinary coarseness of texture than in very open soils with large in- 
terstices which permit freer movement in the upper strata. 
This can be readily demonstrated by means of a simple experiment 
with the apparatus shown in Fig. 17. Here we have a glass cylinder 
inside which is a glass tube extending from the bottom and bent over 
Fig. 17. 
Apparatus to show action 
of wind on soil air. SOIL AIR. 
265 
at the top so as to form a U, into which an amount of water sufficient 
to form a seal may be introduced. If now we fill the intervening 
space up to the top with sand and then direct against the surface of 
the latter a current of air by means of a bellows or by blowing sharply 
through a tube of glass or other material, the whole volume of air in 
the interstices is set in motion, which is communicated to the air within 
the enclosed tube so that the water in the U-shaped depression is caused 
to oscillate. If the water completely fills the short leg of the U, it 
may be forced over and caused to drip. 
If, however, instead of employing sand, we fill the cylinder with 
coarse gravel, the oscillation of the water will be either less noticeable 
or entirely absent, the air which enters at one point on the surface 
communicating its motion to that immediately adjacent in the upper 
part. 
The rise and fall of the water in the subsoil assists in the production 
of variations in the amount of carbon dioxide; on the one hand, by its 
rise, forcing the rich soil air upward and outward, and on the other 
hand, by its fall, drawing it downward and causing its place in the 
upper strata to be filled with atmospheric air with low content of the 
gas. . 
Differences in temperature and barometric pressure have also been 
mentioned as exerting influence on the motion of the ground air. In 
spring and summer, the ground air is colder and denser, and in autumn 
and winter, it is warmer and lighter than the air above. Hence in the 
former, it tends to remain stationary or to sink, while in the latter, 
it rises and mingles with the atmosphere, which, under proper con- 
ditions, replaces it. Again, these changes may occur in both direc- 
tions within the same space in twenty-four hours. For instance, at 
evening and at night the atmospheric air, being colder, enters the soil, 
while by day, being warmer, its direction is reversed and air is drawn 
up from below. 
Movement due to temperature differences is almost constant, since it 
is only rarely that the temperatures of the air and soil are in agree- 
ment. The influence of barometric pressure changes is not very great; 
with fall in pressure, the tendency is toward upward movement, and 
with rise, toward downward movement; but Fodor found from the 
study of a large number of observations that the actual observable 
changes were insignificant. 
With the various influences at work causing movement of the soil air 
in all directions, it must be plain that the soil, especially if highly per- 
meable, is endowed with a sort of respiratory function which keeps it 
more or less well ventilated. 
It was formerly believed by Pettenkofer and others of the " Munich 
School " that the amount of carbon dioxide in soil air might serve as 
an index of the amount of impurity and of the rate at which the latter 
is decomposing, and that comparison of the amounts obtainable from 
different soils would serve to indicate their relative cleanliness. But 
such is not the case with soils equally permeable,.owing to the influence 266 
THE SOIL. 
exerted on soil ventilation by so many varying and conflicting causes. 
Indeed, it has been proved by Fodor that a permeable soil extensively 
contaminated by organic filth may yield less of this index of impurity 
than one far cleaner but less susceptible to ventilating influences. 
Soil Water. 
The moisture contained in the soil may be designated in three dif- 
ferent ways, according to its position and the forces by which it is 
held in place ; namely, hygroscopic, capillary, and gravitation. 
Hygroscopic water is that which adheres to the surfaces of the soil 
particles in the presence of air. A certain amount of moisture is con- 
densed upon the surface of most solid substances exposed to ordinary 
dampness, and it adheres with great tenacity. The amount of water 
so obtained differs, other conditions being the same, according to the 
nature of the soil, some soil constituents surpassing others in their 
power to attract it. 
Thus, soils rich in organic matter (humus) have a greater degree of 
hygroscopicity than others in which this constituent is present to a 
lesser extent. In some soils, the amount of hygroscopic water is very 
marked by reason of the large amount of organic matter and because 
also of the large surface area presented by the soil particles. Some 
idea of the tenacity with which this moisture is retained may be de- 
rived from the fact that air-dried soils which appear to be quite dry, 
even the dust of country roads for instance, may yield even as much 
as a tenth of their weight of water on complete drying by ordinary 
laboratory methods. 
Both the moisture absorbed from the air and the water held on the 
soil grains by surface attraction after a condition of decided wetness 
has been reduced by the draining away of the rest, may be termed hy- 
groscopic. The capillary moisture is that which is held within those 
spaces which have been already spoken of as capillary in their nature. 
Under ordinary conditions, these are intermingled with spaces which 
may not be so designated and which contain air, and so the capillary 
moisture does not ordinarily equal the pore-volume. The water in the 
capillary spaces may be that which is retained after thorough wetting 
from above, or it may have crept upward or laterally from points 
completely saturated. Capillary movement occurs in all directions, but 
it is most marked from below upward to points where water is being 
withdrawn by evaporation or by the demands of growing vegetation. 
The height to which water may rise by virtue of this force depends 
upon the diameter of the spaces; the smaller the diameter, the greater 
the rise. Jurin's law of capillary movement is that the height of 
ascent of one and the same liquid in a capillary tube is inversely as 
the diameter of the tube. Thus, water will ascend ten times as high 
in a tube having a diameter of 0.1 as it will in another with a diam- 
eter of 1.0. It follows, therefore, that capillary movement is most 
marked in soils of fine texture. SOIL WATER. 
267 
Capillary movement is materially influenced also by temperature 
and by the nature of substances held in solution. It diminishes as the 
temperature rises, and increases as the temperature falls, so that cool- 
ing a soil uniformly will cause increased capillary movement, and 
heating it will cause a fall. But with uneven temperatures, the mo- 
tion will be different according as the temperatures vary. Thus, if the 
lower part of a column of soil be cooled, the surface tension of its con- 
tained water will be increased at that point and water will be attracted 
from the parts above, gravity assisting; whereas, if it be heated, its 
contained water will be attracted upward. 
In saturated soils, motion of the water in any direction is very 
greatly influenced by temperature, because of the effect of heat in 
changing the viscosity of water. The higher the temperature, the 
greater the diminution in viscosity and the freer the movement. 
The influence of dissolved substances depends upon their nature, 
some favoring and others retarding movement. The rate is increased 
by the presence of nitrates, and is diminished by common salt and 
sulphate of calcium, but the favoring influence of the presence of 
nitrates is most markedly counteracted by organic substances produced 
in the decomposition of matters of vegetable origin, for a minute trace 
of these completely neutralizes the effect of such amounts of the for- 
mer as are commonly present in cultivated soil. 
It goes without saying that anything tending to the diminution of 
capillarity of a soil diminishes the rate of capillary flow. When the 
soil is worked in such a way, therefore, as to produce an open 
crumbly condition in place of one of compactness, the rate of capillary 
movement within it is very greatly diminished. 
We come now to the third division, which has been designated as 
gravitation water. This is the water which has drained away through 
the soil by the force of gravity and accumulated in the subsoil over an 
impermeable stratum which has arrested its further downward journey. 
This is what is commonly known as ground-water, or subsoil water. 
Its zone extends from the surface of the impermeable barrier upwards 
to that point where the interstices of the soil cease to be completely 
filled with water, but are filled partly with air. 
This point is known as the ground-water level. The zone above it, 
through which water is moved in the capillary spaces, is known as that 
of capillary soil water, and extends as far as the water is moved 
through that force. Above this, at and near the surface, is the zone 
of evaporation, from which water is evaporated into the atmosphere. 
The impermeable stratum beneath the subsoil water may be either 
very fine sand, compact clay, or rock. It may be thin or thick, ac- 
cording to circumstances. Below it, there may be a succession of alter- 
nating permeable and impermeable strata, so that in driving deep wells 
a variety of strata are pierced, and waters of varying composition may 
be secured. Dense clay is practically impermeable to water, but at 
the same time it can communicate its moisture to surfaces with which 
it comes in immediate contact, a fact which renders necessary the in- 268 
THE SOIL. 
terposition of damp-proof material in the foundations of houses built 
upon it. 
Rocks vary greatly in impermeability ; the densest of them con- 
tain very small amounts of moisture in their pores, while others are 
so porous that they may contain as much as a third of their volume 
of water. Again, most rock deposits are more or less fissured and 
seamed and thus permit to a greater or less degree the passage of 
water at these points. 
The water-bearing stratum is usually gravel or sand, but may be 
porous or fissured rock. Its depth is exceedingly variable, depending 
upon local geological conditions, and at two points not widely sepa- 
rated, it may be respectively slight and considerable. 
The ground-water is in constant motion both laterally and verti- 
cally. Its lateral movement, whatever its rate, depends upon the con- 
figuration of the impermeable layer below and not upon that of the 
surface of the land. Generally speaking, the direction of the move- 
ment is toward the nearest large body of water, be this the sea, a 
lake, or a river; but it is not often possible to determine, except in a 
general way, from surface observations, whether at any given point the 
flow is in one direction or another. This is especially true when the 
water-bearing stratum is thin and underlaid by an impermeable 
stratum of very irregular conformation. 
The rate of movement is also exceedingly variable ; it may be fast, 
or slow, or hardly perceptible. In Munich, for instance, according to 
Pettenkofer, it amounts to about fifteen feet daily, while at Berlin, it 
is only very slight and at times is wanting. It is influenced by the 
configuration of the sub-surface, by the permeability of the subsoil, 
by the amount of the accession of moisture from rainfall and melting 
snow, by the obstacles interposed by the roots of trees and other 
plants, by others at its outfall, and by the withdrawal of moisture by 
the needs of vegetation and of communities of men. 
The rise and fall of the ground-water, that is, its vertical move- 
ment, depend chiefly upon the amount of rainfall, and, on the other 
hand, upon the rate of withdrawal by evaporation, vegetation, and 
water supply of communities, and upon the freedom of, or obstacles to, 
the outflow. 
The effect of rainfall is generally not immediately perceptible, for 
so much time intervenes between heavy falls and penetration that a 
falling of the ground-water level may continue to be observed for a 
long time after a period of great wetness. But when the level rises, it 
is a proof that additions have been received from above, though per- 
haps the accession has travelled through a long distance in the soil. 
When it falls, it is a sign that the upper strata have become dry through 
evaporation and that capillary attraction has carried moisture upwards 
to replace the loss. 
The rise and fall of the ground-water level can be determined by 
measuring from day to day the distance between the surface of the soil 
and the height of 'the water in a number of wells of a given locality. INFLUENCE OF VEGETATION ON SOIL MOISTURE. 
269 
This can readily be done by means of a tape-measure or chain to which 
is attached a rod bearing a number of shallow metallic cups which are 
allowed to reach below the surface. The distance between the point 
on the chain at the mouth of the well and the uppermost cup in which 
water is found indicates the position of the water-level with respect to 
the surface. 
By removing obstacles to the outfall of the underground river, as it is 
sometimes called, and by creating new outfalls by ditching more or less 
deeply, according to individual conditions, by sinking drainage wells, 
or by laying drain tile beneath the surface at such depths as may ap- 
pear to be advisable, the level of the ground-water may be consider- 
ably lowered and the soil thereby rendered correspondingly drier, and 
also, by reason of the influence of water on soil temperature, warmer. 
Sources of Soil-water.-The principal source of the soil-water, it is 
hardly necessary to say, is the rainfall, but by no means all of the 
water precipitated from the atmosphere during a storm penetrates to the 
subsoil. Light rains may be wholly lost by evaporation and heavier 
ones, especially during active vegetation, may penetrate but very 
slightly beneath the surface. In early spring and in autumn, the 
amount which percolates downward is naturally much larger in pro- 
portion. A by no means insignificant amount of moisture is that de- 
rived by absorption and condensation from a moist atmosphere. 
In periods of drought, this power of dry soil to absorb water from 
humid air is of the greatest value to vegetation. The amount ab- 
sorbed differs according to the nature and hygroscopicity of the soil 
elements. Thus, a soil rich in humus will attract more water than 
another composed wholly of sand. Condensation of water occurs when 
the surface is cold and in contact with moist air. This condensation 
may occur from above or from the rising moist soil air just below. 
A third source of moisture of no great importance is the breaking 
up of organic matter into its constituent elements, in which process the 
hydrogen is in great part ultimately released in combination with oxy- 
gen as water. Another and exceedingly important source of soil 
moisture, important not because of the amount, but because of the 
quality of the water, and because of its possible effect on the supply of 
drinking water and on public health, is the waste waters incident to 
human life, which in so great a proportion of communities are dis- 
charged directly into the soil, where, being out of sight, they are equally 
out of mind. 
Loss of Soil Moisture by Evaporation.-The amount of water 
which a soil loses by evaporation is influenced by a number of factors 
which include the water content of the soil, the height of the permeable 
layer, the composition and structure of the soil, and the character of 
its surface and, particularly, whether it is covered. In other words, 
the rapidity of the process is proportional to the combined area of sur- 
faces exposed, and to the facility for replacing the loss by withdrawals 
from below. 
Influence of Vegetation on Soil Moisture.-The amount of water 270 
THE SOIL. 
in soils is greatly influenced by growing vegetation, which requires a 
vast supply for the proper maintenance of its functions. It withdraws 
it by absorption by the roots, which extend downwards to surprising 
depths, the roots of wheat, for instance, attaining sometimes a length 
of eight feet and more. From the roots, the water passes into the cir- 
culation of the plant, assists in the various physiological processes, 
and then for the most part is given off from the leaves into the at- 
mosphere. 
It has been calculated by Pettenkofer that an oak evaporates more 
than eight times the rainfall, and that the Eucalyptus globulus is even 
more active. The difference between the rainfall's contribution and 
the amount exhaled represents the amount which has been withdrawn 
by the roots from the capillary spaces and from the water table itself. 
As the water in the capillaries is relinquished by them, more comes up 
from below to take its place. 
Thus it is that a plant or tree acts during the growing season as a 
constantly working su(?tion apparatus tending to dry the ground, and 
so may be explained, in part at least, the condition of wetness that is 
acquired by some lands after removal of trees. 
All growing crops withdraw enormous amounts of water, and after 
the growth becomes well advanced, it is the capillary water upon which 
dependence is placed, for the rainfall penetrates but a short distance 
into cultivated land and most of it is lost by evaporation. Were it 
not for the capillary water supply, no crops could be raised except 
under most extraordinary conditions of weather and by artificial irri- 
gation, since but a short period of drought would suffice to produce 
wilting. According to Stockbridge,1 " The quantity of water thus 
required and evaporated by different agricultural plants during the 
period of growth has been found to be as follows : 
1 acre of wheat exhales 409,832 lbs. of water. 
1 " " clover exhales 1,096,234 " " " 
1 " '' sunflowers exhales 12,585,994 " " " 
1 " " cabbage exhales 5,049,194 " " " 
1 " " grape vines exhales 730,733 " " " 
1 " " hops exhales 4,445,021 " " " " 
But the influence of vegetation on the water content of the soil is 
not limited simply to its withdrawal and evaporation into the atmos- 
phere, for it acts in the other direction to impede surface flow and sub- 
surface drainage. This is seen more particularly in the case of trees 
and forests. The forest cover keeps the soil granular and promotes 
downward percolation ; the tree roots, penetrating in all directions, 
present an effective obstacle to rapid lateral movement through the soil. 
Removal of forests and clearing away the surface of the forest 
litter promotes sudden and destructive freshets in the springtime and 
drought when, later in the year, the water is needed. The ill-effects 
of deforestation are particularly noticed in parts of Maine and in the 
Adirondacks, where streams that formerly ran full the year round are 
1 Kocks and Soils, New York, 1888. OTHER EFFECTS OF VEGETATION UPON THE SOIL. 
271 
raging torrents when the winter's snows are melting and insignificant 
brooks or wholly dry during the summer months. It has been stated 
by Major Raymond of the U. S. Engineers that in forest areas, four- 
fifths of the rainfall are saved, while in cleared land the same amount 
is lost by evaporation and surface flow. 
Other Effects of Vegetation Upon the Soil.-In addition to its 
influence on the movement of soil water and on its amount, vegeta- 
tion is an important factor in the determination of soil temperature 
and of the amount of mineral matter available for succeeding growths. 
The deeply penetrating roots bring up to the tissues of the growing 
plants a large amount of mineral matters from the subsoil. On the 
death and decay of the plant, these matters are returned to the soil at 
its surface where they are ready for reabsorption as plant food. 
The effect of vegetation on soil temperature is of much importance 
in both hot and cold climates. A barren soil or one from which veg- 
etation has been stripped absorbs the heat rays of the sun more rap- 
idly and becomes much hotter than one which is protected by growth 
of any kind. The air above the soil becomes hotter, too, because of 
greater heat radiation, and the difference in the surface temperature of 
bare ground and that covered by grass or other vegetation is further 
increased by the cooling effect of evaporation of moisture by the 
leaves. Herbage acts as a protection against too much heating in hot 
climates, and as a blanket to prevent loss of heat in cold ones. 
In summer, the areas covered by vegetation are cooler than those 
which are unprotected against the direct rays of the sun, and in winter, 
they are warmer because of the obstacle to heat loss. 
Trees obstruct the sun's rays and impede wind currents, and thus 
the soil is cooler and at the same time suffers less loss of moisture by 
evaporation. The obstruction of the wind currents deprives the soil 
air of one of the influences having to do with its movement, and thus 
interferes with the soil respiration. The obstacle opposed by trees to 
the motion of air is so great that in the interior of a piece of woods the 
air may be quite calm while a gale is blowing outside. 
In winter, the obstruction of the sun's rays aids in the conservation 
of the soil heat by protecting the accumulated snow from melting and 
thus keeps the surface protected by a blanket. 
In cold climates the influence of trees may be at the same time per- 
nicious and beneficial; that is to say, pernicious, in that the ground is 
colder and moister than it would be had the sun's rays free access, and 
beneficial, in that they afford protection against wind. The judicious 
removal of trees will often render a climate more equable. In hot 
climates, as in cold, trees should be removed only in case of necessity 
and after due consideration of the probable results. The hottest spots 
in hot countries are those deprived of the beneficial influences of vege- 
tation. 
It may not be out of place here to mention the supposed agency of 
woodland in protecting communities from " malarial exhalations " from 
swamp localities beyond. That the interposition of a belt of trees has 272 
THE SOIL. 
been followed in a number of instances by decided improvement in public 
health so far as malarial troubles are concerned, cannot well be denied, 
but the improvement is not owing to the fancied property of leaves to 
condense upon their surfaces the malarial poison, but to the fact that 
the winged bearers of this poison, blown along by the wind, are filtered 
out of the air by the leaves, or themselves seek the protection thus af- 
forded against further involuntary movement and attach themselves 
to the leeward side of leaves and trunks. 
Pollution of the Soil. 
The soil receives polluting matters of infinite variety and in widely 
differing amounts, but their nature and their amount are of less im- 
portance relatively than their point of entrance. Some of these pollu- 
tions are unavoidable, and these, indeed, are the ones concerning 
which we may give ourselves the least concern; others are avoidable, 
though not always, or even usually, without the incurring of expense. 
The unavoidable pollutions include the urine and droppings of 
animals, the carcasses of such as have died and have escaped the 
notice of other animals that act as scavengers, and the vegetable matters 
of every conceivable kind in the various stages of decay. Excepting 
under very unusual conditions, such, for instance, as may exist in 
time of war or flood or famine, when large numbers of horses, cattle, 
and other animals are killed or die, these, lying at or near the surface, 
are of comparative unimportance, since, exposed to natural processes of 
purification, they are resolved into simple innocuous substances, which 
are absorbed by plant life or washed downward into the soil. 
The avoidable pollutions are mainly those which man deposits 
beneath the surface, and these are first, and of lesser importance, the 
bodies of the dead, and second, of vast importance, the excreta and 
other organic filth that constitute sewage. The temporary storage of 
filth in water-tight receptacles built under ground can, of course, do 
no harm to the surrounding soil, but it is not into such that man usu- 
ally chooses to deposit his waste. Water-tight cesspools become grad- 
ually filled and then require to be emptied, while those with pervious 
bottoms permit the escape of the contents downward, require no 
thought or trouble and are, therefore, a source of contentment and of 
saving of expenditure. 
The filth thus introduced is, however, below the zone of bacterial 
activity of the beneficent kind, and becomes stored up in the subsoil or 
is gradually washed away by the ground-water, which is thereby made 
unfit for human consumption. Organic matters deposited in the upper 
strata of the soil are resolved into their constituent elements with 
greater or less rapidity according to local conditions of distance from 
the surface, temperature, degree of moisture, and permeability to air, 
the process advancing most rapidly in a well-ventilated, moderately 
dry soil near the surface, and most unfavorably in wet compact soils, 
far from the surface. 273 
POLLUTION OF THE SOIL. 
The influence of the physical condition of the soil is frequently ob- 
served in the exhumation of bodies for one cause or another after vary- 
ing periods of interment. Thus, in open soils, bodies may almost com- 
pletely disappear in the course of a few years, while in stiff wet clays 
they may be found even after twenty and more years to be putrid 
masses, still undergoing a most gradual process of disintegration. 
Indeed, it is stated that in excavating an ancient churchyard in 
London, the soil of which was a wet clay, bodies were removed that 
showed after two centuries of interment no materially different appear- 
ance from those of others which had been buried not over a score of 
years. Recently, Dr. A. Riedel1 had an opportunity to compare the 
results of decomposition proceeding in bodies buried for about the same 
period in soils that were respectively loose, well-drained and well-ven- 
tilated, and compact, wet and impermeable to air. 
In the first instance, the remains were fairly dry and quite inoffensive to 
the sense of smell; in the other, they were a slimy loathsome mass of rot- 
tenness which gave out such a horrible stench that the crowd of idlers that 
had gathered was quickly dissipated, while those whose duty compelled 
them to remain were made unpleasantly sick and could not rid them- 
selves of the smell which clung to them until several days had elapsed. 
In the decomposition of organic substances in the soil, no offensive 
emanations are noticed if a substantial layer of earth is interposed be- 
tween them and the atmosphere. Just as it has power to retain water 
in its interstices and on the surface of its constituent particles, so has 
the soil the faculty of absorbing gases and vapors, a property which 
cannot have escaped the notice of any person acquainted with the com- 
mon earth-closet. The soil acts in this respect like charcoal, and can 
take up not only odors, but coloring matters and other substances. 
Perhaps the most striking illustration of its affinity for odors is the 
fact that illuminating gas from leaking street mains has in some cases 
been known to be divested of its odorous constituents in its journey 
through the soil to such an extent that, being drawn into houses with 
the soil-air, its presence has escaped observation until the production of 
poisonous effects has drawn attention to the existence of an unusual 
condition of the air. 
The same retaining action is manifested in a less marked degree 
toward substances in solution 2 which are held back by surface attrac- 
tion, a fact which has been repeatedly noted by hygienists and agri- 
cultural chemists. This is more noticeable in soils of fine grain, since 
such present a far greater area of grain surface. Hofmann 3 filled two 
cylinders of equal size with sand of different degrees of fineness, but 
with the same total pore-volume, and to each was added from above an 
equal volume of the same solution of common salt, and then daily for 
ten days an equal volume of distilled water. 
iMunchener medicinische Wochenschrift, June 6, 1899. 
2 See page 275 for an unusually striking example. 
3Ueber das Eindringen von Verunreinigungen in Boden und Grundwasser. Archiv 
fur Hygiene, IL, p. 145. 274 
THE SOIL. 
The drainage of each day was tested as to its content of salt, and it 
was found that whereas that from the coarser sand yielded salt on the 
second day and gave the highest results on the third, from which time 
the yield progressively dwindled, that from the finer showed no trace 
until the sixth day and its maximum on the seventh. Repetition of 
the experiment in the same way in all particulars yielded identical re- 
sults. Thus it is shown that pollution travels more quickly in coarse 
soils than in fine. In the former, it is shown quickly, and in the latter, 
only after more or less delay. 
In the decomposition of proteid substances in the soil, basic sub- 
stances are believed by some to be formed, which may be taken in some 
way into the system and so affect the resistance of the body to disease 
as to favor infection. This, however, is purely hypothetical. 
As has been already remarked, for the resolution of organic matters 
in the soil, the presence of bacteria is essential. This has been illus- 
trated in a striking manner by Duclaux,1 who treated sterile soil with 
sterile organic matters such as milk, sugar and starch paste, and then 
planted therein peas and beans. Though the resulting plants were well 
cared for, it appears that they would not thrive, but remained as thin 
and weak as though growing in distilled water. 
The organic matters in the soil were of no use to their growth, for 
they could not be absorbed as such, but only after decomposition. The 
addition of a little unsterilized earth was enough, however, to start the 
required process, and then the growth improved at once. 
Bacteria of the Soil. 
The bacteria of the soil are found almost wholly in the superficial 
layers, and below a depth of twelve feet their number is relatively few. 
As they need organic matter for their growth and multiplication, it 
may be inferred that the greater the amount present, the greater will be 
their number. Thus, they are far more numerous in rich garden soil 
than in ordinary sand and clays. 
The conditions most favorable to their development are, in addition 
to the presence of the organic pabulum, moisture and certain limits of 
temperature. Dryness and extremes of heat and cold are all unfavor- 
able ; saturation with water may or may not be, according to the va- 
riety, for there are some that in a wet rich soil can go on decomposing 
organic matters. 
In ordinarily rich soil, the number of bacteria ranges from hundred 
thousands to millions per cubic centimeter in the surface layers, below 
which they diminish in number very rapidly, until at ten to twelve 
feet below the surface, the soil is practically sterile, except for those 
that have been washed down or carried by burrowing animals, or, as 
above stated, deposited by man in organic filth. 
The soil bacteria are mainly of the beneficent varieties, the sapro- 
phytes which perform only useful offices, including the numerous va- 
1 Comptes rendus, C. SOIL AND DISEASE. 
275 
rieties of the nitrifying organisms. While a variety of pathogenic 
bacteria have been found in the soil, and though certain of them, the 
bacilli of tetanus and of malignant oedema, are very generally present, 
this class of organisms finds, as a rule, the conditions present in the soil 
unfavorable to development. 
In the first place, the temperature is too low, excepting in the very 
uppermost layers in warm weather, and, furthermore, they cannot 
thrive in the presence of the enormously numerous saprophytes which, 
in some manner as yet unsatisfactorily explained, bring about their de- 
struction. This action has been repeatedly demonstrated by Koch and 
others, who have shown that anthrax bacilli and other pathogens can 
be grown in sterilized soil, but not in soil unsterilized. 
It is believed that in the deeper layers away from the saprophytes 
the spores of pathogens may find a lodgment favorable to storage, but 
not to development, and that they may remain with dormant vitality. 
Many examinations of graveyard soils and of bits of coffins have 
been made by Dr. E. H. Wilson, of Brooklyn, to determine, if possible, 
the presence of pathogens as well as the number of bacteria as com- 
pared with those in other kinds of soils. He found no more bacteria 
than in others, and no pathogens at all. 
There is one kind of soil that has been found again and again to 
have a destructive action on pathogens, and that is peat, which kills 
them very quickly, probably through the contained organic acids. 
The soil acts as a very good filter and holds back most of the 
organisms, but by the aid of flowing ground-water or water entering 
from above, they may be carried through considerable distances. Thus, 
Drs. Abba, Orlandi and Rondelli,1 experimenting on the filtration ca- 
pacity of the soil about the filter galleries of the Turin water supply, 
found that cultures of Micrococcus prodigiosus, poured with large vol- 
umes of liquid into the ground at various points, made their appearance 
200 meters away in 42 hours, and 12 and 27.5 meters away in 7 hours. 
In these experiments the property of the soil for holding back sub- 
stances in solution was manifested in a remarkable degree, methyleosin 
and uranin, substances which impart intense red and green coloration 
to water, and which were added with the cultures, not appearing until 
long after the organisms had passed through. In the above instance 
in which they appeared in 42 hours, the coloring agents could not be 
detected until after 75 hours had elapsed. 
The relation of the soil to the various pathogenic bacteria will be 
discussed under separate headings further on. 
Soil and Disease. 
The influence of the soil on health and disease is very generally ad- 
mitted, but only little understood. We know that certain soil condi- 
tions favor the occurrence of certain diseases, but why this is so re- 
mains a great problem for future research to solve. 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXI., p. 66. 276 
THE SOIL. 
Our notions concerning the causal relation of the soil are probably 
greatly in error with respect to certain diseases, being doubtless 
greatly exaggerated as regards some, and equally undeveloped with 
others. Composition, permeability, temperature, moisture, evapora- 
tion, soil air, and fluctuations of the level of the subsoil water are all 
supposed to bear important relations to many of the diseases of man- 
kind and animal life in general. 
Such evidence as bears on the relation of the soil to diseases is given 
in general terms below. 
Soil Dampness and Disease in General.-It has long been univer- 
sally noticed that dampness in and near the surface of the soil injuri- 
ously affects the health of those dwelling nearby. It causes coldness 
of the soil and dampness in the atmosphere immediately above, and 
appears to conduce more particularly to rheumatism, neuralgias, and 
diseases of the respiratory tract. It has been noticed by many who 
have investigated the subject that the general health of those dwelling 
over damp soils is much inferior to that of those more favorably cir- 
cumstanced in that regard, and instances of improvement on removal 
from damp to dry localities are too commonly known to need any 
illustration. 
It is generally agreed that a soil in which the ground-water level is 
high, five to ten feet, for instance, from the surface, is not favorable to 
health, and that a deep level, fifteen feet and more, is unobjectionable 
on the score of dampness. This being admitted, it might reasonably 
be inferred that artificial lowering of the ground-water will be fol- 
lowed by increase in salubrity, and as a matter of fact that is precisely 
what does occur. But it must be stated in order to be historically 
accurate and in all fairness, that while increased healthfulness is a con- 
sequence, as a rule it is not the object sought, for as a general thing, 
soil drainage, especially on a large scale, has been carried out to meet 
the demands of successful agriculture rather than in consequence of 
solicitude for public health. 
The methods employed may be generally stated as increasing the 
outlet and removing obstructions to the outfall. Deepening and clear- 
ing the surface of waterways has often enormous effect. Ditching 
and the construction of underground channelways by means of drain- 
tile or rubble and fieldstones are the most common methods of drain- 
ing. Sometimes, drainage wells are driven at intervals down through 
the impermeable stratum into an open subsoil into which they then 
drain. 
The difficulties in the way of draining extensive areas of unhealthy 
and agriculturally unproductive land lie chiefly in the lack of indi- 
vidual cooperation. Such undertakings must necessarily be pushed 
in a systematic manner, and ought always to be under the direction of 
some central authority-municipal, state, or national. 
By means of under-drainage, thousands upon thousands of acres in 
various parts of this country, notably in Illinois and Indiana, and 
vast areas of land in England and on the continent have been con- TYPHOID FEVER. 
277 
verted from unhealthy, malarious and more or less unproductive tracts, 
into healthy and richly productive country. But the scheme is not 
always successful in relieving a locality of disease, especially of ma- 
laria, as has been proven in parts of Italy, Australia, and elsewhere. 
Soil and Pulmonary Tuberculosis.-There is an undoubted con- 
nection between this disease and soil dampness, which is most manifest 
when one investigates the prevalence of the disease over the same soil 
before and after soil drainage, by which it will always be found to be 
diminished. Why this is so we can only conjecture. 
We know that dampness is one of a possibly considerable number 
of factors in producing predisposition to the disease. We know that, 
other conditions being the same, the disease is far more common on low 
damp soils than on elevated dry ones. We know also that the dis- 
ease is comparatively rare in some parts of the earth where the soil is 
exceptionally dry. 
The distribution of the disease and its relation to soil dampness were 
first brought to public notice by Dr. Henry I. Bowditch,1 of Boston, 
at the annual meeting of the Massachusetts Medical Society, in 1862, 
who submitted two propositions, the results of most extensive investi- 
gation, which were in substance that dampness of the soil, whether in- 
herent or acquired by reason of proximity of bodies of water, is an ex- 
citing cause of consumption, which disease can be checked in its course 
or even prevented by proper attention to soil conditions. 
Shortly afterward, similar conclusions were promulgated in England 
by Dr. Buchanan, who had been making observations along the same 
line, not knowing that Dr. Bowditch was similarly engaged. These 
propositions were accepted by the profession and have been maintained 
ever since. 
Typhoid Fever.-It is quite generally believed that this disease is 
in some way connected with soil conditions as well as with drinking 
water. Indeed, there are some authorities who regard the soil as of 
infinitely greater importance in the causation of epidemics of this dis- 
ease and of cholera than the drinking water, which to their minds has 
absolutely no influence one way or another. The Pettenkofer theory 
of the cause of these outbreaks attributes it to the soil, from which the 
exciting cause is distributed by the ground-air, which, as has been 
stated, is in constant movement. 
According to the distinguished originator of the soil theory, the un- 
known poison is introduced into the soil, where, under proper condi- 
tions of organic filth and other influences, a species of fermentation 
occurs, the end product of which is the exciting cause, which is then 
capable of inducing the disease in those by whom it is inhaled. All 
important in this process is the vertical movement of the ground- 
water, and it is certainly true that over a long period of years of ob- 
servation at Munich, there was a most remarkable coincidence between 
epidemics of typhoid and fluctuations in the ground-water level. 
1 Topographical Distribution and Local Origin of Consumption in Massachusetts. 
Transactions, 1862. 278 
THE SOIL. 
The condition most favorable to high morbidity was demonstrated 
to be a rapid fall after an unusually high level. The highest death 
rates during the time covered occurred during the years of lowest 
level, and the lowest rates in the years of the highest level. The same 
coincidence has been noticed elsewhere, but by no means in all or even 
a majority of the localities where investigations have been made. 
The theory had, for a time, many adherents, and the controversy be- 
tween the soil-theorists and the " water-fanatics," as Pettenkofer called 
them, was carried on at times with exceeding bitterness. But within 
the past decade, the water theory has been so thoroughly proven as 
the chief, if not the sole cause of extensive outbreaks, that interest in 
the theory has fallen off, and its supporters are now few in number. 
Pettenkofer himself, however, is as uncompromising as in the very 
beginning, and in a recent paper 1 finds no difficulty in applying it to 
the great epidemic of cholera at Hamburg, in 1892. 
The contention that the extraordinary endemicity that prevailed so 
long at Munich was due to the filthiness of its subsoil, which was 
honeycombed with cesspools, cannot be lightly brushed aside, for it 
is a fact that with discontinuance of these abominations, and with a 
system of improved sewerage, the typhoid fever rate fell from its posi- 
tion as a leader down among the lowest known. Nor is this fall due, 
as has been claimed, to change in the water supply, for the great epi- 
demics had ceased and the fall had long continued before the water 
supply was changed at all. 
Experiment has shown that the typhoid organism can retain its 
vitality in the soil for considerable periods under favoring conditions 
of warmth and moisture. Robertson2 removed sods from several 
places in a field, and wet the exposed soil with diluted typhoid cul- 
tures, one at the surface, one at a depth of nine inches, and a third 
at eighteen inches. After 130 days, the bacilli on the surface had mul- 
tiplied, and where they had been placed eighteen inches below, they 
could also be found in the surface layer. Later on, in the winter, no 
results could be obtained, but in the spring, he moistened the patches 
with sterile bouillon in very dilute condition, and afterwards succeeded 
in obtaining growths. 
This is not in disagreement with the views of Germano,3 who found 
that they will live for months when incompletely dry ; but according to 
Fliigge, they do not survive complete drying longer than fifteen days. 
In air-dried condition they appear to have unimpaired vitality for some 
days, according to Brownlee,4 who dried and sterilized some ordinary 
soil and then infected it with a broth culture of typhoid and kept it at 
98° F. for a day. It was then left exposed to the air for a week, dur- 
ing which time it became dry enough to be easily scattered by the 
breath. Cultures from this gave positive results. 
1 Miinchener medicinische Wochenschrift, May 2, 1899. 
2 British Medical Journal, Jan. 8, 1898. 
3Zeitschrift fur Hygiene und Infectionskrankheiten, XXIV., p. 403. 
4 Public Health, Jan., 1899, p. 272. TYPHOID FEVER. 
279 
But it will be remembered that air-dried soil has quite an amount 
of hygroscopic water; consequently his bacilli were doubtless fairly 
well supplied with the necessary moisture. Of more importance, ap- 
parently, than the question of moisture-for all soils possess some-is 
the nature of the contained organic matter. Dr. Sidney Martin 1 has 
shown that unpolluted (virgin) soils are inimical to the typhoid bacil- 
lus, regardless of the amount of their contained organic matter of 
vegetable origin, while specimens containing polluting material of ani- 
mal origin favor its existence. 
Such, after sterilization, were planted successfully, and it was learned 
that in the presence of moisture, differences in temperature had but 
little influence. Thus, the organism thrived about equally well when 
specimens were kept at 98° F., at ordinary room temperature, and as 
low as 37° F. By no means the least interesting observation made 
was with regard to the duration of viability of the bacillus. In one of 
the sterilized polluted soils, the organism was still active at the expi- 
ration of 456 days ; and even then, after thorough drying and pulveri- 
zation, active growth could be obtained. 
The influence of other species of bacteria has not yet been thoroughly 
studied. Martin has thus far found that in company with various 
bacteria, among which the predominant species were members of the 
bacillus coli group, the typhoid organism could be recovered after fifty 
days' exposure of the specimen to temperatures ranging between 37° 
and 61° F. 
The effect of temperature changes due to the presence of animal ex- 
creta mixed with the soil is shown by Gaertner2 to be considerable. 
He introduced cultures of various organisms in wire baskets into the 
interior of compost heaps of various composition, which became heated 
to quite different extents, and observed that the bacilli of typhoid and 
cholera were the least resistant of all. With rapid and marked heat- 
ing, their life was short, but it appears probable that in the absence of 
heat, even with the given surroundings, they may be carried through 
the winter. Under the ordinary heating that occurred in the compost, 
these two organisms were destroyed in a week, while the bacillus 
of tuberculosis remained virulent a number of months. 
But aside from what we glean from scientific research with the spe- 
cific organisms, we know from experience that there are many places 
with polluted soils where typhoid fever was unknown until the impor- 
tation of a single case from without, and that afterwards sporadic cases, 
for which no convincing explanation is afforded, have occurred at vary- 
ing intervals. And in country districts whose inhabitants are not given 
to traveling much beyond the confines of their own farms, it is fre- 
quently noticed that single cases occur in the same household at inter- 
vals of a year or longer. 
In these cases, it seems hardly reasonable to say that the original 
case has left nothing as an exciting cause for later attacks, and that 
1 Report of Local Government Board for 1898, London, 1899. 
2 Zeitschrift fur Hygiene und Infectionskrankheiten, XXVIIL, p. 1. 280 
THE SOIL. 
fresh introductions of the specific organism must have occurred from 
some unknown source, for it is not unlikely that the variety of condi- 
tions that affect the viability of the organism may, in some cases, act 
to keep it alive, and, on occasions, stimulate it into a condition of 
augmented activity. 
Cholera.-Concerning the relation of this disease to the soil, there is 
but little to be said. Prior to the discovery of the specific organism, 
the soil theory of the origin of epidemic outbreaks had considerable 
vogue, but now it is known that even in times of greatest prevalence of 
the disease the organism has never been found under natural conditions 
in the soil. It can be kept alive under certain favorable conditions of 
moisture and heat for varying periods, but under natural conditions it 
is one of the least resistant bacteria and quickly dies. We have no 
evidence whatever that it is a soil disease. 
Bubonic Plague.-This has been regarded as a soil disease, and it 
has been believed from the fact that rats have been conspicuous as vic- 
tims of it in the early stages of its devastating outbreaks, that these 
animals have acquired the infection in the soil and have brought it up 
to the surface and thus acted as its carriers. But rats are notorious as 
frequenters of places where filth of all kinds can accumulate, and it is 
not strange that where they and filth abound, they become diseased, if 
the infective agent is present. 
The tremendous epidemics that have raged within the past few 
years have presented unusual opportunities for extensive study, which 
thus far has afforded no evidence whatever that the disease is soil- 
borne. It has been shown, on the contrary, that the plague bacillus does 
not long survive in the soil. Yokote,1 for instance, obtained a number 
of mice that had died of the disease, and buried them in garden soil which 
was kept well moistened. At short intervals, he removed them succes- 
sively and examined them culturally and by animal experimentation. 
The longest interval between interment and proof of continued viru- 
lence was thirty days, and it was shown that the higher the tempera- 
ture and the more rapid the decomposition, the shorter the life of the 
organism. The soil in the immediate vicinity of the animals proved 
to be free of the bacilli. 
Diphtheria.-Although there is no proof that the bacillus of diph- 
theria is found even as an occasional lodger in the soil, there is a gen- 
eral agreement that a close connection exists between soil dampness and 
the prevalence of this disease. It is true that experiment has demon- 
strated the viability of the organism in moist soils for limited periods, 
but it has never been found in soils outside of those in which it was 
intentionally deposited. The common belief is that a moist soil is an 
invariable concomitant of unusual prevalence, and that in times of com- 
parative freedom from the disease, the soil is dry and the level of the 
ground-water low. 11 As long as the soil is well washed by the win- 
ter's high tide and afterwards dried and aerated during the summer's low 
tide, all goes well: but so soon as these salutary movements are arrested 
1 Centralblatt fur Bakteriologie, Abtli. I., XXIII., p. 1030. DIPHTHERIA. 
281 
or their order disturbed, diphtheria prevails, reaching its acme of preva- 
lence when stagnation at a relatively high level is most complete." 1 
According to Dr. S. M. Copeman 2 there appears to be no direct 
relation between epidemics and rise or fall of the ground-water u pro- 
vided that the structure and atmosphere of the houses are not affected. 
Many districts, which, usually dry, are liable to occasional floods, are 
remarkably free from the disease, so that it appears that a persistent 
impregnation of the soil with moisture is of more importance than 
fluctuations in the height of the ground-water, particularly if these 
have any considerable range." 
Opposed to the views above expressed are the conclusions based on 
a most careful and extensive investigation by Dr. Arthur Newsholme 3 
of epidemics of diphtheria in all civilized countries and their incident 
conditions of rainfall and soil moisture. Dr. Newsholme's eminence 
as a skilful interpreter of the value of statistics and the fact that no 
such exhaustive inquiry into this question has ever before been made, 
entitle his conclusions to more than ordinary weight. 
Admitting that personal infection is the chief means by which diph- 
theria is spread from town to town and from country to country, he 
summarizes his observations on the relation between rainfall and 
ground-water and the rise of epidemic diphtheria as follows : 
1. An epidemic of diphtheria never originates, in the towns and 
countries in which I have been able to collect facts, when there has 
been a series of years in which each year's rainfall is above the aver- 
age amount. 
2. An epidemic of diphtheria never originates or continues in a wet 
year (i. e., a year in which the total annual rainfall is materially above 
the average amount), unless this wet year follows on two or more dry 
years immediately preceding it. 
3. The epidemics of diphtheria, for which accurate data are avail- 
able, have all originated in dry years (i. e., years in which the total 
annual rainfall is materially below the average amount). 
4. The greatest and most extensive epidemics of diphtheria have 
occurred when there have been four or five consecutive dry years, the 
epidemic sometimes starting near the beginning of this series, at other 
times not until near its end. 
5. Dry years imply low ground-water, and we find therefore in the 
years of epidemic diphtheria that the ground-water is exceptionally low. 
The exact variations in the ground-water which most favor epidemic 
diphtheria cannot, with the data to hand, as yet be stated; but it is 
probable that when this is cleared up it will become clear why in ex- 
ceptional years which have a deficient rainfall epidemic diphtheria is 
either absent or but slight. 
It has been often pointed out that local soil conditions causing 
dampness of habitations even in dry years, such dampness for instance 
as obtains in houses built over wet impervious clays, conduce to out- 
1 Notter and Firth, Treatise on Hygiene, 1896, p. 463. 
2Stevenson and Murphy, Treatise on Hygiene, 1892, Vol. I., p. 338. 
3 The Origin and Spread of Pandemic Diphtheria, London, 1898. 282 
THE SOIL. 
breaks of diphtheria in the dwellers therein, but, as is well known, such 
dampness acts as a very important depressant of the vital forces and 
prepares the mucous membranes of the respiratory tract for the favor- 
able reception of specific organisms of various kinds. 
Malaria.-It has ever been held that the most intimate relation 
exists between the soil and malaria, especially prominent in districts 
abounding in marsh lands. It has been repeatedly noticed that in 
malarious countries the upturning and excavation of wet or damp soil 
are commonly followed by the occurrence of the disease among the 
laborers so engaged. 
Infection appears to be especially common after sundown and at 
night, wherefore dwellers in places wrhere the disease is rife are en- 
joined to avoid going about after nightfall. This is explained by the 
assumption that the poison, resident in the soil, is brought up into the 
atmosphere by the soil air which rises toward evening by reason of 
changes in density. As to the influence of the rise and fall of the 
level of the ground-water, the evidence is very conflicting. 
Some authorities find that it plays a very important part, some find 
no connection whatever. Some of those who recognize the connection 
assert that the disease increases as the level rises, while others, notably 
Fodor,1 have found the relation to be exactly reversed. With such 
absolutely contradictory conclusions based on observations conducted 
mostly without system and for short periods, it would seem reasonable 
to regard the matter as an open question, with the chances in favor of 
the position taken by those who deny all connection between the dis- 
ease and movements of the water in the subsoil, except in so far as the 
movement is downward by reason of soil drainage, whereby the sur- 
face layers are rendered dry. 
With regard to the very common association of the disease with 
marshy localities, it must be said that malaria in its worst forms is by 
no means uncommon in districts that are not to be classed as wet, and, 
furthermore, that there are many and extensive marshes in this country 
and elsewhere, in and near which the disease is unknown. Sandy soils 
resting on wet clay, and rocky soils in which considerable volumes of 
water are held in fissures may be quite as malarious as the average marsh. 
The association of malaria with marshes and other wret soils, the 
fact that breaking into and excavating wTet soils has the disease as a 
common consequence, the danger of going about after sundown and 
especially of sleeping out of doors in malarious districts, and other ap- 
parent evidences of causal relation of the soil are all compatible with 
the old theory of transferrence by mosquitoes, which has lately engaged 
the attention of so many scientists. 
This theory was originally advanced by Linnaeus, and later, inde- 
pendently, by an acute and accurate observer of nature, Dr. John 
Crawford, who came to this country a little more than a century ago 
and settled in Baltimore, where, in 1807, he published an article in 
which the connection was suggested. After an interval of forty-one 
1 The Origin and Speed of Pandemic Diphtheria, London, 1898, p. 160. MALARIA. 
283 
years, it was again put forth by Dr. Josiah Nott,1 of Mobile, and within 
the past few years, the researches of MacCallum, Ross, Manson, Lav- 
eran, Smith, Grassi, Feletti, Bignami, Bastianelli, Mattei, and others 
have demonstrated its truth. 
It would appear that for the production of malaria the first essential 
is the primary parasite, and next, the conditions favorable to the breed- 
ing of the intermediate host, the mosquito, from which the then poten- 
tial agent is transferred to man. The mosquito breeds in stagnant 
water and in puddles; marshes abound in stagnant water, and heavy 
soils, newly upturned or excavated, abound in puddles. 
The female, already infested with the parasitic protozoa, lays here her 
eggs and, having fulfilled this duty, perishes. In a short time, her body 
is devoured by her progeny, who in turn become carriers of the para- 
site in their first flight, or beginning life, perhaps, free from the con- 
tamination, acquire it later, or not, according to circumstances. 
But if the soil have no direct causal relation, how can one explain 
the supposed influence of the soil air at night? Very simply. Ad- 
mitting that infection is most commonly caused at night or after sun- 
down, it may be added that it is at these times that mosquitoes are 
most active. But, again, malarial poison is said to be concentrated in 
the lower strata of the atmosphere, that is to say, not many feet from 
the ground. So, indeed, are mosquitoes. 
It has been stated that subsoil drainage has converted vast tracts of 
malarious country into salubrious farming land and sites for flourish- 
ing towns. Here the ground-water level has been drawn down ; how 
does this affect mosquitoes? By draining the subsoil we drain the 
surface, and by draining the surface we reduce the opportunities for 
mosquito breeding. Moreover, the soil is cleared up, settled and cul- 
tivated, and cultivation is incompatible with standing puddles. 
Believers in the soil-malaria theory point out that mosquitoes are 
much more widely distributed than malaria, and ask why the two are 
not in this respect in greater agreement. If it could be added that the 
original parasite is as widely distributed as the mosquito, and that all 
varieties of mosquitoes have exactly the same characteristics, or that 
there is but one species, the question would be a difficult one. But we 
cannot assert that the parasite is so widely disseminated, and we know 
that different kinds of mosquitoes have very different characteristics. 
We have in this country no less than thirty and probably many 
more species of mosquitoes, representing five genera. The most nu- 
merous species are those of Culex2 of which there are seventeen, but it 
happens that there is as yet but scanty evidence that any species of 
Culex carries malaria, and it is the belief of Ross 3 and others that the 
dangerous mosquitoes are confined to the few species of the genus 
Anopheles. While these are much less common than Culex, their dis- 
tribution is in very close agreement with that of malaria. 
JNew Orleans Medical and Surgical Journal, 1848, p. 563. 
2 The Principal Household Insects of the United States. U. S. Department of 
Agriculture, Division of Entomology. Bulletin No. 4. New Series. Washington, 
1896. 
3 British Medical Journal, July 1, 1899. 284 
THE SOIL. 
In Italy the attention of numerous investigators is drawn wholly to 
the Anopheles, the other genera being regarded as troublesome and 
annoying pests. 
Grassi,1 however, has announced his belief that in addition to the 
Anopheles two of the numerous species of Culex, C. penicillaris and C. 
malarice, are to be included among the carriers of the parasite. 
From the accumulating mass of evidence that the mosquito theory 
of transmission is correct the following instances may be cited. Ross 2 
reports that of 21 persons in a camp near Calcutta, 17 who slept 
without the protection of mosquito netting came down with malaria, 
while the others who slept under nets escaped. Grassi's experience is 
equally convincing though without a control. For eight consecutive 
days, accompanied by a family of seven, he left Rome each day at 5.30 
in the afternoon and went to a cottage in a notoriously malarious dis- 
trict between Rome and Civitavecchia where they passed the nights in 
a cottage the windows of which, covered with perforated zinc, were left 
open all the time. Not one of the party was in the least affected. 
The longer experiment of Sambon and Low in an equally malarious 
district is even more convincing. They spent several months, includ- 
ing the summer of 1900, with malaria raging all about them, but 
were themselves not affected. They took no drugs by way of pro- 
phylaxis, and went about freely by day, but kept indoors between sun- 
set and sunrise protected by nettings and screens. 
Fermi and Tonsini3 have reported a noteworthy instance of diminu- 
tion in the amount of malaria after systematic destruction of the larvae 
of mosquitoes. The Island of Asinara, inhabited solely by convicts 
and their guards, has been extensively afflicted with malaria. The 
larvae of different species of mosquitoes were found in many wells and 
horseponds and were treated with kerosene a number of times. Screens 
were placed in the windows and doors of the dormitories. The results 
were most satisfactory, only nine cases of malaria occurring'during the 
year against ninety-nine in the year preceding. 
The most convincing proof of the agency of mosquitoes may be 
said to be the occurrence of the disease in a non-malarious country 
through inoculation by mosquitoes imported from another where ma- 
laria abounds. Such an instance is reported by Manson,4 whose son, 
23 years of age, was bitten in London on three different days by in- 
fected mosquitoes brought from Italy. Within a few days of the 
third inoculation, the characteristic symptoms of tertian malarial fever 
appeared and the parasites were found in the blood. 
The assertion that in Java there are places where malaria abounds 
without mosquitoes has been investigated by Koch, who found that the 
mosquitoes were everywhere present where malaria prevailed. He 
found also a place in East Africa with all the conditions favorable to 
1Kapporti tra la malaria e peculiar! insetti (zanzaroni e zanzare palustri). Il Poli- 
clino, Oct. 1, 1898, p. 469. 
2 British Medical Journal, July 22, 1899. 
3 Zeitschrift fur Hygiene und Infectionskrankheiten, XXX., p. 534. 
4 British Medical Journal, Sept. 29, 1900. ANTHRAX. 
285 
malaria excepting mosquitoes but with no evidence of the disease. In 
many of the islands of Polynesia, where marshes are very extensive and 
all malarial conditions are present at their maximum with the excep- 
tion of mosquitoes, no malaria is known. 
Aside from the actual transferrence of the parasite by the mosquito 
in the process of stinging, we have no accurate knowledge of the mode 
of infection, but it is regarded as not impossible that the drinking of 
water contaminated by these insects and the inhalation of dust from 
spots where the puddles in which they have been reared have dried up 
may have a part in the dissemination. 
Tetanus and Malignant (Edema.-It is well known that the 
organisms of these two diseases are very commonly found in most 
garden soils, in road dust, and in soil in general which has been en- 
riched by the addition of decomposing organic matter. But in spite 
of the fact that opportunity for infection through abrasions, cuts and 
wounds of the hands, feet and other parts is a matter of daily occur- 
rence with a large proportion of the people, these diseases are compara- 
tively uncommon. They are most commonly noticed in cases of severe 
injuries, such as compound fractures, and in shattering wounds due to 
explosives. 
An unusual number of cases of tetanus occurred in various localities 
in this country following on the annual celebration of national inde- 
pendence in 1899. In New York City there were eleven deaths in a 
single day, and in Boston no less than six on the same date, all follow- 
ing injuries to the hand due to cannon crackers made, it is claimed, 
with nitro-glycerin or ammonium picrate as an explosive, combined 
with ordinary earth or sand as a vehicle. 
Anthrax.-The bacillus of anthrax has been found in the soil of 
pastures in which infected animals have been confined, and it was 
thought at one time that following the burying of animals dead with the 
disease, the soil could be thoroughly infected through spore formation, 
the spores being brought up to the surface by earthworms, there to be 
the cause of fresh infections. This view is now, however, regarded as 
untenable since the spores are not formed within the putrefying carcass, 
and the bacillus itself is soon destroyed in the process of decomposition 
of the tissues. Thus when a body is buried the organisms are soon ren- 
dered incapable of reproduction or of continuing their own existence. 
The theory that the spores are brought up to the surface by burrow- 
ing earthworms was demolished by Koch,1 whose conclusions were 
based upon direct experiment, and was abandoned by Pasteur himself, 
who first suggested it because of finding spores in the superficial layer 
of soil at a spot where, two years before, a cow, dead of the disease, 
had been buried at a depth of over two meters, a depth not ordinarily 
reached by earthworms in their burrowing. 
Therefore, it seems most likely that fresh outbreaks among cattle 
grazing on fields where others have died and have been buried are due 
not to the buried organisms, but to those which in one way or an- 
other, from the blood or dejecta of former cases, have been deposited 
1 Mittheilungen ans dem kaiserlichen Gesundheitsamte, 1881. 286 
THE SOIL. 
on the surface. We have no evidence whatever that man is even oc- 
casionally directly infected with the disease from the soil. 
Epidemic Diarrhoea.-The great prevalence of diarrhoeal diseases, 
especially among very young children, during the hotter months of the 
year has long engaged the attention of sanitarians as a tremendous fac- 
tor in the always high death rate of the first age periods, but beyond 
the observance of a few coincidences, no connection has been proved to 
exist between it and the soil. 
Some authorities have advanced the rather safe proposition that an 
unusual degree of organic pollution, not necessarily excremental, prob- 
ably makes a soil more favorable to high morbidity and mortality from 
diarrhoea, but this is a proposition that is offered with equal or greater 
security in the case of any infective disease the cause of which has not 
been accurately demonstrated, for the less we know of a cause, the 
greater the difficulty of refuting gratuitous theories concerning it. 
It has been noticed that the upward curve of the disease does not 
begin until the soil at a given depth has attained somewhere about a 
given temperature, and from this is inferred a causal relation. But 
one might go further and note that at this somewhat advanced stage 
of the warmer season certain fruits have just appeared in the market, 
or that the season for others has gone by, or that certain birds of the 
air have just hatched their first broods, and then with equal right dis- 
cover causality in any of these coincidences. 
In the investigation of milk supplies in single cases and in groups 
of cases in single households and institutions, various very virulent or- 
ganisms have been found, including the bacillus enteritidis sporogenes, 
and this organism has been much sought for in the soil. 
The results obtained by Houston 1 are thus far the most indicative 
of possible implication of the soil. He examined twenty-one samples 
of soil in various conditions as to organic matter and found that posi- 
tive results were very dependent upon the nature and extent of the 
organic pollution. Seven soils, six of which were virgin soils contain- 
ing from very little to moderate amounts of vegetable matter, and the 
seventh from an unmanured orchard, gave absolutely negative results. 
Three supposedly virgin but rich in vegetable matter, and four unma- 
nured orchard and garden soils gave very slight evidence of a positive 
character, and the balance consisting of one from an orchard, four from 
manured gardens, and two which had been extensively polluted with 
excremental matters, yielded the spores in abundance. 
It is not unlikely that the infective agent, whatever its origin, owes 
much of its dissemination to being blown about in the dust of the air, 
and on this point Dr. E. W. Hope 2 has made the interesting observa- 
tion that during a period of twenty years at Liverpool, the highest 
death-rate occurred in the year whose summer had the least rainfall, 
and the lowest in that in which the summer rain was greatest in 
amount; and that the fourteen years with average dry summers, in 
which the mean June to September rainfall was 10.9 inches, averaged 
•Report of Local Government Board for 1898. London, 1899. 
2 Public Health, July, 1899. 287 
OTHER DISEASES. 
about fifty per cent, more mortality during the quarter than the six 
average wet summers with a mean rainfall of 13.8 inches for the cor- 
responding period. 
The explanation offered is the very plausible one that heavy showers 
wash the atmosphere and the accumulations of dust and filth in the 
streets, on roofs and elsewhere, and thus diminish the dust supply. 
But until we have further evidence of connection, based upon actual 
investigation and not upon conjecture, we cannot make any positive as- 
sertion of the relation of the soil to the disease. 
Other Diseases.-The various theories connecting individual con- 
stituents of the soil with goitre have now been well-nigh universally 
abandoned, since no one of them has been found to hold good in dif- 
ferent localities having the same general soil characteristics. Thus, 
the magnesian limestone theory which in some quarters is still in favor, 
can hardly stand in the face of the fact that in some vast tracts of such 
formation, as in parts of New Zealand for instance, the disease is prac- 
tically unknown. Similarly the metallic sulphides escape conviction, 
for in districts where they abound extensively the disease may be absent, 
and in others where they are unknown it may prevail. 
Concerning yellow fever as a soil disease we can only say that the 
evidence of connection is purely circumstantial, and much resembles 
that advanced in support of the theory as to malaria. The same dis- 
astrous effects of excavating wet soils and especially those in which 
victims of epidemics long gone by have lain undisturbed for many 
years have often been reported in a very general way, but one may ex- 
pect great difficulty in attempting to locate with geographical accuracy 
the scene of many of the most interesting and striking of these reported 
happenings. While it may be possible that the soil may offer the 
cause-a residence within itself where vitality may be conserved and 
perhaps multiplication favored-we have as yet no evidence bearing on 
the question. 
When the exciting cause shall have been discovered and proved ab- 
solutely, we shall be in a better position to make positive statements 
concerning its habitat. 
Against the theory of causal relation between disturbance of the soil 
and outbreaks of yellow fever, many instances can be cited in which, 
under apparently favorable conditions, the occurrence of the one has 
not been followed by the other. Thus, in 1894, the streets of Jackson- 
ville, Fla., and of Brunswick, Ga., were dug up during the entire sum- 
mer ; in 1899, at Mobile, Ala., about 125 miles of aqueduct and sewers 
were laid during the summer; between 1890 and 1900 the streets of 
New Orleans, La., were extensively dug up in the course of public 
improvements, and in not one of these places did the public health ap- 
pear to suffer in consequence of the excavations. On the contrary, in 
New Orleans when it was visited in 1897 and 1898 by yellow fever, 
the parts of the city where the streets were dug up happened to be 
singularly free from the disease. 
As in the case of malaria, the soil theory is giving way to the theory 288 
THE SOIL. 
of transmission by mosquitoes. The agency of these pests in spread- 
ing yellow fever was suggested originally by Nott1 in 1848, and 
studied for the first time by Dr. Charles J. Finlay of Havana in 1881. 
Lately, the subject has been taken up by the Medical Department of 
the United States Army. Dr. Walter Reed, U.S.A.,2 has reported 
positive results from experiments conducted by himself and Drs. Car- 
roll, Agramonte, and Lazear with mosquitoes (Cl fasciatus} furnished 
by Dr. Finlay. Carroll was bitten by one that had bitten a severe 
case of yellow fever 12 days before, a mild case 6 days before, a severe 
case 4 days before, and a mild case 2 days before. Four days after- 
ward, he took to his bed, and on the following day it was demon- 
strated that he had the disease. Another person was bitten by the 
same mosquito and by three others that had bitten patients with the 
disease; in seven days he had the fever. One of the investigators 
(Dr. Lazear) was bitten without result by an infected mosquito on 
August 16th, and by another, a stranger, on September 13th. Five 
days later, he had a chill; on the following day, the diagnosis of yel- 
low fever was made. In one week from the onset, he died. 
In November, 1900, an experiment station was established at Co- 
lumbia Barracks, Cuba, under the direction of Dr. Reed,3 who reported 
on December 16th to the Surgeon-General that inoculations, made upon 
Spanish immigrants who volunteered in the hope of securing immunity, 
had been successful in 80 per cent, of the cases. 
With regard to the connection which may exist between the soil 
and dysentery, scarlet fever and other diseases, concerning the organ- 
isms of which we are in the dark, it is best to admit frankly that we do 
not know, rather than to make general statements based on imaginings. 
Our actual knowledge of the relation of the soil to disease amounts 
in brief to this : that surface dampness is favorable to the develop- 
ment of certain diseases, as rheumatism, neuralgias, and affections of 
the respiratory tract; that concerning some diseases there is a wealth 
of purely circumstantial evidence of connection opposed in each case 
to evidence to the contrary ; that the soil is the home of many species 
of organisms, some of which are pathogenic, and offers under certain 
favorable conditions an at least temporary asylum to others. But the 
preponderance of evidence thus far goes to show that under normal 
conditions the soil is more likely to prove hostile than hospitable to 
most of the infective agents with which we are well acquainted. 
Examination of Soils. 
The complete examination of a soil includes chemical, physical, and 
bacteriological determinations, but inasmuch as the chemical analysis, 
beyond the estimation of water and organic matter, is of no especial 
interest to the sanitarian, though of great importance to the agricul- 
tural chemist, we will, with the exceptions noted, coniine ourselves to 
the processes involved in the physical and bacteriological tests. 
'Public Health, July, 1899. 
2 Philadelphia Medical Journal, Oct. 27, 1900. 
3 Ibidem, Dec. 22, 1900. EXAMINATION OF SOILS. 
289 
In taking samples, a place should be selected which fairly represents 
the locality, and under some circumstances a number of specimens 
must be obtained. These may or may not be mixed together and 
treated as one. About two pounds of the soil may be broken up by 
being passed through a coarse sieve, then spread out and left for one 
or several days exposed to the air, and to that extent dried. To de- 
termine the relative proportion of the grains of different sizes, a weighed 
amount of the sample is now passed through a series of sieves of vary- 
ing coarseness, made of metal or porcelain with circular open spaces, 
which in each sieve are of uniform diameter. 
Those used by the German scientists have openings respectively 
1, 2, 4, and 7 mm. in diameter, by means of which a speci- 
Apparatus for separation of fine particles of soil. 
Knop's silt cylinder. 
men is separated into grains of less than J, from | to 1, from 1 to 2, 
from 2 to 4, from 4 to 7, and over 7 mm. in diameter. Other sized 
openings may be used, but these fulfil all requirements. The specimen 
is passed first through the coarsest of the set and then, in order, down 
to the finest. If the particles adhere firmly, the separation is best done 
with the assistance of water, and should it be necessary, a pestle covered 
at the working end with rubber may also be employed. The separate 
parts are then dried and weighed, and their respective amounts ex- 
pressed in percentages of the whole. 
The finest particles, that is, those of less than mm., may be still 
further separated by the process of washing in an elutriating apparatus, 
of which there are several kinds, none of which, however, give results 
that are more than approximately accurate, since so many different 290 
THE SOIL. 
forces and conditions come into play to influence the process. \v ith 
some, the separation is effected by causing the particles to settle down- 
ward through a volume of water, the heaviest ones reaching (theoret- 
ically, but not wholly in practice) the bottom first, and the lightest 
settling out last or remaining a long time in suspension. 
An apparatus of this sort is shown in Fig. 18, which requires no 
explanation. Another, known as Knop's silt cylinder, is shown in 
Fig. 19. This is a cylinder carrying lateral tubes fitted with stop- 
cocks, situated at equal distances (10 cm.) apart. The sample is 
placed in the cylinder which is then filled with water and well shaken. 
After a given time the upper stopcock is opened and the water above 
it drawn off. Then after the lapse of another interval, the second is 
opened, and next, in the same way, the third. 
The process is repeated until the wash water comes away clear, then 
the lowest tube is opened, and the rest of the water above the remain- 
ing material drawn off. The different portions may then be collected, 
dried, and weighed, and their relative proportions expressed as before 
in percentages. Or the residue may be dried and weighed and the 
balance estimated by difference. 
By another method, the washing is carried out by means of an up- 
ward flow of water in a conical vessel at the bottom of which the 
sample is placed. The water, delivered through a tube reaching to 
near the bottom of the vessel, carries the lighter finer particles upward 
and out through the exit tube near the top. Such an apparatus, known 
as Schultz's, is shown in Fig. 20. 
Pore-volume.-The pore-volume is de- 
termined very simply by adding to a volume 
of water in a graduated cylinder a known 
volume of soil in the dry state, and not- 
ing the height to which the water rises. 
If, for instance, to a liter jar containing 
water up to the 500-cc. mark, we add 
500 cc. of dried soil in as nearly as pos- 
sible its natural state of compactness, and 
observe that the level of the water is in con- 
sequence raised to the 850-cc. mark, it fol- 
lows that the increase, 350 cc., represents the 
actual bulk of the soil grains, and that the 
difference between this and the volume occu- 
pied originally by the sample (500 cc.), that 
is to say, 150 cc., represents the amount of 
interstitial space filled with air. Then as 
500 cc. of soil contains 150 cc. of air space, 
it follows that the pore-volume of the 
sample is x in the equation 500 : 150 
:: 100 : x, or 30 per cent. 
In order to approximate more closely the natural condition of com- 
pactness, the sample may be taken from the soil by means of a metallic 
Fig. 20. 
Schultz's elutriating apparatus. PERMEABILITY TO AIR. 
291 
cylinder with a cutting edge. It is then dried in order to expel the 
contained water, which otherwise would constitute a source of error, 
and is then added to the water in the liter jar as before. 
Permeability to Air.-Permeability to air may be determined by 
forcing measured volumes of air under constant pressure through a 
cylinder closely packed with the sample, and noting the amount which 
is delivered during any given unit of time. In making comparison 
Fig. 21. 
Apparatus for determination of permeability of soil to air. 
tests between different soils, the same conditions must be observed in 
every case; that is to say, the length of the column of soil in the cyl- 
inder, the pressure employed, and the unit of time. 
A still further condition which must be observed, but which is com- 
monly disregarded, is the temperature of the air, for as is the case with 
liquids, the viscosity of gases varies with changes in temperature, 
though not in the same direction. The viscosity of liquids is in- 292 
THE SOIL. 
creased with diminished temperature, whereas in the case of gases the 
reverse is true. Disregard of this fact leads to important degrees of 
error. The apparatus for this determination, shown in Fig. 21, com- 
prises a gas-holder (A), a gas-meter (J?), and a cylinder (O') provided 
with a manometer (D). For the purpose of keeping the soil in posi- 
tion, tightly fitting perforated discs (E and F) of metallic gauze are 
introduced into the cylinder at both ends of the column of soil. 
In the preparation of the cylinder, the disc F is first introduced, and 
then the soil is added a little at a time, and made as compact as pos- 
sible by striking the lower end of the cylinder downward with reason- 
able force against the table. When the desired length of column 
has been reached, the disc E is introduced, between which and the in- 
let end (G) an air space is left of sufficient size to ensure uniform 
pressure against the entire surface of the disc. The inlet end is closed 
by means of a tightly fitting rubber stopper with two perforations, one 
of which carries the inlet tube from the gas-meter, and the other the 
manometer indicating the pressure employed. 
The pressure is obtained by means of a column of water communi- 
cating with the chamber of the gas-holder, which is connected by a 
rubber tube with the inlet of the meter; and it is regulated by a screw 
pinchcock on the outlet tube of the latter. The force is applied, the 
reading of the meter is noted, and at the expiration of the unit of 
time, one, five, or whatever number of minutes it may be, the reading 
of the meter is again taken. 
Permeability to Water.-The permeability of a soil to water is 
expressed in terms indicating the amount of water which will pass 
from above downwards through a column of saturated soil during any 
given unit of time under a given pressure. The apparatus for this de- 
termination, shown in Fig. 22, consists of a metallic cylinder (2I) with 
a perforated or gauze bottom on which the sample of soil is closely 
packed, and another cylinder (F), likewise of metal, provided with a 
number of outlet tubes, (c), at regular intervals, preferably of five or 
ten cm. The lower end of B fits tightly into the upper end of A and 
the joint is made impervious to water by means of adhesive plaster, 
sealing-wax, or other suitable material. The soil within the lower cyl- 
inder is kept in place, and its surface kept intact, by means of a super- 
imposed disc of gauze or coarse cloth. The outlet tubes, provided with 
corks, serve to maintain a constant level and, therefore, a constant 
pressure of water as desired. Water is admitted in a constant stream 
to the cylinder through its upper end by means of a rubber tube con- 
nected with a water faucet. 
If it be desired to employ the highest pressure obtainable with the 
apparatus, all the corks of the outlet tubes, except the upper one, are 
kept in place. In this case, the pressure would be expressed by the 
distance between the top of the soil under investigation and the upper- 
most outlet through which the excess of water from the faucet is al- 
lowed to escape, by way of a rubber tube leading to a sink. Similarly 
any other height and pressure may be employed by removing the cork BUTES CAPACITY. 
293 
of the corresponding outlet, which thus becomes the effluent. What- 
ever the height maintained, it is necessary to keep the delivery end of 
the inlet tube below the surface of the water. 
The process is as follows : Having chosen the pressure and adjusted 
the waste tube to the proper outlet, the water is allowed to run in and 
force its way down through the soil until the latter becomes saturated. 
In order to insure complete saturation it is best, however, to immerse 
the soil cylinder in order that all the air may be thereby displaced up- 
wards. When this has been accomplished and water begins to run or 
Apparatus for determination of permeability of soil to water. 
drip through the gauze bottom, the time is noted, and the discharged 
water is received in a suitable graduate. At the expiration of the unit 
of time, the latter is removed and its contents measured. The experi- 
ment may be repeated as often as may seem advisable, and the effects 
of varying pressures may be also determined. 
Water Capacity.-The power to hold water is determined by 
means of a metallic cylinder of known capacity with a gauze bottom. 
This is weighed, then filled with the dried sample and again weighed. 294 
THE SOIL. 
The soil is next completely saturated by immersion of the cylinder in 
water, and then it is allowed to drain as long as any water continues to 
escape. When the water ceases to drain away, the cylinder is wiped 
dry outside, and the weight of the whole is again taken. The increase 
in weight is the amount of water retained, and it may be stated in 
percentage of the pore-volume which must have been previously 
determined. 
Capillarity.-The height to which water will rise in a column of 
soil by capillary attraction is determined by packing the sample tightly 
into a graduated glass tube, the lower open end of which is covered 
with coarse linen tied securely on so as not to slip. The tube is sup- 
ported with its cloth-covered end resting in a shallow dish filled with 
water, which is kept at constant level. The height to which the water 
rises through the column of soil is noted from time to time, until ascent 
ceases. The change in the color of the soil, due to wetting, indicates 
the progress of the action. 
Moisture.-The amount of moisture in a soil is most accurately de- 
termined by taking a sample in its natural condition by means of a 
brass cylinder with a cutting edge, weighing a portion of it, and then 
drying it in a hot-air bath at 105° C. until it ceases to lose weight. 
The difference between the original and final weighings represents the 
amount of water in the given weight of soil. If it is desired to know 
the amount of water which the same soil will absorb from a saturated 
atmosphere, the thoroughly dry sample may next be placed with a 
dish of water under a bell-glass. The confined air will become satu- 
rated with aqueous vapor in a short time, and this will be absorbed by 
the soil up to the limit of its capacity which is shown when its weight 
no longer continues to increase. 
The hygroscopic moisture of a soil may be roughly determined by 
air-drying a sample and then taking a known weight of it and heating 
it in an air-bath at 105° C.; or by exposing it to a dry atmosphere in 
a bell-glass containing an open dish of strong sulphuric acid, until it 
ceases to lose weight. 
Organic and Volatile Matters.-Since it is impossible to deter- 
mine by ordinary processes the exact amount of organic matter present 
in any soil, it is necessary to designate the diminution in weight which 
occurs on subjecting a sample to such a heat as will burn off the organic 
matter, and which represents other losses than the latter, as " loss on 
ignition " or " organic and other volatile matter." For this determina- 
tion, the soil which was used for the estimation of moisture, or another 
sample, thoroughly dried, may be placed in a platinum dish and heated 
over a Bunsen flame at no higher temperature than is sufficient to keep 
the dish at a dull red heat. 
When all the organic matter has been destroyed, the residue is al- 
lowed to cool, and is then moistened with a little saturated solution of 
carbonate of ammonium in order to restore the carbonic acid that be- 
longs to the inorganic constituents, then dried and gently ignited to 
expel the excess of ammonia, and finally weighed. The loss represents DETERMINATION OF CO., IN SOIL AIR. 
295 
organic matter, ammonium salts, nitrates, water of crystallization, etc. 
Determination of CO2 in Soil Air.-The analysis of soil air is 
conducted upon the same principles as that of ordinary air, but the 
method employed is necessarily different so far as the obtaining and 
handling of the sample are concerned. The reagents are the same as 
required in the analysis of atmospheric air; the apparatus, however, is 
quite different. It consists of a number of sections of water-pipe 
with screw joints, one having a pointed foot above which are a number 
of perforations within a limited area, an absorption tube in which the 
Fig. 23. 
Apparatus for determination of CO2 in soil air. 
barium hydrate solution is held and through which the air is drawn, 
and an aspirator. (See Fig. 23.) 
The section with the pointed end is driven into the soil, and the pipe is 
lengthened by the addition of the other sections so that any desired depth 
may be reached, and thus the air of any stratum may be withdrawn. Its 
upper extremity is connected by a rubber tube with the inlet tube of 
the absorption apparatus, which latter may be a plain glass tube about 
an inch in diameter with a bend of about 130 degrees near one end. 
Better, however, is the apparatus shown in the illustration. Here the 
short leg of the bent tube is a large bulb, and the long leg is a series 296 
THE SOIL. 
of small bulbs the communications between which are of small diame- 
ter. In either case the inlet tube passes through a tightly fitting 
rubber stopper and extends to a point just beyond the bend. The 
other end of this apparatus is connected by means of a rubber tube 
with the inlet of the aspirator. Any form of aspirator may be used, 
but preferably one of a capacity of about twenty liters. A measured 
amount of the dilute solution of barium hydrate, sufficient to occupy 
the greater part of the long leg, is introduced into the absorption ap- 
paratus, and the connections throughout are tested to prove the ab- 
sence of leaks. When the outlet cock of the aspirator is opened, the 
escape of the contained water creates a partial vacuum which is re- 
lieved by suction of air from the soil and through the whole apparatus. 
As the air emerges from the inlet tube of the absorption apparatus, it 
passes upward in the form of bubbles through the reagent, to which it 
gives up its content of CO2. The reason for preferring the bulbed 
tube is that each bubble of air in its passage from one bulb to the 
next above is necessarily brought into more intimate and prolonged 
contact with the reagent than is the case when the plain bent tube is 
employed, for here the air bubbles pass quickly along the upper inner 
surface of the tube and are not so exposed to the reagent as to lose all 
the contained CO2. For this reason, it is necessary to draw the air 
through a second and, perhaps, a series of such tubes, but one bulbed 
tube as pictured above is sufficient. 
The water from the aspirator is carefully measured, and its amount 
indicates the volume of air that has been sucked up out of the soil to 
take its place. When the desired amount has been acted upon, the 
stopcock of the aspirator is closed, and the reagent in the absorption 
tube is transferred quickly to a glass-stoppered bottle of suitable size. 
From this point out the determination is the same as described in the 
chapter on air. 
The bacteriological examination of the soil requires necessarily an 
intimate acquaintance with bacteriological technique, a subject beyond 
the scope of this work. It may be stated briefly that many of the 
organisms that inhabit the soil may be isolated by adding small por- 
tions of the sifted sample to liquefied gelatin and then plating, or by 
sprinkling over the surface of a nutrient medium, or by shaking with 
distilled water and transferring thence to the proper media. 
The many anaerobic forms require, of course, the special treatment 
of their class, and some of them may be grown on ordinary culture 
media; but many of the saprophytes, notably the nitrifying organisms, 
cannot be isolated by the ordinary methods. For the details involved 
in the separation and identification of the numerous varieties of soil 
organisms, the reader is referred to the standard works on bacteriology. 
Bacteriological Examination of Soil. CHAPTER IV. 
WATER. 
Absolutely pure water, that is, the substance composed wholly of 
hydrogen and oxygen and represented by the symbol H2O, is never 
found in nature, and is never seen except in small amounts as a labora- 
tory curiosity. In the broad sense, however, the word pure as applied 
to water conveys the idea of freedom from harmful ingredients and of 
wholesomeness and suitability for drinking and for the preparation of 
food. In nature all water contains more or less of gaseous and solid 
substances in solution and suspension, and so long as these are not 
present in such amounts as to affect the quality injuriously, and so 
long as they are not intrinsically dangerous to health, the adjective is 
commonly held to be appropriate. 
But in the sense that purity involves the limitation of the amount 
of contained substances of a harmless nature, it becomes a difficult 
question where to draw the line where water ceases to be pure, and 
what term to apply as an antonym. In the sense that it involves 
complete absence of matters intrinsically dangerous, the line can be 
sharply drawn, and water which fails to satisfy the requirements of 
the term may be designated indifferently as impure, polluted, or con- 
taminated. 
In the classic reports of the State Board of Health of Massachu- 
setts on public water supplies, waters are classed as 11 normal " or 
11 polluted " according as they are or are not free from direct or indi- 
rect pollution by the waste products of human life and industry. 
Under this classification it follows naturally that normal waters must 
vary very widely in appearance, composition and general character, 
and that a normal water is not necessarily suitable for drinking, 
although incapable of causing specific disease. The nature and 
amount of the dissolved matters cannot but have considerable influ- 
ence in modifying the properties and effects of a water. 
Waters are classified according to source as follows : 
1. Rain and snow. 
2. Surface-water. (Rivers, ponds, basins, etc.) 
3. Ground-water. (Also known as subsoil water.) 
4. Artesian or deep well-water. 
RAIN. 
Rain is the original source of all natural waters of whatever class. 
It results from condensation of the aqueous vapor of the atmosphere, 298 
WATER. 
and in its descent to the earth it takes up gaseous and suspended mat- 
ters from the atmosphere, which to that extent becomes thereby puri- 
fied. In the open country, after the air has been washed for a while, 
the collected rain is very clean and is, in fact, the purest form of nat- 
ural water. If its fall is accompanied by wind from dusty localities, 
it cannot be obtained in so clean a condition within so short a time, on 
account of the greater amount of suspended matters to be washed down. 
Near the sea, it contains more or less salt; and in cities and large towns, 
it may have a slightly acid reaction. 
In its passage downward through the atmosphere, it absorbs consid- 
erable air, or more properly, constituents of air, that is, oxygen, nitro- 
gen, carbon dioxide, and ammonia compounds. Since each gas has its 
own coefficient of solubility in water, and as air is a mixture and not 
a chemical union of gases, it follows that water will absorb the con- 
stituents of air separately and according to their respective solubilities. 
So it happens that the absorbed air has a very different composition 
from that of atmospheric air, being much richer in oxygen and poorer 
in nitrogen, its oxygen content being 35 instead of 21 per cent. On 
reaching the earth, some of the rain is evaporated, some sinks into 
the soil, and some runs away over the surface to streams or other bodies 
of water. 
The amount that sinks into the soil depends upon the permeability 
of the latter to water. Thus, a sandy or gravelly soil will take up 
more of the rainfall than a close-grained clay. The amount which is 
returned to the atmosphere by evaporation is surprisingly large. It 
has been reckoned by Dalton that in the whole of England and Wales, 
about 60 per cent, of the total annual rainfall is lost by evaporation. 
In the watershed of the Rhine, the loss is reckoned at 50 per cent.; 
in that of the Rhone, at 42 ; of the Seine, at 67, and of the Garonne, 
at 35. 
SURFACE-WATERS. 
Surface-waters are collections of water running along or stored upon 
the earth's surface in contact with the atmosphere. Under this head 
are included rivers and smaller streams, ponds, lakes, and impounding 
basins. They vary according to the different characters of the areas 
which they have drained or passed through, or in which they are 
stored. Thus, a w jr which has flowed over a rocky soil is more 
likely to be free fr m organic impurity than one that has flowed over 
loamy soi or has stood in swamps; and one that has flowed through 
sandstone bottoms is more likely to contain mineral impurities than 
one that has flowed down over the virgin soil of a forest. 
Surface-water means something more than the rain of the district 
plus the impurities of whatever character, organic and mineral, which 
it has collected. Rivers and lakes, for example, are made up of rain 
that has run over the surface of the ground, dissolving in its course 
small amounts of easily soluble matters, and of water that has come up 
from the soil below through springs, or that has trickled in from the GRO UND- WATERS. 
299 
upper layers of the soil; and these latter contribute matters which may 
be of very widely different character from those obtainable along the 
surface, according to the geological character of the soil strata that have 
been acted upon. 
A river may take its origin in a spring and consist for some time of 
ground-water alone, but usually it is not long before it receives acces- 
sions of surface-water and soon acquires the characteristics of the latter. 
Again, some lakes and ponds are fed almost wholly by springs at their 
bottoms and sides, but even so, their waters soon change in character 
and acquire the various forms of aquatic life. 
Surface-waters may contain much or little or no organic matter, ac- 
cording to circumstances. They may be colored or colorless ; they 
may be rich or poor in mineral substances. Those which come largely 
from the ground will naturally possess largely the characteristics of 
ground-water, and those free from accessions from this source will more 
nearly approximate the character of rain. The quality of surface- 
waters is influenced by the seasons, by drought and rainfall, by vege- 
tation, by rate of movement, and by other conditions. 
GROUND-WATERS. 
Ground-water is that which penetrates the soil, sinks to various 
depths, according to the nature of the soil, and accumulates on some 
more or less impervious stratum. It is not exposed to light and the 
atmosphere like surface-water. 
It varies widely in character according to the nature of the soil over 
which it has once flowed and through which it has percolated. It 
enters with more or less air and CO2 in solution, and comes in contact 
with the soil air in the interstices, which is much richer than atmos- 
pheric air in this gas. With the assistance of the CO2 which it has 
brought, and that which it further acquires in the interstices, it dis- 
solves various mineral constituents of the soil. 
That which penetrates very deeply has its solvent power increased 
by increased temperature and pressure. As it enters the soil, it brings 
with it whatever organic matters it may have dissolved out of the sur- 
face layers, and in its descent it may lose them entirely through the 
action of the saprophytic bacteria of the soil, or it may acquire still 
more if the soil be polluted and so permeable as to permit rapid pas- 
sage downward. It passes slowly or rapidly through the interstices 
until it reaches an impermeable stratum over which it accumulates, 
filling the interstices completely. 
The soil at this point is said to be saturated, and the upper limit 
of saturation is known as the ground-water level, or water table. Be- 
tween this and the surface, the water is in contact with the air of 
the interstices, and is known as capillary moisture. The water table 
is by no means necessarily horizontal, but follows in a general way the 
contour of the surface of the soil, and often it is much more irregular, 
and, by reason of local geological conditions, even quite different from 300 
WATER. 
what the surface formation would indicate. Thus, at one point in a 
level stretch of country, the table may be quite near the surface, and 
at another, a short distance away, it may be much more deeply situ- 
ated, owing to abrupt changes of level of the impermeable stratum. 
Irregularity of the surface of the water table is largely due also to 
the rainfall, which, coming at frequent intervals, falls upon surfaces of 
differing permeability, so that while one part is still draining its water 
downward, another has completed the process and is ready for more. 
When drought occurs, however, the level becomes more and more uni- 
form until it may become quite horizontal. With return of rainfall, 
the level rises, and irregularity of the surface of the water table is 
again produced. The level at any point is also influenced by the 
amount of water withdrawn from the soil by the demands made upon 
wells. When the amount of percolation is exceeded by the amount of 
withdrawal the level falls; when the conditions are reversed the level 
rises. 
The water table in its irregular course touches the surface of the 
ground here and there, and gives rise to springs which may flow the 
year round regardless of drought, or may dry up completely with fall 
of the level. Similarly, all permanent ponds are outcroppings of the 
water table, and the beds of all rivers as well, but the level of the table 
in the near vicinity is almost invariably higher than the surface of 
these bodies. Sometimes, however, the water level is so near the sur- 
face that without emerging in the form of springs it extends in a broad 
sheet just at oi' below it and causes marshy conditions. In Fig. 24 
Fig. 24. 
Outcropping of water table."1 
the manner in which the water table crops out in springs and feeds 
lakes and other bodies of water is shown. 
By some, the water table is spoken of as an underground river, a 
term which is very misleading in that it suggests a body of water 
rather than a condition of saturation of the soil. There are, to be sure, 
in some localities, especially in limestone districts, bodies of water flow- 
ing between impermeable strata, and instances are known of disap- 
pearance of streams into fissures of rocks and emergence at a distance PHYSICAL AND CHEMICAL CHARACTERISTICS OF WATER. 
301 
elsewhere, but these streams are not a part of the water table as gen- 
erally understood and may not properly be classed as ground-water. 
In most cases and except where the water lies in deep depressions 
or pockets with no side outlets, the ground-water is in constant lateral 
motion in the direction of the outfall, and this is commonly the nearest 
large body of water, either a lake, or a river, or the sea. In its onward 
course over an irregular impervious stratum, the movement is at times 
inclined upwards and at times downwards, but ever in the same gen- 
eral direction laterally. 
The rate of movement is determined by a number of influences, 
among which the most effective are the degree of permeability, the in- 
clination, and the barometric pressure. The degree of permeability, 
dependent upon the coarseness of the soil particles, is of very great 
importance, the more rapid flow occurring through the soils of coarser 
texture. The inclination, or in other words, the influence of contour 
in promoting or preventing the assistance of gravity, has a very de- 
cided effect. 
The barometric pressure affects the rate of movement through its 
effects on the air in the interstices above the water level. While this 
air is itself in constant movement, it cannot move quickly because of 
the great amount of friction created. Lessened pressure above the 
ground causes the soil air to expand, and in so doing it exerts 
pressure in all directions and, therefore, downwards against the water 
beneath it, and thus assists its onward movement. 
At the same time or rather sooner, the influence of diminished air 
pressure is felt at the outfalls, as may be seen by noting the fluctua- 
tions in the water levels in wells which rise as the barometer falls, 
and fall as it rises. Thus, resistance is removed at the outfall and 
coincidently the water is being pushed along by the expansive force of 
the air in the interstices. With increased barometric pressure these 
conditions are reversed and the flow becomes less rapid. 
The rate of movement being so dependent upon local conditions, it 
follows that it must vary widely in different soils. In some places it 
is so slow as to be almost immeasurable; in others it is extremely rapid ; 
and even wi-thin a restricted area it may be exceedingly variable at 
different points. At Budapest, for example, Fodor1 determined the rate 
of movement at five different points to be 95, 125, 199, 209, and 210 
feet daily. The average of these figures, 167.6, represents unusually 
rapid flow. At Munich the daily rate of flow toward the Isar has been 
calculated by Pettenkofer at a trifle over 15 feet. 
Physical and Chemical Characteristics of Water. 
At the standard barometric pressure, 760 mm. or 29.922 inches, 
water boils at 100° C. or 212° F. With lower pressures it boils at 
correspondingly lower temperatures ; on very high land, for example, 
it boils at such low temperatures that meat and vegetables cannot be 
1 Boden und Wasser. Brunswick, 1882. 302 
WATER 
properly cooked in it. Evaporation occurs at all temperatures, even 
below the freezing point. 
Water has its maximum density at 4° C., above and below which 
point it expands. At 0° C. it freezes, and in doing so it expands to the 
extent of about 9 per cent, of its volume and thus acquires a specific 
gravity less than that of unfrozen water in which, therefore, it floats. 
As the surface freezes, it gives out heat to the layer immediately beneath 
and thereby causes a retardation of the process. As this layer be- 
comes cooled, the ice formation continues, and thus the growth in 
thickness of the ice cover proceeds downward. Its specific heat is 
high and is taken as the standard of comparison. As a conductor of 
.heat it stands very low. 
Water is the most universal solvent known, there being but few sub- 
stances which are not acted upon by it to some extent. It takes up 
all known gases, and its solvent power for them is greater according as 
the temperature is depressed and the pressure increased. In the case 
of substances other than gases, with few exceptions its solvent power is 
increased with increased temperature. 
Appearance.-Pure water is clear, and in proportion as it contains 
dissolved air and carbonic acid, is bright and sparkling. Brilliancy 
of appearance is, however, by no means conclusive evidence of purity, 
some extensively contaminated waters showing remarkable brightness. 
Turbidity of water is due to organic and mineral matters in suspen- 
sion ; the organic matters may be ordinary dead vegetable and animal 
substances or microscopic living plants and animals. 
Some public supplies derived from rivers are distinctly muddy in 
appearance. The slight degrees of turbidity designated as milkiness 
and opalescence are commonly due to very minute clay particles which 
may remain in suspension for long periods of time, even when the 
vessel containing the water is allowed to stand undisturbed. Sewage 
matters also may give these same appearances. Turbidity due to clay 
may be readily removed by the addition of various substances, as lime, 
alum, and sulphuric acid, which cause the particles to agglutinate and 
settle out. Water which is apparently clear when viewed in an ordi- 
nary glass vessel may be seen to have decided turbidity when viewed 
through a depth of a foot or two against a pure white surface. 
Some ground-waters which are quite clear when drawn may acquire 
a turbid appearance on standing, due to the presence of compounds of 
iron which undergo changes in character and become precipitated. 
In such cases, the turbidity is accompanied by the development of 
color which, however, disappears on the completion of the process of 
oxidation of the iron compounds and their separation by sedimentation. 
Color.-Water may have color or not, according to circumstances. 
Surface-waters may derive it from contact with grasses, leaves, woody 
matters in general, and peat, the degree of color being dependent upon 
the length of time of contact and upon the character of the sub- 
stances. Different kinds of leaves, for example, impart different shades 
and degrees of color, but not always to the extent that their appear- ODOR. 
303 
ance would indicate. The dark colored dried leaves of the oak, for 
instance, might be expected to yield a much darker infusion than the 
much lighter colored leaves of the maple, but such is not the case, as 
may be readily proven by experiment; and those of the butternut give 
a color that is surprisingly light in comparison. Long contact with 
swamp vegetation causes a deep reddish brown color which is often 
very stable on long keeping. Not all surface-waters, however, are 
exposed to color-imparting substances, and waters of this class may 
be quite free from color. 
Ground-waters of good quality are ordinarily colorless or appear to 
have, when viewed through considerable depths against a white surface, 
a faint bluish or greenish blue tinge. Sometimes they contain iron 
and organic matter in combination and have in consequence a brownish 
tint which, by reason of very slow oxidation, may persist for a long 
time. Color derived otherwise than from contact with vegetable mat- 
ter is usually accompanied by more or less turbidity. Absence of 
color is not a sign of purity, for polluted waters may be quite free 
from it; nor is its presence an indication of unfitness for domestic use. 
Reaction.-The dissolved carbonic acid in water tends to give it a 
slightly acid reaction, but most potable waters are very faintly alkaline 
to delicate indicators, owing to minute amounts of alkaline carbonates. 
Rain waters, especially in the vicinity of cities and large towns, are 
generally slightly acid on account of impurities of the atmosphere, aris- 
ing from combustion. Peaty waters also are slightly acid on account 
of organic acids produced by the action of the peculiar bacteria existing 
in peat. River waters in mining districts often contain considerable 
amounts of free mineral acids. 
Odor.-Pure water has no odor, but good surface-waters containing 
coloring matters have more or less odor, which is especially marked on 
heating. It is generally suggestive of vegetable matter, and may be 
variously characterized as grassy, peaty, etc., according to the impres- 
sion produced. Such odors may persist even on long boiling, while 
those due to dissolved gases will disappear quickly on heating. Many 
otherwise good surface-waters are particularly prone to the develop- 
ment of disagreeable odors attributable to minute living organisms. 
The subject has been very extensively studied by Mr. Gary N. 
Calkins,1 whose report is extensively quoted as authoritative. To the 
two general classes of odors formerly distinguished, those produced by 
the presence of the living animal or plant, and those produced during 
its decomposition or decay, he adds a third; namely, odors produced 
by disintegration. He states that the disagreeab e odor which sud- 
denly develops in a water normally od- 'ss 11 is usually found to be 
due to some one or more species of microscopical organisms, and ap- 
parently, it may result (1) from the excretion of certain body products, 
(2) from the liberation of certain internal substances, or (3) from the 
bacterial decomposition of their dead bodies." 
" If a water, free from organisms and odors, suddenly develops a 
1 Report of the State Board of Health of Massachusetts for 1892, p. 355. 304 
WATER. 
peculiar odor, and if microscopical examination shows that only one 
organism is present, we may infer that the odor is due to that organ- 
ism. If the same odor occurs again in perhaps some different supply, 
and if the same organism is present, we have corroborative evidence 
of our inference. The more instances that we have of this concomit- 
ance of specific organisms and certain odors, the more sure we are of 
their relation as cause and effect. The further proof of this relation- 
ship comes when, in filtering out these organisms and in transferring 
them to pure, odorless water, they impart to that water the character- 
istic odor." 
Proceeding on these lines he succeeded in demonstrating the par- 
ticular organisms connected with the development of particular odors 
which are classified as vegetable, sweetish, aromatic, grassy, mouldy, 
fishy, disagreeable, offensive, musty, and earthy, according to the im- 
pression conveyed. Odors suggesting straw, peat, or swamp are 
grouped as vegetable ; those suggesting a cellar or vault as mouldy; 
those peculiar to water contaminated by sewage as musty. " The odor 
termed disagreeable is usually associated with waters in which there is 
a considerable decomposition of vegetable matter. Offensive is used to 
designate the odors of water in which there is a considerable amount 
of decomposition of animal matter; and the term unpleasant is used 
for waters in which there is a large amount of either vegetable or ani- 
mal matter, yet without decomposition. 
" The term grassy is employed to describe a certain odor observed in 
waters which contain great quantities of live vegetable matter. The 
sensation which it excites resembles that arising from freshly cut grass. 
The odor is usually very distinct, and suggestive of the seashore. 
It may remind one of salt marshes, of seaweed, of fish, or even of Irish 
moss, but it invariably suggests something connected with the sea. 
Still another group of odors is denoted by the term aromatic, the most 
familiar example of which is the fragrant odor which has been called 
geranium because of its strong resemblance to the odor of that plant." 
Of 1,404 samples examined, 384, or about 26 per cent., contained no 
organisms. Rather more than half of these (57 per cent.) had an odor 
of some sort, usually referable to matters extracted from leaves and 
other vegetable matters. Diatoms were found in 174 specimens, 
among which the vegetable and aromatic odors predominated. Cyan- 
ophycese were found in 85 ; 58 per cent, of these had a grassy odor, 
and 28 per cent, had either vegetable or mouldy odor. 
In the small number in which the Algae were the only organisms in 
abundance, the predominating odors were vegetable, grassy, and sweet- 
ish or aromatic. The infusoria caused most commonly the fishy odors, 
and next in order, disagreeable and vegetable odors. Fungi (under 
which head Zobgloea is included) were found alone in 386 specimens; 
35 per cent, of these had offensive odors ; 24 per cent., vegetable odors; 
15 per cent., mouldy and musty odors. In those waters, however, 
which had offensive odors there were other substances (sewage) than 
organisms, and it would appear that to these matters, rather than to ODOR. 
305 
fungi, the odors were due. In those waters which contained a variety 
of organisms the odor was found to be characteristic of the class which 
was in excess. 
Certain particular species of organisms were found to be responsible 
for certain distinct odors. Different but very distinct fishy odors, for 
instance, are due to several species of Uroglena, one of the genera of 
infusoria. These odors are not due to growth, putrefaction, or decom- 
position, but to the liberation of oil globules in the process of disinte- 
gration. Others of the fishy group have been traced to species of other 
genera which yield abundance of oily matter in the physical disintegra- 
tion of their cells. Odors belonging to other groups were likewise 
identified as products of different animal and vegetable organisms. 
Mr. Calkins concludes that odors in drinking waters " may be pro- 
duced by the putrefactive decomposition of the body plasm through 
the agency of bacteria, and by the excretion of certain products of 
growth, or by the liberation of products by the physical disintegration 
of the body or breaking down of the enclosing cell walls. These three 
causes give rise to three classes of odors, as follows : (1) odors of chem- 
ical or putrefactive decomposition, (2) odors of growth, and (3) odors 
of physical disintegration." 
While sewage matters impart mouldy or musty odors to water, it 
must not be inferred that these odors are of themselves indicative of 
sewage pollution, for good surface-waters sometimes will acquire them 
on standing. 
Sometimes it will be noticed that water on long boiling not only con- 
tinues to evolve a vegetable odor, but gives it off in greater intensity. 
This is true particularly of waters rich in algse. If they are first fil- 
tered, the odor will not be given off on boiling. But other waters may 
continue to evolve odors even after filtration. Peaty waters, for in- 
stance, often persist in yielding odor on long boiling, and this is not 
affected in any way by filtration. Waters containing products of physi- 
cal disintegration and various other substances also are not influenced 
by filtration. 
Odors which disappear on boiling may develop again after a time if 
their cause is not removed ; if, however, the matters from which they 
are derived are no longer present, the odor will not return. Some 
most troublesome odors are known to be the results of decay. The 
public supply of Boston was, in 1878, seriously affected in this way, 
and gave off an odor which was likened to that of cucumbers. This 
was investigated by Professor Ira Remsen, who found the cause to be 
decomposition of a fresh-water sponge. Odors suggestive of pig-pens 
and horse-dung have been proved to be due to decay of various forms 
of algse. 
Water sometimes contains sulphuretted hydrogen from reduction of 
sulphates by bacterial action, and sometimes mixtures of products of 
organic decomposition which suggest that gas. Very marked and 
most offensive odors are often due to the presence of dead animals, such 
as toads and mice in wells, and when they arise, the remedy is obvious. 306 
WATER. 
Some wells become stagnant at the bottom, and if organic matter is 
present, it may cause foul odor, suggestive of dead animals, by putre- 
faction in the absence of a sufficient supply of dissolved oxygen. 
Stagnation may be prevented by connecting the pump nearer the bot- 
tom, or by filling up the unnecessary space with clean gravel and sand. 
Odors in water are not necessarily indicative of danger to health, but 
distinctly unpleasant ones are quite sufficient as a disqualification, on 
account of the repugnance which their use for drinking and other do- 
mestic purposes would cause. On the other hand, as in the case of 
color, absence is not indicative of purity, for dangerous waters may be 
quite inodorous. 
Taste.-Pure water has no distinct taste, and whatever the impres- 
sion made, it is due to dissolved gases. That this is so is most evi- 
dent when one compares the taste of a well aerated water, before and 
after heating to the boiling point with subsequent cooling. Saline con- 
stituents impart no distinct taste unless they are present in quite large 
amounts, as in waters of a high degree of permanent hardness. The 
only substance which imparts taste when it is present in very small 
quantities is iron. Dissolved organic matters cause no taste, unless 
present in considerable amount and accompanied by odor. 
Water containing very little coloring matter is often said to taste 
distinctly, but it must be remarked that the senses of taste and smell 
are often unconsciously influenced by the sense of sight, and colored 
water supposed to have both odor and taste may, if drunk in the dark, 
give no impression of either. 
Badly tasting water, whether dangerous or not, is objectionable on 
the same grounds as mentioned under odor. Not only is absence of 
bad taste no evidence of purity, but it is well known that waters con- 
taining the products of oxidation of sewage are often remarkable for 
unusual palatability. 
These include : 
1. Gases in solution. 
2. Organic matters in solution and in suspension. 
3. Mineral matters in solution and in suspension. 
1. Gases.-First in importance is air. Strictly speaking, water con- 
tains no air as such, but only the constituents of air, for the oxygen and 
nitrogen, dissolved by water, are not present in the same proportion in 
which they exist in the atmosphere. In salt water, the variations in 
their proportions are less wide. We will, however, consider the two 
gases as air. The dissolved oxygen is the important element. One 
hundred volumes of water at 15° C. will dissolve nearly 3 volumes of 
oxygen (2.99), and at 20°, 2.80 volumes, and it is not altogether re- 
moved by boiling. 
The amount of oxygen in solution is fairly constant in waters of 
uniform composition freely exposed to the atmosphere, but when they 
receive additions of sewage and other oxidizable matters they begin to 
Substances Found in Water. ORGANIC MATTER. 
307 
lose it. River waters may thus show notable differences in the 
amount of dissolved oxygen present in samples taken above, within, 
and below towns situated on their banks. The Thames and the Seine, 
for instance, show this in a remarkable degree. 
The progressive diminution is due to the constant access of or- 
ganic matter which undergoes oxidation at the expense of the dis- 
solved oxygen. When a river water is deprived of its dissolved 
oxygen in this manner, or by reason of chemical changes due to the 
inflow of sewage from manufacturing establishments, containing com- 
pounds, ferrous, for instance, having a strong affinity for oxygen, fish 
life cannot be supported. Absence of fish in polluted streams is due 
much more to diminution of dissolved oxygen than to the poisonous 
effects of organic sewage. 
Aeration of water is very largely influenced by the dust which falls 
into it, for each particle carries with it more or less adherent air, as 
may be readily seen when one drops small particles into water inten- 
tionally and observes their descent. Aeration of water proceeds to 
great depths, as is shown by chemical analysis of samples of water ob- 
tained by deep sounding, and also by the fact that great numbers of 
organisms which require oxygen for their respiration are found far 
beneath the surface; but water at 40 and 50 feet below the surface may 
contain no oxygen. Water from deep wells is very commonly free 
from dissolved oxygen, because of abstraction by compounds of iron or 
manganese, organic matters, and other substances. 
The presence of considerable dissolved oxygen in water leads to 
beneficial changes in the organic matter present. Diminished oxygen 
permits the development of low forms of vegetable life which fre- 
quently give rise to unpleasant tastes and odors. Their growth is in- 
hibited by a large degree of aeration, and their disagreeable effects are 
thereby prevented. 
Carbonic Acid.-The carbonic acid contained in water is derived 
largely from the atmosphere and in great part from the soil, where it 
is present in abundance. Its amount in any water depends upon a 
number of circumstances : upon the amount carried in by rain and 
dust, the character of the soil, and the extent of oxidation of organic 
matter occurring in the interstices. It is greatest in amount at great 
depths, and it may constitute almost the entire content of dissolved 
gases. It has been calculated that the ocean contains about ten times 
as much as the entire atmosphere. 
2. Organic Matter.-The organic matters in water are of both ani- 
mal and vegetable origin and consist of organisms, products of organic 
life, and results of disintegration and decomposition. The animal 
matters include dead and living organisms and dissolved and sus- 
pended products of animal life and decay, such as albuminous sub- 
stances, urea, and tissues. In the tropics and subtropics, ova and 
young of various parasites are common. Ordinarily our interest in 
animal organic matter is confined to the products of human life as 
represented by sewage, which may contain the exciting causes of 308 
WATER. 
specific diseases. Vegetable organic matter exists as living and dead 
organisms and tissues in suspension, soluble and suspended substances 
given off during life, and soluble matters extracted by the water after 
death. 
The vegetable organisms are represented by very numerous species 
of microscopic plants which act beneficially by absorbing the products 
of organic decomposition for their growth, but which may, on the other 
hand, under favorable conditions, become the source of much trouble 
by over-abundant growth, disintegration, and decay. They may prop- 
erly be regarded as normal constituents of surface-waters, for they are 
always present in such, and, moreover, they develop quickly in stored 
ground-water exposed to light and air. When they die, most species 
appear to decay rather slowly, and the products of their decomposition 
are absorbed by new growths; but when present in great abundance, 
the progress of decay may exceed that of growth, and then their prod- 
ucts may accumulate and cause foulness. 
The presence of living forms, either vegetable or animal, indicates 
that the water contains at least whatever food materials are necessary 
for their existence, but not necessarily that these are in excess. Algae, 
for instance, require mineralized nitrogenous matter (nitrates), and 
other substances ; fungi suggest the presence of carbohydrates, pro- 
teids, and mineral substances common to domestic sewage ; infusoria 
suggest organic decomposition. Dissolved vegetable matters ordinarily 
amount to but little in weight. Even in some very brown waters 
whose appearance would suggest large amounts, they may be present to 
the extent of not more than one or two parts in a hundred thousand. 
The organic matters, both animal and vegetable, which are of in- 
terest to the sanitarian, consist chiefly of carbon, hydrogen, oxygen, and 
nitrogen with, in many cases, small amounts of phosphorus and sul- 
phur. In the process of decomposition, which owes its inception, 
progress, and completion to bacterial activity, the carbon is combined 
with oxygen to form carbonic acid, and the hydrogen unites with nitro- 
gen to form ammonia, the presence of which in water indicates that the 
process of decomposition is under way. In its turn, as will be shown 
later, the ammonia is converted eventually to nitric acid, which unites 
with bases to form nitrates. 
Ammonia.-From the standpoint of sanitary significance, ammonia 
in water is of prime importance. Only under very unusual conditions 
does it exist in the form of hydrate, but usually as chloride or car- 
bonate. We speak of it commonly as/ree ammonia, for on boiling the 
water, these salts are decomposed and the ammonia is expelled in the 
steam. Among the direct sources of ammonia in water is rain, which 
brings it down out of the atmosphere in varying amounts according to 
location. Rain always contains it, but more is present in that of 
thickly populated districts than in the open country. 
In one instance, reported by Drown,1 it was found to the large ex- 
1 Massachusetts State Board of Health : Report on Water Supply and Sewerage. 
Boston, 1890. Part 1, p. 562. ORGANIC MATTER. 
309 
tent of 0.0564 in 100,000. Its presence, however, in surface- and 
ground-waters is due for the most part to decomposition of nitrogenous 
organic matter. It is not abundant in ordinary unpolluted waters, but 
is often present to a very considerable extent in that of deep driven 
wells. Here its origin is not always clear; in some cases it is sup- 
posed to be referable to coal deposits, in others to reduction of accu- 
mulated nitrates. 
Under ordinary conditions in surface-waters it is absorbed very 
quickly by growing vegetation, and the more active the growth, the 
greater the appropriation. For this reason, water from the same source 
will often show less on analysis in summer than in winter. But ac- 
tivity of vegetation is not always responsible alone for this difference 
in amount, for in the case of large bodies of water, as lakes and ponds, 
the rate of movement of the water has great influence. During the 
warmer months, when the upper layers are warmer and consequently 
lighter than the lower, the latter becomes necessarily stagnant and 
stratified. 
The ammonia which accumulates in these lower strata does not, 
therefore, come to the surface until cold weather approaches. Then 
the upper layers become more dense and tend toward the bottom, 
causing a displacement of the lower layers toward the surface and a 
general uniform mixing of the entire volume of water. Another ele- 
ment in the stirring up of the water of ponds and lakes is the action 
of wind, which, however, does not extend beyond twenty feet. Still 
another influence to be considered is that of springs at the bottom and 
sides, which tend to keep the water in motion. In the case of flowing 
rivers, the water is of comparatively uniform composition at all depths. 
Ammonia is very characteristic of sewage pollution the oxidation of 
which yields it in such abundance that it may not be absorbed by 
growing vegetation; or the conditions are such that it cannot be oxi- 
dized to nitric acid. 
Ammonia as it occurs in drinking water is of itself incapable of 
producing any harmful effects. Its amount, however, is of greater or 
less significance according to circumstances : that from clean and prop- 
erly stored rain-water is of far less significance than that of other 
waters. In this case it may be considerable in amount and mean but 
little ; in others, it is usually evidence of decomposition of organic 
matter. Its amount in good water is not large, and on account of 
oxidation and absorption by vegetable growth it does not accumulate. 
And even in sewage-polluted waters, when vegetation is active, ab- 
sorption may so diminish its amount that, taken alone, it might lead to 
false conclusions as to the character of the water. 
Albuminoid Ammonia.-The so-called albuminoid ammonia is am- 
monia which is produced in the process of analysis of water by the 
action of alkaline permanganate of potash on nitrogenous organic mat- 
ter hitherto undecomposed. The result of the action is a splitting up 
of the organic matter and the conversion of the nitrogen to ammonia, 
which, as is the case with " free " ammonia, passes out of the water in 310 
WATER. 
the steam. This matter may be of either animal or vegetable origin, 
and its character is of far greater importance than the amount of the 
yield. Thus, a water grossly polluted by sewage may yield less than 
another quite free from such contamination, but rich in dissolved 
vegetable matter of no great sanitary importance. 
Animal organic matter is decomposed much more rapidly than veg- 
etable matter, some kinds of which are remarkably permanent, such, 
for instance, as the substances which impart the brown color to the 
waters of swamps. Animal matter is richer in nitrogen than vege- 
table, and consequently a stated amount of albuminoid ammonia rep- 
resents decomposition of a larger amount of the latter than of the 
former. In other words, a small amount of animal matter will yield 
as much albuminoid ammonia as a large amount of vegetable matter. 
Inasmuch as animal matters are of far greater significance than 
vegetable matters, it must be clear that the amount of albuminoid 
ammonia is of less importance than its origin. And since in the an- 
alysis of water the ammonias themselves give no indication of their 
origin, their significance can only be measured with the aid of estima- 
tions of other substances, and often, also, a knowledge of the source of 
the water and its surroundings will be required. 
Nitrites and Nitrates.-The ammonia formed in the first stage of de- 
composition and that washed out of the air by rain are eventually oxi- 
dized to nitrates under the influence of the so-called nitrifying bacteria, 
and this stage marks the completion of the process. The nitric acid 
formed, coming in contact with earthy and alkaline carbonates, attacks 
them and unites with the bases to form nitrates and, in so doing, liberates 
carbonic acid. The nitrifying process occurs not alone in the body of 
the water itself, but to a much greater extent in the interstices of the 
soil, so that a water rich in all manner of organic substances undergoes, 
under favorable conditions, this purifying process in the fullest degree 
when it enters the soil at the surface and percolates slowly downward. 
Before the stage of complete nitrification is reached, there is an in- 
termediate stage, that of nitrous acid and nitrites, but it is probable 
that the time during which a given amount of nitrogen on its way to 
mineralization remains in the nitrous form is extremely short; in fact, 
that the step from ammonia to nitric acid is practically instantaneous. 
Nitrates are seldom absent in either surface- or ground-waters, and 
may be present, especially in the latter, in quite large amount (as much 
as six or seven or more parts in 100,000), while, on the other hand, 
nitrites are not ordinarily present in unpolluted waters, and as little as 
one one-thousandth part in 100,000 of any water is looked upon as 
" high." 
It is a fact that nitrates are very readily reduced to nitrites and 
further back to ammonia, and even to nitrogen gas itself, by the action 
of a variety of organisms which act in the absence of oxygen. These 
are known as the denitrifying bacteria, and while these species are 
doubtless very numerous, only a limited number have been isolated 
and identified. Their action is inhibited by oxygen as has been 311 
ORGANIC MATTER. 
proven by Stutzer and Maul,1 who found that in cultures through 
which a stream of oxygen is passed, the process of denitrification ceases. 
This was confirmed by Weissenberg, who observed, further, that when 
the bacteria were cultivated in small volumes of nitrate bouillon in 
flasks of such shape that the surface of the liquid was very great in 
comparison to its depth, and exposed to the air, they did not act. 
These bacteria are common in sewage in which the conditions for 
their growth and activity, absence of dissolved oxygen, for instance, 
are present. Grimbert2 has shown that the Bacillus typhosus and Ba- 
cillus coli communis reduce nitrates and amido principles in culture 
media. The production of gas appears to be a result of the secondary 
reaction on the amido compounds by the nitrous acid formed through 
bacterial action. 
Small amounts of nitrites in water may be derived from the air by 
absorption or by the cleansing action of rain, and may be due to con- 
tact of metallic surfaces, brickwork, and new masonry with the nitrates 
in solution ; but they are almost never present in what are called large 
amounts (one part in a hundred million) except as an indication of 
sewage pollution. 
The disproportion between the amounts of nitrites and nitrates in 
water may also, perhaps, be explained as follows : The nitrates are the 
final stage of complete oxidation; they do not go on to a higher form, 
but, being permanent in character, accumulate in the water, unless with- 
drawn by vegetable life or reduced. The nitrites can not accumulate 
as such, but are converted to the higher form. Thus, the lower form 
is constantly passing into the higher and is stored as such. 
Nitrates vary considerably in amount, owing to various causes. 
They are almost always present in both surface- and ground-waters 
unless there is some process at work causing a reduction to nitrites. 
In unpolluted surface-waters they are usually low in amount, but 
such waters generally contain more nitrogen in this form than as am- 
monia. They do not accumulate greatly in such waters during the 
warmer months, for they are largely absorbed by growing vegetation. 
Hence they are more abundant in winter. In the warmer months 
they may be almost wholly absorbed by growing Algse. 
Ground-waters contain little or much, according to circumstances ; 
in virgin and thinly-settled districts the amount is small; in others, it 
is usually fairly high. In the former, it is mainly from the ammonia 
of the rain and that formed in the decay of the organic matters nat- 
urally in the soil; in the latter, it is due largely and mainly to the 
ammonia of domestic sewage. 
Ground-waters rich in nitrates, when exposed to light and air, gen- 
erally become more or less rich in vegetable growth, and poorer in 
nitrates. 
Like ammonia, nitrates in water are not of themselves in any way 
harmful in the amounts found. They simply represent what was once 
1 Centralblatt fur Bakteriologie. Abth. II., Bd. 2, 1896, p. 473. 
2Annales de 1'Institut Pasteur, Jan., 1899. 312 
WATER. 
organic nitrogen, but now completely mineralized. Nor is their pres- 
ence any indication of the nature of the original organic matter, whether 
animal or vegetable, and this can be inferred only when other constit- 
uents are considered. When present in considerable or very high 
amounts, they indicate a corresponding degree of past pollution, per- 
haps nearby existing pollution, and the possibility of future danger from 
its recurrence. Therefore, high nitrates must sometimes be looked upon 
with suspicion. 
And, furthermore, it must be borne in mind that the evidence of 
extensive mineralization does not preclude the existence of present proc- 
esses and the presence of active pathogenic micro-organisms, for or- 
ganic matter may be rapidly oxidized in the presence of living patho- 
genic germs. Sometimes very large amounts of nitrates are found in 
the waters of very deep wells, so large that they cannot be explained 
by the supposition of oxidized sewage. In these cases the cause is sur- 
mised to be fossil remains or natural nitrate deposits. 
The presence of nitrites in water is of far more importance than 
nitrates. It means that fermentative changes are in progress, and 
that oxidation is not being completed. When this condition obtains, 
they may be very persistent. Sometimes, they mean a reduction of 
the nitrates, which takes place mainly under the influence of denitri- 
fying organisms, quite likely to be present in large numbers in decom- 
posing organic matter. Sometimes, neither nitrates nor nitrites are 
present in sewage-polluted water; in such cases, either they have not 
been formed or have been completely reduced. 
When nitrites are present at the expense of the nitrates by the ac- 
tion of metallic surfaces, lead and iron, for example, the metals them- 
selves are present in at least detectable traces. 
3. Mineral Matters.-Chlorine as common salt is a normal con- 
stituent of all waters. Rain-water takes it up from the air in small 
traces, particularly near the sea coast. In the specimen of rain re- 
ferred to on page 308 as rich in ammonia, the chlorine content was 
0.13 per 100,000, which is much in excess of that found in many in- 
land waters. The amount of chlorine normally present in the water 
of a district depends on location and other conditions. It is very 
greatly influenced by proximity to the sea, the air above which con- 
tains necessarily more than that at a distance inland. It varies in 
amount in the same water with differences in the amount of rainfall 
and evaporation, and in the direction of the wind. 
Chlorine increases directly with the population, and its amount is 
very greatly influenced by a proper system of sewerage which carries 
the sewage matters, rich in common salt, beyond the limits of the 
drainage area. When its amount rises above the normal of a locality, 
it is indicative of sewage, though not necessarily of recent pollution. 
As we have seen, the organic matters become mineralized and no 
longer' exist in their original form, but no such change occurs in the 
chlorides, which remain fixed and unchanged, and they may be the 
only evidence remaining. Thus a water polluted by sewage may have 313 
MINERAL MATTERS. 
its organic nitrogen converted to nitrates, and these in turn may be 
absorbed by vegetable growth ; it may be clear, colorless, odorless, and 
palatable, free from pathogenic bacteria and in every way suitable for 
drinking, but, nevertheless, the chlorine remains as a witness that pol- 
lution has occurred in the past. 
According to Professor Drown, in a general way four families or 20 
persons per square mile will add on an average 0.01 part of chlorine 
per 100,000 to the water of a district in seasons of average flow, and 
more in time of drought. 
Other Mineral Matter.-The total amount of dissolved mineral mat- 
ter in any drinking water depends upon the character of the soil with 
which it has been in contact, upon the length of time of exposure, 
and upon the amount of carbonic acid which it holds in solution. 
Not even the hardest and most insoluble rocks wholly escape the sol- 
vent power of water : no mineral is absolutely insoluble. Silicate of 
aluminum, which is least acted upon, is soluble to the extent of about 
1 in 200,000. Silicious rocks in general are attacked only very 
slightly, while limestones are dissolved with comparative ease and 
yield considerable calcium and magnesium carbonates, especially if 
the water is rich in free carbonic acid. Gypsum also is acted upon 
very freely. 
Some waters contain very large amounts of mineral matter derived 
from deeply situated natural deposits. The Carlsbad springs, for ex- 
ample, are said to bring annually to the surface enormous amounts of 
sodium chloride and calcium carbonate, besides 2,500 kilos of calcium 
fluoride, 600,000 of sodium carbonate, and 11,000,000 of sodium sul- 
phate. 
Besides the ordinary salts of the alkalies and alkaline earths, most 
natural waters contain at least very minute amounts of iron. Appreci- 
able amounts of iron make water unsuitable for general domestic and 
technic purposes. It causes staining of clothes if used in the laundry, 
and headache, dyspepsia and constipation if used habitually for drink- 
ing. It cannot be used for dyeing, and as little as 1 in 1,000,000 
makes it unsuitable for use in bleacheries. A quarter of a grain per 
gallon is sufficient to impart a distinct chalybeate taste. The permis- 
sible total amount of dissolved mineral constituents cannot be stated, 
but 50 parts in 100,000 are generally held to be excessive. 
Hardness.-Hardness is the capacity a water has for decomposing 
soap. It depends on the amount of salts of Mg and Ca in solution, 
and hence upon the character of the soil with which the water has been 
in contact. Water from rocks which yield lime and magnesia will 
probably be hard, while that from those composed of alumina, silica, 
etc., will probably be soft. Some sandstones will yield soft and others 
hard water, according to the nature of the cement which binds the 
grains together. The elements causing hardness, particularly the cal- 
cium salts, have the property of making new combinations with the 
fatty acids of the soap and preventing the formation of a lather until 
they have been satisfied : one grain of chalk, for instance, will use up 314 
WATER. 
eight of ordinary soap before any effect can be produced; hence enor- 
mous waste of soap occurs from the use of hard water. 
Hardness is divided into " temporary " and " permanent." The 
former is due to salts which are removable by boiling; the latter to 
those which are not thereby affected. 
Water containing considerable free CO2 can take up and hold by 
means of this gas considerable carbonate of lime. Some claim that the 
carbonate is changed to bicarbonate, but this compound has never been 
isolated. If the gas be expelled by heating, the solvent power no 
longer remains, and the amount so held is precipitated and can then 
exert no more influence in causing hardness. The chloride and sul- 
phate of calcium are not affected by boiling. Magnesium carbonate is 
precipitated, but redissolves on cooling. 
The difference between the original hardness and the hardness re- 
maining after boiling is the " temporary " hardness. Permanent hard- 
ness is, then, due to those salts not affected by boiling, that is, to cal- 
cium sulphate and chloride, and magnesium salts ; and if above 5 parts 
in 100,000, is commonly regarded as excessive and injurious. Cal- 
cium sulphate is not alone objectionable in drinking water, but also in 
water used in boilers, since it is less soluble in hot than in cold water 
and thus forms a " scale." Scale is of two kinds : that due to the tem- 
porary hardness, easily removed, and that from CaSO4 which is hard, 
very adherent, and removed with difficulty. The latter is deposited 
the more freely, the higher the temperature of the water. 
Boiler scale is also sometimes due to other causes. For instance, 
A. Reichard 1 has reported a case where serious trouble was caused by 
the formation of a scale of silica and lime from a water which con- 
tained only 2.30 parts of lime and magnesia, but as much as 2.60 of 
silica. Boiler scale causes great loss of fuel by interfering with the 
transmission of heat to the water. Hardness is not only undesirable 
in water used in the laundry and bath, but also in that used for cook- 
ing purposes, for it makes certain of the vegetables hard and indi- 
gestible. 
WATER SUPPLIES. 
Immediate sources of water supply comprise : 1. Storedrain. 2. 
Surface-waters, including rivers, lakes, and gathering basins. 3. 
Ground-waters, including wells, filter galleries, and springs. 
1. STORED RAIN. 
Where other water is not obtainable and where the natural water is 
unfit for drinking or for washing and other domestic purposes, stored 
rain-water is used. If this is collected under proper precautions to 
prevent the presence of extraneous matters of undesirable character 
from the receiving area, and properly stored, it constitutes a most 
wholesome supply. But excepting where rainfall occurs with regu- 
larity and frequence, the uncertainty of supply, especially in periods of 
1 Chemiker Zeitung, 1896, p. 65. WATER SUPPLIES. 
315 
drought, acts as a great drawback. An inch of rainfall is equivalent to 
5.61 U. S. gallons per square yard or 27,152 gallons per acre, but 
only a small proportion of this falls upon surfaces (roofs, etc.) from 
which it can be collected. 
The total collecting area of the roof of any building depends not 
upon the shape and style of the roof, but upon the amount of ground 
occupied by the building. Thus, a house forty feet square will have 
practically 1,600 square feet of watershed, or allowing for the projec- 
tion of the eaves, somewhat more, and this whether the roof be flat, 
pitched, gambrel, mansard, or irregularly disposed. Upon such an 
area, one inch of rain will yield nearly a thousand (997) gallons. The 
mean annual rainfall of Massachusetts is 43.17 inches, and on this 
basis, a roof of this size would receive in a year over 43,000 gallons, 
which would allow for all the needs of the occupants, for drinking, 
cooking, bathing, laundry and other purposes, nearly 120 gallons per 
diem. But under ordinary conditions of storage in cisterns, a very 
large amount of loss occurs through evaporation, and thus the daily 
allowance would fall somewhat below this figure. 
In collecting rain from roofs, it is very necessary to ensure cleanli- 
ness of the supply by allowing the first flow to run to waste, thereby 
avoiding contamination by dirt, leaves, bird droppings, soot and other 
matters deposited upon the roof and collected in the gutters. A num- 
ber of automatic devices are in use for the purpose of diverting the 
first washings away from the conductors. After this has been done 
they change position, so that the subsequent fall is saved and stored. 
Irregularity in precipitation is, as has been remarked above, a serious 
drawback to reliance upon rain as a sole supply. Partly owing to a 
general belief that great battles, in which large quantities of explo- 
sives are used, are commonly followed by heavy rain, numerous experi- 
ments have been tried toward breaking drought by discharging pow- 
erful explosives in the upper strata of the atmosphere, but without 
success. As a matter of fact, the idea of connection between battles 
and rainfall is by no means new and has, indeed, come down from 
times antedating the use of gunpowder in warfare. Furthermore, in- 
vestigation of government records has shown that the popular belief 
has no foundation in fact, and that great battles have been as often 
followed by periods of fair weather as by days of storm. 
Rain-water requires no aeration, for in its descent it has already 
absorbed plenty of air; but melted snow and ice must be shaken with 
air or poured repeatedly from one vessel to another in order to lose 
the flat taste so characteristic of unaerated water. Moreover, their use 
in the flat condition is believed to conduce to more or less gastric 
derangement. Snow-water is usually more impure than rain, because 
the snowflakes by reason of their larger surface are more efficient in 
removing dust and dirt from the air. 
Cisterns for storage of rain should be so constructed and arranged 
as to admit of easy inspection and cleansing. They should be kept 
covered so as to exclude dirt and dust of all kinds, insects, mice and 316 
WATER. 
other animals, and to shut off light as well, for the presence of light 
is an important aid to the development of lower plant forms. The 
best materials for their construction are bricks, stone, cement, and 
slate. Cement makes a good lining if one is desired ; mortar, how- 
ever, is objectionable on account of the solvent power of water upon 
lime which will cause progressive increase in hardness. Cisterns 
should be provided with overflow pipes discharging into the open air 
rather than into the house sewer, and their exits should be protected 
by wire netting against the entrance of leaves and small animals. 
2. SURFACE-WATERS. 
For public supplies, especially of large communities, surface-waters 
as rivers, lakes, and collecting basins, are generally more available than 
ground-waters. 
Large rivers and lakes are unfortunately very commonly subject to 
most extensive pollution by sewage of large communities and manu- 
facturing establishments along their borders and by the waste products 
discharged into them from sailing vessels and steamships. Many 
rivers are subject to progressive increase of pollution by reason of 
serving as the most convenient receptacle for the sewage of a succes- 
sion of towns and cities located at Intervals from the source to the 
mouth. Thus, one town takes its water from a point above and dis- 
charges its sewage at another place below; a second, farther down, 
takes the already contaminated water and in its turn discharges its 
sewage at another convenient point, and so on for the rest of the 
course. On account of the dangers attending the use of such waters, 
some process of treatment is imperatively demanded to remove the ob- 
jectionable elements. The different processes available for this work 
are considered elsewhere. 
The public mind is being gradually awakened to the wrong practiced 
upon one community by another by the discharge of untreated sewage 
into what is its only available water supply. In the case of cities lo- 
cated upon the shores of the Great Lakes and other large bodies of fresh 
water, it is commonly the case that the intake of the water supply is 
located at no very great distance from the outfall of the main sewers. 
Smaller rivers and lakes may be subject to the same influences, 
though in lesser degree, but in general it may be said that these are 
more easily controlled, especially when they lie wholly within the juris- 
diction of a single law-making power. 
Basins for the collection and storage of rainfall and surface-waters 
are constructed by throwing a dam across a valley or other convenient 
depression. Experience has taught that even though involving large 
expenditure it is best to strip off the surface layers in order to get rid 
of all organic matter and vegetation, which, if left in place, may prove 
fruitful sources of trouble. The water which gathers in them has op- 
portunity to rid itself of much of its suspended matters by sedimenta- 
tion, and is more often used without further treatment than otherwise. WATER SUPPLIES. 
317 
All surface-waters contain more or less active vegetation, and on 
that account must always be kept exposed to light and air, otherwise 
the minute plants will die, and in their decomposition give rise to un- 
pleasant odor, appearance, and taste# Storage reservoirs should have 
sufficient depth to prevent the water from becoming heated to an un- 
pleasant degree during the warm months of summer; in shallow reser- 
voirs this is found to be a common occurrence. 
All sources of surface-water for public supply should be carefully 
guarded against sewage contamination. It is often necessary to secure 
protection from pollution by taking great tracts of land and keeping 
them free from human habitations and industrial plants. 
3. GROUND-WATERS. 
Some large communities and many small ones where no suitable 
bodies of surface-water are available for public supplies, and most 
thinly settled districts which do not admit of public waterworks depend 
upon the ground-water as the source of supply. For public distribu- 
tion, the water thus derived is stored in suitable reservoirs, which often 
must be covered in order to exclude light. Ground-water is destitute 
of plant life, but is generally more or less rich in mineral constituents, 
nitrates, and lime salts, for example, which constitute appropriate 
plant food. If exposed to air and light, vegetable growth may start 
up and become very luxuriant and give rise to unpleasant tastes and 
repulsive odors, while exclusion of light and air prevent the difficulty. 
For individual domestic supply, storage is not ordinarily necessary, 
the water being obtained only as immediately needed or pumped 
periodically into small distributing tanks. 
In general, unpolluted ground-water of not excessive hardness is 
preferable to surface-water, on account of the greater exposure of the 
latter to the many risks of pollution. But it must be borne in mind 
that all sources of supply, both surface- and ground-waters, may, under 
one condition or another, be liable to polluting influences, and that the 
conditions prevailing in one locality are likely to be quite different 
from those in another. 
Ground-water is obtained from springs, or by sinking wells, or by 
constructing filter galleries. 
Springs are merely local outcroppings of the water table and are 
very subject to variations in the volume of outflow. In time of 
drought they sometimes cease their flow completely because of fall in 
the level of the ground-water, and this may happen even in the case 
of those located at the foot of high hills or mountains. The popular 
mind endows springs with a remarkable and unvarying degree of 
purity, but they share with other waters the likelihood of becoming 
polluted. The possibility of contamination after and even at the point 
of issuance from the ground is too often overlooked. 
Springs are common to some localities and rare in others of similar 
contour, their presence or absence being determined by conditions not 318 
WA TER. 
of the surface, but of the geological formations below. In Figs. 25 and 
26 are shown in profile two depressions having the same contour, but 
with very different arrangement of the underlying strata. In Fig. 25 
the formation favors the outcropping of springs; in Fig. 26 the oppo- 
site is the case. 
Fig. 25. 
Fig. 26. 
Wells may be classed as dug, driven, and bored. Sometimes they 
are divided also into deep and shallow; but these terms as a basis of 
classification are of doubtful utility, since there can be no general agree- 
ment as to the line of division between them, and because of the ab- 
sence of any necessarily distinctive peculiarities in the water yielded 
by ordinary wells of different depths. It is not uncommon to meet 
with general statements that the water of shallow wells is dangerous to 
health and should, therefore, be avoided, and that all shallow wells 
should be condemned and filled. As will be seen, however, shallow 
wells are not necessarily dangerous, nor are deep ones always safe by 
reason of mere depth. 
By some writers, the term deep applies to wells which obtain their 
water from below the first impervious stratum, through and beyond 
which they have been extended, while the term shallow applies to 
those which draw from what we designate as the ground-water, that is, 
that collected over the stratum above mentioned, regardless of the 
depth at which it lies. With these meanings, it follows that a shallow 
well may extend farther downward than another classed as deep. 
The ordinary dug well is a hole dug in the soil down as far as is 
necessary to reach water, and lined with brick or stone, or better, with 
earthenware tubes of large diameter made for the purpose in short 319 
WATER SUPPLIES. 
lengths with bevelled edges to secure good joints. All brick and stone 
linings should be well bedded in cement, except near the bottom, and 
should be faced with the same material throughout their upper part. 
The impervious lining is necessary for the prevention of the entrance of 
surface washings, but it is very generally the case, in some parts of the 
country at least, that the well is lined very simply with field stones, 
without cement, not for the purpose of ensuring freedom from surface 
impurities, but to prevent the sides from caving in. With a proper 
lining, no surface-water can enter until it has passed through a depth 
of soil sufficient to insure proper filtration and purification. 
A dug well should not be left open, but should be closed completely 
against the entrance of dirt, leaves, and animals, such as toads, moles, 
mice, and rats. The cover should be supported on a well set curb, 
and sufficiently tight to prevent the return of water spilled or allowed 
to run to waste. A manhole with a trapdoor should be provided as a 
means of inspection and cleaning. 
For bringing the water to the surface, pumps should be used, and 
not buckets worked by windlass or well-sweep. In country districts 
it is a common practice to use buckets made from kegs, originally used 
as containers for white lead. It is hardly necessary to call attention 
to the injury which may be caused by the use of such vessels. 
The pump may stand directly in the well or away from it and con- 
nected therewith by means of a pipe running laterally and downward. 
The latter is the better way, as any water w'asted at the pump is pre- 
vented by location, if by nothing else, from running back into the well, 
and, moreover, the covering of the well, if of wood, is not continually 
subjected to wetting, which promotes its decay. The best form of 
pump is the simple lifting pump, made of iron or of wood, and con- 
sisting of an evenly bored barrel, closed at the lower part by a valve 
opening upwards, and a piston containing another. The upward stroke 
of the piston, by producing a vacuum, causes the water to pass through 
the lower valve, and its downward stroke forces the water confined in 
the barrel through the upper valve, and then the succeeding strokes 
lift and discharge it continuously. The old-fashioned chain pumps 
cannot be used without more or less chance of exposure to direct con- 
tamination from above. 
The action of the wind is very commonly employed as a labor saver 
for pumping water not only from the well, but upward into reservoirs 
and distributing tanks. For this purpose a variety of wind-mills have 
been invented and put upon the market. 
There are also a number of makes of hot-air engines that are very 
efficient and not unduly expensive. 
Driven wells, otherwise known as "Norton's tube wells," "Ameri- 
can," and "Abyssinian" wells, are made by driving iron tubes of a 
diameter varying from to 4 inches, according to the needs of indi- 
vidual cases, into the ground until water is reached. The first length 
driven in is provided with a pointed perforated foot through which the 
water enters the tube. When this length is driven sufficiently far, an- 320 
WATER. 
other is screwed to it and the driving is continued, new lengths being 
screwed on as necessary. When water is reached-and this is ascer- 
tained by means of a weighted string let down inside the tube from 
time to time-a pump is applied and the water lifted. The first that 
comes contains sand or fine 
gravel and dirt, and as this is 
more and more removed from 
below, a pocket is formed which 
constitutes an underground res- 
servoir. 
Bored wells differ but little 
from tube wells; in fact, they 
are practically the same except 
in the method of their making. 
They are drilled or bored 
through solid rock and other 
strata and are lined or not with 
iron pipe, backed with cement 
according to circumstances. 
Their cost is much greater than 
that of the ordinary Abyssinian 
well, since the labor required 
is much greater. Sometimes 
it is necessary, after proceeding 
several hundred feet with no 
results, to resort to blasting at 
the bottom, so as to shatter 
the rock and form waterways to the well. 
It is self evident that wells of these two kinds last-mentioned can- 
not, under ordinary circumstances, become contaminated with surface 
washings. Both forms are very commonly used not only for individ- 
ual, but for public supplies. In the latter case, they are driven in 
groups, or " gangs," the size of which varies according to the amount of 
water required. Increase in demand must be met by extension of the 
system rather than by over-forcing, for the latter will cause an undue 
lowering of the water level and tend strongly to bring water down- 
ward from the upper strata at such a rate as to preclude the purifica- 
tion which normally is brought about by the saprophytic bacteria of 
the soil. 
In the case of an ordinary well, the bottom should be considerably 
below the level of the ground-water, so that when this falls, the well 
will not run dry, and also because the farther the withdrawal by 
pumping carries the level of the well below that of the water table, the 
faster will be the flow toward the well, and the greater the supply 
immediately available. But deepening a well for the purpose of in- 
creasing the supply sometimes has the very opposite effect, and may 
even cause it to run practically dry. Suppose, for example, the im- 
pervious layer is underlaid by a thick stratum of coarse gravel, and in 
Fig. 27. 
Norton tube well. WATER SUPPLIES. 
321 
the process of deepening the well this stratum is entered : instead of 
an increase in the supply, it then may happen that the water flowing 
into the well finds a ready exit downward by the force of gravity into 
Fig. 28. 
How a well may be spoiled by being deepened. 
the interstices of the gravel, and the usefulness of the well is termi- 
nated. (See Fig. 28.) 
Included under bored wells are those known as Artesian. These 
are bored through impervious strata until a stratum is reached in 
Fig. 29. 
Ordinary ffed 
Artesian Welt 
Geological formation favorable to the obtaining of water by means of artesian wells. 
which the water is under hydrostatic pressure sufficiently strong to 
force it to the surface, or at least to a point nearly as high, the rise 
depending upon the height reached by the water-bearing stratum 322 
WATER. 
in higher land elsewhere. In Fig. 29 is shown a formation favor- 
able to the obtaining of water by means of this class of wells. The 
water in the soil above the first layer of clay may be reached by sink- 
ing wells of the ordinary kinds. Below this is a second supply con- 
fined between two impervious strata inclining upward. The higher 
this formation extends above the level of the outlet A of a well sunk 
into it at that point, the greater will be the pressure at B and the 
higher the rise of the water. Thus, if it extends upward to C, for ex- 
ample, the water will not simply fill the tube, but will be thrown some 
distance into the air. 
In some cases, although the head developed is very considerable, the 
water will not come to the surface, because of the extent of leakage into 
the upper pervious strata of the soil. 
Sometimes the wells are connected with true underground rivers, 
and sometimes with apparently inexhaustible reservoirs which have 
held the water in storage for ages. Sometimes they derive their water 
from fissures draining away the water of surface rivers and lakes, as is 
proven by the occasional occurrence in the overflow of small fish with 
eyes. 
Artesian wells have been known in China and Egypt from very 
ancient times, and centuries ago they were introduced into the prov- 
ince of Artois (Artesium) from which their name is derived. They are 
exceedingly numerous in the western and southwestern parts of the 
United States, where they have produced enormous results in convert- 
ing arid waste lauds into fertile farms. Some of them are exceedingly 
deep and pass through stratum after stratum of different formations 
before water is reached. 
Since the temperature of the earth increases one degree Fahrenheit 
for about 55 feet of depth, it follows that water from these very deep 
wells is materially warmer than that from the upper subsoil. Dis- 
tinctly hot water from deep sources is rarely fit for ordinary domestic 
purposes, because of the large amount of mineral matters present in so- 
lution by reason of the greater solvent power of water when hot than 
when cold. Thus they acquire an abundance of salts, which, taken into 
the body, influence its functions and act as medicines. The presence 
of organic matters is of importance on account of their reducing power. 
The sulphuretted hydrogen so common to mineral springs is due to the 
action of these matters on sulphates. 
Irrespective of the changes wrought by increased temperature, the 
water yielded by this class of wells varies very widely in character. It 
may bear no resemblance whatever to the other waters of the same 
district, nor is there any reason why it should, for the conditions at 
the surface and at points hundreds of feet below are quite different. 
Moreover, one cannot know how far the water has traveled from where 
it originally entered the soil to the point where it makes its escape. 
Of waters from four such wells sunk within the limits of the city of 
Boston to depths of from 870 to 2,503 feet, two were extensively im- 
pregnated with common salt and other mineral matter, one was very WATER SUPPLIES. 
323 
rich in both vegetable and mineral substances, and the fourth was rich 
in both these and sulphuretted hydrogen. 
Drainage Area of Wells.-As to the amount of soil which is drained 
by a well, there can be no general rule. It is commonly asserted that 
the amount drained may be described as an inverted cone, having the 
bottom of the well as its apex, and a base with a radius equal to twice 
the depth of the w7ell. But much depends upon the nature and con- 
figuration of the surrounding soil, and the extent to which pumping is 
carried. If the soil be sandy and open, the base will be much larger 
than if it be clayey and close. If extensively pumped, the well will 
drain a greater area than if the demands be moderate; in fact, the 
amount of water removed by pumping has a greater influence in de- 
termining the drainage area than mere depth. But other things being 
equal, the nature of the water-bearing stratum determines the distance 
to which the measurable influence of pumping is felt. 
Pollution of Wells.-In general it may be stated that as between 
wells of different depths, the shallower are more liable to pollution than 
the deeper, because of the fact that the latter have the advantage of the 
greater opportunity for perfect filtration through the soil. But both 
are liable to pollution by unoxidized matters which enter the soil be- 
low the upper few feet in which the nitrifying organisms already 
referred to are found, as, for instance, from leaching cesspools and 
leaking drains. It is a practice only too common, even on estates of 
considerable size where the excuse of limited area cannot obtain, to 
locate the well and the cesspool very near together. To avoid the 
necessity of having to remove the contents of the cesspool as occasion 
demands when this receptacle is made water-tight, and to avoid the 
expense attending this kind of construction, the bottom is generally 
left open so that the house sewage may drain away into the surround- 
ing soil. Connection between the cesspool and the well may take con- 
siderable time or may occur quickly, but once established, contamina- 
tion goes on uninterruptedly. Often it happens that the direction of 
the flow of filth through the soil is wholly away from the well, and 
contamination may never occur; but this is a point that can never be 
determined in advance. 
It is a common belief that if the well is located in higher ground 
than the cesspool, there can be no danger of pollution of its water. This, 
however, is a most fallacious proposition, for it is not so much the lo- 
cation of the outlet of the well that determines the possibility of pol- 
lution, as the relative position of the cesspool and the point where 
the water enters the well. In Fig. 30 is illustrated the manner in 
which the supply yielded to a pump placed at a point considerably 
above the location of the cesspool is directly polluted by the liquid 
filth issuing from the latter. Again, the geological formation may be 
such that a cesspool on higher ground than the nearby well will have 
no influence on the purity of the water. Thus, a ledge of rock may 
crop up between them, as shown in Fig. 31, and divert the flow of' 
polluting matters away from the well. 324 
WATER 
In locating wells and cesspools, property owners not infrequently 
lose sight of the fact that while they can govern the disposition of the 
surface of their respective estates, the conditions that obtain in the soil 
below are quite beyond their control. In consequence, they may at- 
tempt to guard against pollution of their own water supplies by their 
Fig. 30. 
How a well located on high ground may be polluted by the contents of a cesspool lower down. 
own excretory products, without regarding the possibility of contami- 
nation by those of their neighbors. 
The water of newly dug wells is often of such a character as to lead 
to the perhaps false conclusion that it is probably polluted by sewage. 
It is generally turbid and may, on analysis, yield results which, in 
case the analyst has not full information concerning it, may seem to 
warrant a condemnatory report. It may yield figures indicating a 
high content of organic matters which may disappear as the use of 
Fig. 31. 
How a cesspool located on high ground may fail to pollute a well lower down. 
the water becomes established. It may even show undeniable evi- 
dence of the presence of human wastes, for those engaged in the dig- 
ging and the stoning may be more interested in the completion of the 
work than in the perfect purity of the supply, and may be disinclined 
to go up to the surface for the purpose of relieving the calls of na- FILTER GALLERIES. 
325 
ture. On all accounts, therefore, it is better to await the results of a 
later examination than to condemn and abandon too hastily a supply, 
which, within a short time, may prove to be of exceptional purity. 
Very deep wells may become badly polluted by filth which gains ac- 
cess through open channel-ways, as fissures in rock. A good example of 
this is recorded in the Sanitary Inspector for December, 1896 : A well 
bored 500 feet into red sandstone drained, through fissures, all the shal- 
low wells in the vicinity. These being of no use as wells, were then 
utilized as cesspools, and, draining again through the fissures, caused 
the well to become so foul that it had to be abandoned. Dr. A. C. 
Houston1 shows how deepening a well may, in a similar manner, cause 
its ruin. A well of pure water, 114 feet deep, was deepened by fur- 
ther boring to 294 feet, when its yield was then found to be impure. 
At a distance of 800 feet was an old quarry, into which drained the 
sewage of 25 persons. By fissures in the sandstone, this reached the 
water stratum tapped by the extension of the well and thus spoiled 
the water. 
On account of the possibility of contamination of shallow wells by 
the entrance of surface washings from above, Koch recommends that 
pipes be placed in position so as to reach the water stratum and that 
then the wells be filled up, first with stone and coarse gravel, and to- 
ward the top, for at least six feet, with fine sand. By this procedure, 
the well is converted really into an Abyssinian well, and is quite as well 
protected from surface contamination as though it had been originally 
driven instead of dug. 
Filter Galleries.-A filter gallery is a large underground tunnel 
sunk parallel to a river or lake and near to it; it is in reality nothing 
more than a horizontal well. The idea which led to their construction 
was that in this way the river water, percolating outward from its bed 
through the soil, would be secured in a filtered state and would ac- 
cumulate in the underground reservoirs. Although this method of 
obtaining water has been attended by most excellent results, the fact 
remains that the water so collected comes not from the river, but from 
the ground on its hither side; that is to say, it is the ground-water in- 
tercepted on its way to the river. 
The water of a river does not, except under unusual conditions, 
percolate outward, for the silty matters deposited in its flow clog 
the interstices in the soil of its bed and banks and act as a valve 
against its egress. The ground-water, flowing to the river, finds 
its way in through the silt, which gives way inward against the side of 
least resistance. Thus the silt yields to ingress and is a bar to egress 
of water. 
The fact that the flow of ground-water is toward rather than away 
from rivers and other large bodies of water is well shown by the 
fact that fresh water is obtainable from wells sunk in close proximity 
to high-water mark on the seacoast. Such may be not even slightly 
brackish, though sometimes they are distinctly so by backward diffu- 
1 Edinborough Medical Journal, Nov., 1894. 326 
WATER. 
sion of the salts. In the latter case, removal a short distance back- 
ward obviates the difficulty. 
That the water derived from a filter gallery is not due to percola- 
tion from the river along which it lies, is further proved by the fact of 
difference in composition and especially in hardness. 
Classification of Waters from the Sanitary Standpoint. 
From the standpoint of wholesomeness, waters may be divided into 
two classes: 1. Those free from sewage contamination. 2. Those 
polluted by sewage. 
Unpolluted waters are not necessarily suitable for domestic use, pre- 
senting, as they do, wide variations in character. They may be clear, 
colorless, odorless and palatable, and contain but little organic and 
mineral matter; or they may have high color, turbidity, disagreeable 
odor and taste, and a high content of dissolved and suspended sub- 
stances. A water which, by reason of appearance, odor and taste, due, 
for instance, to luxuriant growth of algse or other forms of life, is re- 
pugnant to the senses, cannot be recommended for use, although in- 
capable of producing a specific disease. Such an one requires no 
chemical analysis to determine its fitness, the evidence of the senses 
being quite sufficient. 
Unpolluted waters free from such qualities as render them repug- 
nant to the senses, and of low content of organic and mineral matters, 
are suitable for general purposes without regard to their classification 
as surface- or soil-waters. But in general, it is commonly held that an 
unpolluted soft ground-water of good composition is preferable to one 
of surface origin. 
Polluted waters may be divided into two classes, according as the 
pollution is direct or indirect. Direct pollution by sewage is, it is 
hardly necessary to say, of prime importance, because of the danger of 
transmission of specific diseases and of lowering the physiological re- 
sistance of the system. But even direct pollution may be productive 
of no harmful results, provided sufficient time elapses between the en- 
trance of the sewage at a given point and the use of the water at a dis- 
tance to permit of the disposal of the noxious elements by natural proc- 
esses. Thus, a volume of sewage entering the upper part of a large 
system of public supply may not reach the distributing pipes for sev- 
eral months, during which time its dangerous qualities will have dis- 
appeared. Notwithstanding this fact, however, direct pollution of 
drinking water should be prevented by all means available, on account 
of possible risk and even on aesthetic grounds alone. 
Indirect pollution is of far less importance than direct. In indirect 
pollution the organic matters of the sewage, including bacteria, are fil- 
tered through the soil, in which they are held back mechanically and 
more or less completely oxidized before the containing water reaches 
its ultimate destination. As to what may be called a safe limit of 
distance from sources of pollution, no fixed rule can be made : each CLASSIFICATION OF WATERS FROM SANITARY STANDPOINT. 
327 
case must be judged according to its own circumstances. The soil as 
a whole has enormous capacity for purifying water of its contained or- 
ganic substances and bacteria, both by mechanical retention and by 
oxidation processes set in motion by the bacteria which inhabit it. 
But all soils have not this power in an equal degree, and the conditions 
favorable to its exercise are not always present to the same extent. 
The soils most favorable for perfect filtration and purification are sandy 
and gravelly ; in these, the water is exposed in thin layers on the in- 
dividual grains to the air in the interstices. The latter must be 
neither too coarse nor too fine. If too coarse, the passage of water is 
too rapid; if too fine, not enough air can be present at the same time. 
The organisms are found only in the upper few feet of soil, and 
it is here also that the contained air is richest in oxygen. When the 
necessary conditions for filtration are present in a given soil, the water 
which percolates through and reaches the ground-water is quite free 
from bacteria of any kind, even though the surface is extensively con- 
taminated. Where the soil is very open and permeable to water or 
fissured, polluting materials may pass through so rapidly that they 
undergo but slight change on the way, while with a not too fine soil 
through which water passes with slowness, purification by bacterial 
action may be completed within a very short distance. 
Again, there may be greater safety at a point quite near to, but on 
one side of a center of pollution, than at another at a considerable dis- 
tance away on the other side, owing to the direction of the flow of 
water. Thus, in Fig. 32, the point S, located quite near the point of 
Fig. 32. 
entrance of the polluting material P into the soil, is far better situated 
in respect to possible contamination of water by P, than the point D 
on the other side but farther away, since the movement of the water 
in the soil is, as indicated by the arrows, from S toward D, and all im- 
purities entering between the two move from the one toward the other. 
Similarly, the point £ may stand in the relation of point D to some 
other polluting influence. 
For the determination of the question whether a given well is re- 
ceiving pollution from any given point, recourse is had to the diffusi- 
bility of coal-tar colors such as fluorescein. An ounce of this sub- 
stance will impart a very decided color to an enormous volume of 
water, and when it is added to the contents of a leaching cesspool, it 
will accompany the escaping pollution and reveal to the eye the pres- 
ence of the latter in any neighboring well water. Pollution can thus 
be traced sometimes through hundreds of feet of fairly close soil. 328 
WATER. 
Before proceeding to the consideration of methods employed to bring 
about purification of water supplies, a few words are necessary on the 
subject of " self-purification " of surface-waters. A river shows, for 
instance, at a given point in its course a certain amount of impurity; 
at another point farther down, this is found to be considerably lessened, 
and farther yet the diminution is still more marked. This progressive 
lowering is attributed to the property the water possesses of bringing 
about its own purification. The practical beginning of this theory was 
the assertion, made, in 1869, by the British Royal Commission on Water 
Supplies, that sewage, diluted twenty times or more by river water into 
which it is discharged, will be completely oxidized before it has trav- 
eled more than a dozen miles. 
Five years later, the Rivers Pollution Commission reported strongly 
against this idea and concluded that oxidation proceeds with such ex- 
treme slowness, even when the polluting matters are very largely di- 
luted by pure water, that not only will a short flow of a dozen miles 
not suffice, but that there is no river in the United Kingdom long 
enough to accomplish the result claimed. It was then believed that 
whatever changes occur are the combined result of oxidation and sub- 
sidence. It is now recognized that these agencies, assisted by more 
important ones, namely, dilution, vegetation and bacterial action, do 
in many cases produce very great changes, while in others the results 
are only partial and of no especial value. Drs. R. Emmerich and F. 
Brunner1 showed that in spite of the large amount of sewage matters 
poured into the Isar in its course through Munich, the water after two 
hours' flow below the city was practically as pure chemically as it was 
before it reached it. E. Duclaux 2 has shown the same to be true of 
the Seine, and other observers have proved it of certain other rivers 
in England, Germany, and elsewhere. On the other hand, opposite 
results have been obtained by other workers in the same field. 
Oxidation undoubtedly plays a more or less important part in some, 
but by no means in all cases. Dr. T. Meymott Tidy proved experi- 
mentally that water containing sewage could lose about half its or- 
ganic matter in from six to nine hours when made to run one mile in 
glass troughs with abundant aeration. Professor William P. Mason,3 
on the other hand, agitated water in a bottle fastened to the connect- 
ing rod of a horizontal engine with a ten-inch stroke of 75 to the 
minute, and found that after 9,000 concussions there was but a trifling 
diminution in the amount of organic matter. A large measure of 
purification, so far as numbers of bacteria are concerned, is caused by 
agitation when there are solid particles in suspension in the water. 
This has been well shown by Dr. Percy Frankland,4 who observed a 
decrease of 96.65 per cent, in the number of bacteria. 
Purification of Water. 
1Die Chemischen Veranderungen des Isarwassers, Munich, 1878. 
2 Annales de 1'Institute Pasteur, 1894. 
3 Water Supply, New York, 1897, p. 175. 
4 Journal of State Medicine, January,»1894. 329 
METHODS OF PURIFICATION. 
Dilution by access of rain, melting snow, ground-water, and other 
clean influents affects chemical composition favorably, but assists, 
for a time at least, increase in the numbers of pathogenic and other 
bacteria. Professor Kebrehl's1 daily bacteriological examinations of 
river water at Prague proved that in general the number of bacteria 
increases with rising water and is subject to very wide variations 
due to a number of causes, among which he mentions changes in the 
rate of flow with consequent alteration of conditions influencing sedi- 
mentation, and the influx of temporary pollutions, such as washings 
from streets and dung-heaps, which, under some circumstances, have 
greater influence than the regular unclean influents. 
Sedimentation, which was formerly thought to play a very great 
part in the improvement of river waters, acts to only a slight extent in 
those which, like the Isar, move swiftly. It is favored by slowing of 
the current, especially at the river mouth, and when it occurs it has a 
very marked influence on the number of bacteria, especially if the water 
be muddy. This has been shown by Bruno Kruger,2 who, by a series 
of experiments, proved that chemically indifferent substances in a state 
of minute subdivision exert a greater influence the more slowly, up to a 
certain limit, they settle, while other matters which act both mechanic- 
ally and chemically, such as lime and hard wood ashes, produce still 
greater effects. In still water, as small lakes and ponds, sedimentation 
goes on unobstructed. 
Bacterial action as a purifying agent is favored by alkalinity and 
retarded by acidity. It may be important or not, according to cir- 
cumstances. Destruction of pathogens by the saprophytic class is 
delayed by dilution by unpolluted water, which, as above stated, 
favors their increase for a short time, after which they rapidly decline 
in number. 
Vegetation was not taken into account by the earlier observers, 
but has now been placed at the head of the important influences in 
the process. Pettenkofer3 believes that the greater part of self-purifi- 
cation is due to the growth of algse and other low forms of vegetable 
life, which clean the water of its impurities in the same way that the 
higher forms take up and dispose of the manurial matters of cultivated 
land. This view is endorsed by T. Bokorny,4 who proved that these 
plants take up all manner of organic substances including volatile fatty 
acids, amido acids, glucose, and urea. He showed that the water of 
the Isar contains vast numbers of algse to whose action much of the 
changes noted by Emmerich and Brunner were undoubtedly due. 
Methods of Purification.-The methods employed for the purifica- 
tion of water embrace : 
1 Bacteriologische und kritische Studien uber die Verunreinigung und Selbstreini- 
gung der Fliisse. Archiv fiir Hygiene, XXX., p. 32. 
2 Die physikalische Einwirkung von Sinkstoffen auf die im Wasser befindlichen 
Mikroorganismen. Zeitschrift fiir Hygiene, VII., p. 86. 
3 Zur Selbstreinigung der Fliisse. Archiv fiir Hygiene, XII., p. 269. 
4Ueber die Betheiligung chlorophyllfiihrender Pflanzen an der Selbstreinigung der 
Fliisse. Archiv fiir Hygiene, XX., p. 181. 330 
WATER. 
1. Chemical treatment. 
2. Boiling and distillation. 
3. Filtration. 
1. Chemical treatment is employed to cause the formation of insolu- 
ble precipitates which settle out and mechanically entangle suspended 
matters, including bacteria, in their descent. 
Alum, for instance, added to the extent of a quarter of a grain to a 
grain per gallon of natural water containing a moderate amount of 
CaCO3, is decomposed and forms an insoluble gelatinous hydrate, which 
combines with the organic matters imparting color and settles out as 
a flocculent precipitate, which entangles mechanically the suspended 
matters, including the bacteria. The sulphuric acid, set free by the 
decomposition of the salt, unites with the lime or other bases present 
and is thus neutralized, and the calcium sulphate thus formed carries 
down suspended matters in the same manner. 
If an excess of alum is added, it will necessarily appear in the puri- 
fied water and be objectionable on account of its effect on the system 
and in the bath and in washing. 
In case of deficiency in CaCO3, lime water is sometimes supplied, and 
the same results are thus obtained. The addition of freshly precipi- 
tated alumina serves the purpose equally well, and avoids the presence 
of the sulphuric acid resulting from the decomposition of alum. 
Alum removes practically all the bacteria, as has been proved by V. 
and A. Babes,1 Professor E. Ray Lankester and others. The use of 
alum in the purification of water is not of recent origin : it was de- 
scribed as early as 1830 by Felix D'Arcet,2 who mentions its extensive 
use in Egypt. 
Lime water or milk of lime, added to water containing calcium car- 
bonate held in solution by carbonic acid, causes a precipitation of the 
former by uniting with the latter. It thus withdraws the solvent from 
active service, causes the precipitation of that which was held in solu- 
tion, and, becoming itself converted to an insoluble substance, is itself 
precipitated. So a double precipitation occurs. 
But water thus treated is not necessarily limited in its changes to a 
removal of its excess of calcium carbonate, for in the precipitation of 
this substance, considerable other matter may be carried down mechan- 
ically, and bacteria are decidedly reduced in number. 
Permanganate of potassium is used more or less, particularly in 
wells in India during the prevalence of cholera epidemics. Enough 
is added to secure a slight pink tinge which indicates a slight excess. 
This acts as an oxidizing agent with good results. For example, Dr. 
P. W. O'Gorman 3 relates that during an outbreak at Midnapore, the 
number of cases, 117, was supposed to have been kept down by its 
use. These occurred in all parts of the town, excepting in the Euro- 
1 Centralblatt fiir Bakteriologie und Parasitenkunde, 1892, XIL, No. 45. 
2Note relative ala clarification de 1'eau du Nil, et en general des eaux contenant 
des substances terreuses en suspension. Annales d'Hygiene Publique, IV., p. 375. 
3 Indian Medical Gazette, July, 1896. METHODS OF PURIFICATION. 
331 
pean quarter and at the jail. The former used water which was 
filtered or boiled and filtered, and at the jail especial care was taken 
of the water supply. Forty-six public and private wells were disin- 
fected with the salt and the outbreak thereupon ceased. An ounce 
or ounce and a-half or more, according to the size of the well, was dis- 
solved in a bucket, poured into the well and stirred about. If after 
half an hour the water showed a red tinge, it was considered that enough 
had been added ; if not, more was added until a tinge was seen. 
In some cases, however, in which this agent is used, too much is 
added, and then the fish, frogs, and turtles, put into the wells to keep 
the water clean, are killed, and the water thereby becoming putrid, the 
people are driven to use other perhaps untreated water. On the other 
hand, too little may be added and thus the desired action is not pro- 
duced. Enough should be added to insure a reddish tinge lasting 
twenty-four hours (E. H. Hankin, Indian Medical Gazette, July, 
1896). 
Sodium hypochlorite, " chlorinated soda," and chlorinated lime, 
" chloride of lime," are sometimes used, but in the case of both not 
without great risk of imparting disagreeable taste. Moritz Traube1 
gives a simple method of purification by means of the latter agent 
which, added to the extent of less than half a gram to a hundred liters, 
kills all bacteria within two hours. The excess of the agent is neu- 
tralized by the addition of somewhat less than half the amount of sul- 
phite of sodium, which, added somewhat in excess, does no harm, 
since it is soon oxidized. The claim is made that water thus treated 
possesses no disagreeable taste and has its hardness not appreciably 
increased. 
The "Woolf" method consists in adding a two-to-three-per-cent. 
solution of salt decomposed by a current of electricity of sufficient 
strength. This is equivalent to adding the sodium hypochlorite itself. 
Chlorine as such is also somewhat used, but, though effective, it is 
open to the objections that apply to the use of the hypochlorites, of 
which it is the active agent. 
Bromine also has its advocates as a chemical purifier, both on a 
small and on a large scale. Schumburg 2 recommends a process which 
in five minutes is said to kill nearly all of the ordinary bacteria and 
all pathogenic organisms found in water. He uses a solution of twenty 
parts each of bromine and potassic bromide in a hundred of water, 
one cubic centimeter of which suffices to sterilize five liters of Spree 
water. After five minutes' contact, the bromine is neutralized with 
ammonia and the result is a clear, tasteless, sterile water. Very hard 
waters and grossly polluted river and marsh waters require larger 
amounts, because of the presence of lime salts in the former and of 
ammonia in the latter, which combine with the bromine before it has 
an opportunity to act as a germicide. With such it is necessary to add 
enough of the solution to produce a yellow tinge which will persist at 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XVI., p. 149. 
2 Deutsche medicinische Wochenschrift, March 4, 1897. 332 
WATER. 
least half a minute. In any case, whatever the amount of the bro- 
mine solution used, an equal volume of nine-per-cent, ammonia water 
must be added. 
This process is particularly recommended for use in the army, and 
in the tropics, for ships' supplies, and for individual use in times of 
epidemics. By this process, a kilogram of bromine will suffice to 
sterilize 16,000 liters of ordinary water. 
Treatment with metallic iron in the form of borings and punchings 
is employed in a number of places in Europe with most successful re- 
sults. The best known of the processes in which this agent is em- 
ployed is that of Anderson, in which the water is delivered into long 
iron cylinders, on the inner surface of which are long curved partial 
diaphragms which, as the apparatus slowly revolves, carry upward the 
pieces of iron, which fill about a tenth of the volume of the cylinder, 
and cause them to shower constantly downward through the water in 
its passage. The carbonic acid in the water attacks the iron and forms 
ferrous carbonate which, when the water is discharged into the open 
air and exposed to its influence, becomes oxidized and converted to 
ferric hydrate. 
This flocculent matter entangles much of the organic matters, in- 
cluding the bacteria, and then the whole is passed through sand filters, 
the effluent from which is very pure and practically sterile. The 
process is unnecessarily expensive, involving as it does in addition to 
the first cost of the plant, considerable outlay for power and other items, 
while the same results in the end can be obtained by the more simple 
process of sand filtration alone. Moreover, it appears that with peaty 
waters, the organic constituents of which form soluble compounds with 
the iron, the results are unsatisfactory. 
The use of ozone has been recommended as a very efficient method 
of sterilizing drinking water, and experiments on a large scale have 
yielded favorable results. Experimenting on very small quantities 
with a Siemens-Halske apparatus, Weyl found that 2.3 milligrams of 
ozone was sufficient to destroy 99 per cent, of the bacteria contained 
in 200 cc. of water from the Tegel Lake. With 3 and 4 milligrams, 
he obtained complete sterilization of a half liter of water containing 
6,000 bacteria to the cc. 
For purification on a large scale*, the impure water is caused to perco- 
late through a tower filled with pebbles, through which the ozonized air 
passes upward. The Siemens-Halske apparatus used will produce 20 
grams of ozone in an hour. The bacteria are reduced at least 99 per 
cent, and the percentage of organic matter is greatly diminished, but 
the process is at present very imperfect, for more than 70 per cent, of 
the ozone produced is lost. 
The ozonized water, though free from odor, has an unpleasant 
taste, and with many its use causes derangement of the stomach. 
This necessitates further electrolytic treatment with aluminum elec- 
trodes, whereby aluminum hydrate is formed and the water is clarified 
and freed from ozone. DOMESTIC FILTERS. 
333 
Chemical purification of water sometimes occurs without the inter- 
vention of processes especially provided, of which fact Professor Leff- 
mann 1 records a conspicuous instance. The Schuylkill River in the 
upper part of its course receives much refuse mine-water and becomes 
impregnated with iron salts and free mineral acids. " In its course of 
about one hundred miles it passes over an extensive limestone district, 
and receives several large streams highly charged with calcium car- 
bonate. The result is a neutralization of the acid and a precipitation 
of the iron and much of the calcium. The river becomes purer, and 
at its junction with the Delaware River, at Philadelphia, it contains 
neither free sulphuric nor hydrochloric acid, only traces of iron, and 
but a small amount of calcium sulphate. In this manner there is pro- 
duced a soft water, superior to that of the river near its source, or to 
the hard waters of the middle Schuylkill region." 
2. Boiling and Distillation.-Boiling as a means of purification has 
been practiced from very early times, and, in fact, was advised by Hip- 
pocrates (460-377 B.C.) for the avoidance of enlargement of the spleen. 
This process is quite efficient so far as destruction of the micro-organ- 
isms is concerned, but it does not diminish the amount of organic 
matter. It does, however, reduce the amount of dissolved mineral 
matter, in that calcium carbonate held in solution by carbonic acid is 
precipitated, and calcium sulphate, being less soluble in hot than in cold 
water, tends to separate out. 
Boiling is available only to a limited extent; that is, it is a process 
which can be carried out in the household, but not on a large scale be- 
fore public distribution of water. Boiled water is not palatable until 
aeration has restored the proper taste, but this is easily accomplished 
by passing it from one vessel to another, or by agitation in contact with 
air. 
Distillation constitutes a most efficient process for obtaining pure 
water. This process produces necessarily a sterile water, which, how- 
ever, needs thorough aeration. In the apparatus used in the United 
States Navy, the steam goes to the condensers in company with air, so 
that condensation and aeration occur coincidently. While no bacteria 
from the original water can pass over into the distillate, other volatile 
matters can and do, and instances are common to prove that the dis- 
tillate of a foul harbor water may produce nausea and diarrhoea in all 
who drink it. 
3. Filtration is a process of purification which is most efficient and 
available for large water supplies. It is employed on a large scale by 
numerous large cities in Europe and in this country. Before describing 
the process, however, it is in order to consider filtration in the house- 
hold. 
DOMESTIC FILTERS. 
The small domestic filters in common use are, as a rule, quite useless 
except for the removal of suspended matters such as iron-rust, dirt, and 
1 Examination of Water for Sanitary and Technic Purposes, Phila., 1895, p. 14. 334 
WATER. 
other coarse particles, and worse than useless in respect of bacteria, the 
removal of which is claimed but not accomplished, in that they 
engender a false sense of safety, while they favor the growth and mul- 
tiplication of organisms. Most of them are small affairs for attach- 
ment to the water faucet, filled with a filtering medium of coarse sand, 
animal charcoal, sponge, ground glass, wool, felt, and other substances 
which simply strain out the visible suspended matters not a whit better 
than the simple flannel bag in common use in New England and else- 
where a quarter of a century ago. They permit the passage of a good 
stream, and this fact itself is proof of their inefficiency as bacteria 
filters, for any material coarse enough to permit rapid passage of water 
is not fine enough to hold back the exceedingly minute suspended 
matters such as bacteria. 
Most of the materials used become very foul 
in a short time, and in consequence the water is 
richer in bacteria on issuing than it was before 
entrance. Theoretically, animal charcoal, on 
account of its oxidizing action, should be an 
ideal filtering medium, and at first it will re- 
move a large proportion of the bacteria and more 
or less of any coloring matters. But very shortly 
it becomes foul ; the calcium phosphate which 
it contains is of great assistance to the growth of 
bacteria ; cleaning is impossible, and the effluent, 
if stored, soon becomes very foul and unpleasant. 
The only domestic filters worthy of the name 
are those which remove mechanically all the 
bacteria of the water and, at the same time, add 
nothing of their own substance to the water. 
Such are the Chamberland-Pasteur, the Berke- 
feld and others based on the same principle. 
In these, the filtering medium is unglazed, well- 
baked, hollow, porcelain cylinders closed at one 
end like a test-tube, enclosed within a metallic or glass jacket, with 
sufficient intervening space for the water, which enters directly from 
the tap under its usual pressure or " head." The open lower end of the 
cylinder discharges the water, which passes directly through the walls 
of the cylinders, or " bougies," in the same way in which it would go 
through blotting paper. The material is such a very fine strainer that 
it will exclude all suspended matters whatsoever. (See Fig. 33.) 
The bougies of the Chamberland-Pasteur filter are made of well- 
baked kaolin of the proper degree of porosity and hardness ; those of 
the Berkefeld were formerly made of a soft friable infusorial earth pe- 
culiar to Germany, called Kieselguhr, but as they were very brittle 
and very liable to fracture while being cleaned, they are now made of 
a special blend of clays used in the manufacture of the finest porcelain. 
Those of other makes are of porcelain of varying grades. 
All these filtering tubes are purely mechanical in their action and 
Fig. 33. 
Chamberland-Pasteur filter. DOMESTIC FILTERS. 
335 
remove none of the matters, poisonous or otherwise, in solution, 
While they remove and retain on their external surface all the bacteria, 
they cannot prevent the growth of the organisms from without inward 
through their walls, and, indeed, this occurs so quickly that in order 
to secure absolutely sterile water continuously, it is necessary to clean 
and sterilize the bougies daily, and thus it is advisable to have two sets, 
one of which can be cleaned while the other is in use. 
It has been proved repeatedly that normal water and water artifici- 
ally and extensively infected will yield on the first day of the use of a 
clean bougie a perfectly sterile filtrate, and that on the second or third 
day a very small number of bacteria will most likely be present; but 
these first ones are invariably ordinary water bacteria, and if the patho- 
genic varieties occur in the filtrate, they must come considerably later. 
Experiments with water infected with Bacillus coli communis, B. 
typhosus, and the comma bacillus have repeatedly failed to prove the 
passage of any of these organisms, while the ordinary water bacteria 
go through very readily. To secure a regular supply of wholesome 
if not completely sterile water, it is, therefore, quite sufficient to clean 
the tubes by scrubbing and boiling or by baking about twice a week. 
It is not infrequently the case, especially when the cleaning is left to 
servants, that it is performed at rare intervals or not at all. 
Dr. W. H. Barr1 describes a new form of domestic filter which, he 
claims, possesses certain advantages over the easily breakable candles. 
It consists of a perforated cylinder of aluminium or tinned copper, from 
seven to thirty-six inches in length by seven-eighths to five inches in 
diameter, covered with a jacket of mercerized cambric coated by auto- 
matic action with a thin, smooth, homogeneous layer of purified earths 
such as china clay, kieselguhr, etc., which instantly close the inter- 
stices of the cloth. All suspended matters, including vegetable slimes 
and bacteria, are retained on the surface of the covering, which, 
after a time, impedes or totally stops filtration by clogging. The film 
of dirty matter is easily removed by a stream of water from the 
top, and the apparatus can be thoroughly cleaned by means of soap 
and brush. The coating is renewed by pouring into the outer pres- 
sure-proof case the earth mixed to the consistence of cream with 
water. The loss by breakage is nil, and large volumes of water are 
filtered in little time. 
In general the requirements of a satisfactory domestic filter may be 
stated as follows : It should yield a sufficient supply of clear colorless 
water free from any taste derived from the filter itself, should arrest 
all bacteria and their spores, and should be simple in construction and 
offered at a low price. Thus far, those made on the principle of the 
Chamberland-Pasteur filter have met these requirements best. Their 
introduction into use in the French army in 1889 was followed within 
two years by a reduction of over fifty per cent, in the number of cases 
of typhoid fever occurring therein. 
1 Public Health, March, 1899. 336 
WATER. 
Filtration of Public Supplies. 
Filtration on a large scale is accomplished by the aid of fine sand in 
filter beds of proper construction, which act both mechanically and 
biologically. The first beds of which we have any accurate knowledge 
were those constructed by Simpson in London in the year 1830, and 
those were intended primarily for the removal of dirt and other sus- 
pended matters causing turbidity. The process was regarded at that 
time as a purely mechanical one, and though in course of time the use 
of this kind of filtering medium became very extensive, it was gen- 
erally believed that as carried on there was no very marked chemical 
change in the water, and that what there was was attributable to oxi- 
dation of organic matter by air in the interstices of the sand. This 
was, indeed, the view held generally up to the time when the exten- 
sive researches begun by the State Board of Health of Massachusetts 
in the summer of 1887 proved the great influence of biological agen- 
cies, although it had been already shown by Meade Bolton, Heraeus, 
Plagge, Proskauer and others that filtration removed all but a trifling 
percentage of micro-organisms and that water bacteria exerted some 
influence on the amount of the usual constituents of water. 
Although sand filtration of public supplies is of comparatively 
recent origin, its use for individual house supplies antedates Simpson 
by at least a century and a-half, for Portius,1 writing in 1685, relates 
that the Venetians were accustomed to filter their drinking water 
through layers of sand within their cisterns, in order to rid it of disa- 
greeable odor and taste. 
The first beds constructed by Simpson were broad basins twelve feet 
in depth with impervious bottoms and sides, containing layers of 
stones, gravel, and sand, 
which occupied half their 
depth. Beneath the stones 
were laid ordinary drain 
pipes through which the 
filtered water was dis- 
charged. As the top 
layers of sand became 
clogged, they were scraped 
and renewed. The beds of 
the present day are con- 
structed on very similar 
lines. They are virtually 
immense tanks of varying 
size, shape, and construc- 
tion. The walls are some- 
times vertical, but more often sloping, sometimes built of stone or con- 
crete, and sometimes consisting of ordinary embankment. Upon the 
Fig. 34. 
FINE SAND 
COARSE SAND 
FINE GRAVEL 
COARSE GRAVEL 
DRAIN PIPES 
Partial vertical section of one form of filter bed. 
1 De militis in castris sanitate tuenda, anctore Luca Antonio Portio, Vienna, 1685. 337 
FILTRATION OF PUBLIC SUPPLIES. 
paved bottom of a bed is laid a system of perforated or disjointed drain 
pipes leading to a central culvert or well from which the filtered product 
is drawn. Above the drains are successive layers of coarse gravel, fine 
gravel, coarse sand, and, at the top, one of fine sand from three to five 
feet in depth. (See Fig. 34.) 
The fine sand is sharp-grained in character, such as is obtainable at 
the seashore, and it must not contain clay or other material of similar 
minuteness of particle; if present, such must be completely removed 
by thorough washing. As to the size of the sand particles, it may be 
stated generally that the finer the grain, the better the effluent, but, it 
must be added, the more rapidly it becomes clogged and the more 
frequently it must be scraped off, and finally, the more difficult it is 
to wash for future use. With the finest sands, the bacteria are abso- 
lutely removed, but filtration proceeds so slowly that their use is not 
practicable. The most effective size of grain is a matter on which 
opinions differ, but whatever the size adopted, it is important that es- 
pecial care be taken to insure uniformity. It is variously stated to be 
from a fifth to one millimeter in diameter, that is, the diameter of a 
sphere in volume equal to that of the grain without regard to the 
shape of the latter. The higher figure is the one adopted by the au- 
thorities at Hamburg. 
Before the water is applied to the bed, it may be advisable-and if it 
is from a turbid river, it will be necessary-to allow it to stand several 
days in a settling basin or reservoir, in order that the suspended mat- 
ters may subside and thus the too rapid clogging of the interstices 
of the sand with mud be prevented or retarded. Observance of this 
precaution will result in lessened necessity of frequent cleaning. Not 
only are the suspended matters reduced in amount, but organic mat- 
ters in solution may be more or less destroyed by bacterial action, 
and the bacteria, too, may be reduced in number by being carried 
down with the settling matters with which they are in contact, and by 
the death of the less hardy varieties. In the case of waters from ponds 
and lakes, the preliminary sedimentation proceeds in situ and the set- 
tling tank is not needed. 
The water is delivered continuously at the surface of the bed by de- 
vices automatically regulated, and percolates downward through the 
various layers of sand and gravel to the outlet pipes. Except with 
very fine sands, the first water of the effluent is not much, if any, 
purer than the original, but in a short time a sediment layer is formed 
on the surface and a slimy algoid growth occurs. This superficial 
layer acts both mechanically and by its contained bacteria to cause the 
removal and oxidation of organic matter and destruction of bacteria. 
The resulting effluent is quite pure and practically sterile. The Law- 
rence filter, for instance, removes over 97.50 per cent, of the organ- 
isms present in the water as delivered, and the reduction is still more 
marked at the house service pipes, where 99.17 per cent, is recorded, 
the increase in purification being supposedly due to the fact that their 
necessary food material has been removed and hence they cannot long 338 
WATER. 
survive. At Hamburg, Altona, Stuttgart, London, and other places, 
the reduction in bacteria is about the same as at Lawrence. 
All organic matters are not acted upon to the same extent during fil- 
tration ; some are very rapidly decomposed and mineralized, while 
others are so slowly attacked that complete removal during the short 
period elapsing between entrance and exit is often quite impossible. 
This latter class includes the brown coloring matters so commonly 
present in surface-waters. These are very stable compounds : they 
persist during long storage and are nitrified but slowly. In the proc- 
ess of chemical treatment with alum, however, they are very quickly 
coagulated and removed. 
The slime layer, mud layer, or " schmutzdecke," is believed by some 
to constitute the sole actual filtering medium, the sand beneath acting 
only as a means of support. But experiments conducted at Lawrence 
and elsewhere show that this is not true, and that if the greatest care be 
exercised not to disturb the immediately underlying sand, almost the 
whole of the slime layer may be stripped off without causing any 
change in the bacteria count. The greater part of the work is done in 
the upper layers of the bed, and yet bacterial efficiency is not neces- 
sarily established as soon as a coating has been formed. A perfectly 
new filter does not show its best results until it has been in use for 
some little time, during which the sand particles for a considerable 
depth become coated with the jelly-like deposit. 
The active agents in bringing about the death of the bacteria con- 
tained in the effluent and in accomplishing the destruction and miner- 
alization of the organic matters are of the same class of nitrifying 
organisms as are constantly at work in the soil. The death of the 
bacteria is not directly due to the process of nitrification, for it has been 
proved that a very marked increase in the process is not necessarily 
accompanied by any diminution in the number of organisms which 
manage to pass through to the drains. It is possible that the supposed 
relation of cause and effect is merely a coincidence of conditions, that 
is, that the conditions favorable to nitrification are unfavorable to the 
vitality of the ordinary bacteria. It is also possible that through 
nitrification the latter are deprived of at least part of the food materials 
necessary to their continued existence and multiplication. 
Nitrification sometimes ceases suddenly after it has been proceeding 
for a long time at a proper rate, and then, after an interval, begins 
again without any apparent reason. One explanation offered is that 
the process begins only when a certain amount of nitrogenous matter 
has accumulated within the interstices, that it then proceeds until the 
store is consumed, and that pending a further accumulation the process 
lapses. In winter it does not begin again until the temperature of the 
effluent reaches at least 39° F., but after it is once started it is un- 
affected by a fall to 35°. The most favorable temperatures for the 
process are those of the hot summer months. 
As to the rate of filtration, it is important that whatever the rate, it 
shall be uniform all over the filter. It has been proved by the Massa- FILTRATION OF PUBLIC SUPPLIES. 
339 
chusetts State Board of Health that 2,000,000 gallons per day can be 
filtered through each acre of filter bed with the removal of substantially 
all the bacteria originally present. The Imperial Board of Health of 
Germany fixes as a maximum amount permissible 2,500,000 gallons 
per acre. Koch's three rules of filtration are that the rate of down- 
ward movement shall not exceed 100 millimeters an hour, that the 
filtrate of each section shall be examined daily while the bed is at work, 
and that filtered water containing over 100 bacteria to the cc. must 
not be allowed to enter the pure water reservoir, but must be rejected 
or refiltered. The bacteriological test is much superior to chemical 
analysis for watching the efficiency of a filter, and a simple count is 
quite sufficient without attempting to identify the species. 
When the filter begins to discharge slowly on account of the extent 
of the algoid growth at the surface, it is not safe to increase the pres- 
sure unduly by flooding the bed with an increased depth of water, for 
as was shown by an experience at Berlin, such a procedure may force 
the bacteria, which have accumulated largely in the meshes of the 
growth, down through the filter at such a rate that they are not de- 
stroyed by the usual agencies. In this case the water level was raised 
two feet with the result that the portion of the city which was supplied 
with the water of that particular bed was visited by an epidemic of 
typhoid fever. The same sort of accident occurred at Altona a few 
years ago, when a year after successfully going through the cholera 
epidemic which so devastated the neighboring city of Hamburg, a de- 
fect in the filter beds was followed by an outbreak of cholera, which 
disease had then died out in Hamburg. 
When the sediment layer becomes so thick and dense that with the 
maximum pressure allowable the required amount of water fails to 
pass, it becomes necessary to scrape off the inch or so that has formed, 
and then to proceed as though the bed were new. 
It will require, as a rule, several days for the formation of a new 
sediment layer, and until it is well developed the effluent must either 
be rejected or pumped back. The frequency with which a bed will 
require to be scraped depends upon individual circumstances such as 
the size of the grains, the character of the water as applied, the rate 
of movement, the season of the year. The removal of the top is not 
difficult. It is quite compact and distinct from the sand beneath it, 
and is readily pared off with shovels or other tools. Successive clean- 
ings may take place without replacement of the sand until the depth 
of the filtering material is reduced to about 15 inches, but not below 12. 
The scraped-off sand may be thoroughly washed in a machine for 
the purpose until a sample in a beaker yields no turbidity to clean 
water, and it may then be stored until needed for future application. 
Experiments have been tried repeatedly in Berlin, Massachusetts, 
and elsewhere in sterilizing sand by boiling it in water or otherwise 
subjecting it to high temperatures, and then determining its efficiency. 
The results have invariably proved that more bacteria are found in the 
filtrate than in the original water, and this is explained by the suppo- 340 
WATER. 
sition that the bacteria that enter find in the cooked organic matter a 
food supply most favorable to enormous multiplication, and that the 
bacteria in the washed sand are necessary for the destruction of organic 
matter and of some of the varieties of water bacteria. 
During and immediately after the scraping process, the bed is neces- 
sarily out of use and, therefore, it is necessary in order to ensure con- 
tinuous filtration to have a number, of separate beds, and to scrape 
them in turn. In this way, while one is out of use, the others can carry 
on the work. 
In cold weather, owing to increased viscosity of the water, the rate 
of filtration is less than in the warmer months. In very cold climates, 
the formation of thick ice makes proper cleansing of the surface im- 
possible ; and imperfect scraping causes imperfect filtration. The re- 
moval of the ice considerably augments the cost of maintenance, and 
this item alone is one of sufficient importance to warrant the expense 
of covering the beds. But aside from cost, the efficiency of the process 
is so much greater and the danger of epidemics of water-borne disease 
so much diminished that the plant in a cold climate should always be 
covered. With an uncovered filter subject to freezing temperatures, 
imperfect filtration is almost sure to occur periodically and this is indi- 
cated by an increase in the daily bacteria count. Thus, Wallichs1 has 
noted that after freezing had occurred in the filters of Altona in Feb- 
ruary, 1886, January, 1887, February, 1888, and January, 1891, the 
number of germs in the filtered water rose considerably, and in each 
instance, in the following month, there was an unusual increase in the 
amount of typhoid fever. 
Freezing of the surface causes imperfect filtration by bringing it 
about that the bed is overworked in those places which are still per- 
vious. The application of water to the frozen surface thaws the ice 
slowly and unequally, and where the filter is active, it is doing the work 
of its frozen neighboring areas. 
Scraping of a bed below the ice cake is performed with a machine 
which runs between the sand and the ice, cuts the layer and receives it 
in a bag as fast as it is removed. It is dragged from side to side 
without breaking the ice above it. 
Covering a filter is advantageous in another direction, for by the ex- 
clusion of light, growths of algae are inhibited, and there is, therefore, 
less need of frequent cleaning. 
On the other hand, open filters get the benefit of the sterilizing in- 
fluence of direct sunlight, but this is more than offset by the promo- 
tion of luxuriant growth of algae and other microscopic plants in the 
warmer months. It is sometimes hardly possible to keep filters in 
good working order in summer owing to these growths, which clog the 
interstices very quickly and cause diminished efficiency just at a time 
when the demand for water is greatest. The coincidence of greater 
demand and more frequent cleaning does not permit of sufficient in- 
tervals of rest after the completion of the scraping process. 
1 Deutsche medicinische Wochensclirift, 1891, No. 25. FILTRATION OF PUBLIC SUPPLIES. 
341 
In what is known as " intermittent filtration/' the filter bed is used 
for the reception of water during part of one day, say 16 hours, or 
even during several days, and then is allowed to drain off and rest for 
a while. As the water drains away, the interstices of the sand become 
filled with air, that is, the bed becomes aerated, and thus the nitrify- 
ing bacteria which bring about the destruction of organic matter and 
its subsequent mineralization to nitrates are assisted to maintain their 
vitality. The intermittent process is superior to the continuous in 
that nitrification proceeds more strongly, the organic matter is, there- 
fore, more completely removed, and the ordinary bacteria do not sur- 
vive so long in aerated sand; but on the other hand, it is inferior in 
that, being so much out of active use, the main plant needs to be so 
much the larger for the accomplishment of a given amount of work. 
Asa matter of fact, however, all sand filters are at one time or 
another intermittent, since each time a bed is scraped the water is 
drained away, and the space formerly occupied by it is then filled with 
air. Sometimes it is proposed to put the water through a process of 
double filtration, that is, to pass the filtrate on to another bed for still 
further purification. But if the first filtration has been properly carried 
out, the filtrate will have been deprived of all the materials necessary 
for the formation of the real filtering surface on the second bed. Thus 
the passage of the water through a second filter would be much in the 
nature of a mere form, for it would pass practically unchanged. 
Sand filtration, when properly managed, has proved itself so efficient 
that the number of cities and towns making use of it is growing almost 
daily. Although protection of a supply at its source may be prefer- 
able to pollution followed by sand filtration, it is not always so trust- 
worthy, since pollution may creep in by accident at any time in the 
best guarded supplies. The ideal course is protection at the source, 
followed by filtration before distribution. This is the method now 
adopted by the authorities of a number of cities in Europe. 
So great is the importance of filtration and so far reaching in its 
effects on public health, as shown by vital statistics, that the use of un- 
filtered surface-waters for public distribution is, in Germany, prohibited 
by law. 
In some places, particularly in the United States, the water supply is 
treated in what are known as mechanical filters, of which there are a 
number of varieties all based on a common principle. Such a machine 
consists chiefly of an iron or wooden cylinder filled with a rather coarse 
sand or crushed quartz, through wliich the water passes by gravity or 
is driven under pressure at a much faster rate-from 50 to 150 times 
faster than it moves in a bed. To take the place of the sediment layer 
which forms in the latter, an artificial film is produced by the use of 
alum as a coagulant. This is formed quickly and serves the same pur- 
pose, though not with the same thoroughness. The filter is called me- 
chanical only because power and mechanical devices are employed in 
regulating the rate, pressure, the application of the alum solution, 
and the raking and shaking of the sand in the process of cleaning, 342 
WATER. 
which process it is necessary to carry out at short intervals. Instead 
of removing the top layer, the whole body of sand is agitated and 
thoroughly washed. 
With careful management, upward of 99 per cent, of bacteria are 
removed, but the running expenses are very much higher in propor- 
tion to the work performed than is the case with ordinary sand filtra- 
tion. Economy of space is the only advantage of this process. 
Another form of filtering apparatus is known as the Fischer plaque 
filter, which is made of porous bricks about 6 inches in thickness (15 
cm.) and about 40 inches square (1 m.). The porosity is greater than 
that of the Berkefeld and Chamberland-Pasteur filter, but not to a 
very great extent. The water is filtered under pressure, and the results 
are quite favorable. At Worms, where both this and sand filtration 
are employed and hence can be fairly judged, it is found that the two 
processes are about equal in results so far as chemical analyses can show, 
but that the Fischer process passes a somewhat higher proportion of 
bacteria. The bricks are cleaned by applying a reversed current of 
water under pressure, but cannot be sterilized like the porcelain bougies, 
and hence there is likelihood of producing an inferior filtrate by reason 
of growths occurring in the pores. 
Removal of Hardness. 
On account of the enormous waste of soap as well as loss of time 
which the use of hard waters in washing entails, and of the injury to 
which boilers and hot-water pipes are subject from their action, it often 
becomes necessary to apply some remedy whereby the degree of hard- 
ness may be lessened. This can be accomplished by the aid of heat or 
by the addition of chemicals. Boiling, as we have seen, drives off the 
contained carbonic acid gas and causes the precipitation of the carbo- 
nates which have been held in solution by this agent, but it has no effect 
on the salts which cause the permanent hardness. For use on a large 
scale for public supplies, this means is hardly applicable, on account of 
the necessary cost of plant and of fuel; but for domestic purposes the 
cost is comparatively slight, in that the fuel necessary in cooking may 
be Utilized coincidently for the purpose of heating water. For the 
chemical treatment of hard waters, the first process devised was that of 
Dr. Clark, patented in 1841. This process is based upon the affinity 
of caustic lime for carbonic acid, with which it forms the practically 
insoluble carbonate. 
On the addition of lime water to water containing chalk and mag- 
nesium carbonate held in solution by carbonic acid, the reaction occurs, 
and a double precipitation of the carbonates present and of that formed 
is brought about. The process is very economical so far as cost of 
material is concerned, in that a few cents' worth of lime will remove an 
amount of hardness which will decompose many dollars' worth of soap. 
Lime water, however, does not affect the chlorides and sulphates, and 
hence, like boiling, reduces only the temporary hardness. For the REMOVAL OF IRON. 
343 
employment of this process on a large scale various forms of apparatus 
have been invented, consisting of chambers, or tanks, in which the 
lime is mixed with water and from which the mixture passes into other 
large receptacles wherein it meets the water to be treated. Thence, ac- 
cording to the nature of the apparatus, the water passes on to settling 
tanks or to mechanical filters, where the separation of the precipitate is 
completed. 
The largest plant of this kind in the world is located at Southamp- 
ton, England, where two million gallons of water are treated daily at 
what may well be regarded as an almost insignificant cost. The 
building in which it is installed covers less than a seventh of an acre 
and is sufficiently large to accommodate additional apparatus whereby 
its working capacity can be increased by half. Whatever the forms 
of apparatus employed, the process must be carefully supervised, and 
the amount of lime added must be constantly regulated, for if too lit- 
tle is employed, the full extent of possible softening is not reached, 
while with too much, the water is made alkaline and the carbonate of 
magnesium is retained. 
Caustic soda may be used for softening waters containing carbonic 
acid and the salts causing permanent hardness. Added in proper 
amount to combine with all of the free carbonic acid, it forms carbo- 
nate of sodium, which, in its turn, attacks and decomposes the other 
salts and causes their precipitation. Sodium carbonate itself may be 
added in the absence of free carbonic acid to bring about the same re- 
sult. In some processes for softening water, both lime and ^caustic 
soda or sodium carbonate are employed, the object being the reduction 
of both temporary and permanent hardness. 
Removal of Iron. 
Some ground-waters contain iron in such amounts as to be objection- 
able, both on account of its influence on the system and because of its 
production of stains on linen and other textiles in the laundry. There 
are two principal methods of removing it, both of which depend upon 
the conversion of the ferrous compounds into the ferric form with con- 
sequent separation as a precipitate. These are filtration and aeration. 
Filtration may be conducted through sand or coke or animal charcoal, 
and with either material the iron in solution is exposed to the action 
of air in the interstices and becomes oxidized to the sesquioxide, which 
is left on the filtering material. If the air supply is insufficient, and 
if there is much organic matter present in the water, the sesquioxide 
may be reduced to the ferrous form and again pass into solution. 
When ground-water containing less than three parts of iron per million 
is exposed in large volumes to air, the iron will settle out almost com- 
pletely within a day or a day and a-half. 
Another method of removal by chemical treatment involves the use 
of ferric chloride and caustic lime in the proportion of one and five to 
ten grams respectively to each hundred liters of water. By this, the 344 
WATER. 
11 Kronke" method, all the iron can be removed, but it necessitates the 
use of a mixing tank, constant attention, and eventual filtration for 
the removal of the precipitated iron. 
Action of Water on Lead and Other Metals. 
Action on Lead.-The question as to the best material for house- 
mains and distributing pipes is always an interesting one, and never 
more so than when a considerable number of persons in a community 
begin to show symptoms of lead poisoning and evidence is presented 
which incriminates the water supply. Aside from the matter of cost, 
the advantage of using lead pipes lies in the comparative ease with 
which lead is worked, since it may be bent to any necessary extent and 
thus can be fitted to all manner of irregularities of construction without 
the nee'd of the frequent cutting, thread-making, and coupling, which 
the use of inflexible material involves. 
All ordinary waters have a greater or less tendency to attack lead, 
according to the nature and amount of the substances held in solution. 
The commonly accepted statement that pure soft water is prone to at- 
tack lead and that hard waters tend to protect it by forming encrusta- 
tions over the exposed surface is true only in part, for some very pure 
soft waters exert only very slight action, while some very hard ones act 
with unusual intensity. 
Waters containing very low amounts of organic and mineral matters 
act or not, according as they contain much or little dissolved oxygen 
or carbonic acid or both. 
A chemically pure water would probably exert no action what- 
ever on chemically pure lead, but neither the one substance nor the 
other is commonly seen in such a state of purity. Ordinary distilled 
water, however, which is a nearer approach to absolute purity than 
any other natural water can be, will under certain conditions act very 
corrosively, the conditions being the presence of the above-mentioned 
gases. It is generally held that either oxygen or carbonic acid alone 
in water has but little influence, but that the two together act with 
varying intensity up to a certain point, directly proportionate to the 
amount of carbonic acid. 
This belief, based on experimental observations of Muller,1 was 
strengthened by Drs. Antony and Benelli,2 who found that the highest 
results in lead corrosion were obtained by the use of aerated water 
charged with carbonic acid. Investigating the plumbo-solvent prop- 
erty of a particular water, A. Liebrich3 came to the same conclusion : 
that the simultaneous presence of air and carbonic acid favors action, 
while either alone has no power. Recently, however, a very extensive 
inquiry into the subject of metallic contamination of water supplies 
has been conducted by Mr. H. W. Clark,4 chemist of the State Board 
of Health of Massachusetts, whose results indicate that oxygen is the 
1 Journal fiir praktische Chemie, Series 2, 36, p. 317. 
2 Gazetta chimica italiana, Jan. 21, 1896, p. 275. 
3Zeitschrift fiir angewandte Chemie, 1898, p. 703. 
4 Annual Report for 1898, p. 541. ACTION OF WATER ON LEAD AND OTHER METALS. 
345 
more active corrosive and that either gas can act alone. He employed 
distilled water, freed in the first place as completely as possible from 
these and all other gases, and then impregnated with known amounts 
of either or both. Clean bright lead pipe in equal amounts was 
placed in half gallon bottles filled with water containing the gases in 
the proportions stated below, then sealed and set aside at a tempera- 
ture of 68° F. for one week, at the end of which time the amount of 
lead taken up was determined. The results are shown in the follow- 
ing table : 
No. 
Gases Present. 
Amount of lead taken up 
(parts per 100,000). 
1 
Oxygen to saturation 
2.4100 
2 
Carbonic acid 4 parts per 100,000 
.4993 
3 
Carbonic acid 20 parts per 100,000 
.8935 
4 
Oxygen of saturation, CO2 4 parts per 100,000 
.0861 
A specimen of lead in a bottle containing water from which the 
oxygen had been boiled out as completely as possible and the carbonic 
acid removed by barium hydrate was kept at 82° F. for a week un- 
changed. At the end of the second week, slight action was discernible 
in spots on the surface, and analysis showed 0.0774 part per 100,000 
of water. A specimen of ordinary distilled water in a bottle with a 
small air space in the upper part attacked a similar piece of lead pipe 
to such an extent that it yielded 10.58 parts per 100,000. In this case, 
the temperature at which it was kept was 81° F. 
Inasmuch as all drinking water contains more or less air in solution, 
oxygen is always present in some amount, and since, furthermore, car- 
bonic acid is also generally present, it follows that unless substances 
with a decidedly deterrent influence are present, more or less corrosion 
is to be expected. Numerous instances of chronic lead poisoning 
due to water rich in carbonic acid are on record. At Sommerfeld,1 for 
instance, where, in 1888, numerous cases occurred, it was found that the 
very pure water, rich in this gas, dissolved lead to the extent of about 
six milligrams per liter. At Lowell, Massachusetts, numerous cases 
were observed during the years 1898 and 1899, and it was discovered 
that one source of supply was rich in dissolved oxygen and that the 
other, which caused the greater part of the trouble, was rich in car- 
bonic acid. 
Professor A. W. Hofmann believes that a moderate amount of car- 
bon dioxide lessens corrosion by forming a protective coating of car- 
bonate, but that an excess of the gas dissolves it as bicarbonate. The 
gas is said also to have no action on lead coated with suboxide. 
Water containing free acid of any kind attacks lead. Sulphuric 
acid, which is erroneously supposed to form an absolutely insoluble 
compound, the sulphate of lead, is particularly active. In the ordinary 
chemical sense, sulphate of lead is insoluble in water, but in the hy- 
gienic sense, it is sufficiently soluble to be capable of producing serious 
1 Deutsche Vierteljahrsschrift fur offentliche Gesundheitspflege, Suppl. XXIV. 346 
WATER. 
symptoms. This acid is not an uncommon constituent of water in 
minute amounts, especially in the vicinity of cities and large towns, 
where it exists in the atmosphere as an impurity due to the combustion 
of coal. The peaty acids also have considerable action on lead, but 
they are not always present in waters from peaty deposits. Some very 
brown waters appear to exert but very slight action, while others are 
intensely corrosive. The peat acids are supposedly due to the growrth 
of certain micro-organisms found in peaty soils, for a neutral sterilized 
decoction of peat to which a small amount of fresh peat is added will 
in a short time develop an acid reaction and ability to dissolve lead. 
Liebrich1 reports a peaty water poor in carbon dioxide and carbonates 
which took up 300 parts of lead per 100,000 over night, and more 
when calcium carbonate was added. 
The ammonium compounds and the nitrates have been commonly 
supposed to have a very marked corrosive action on lead. That this 
supposition is correct, has been amply proved by Mr. Clark's researches. 
Their action is, however, manifested only when the water containing 
them is exposed to air. Pond water containing 0.0036 part of 
ammonia and 0.0040 part of nitrogen as nitrates in 100,000 was 
found to have a more corrosive action on lead kept in bottles out of 
contact with air than when its ammonia and nitrate content had been 
increased to 0.0250 and 2.30 parts respectively ; but when an air space 
was left in the bottles, the difference in action was most remarkable. 
The results of these experiments are shown in the tables below. The 
original water yielded the following results on analysis. 
Free ammonia 0.0036 
Nitrogen as nitrates b. 0.0040 
Chlorine 0.15 
Total solids 1.56 
Hardness 0.30 
Color 0.15 
The water was kept in half-gallon bottles into each of which a piece 
of clean lead pipe eight inches long was introduced. In one series, the 
bottles were completely filled, and in the other, an air space was left. 
At the end of a week, the water in each bottle was analyzed. 
Nature of the added substance. 
Parts of lead per 100,000. 
Bottles filled. 
Air space left. 
Nothing added 
0.1226 
0.8301 
200 cc. swamp water. Color increased to 0.50 
0.1686 
0.3642 
Salt. Chlorine increased to 5.00 from 0.15 
0.0920 
0.1319 
Calcium carbonate. Hardness increased to 1.60 
0.0409 
0.1090 
Sodium silicate. Total solids increased to 5.80 
0.0715 
" " " " " "6.60 
0.0914 
Ammonia. Increased from 0.0036 to 0.0250 
0.0588 
2.1860 
Nitrate of potassium. Increased from 0.004 to 2.30 
" " " " " " " 1.72 
0.0128 
11.8800 
Carbonic acid and magnesium carbonate. Hardness 71 ... 
" " " " " " 14... 
0.0084 
0.3695 
1 Zeitschrift fur angewandte Chemie, 1898, p. 703. ACTION OF WATER ON LEAD AND OTHER METALS. 
347 
It will be noted that in every instance the amount of corrosion was 
increased in the presence of air and most intensely in those in which 
the ammonia and nitrates had been increased. 
Substituting distilled water for pond water, and adding the same 
substances in practically the same amounts and leaving an air space, 
the action was still more intense, excepting in only one case; namely, 
that in which carbonic acid and magnesium carbonate were added. 
For the sake of comparison, the results are given below. 
Substance added. 
Parts of lead per 100,000. 
Pond water. 
Distilled water. 
Nothing added 
0 8301 
10 5800 
Swamp water, 200 cc 
0.3642 
1.0220 
Common salt 
0.1319 
0 6390 
Calcium carbonate 
0.1090 
1 1960 
Sodium silicate 
0.0914 
0.1895 
Ammonia 
2.1860 
11 6280 
Potassium nitrate 
11.8800 
16.5460 
Carbonic acid and magnesium carbonate 
0.3695 
0.0648 
The presence of organic matter in the form of peptone was found to 
lessen the corrosive action of nitrates and of ammonia very materially. 
Thus : 
Distilled water containing nitrates 0.51, took up of lead 14.1630 
Containing nitrates 0.54 and peptone J gram 0.6594 
Distilled water containing ammonia 0.026 15.3290 
Containing ammonia 0.028 and peptone J gram 0.3614 
The peptone is supposed to have acted by using up the dissolved 
oxygen of the water. The action of the brown coloring matter is 
explained by the theory that as it undergoes chemical change carbonic 
acid is developed. In order to ascertain the influence of active fer- 
mentation, Mr. Clark filled four bottles as follows: 
1. Merrimac River water. 
2. f river water, J hay infusion. 
3. I river water, f hay infusion. 
4. Hay infusion. 
The hay infusion was free from dissolved oxygen and contained 
little or no carbonic acid. Into each bottle was introduced a piece of 
clean lead pipe eight inches in length. They were allowed to stand 
85 days, and then half the contents of each was withdrawn for analysis. 
At the end of a further period of 129 days, the balance of each was ex- 
amined. The first and second portions of the river water yielded re- 
spectively 0.2156 and 0.3153 ; that is, nothing striking. The second 
portions of Nos. 2 and 3 yielded five and seven times as much re- 
spectively as the first portions, while the increase in the second por- 
tion of the hay infusion alone was even more remarkable. 348 
WATER 
No. 
1st portion. 
2d portion. 
1 
0.2156 
0.3153 
2 
0.2156 
1.0950 
3 
0.4312 
2.8178 
4 
0.0270 
3.6865 
During the first period, no carbonic acid was formed, owing to the 
exclusion of air, but during the second period, each bottle was half full 
of air and the process of fermentation of the hay infusion became active 
and energetic, carbonic acid was developed, and the pieces of lead were 
thereby attacked. 
The constituents of water which tend to bring about corrosion of 
lead are, then, carbonic acid, oxygen, ammonia, nitrates, and free acids. 
The substances which, on the other hand, exert a protective action in- 
clude chlorides, carbonates and silicates, and, probably, sulphates. Ac- 
cording to Crookes, Odling, and Tidy, a half grain of silica to the im- 
perial gallon is sufficient to afford complete protection in all but very 
exceptional cases, even when free acids are present, but certain waters 
containing very considerable amounts of silica are known to be corro- 
sive to a very decided extent. The protection due to silica may be 
obtained by allowing the water to flow through broken flint, flint and 
chalk, or limestone, but such treatment sometimes has the undesired 
effect of increasing corrosive power. 
Sodium and calcium carbonates are very efficient. The bicarbonate 
of sodium is generally present in those very soft waters which have 
the slightest action ; calcium carbonate is efficient whether or not car- 
bonic acid is present in the water at the same time. Four grains per 
gallon are generally considered to be quite sufficient to afford pro- 
tection under most circumstances. As an illustration of the influence 
of this agent may be cited the fact that the very pure water with 
which Glasgow is supplied has, before its entrance to the aqueduct, a 
marked pl umbo-solvent property, but loses it entirely in its passage 
to the city, owing to contact with this substance. In 1887, the wTater 
of Dessau was treated successfully with calcium carbonate. Sodium 
carbonate is even more efficient than the calcium salt, but not always 
equal to the bicarbonate. At Emden, in 1897, treatment with the 
latter was successful after the carbonate had failed. 
Inasmuch as the influences for and against corrosion are numerous 
and conflicting, the surest method of determining whether a given 
water will attack lead is to ascertain the truth by actual experiment. 
Regardless of the character of a water itself, it may be said that its 
action is greater if the lead is in contact with other metals so that a 
galvanic couple is formed. Such may occur, for instance, when a tin- 
lined lead pipe is bent so that the lining is fractured. Then the two 
metals being in contact with each other in a more or less saline liquid, 
the lead, being the more easily oxidized, is dissolved. Again, the tin 
lining may develop weak spots which may become corroded, and as ACTION OF WATER ON LEAD AND OTHER METALS. 
349 
soon as the lead casing is reached, the galvanic action becomes estab- 
lished. Lead pipe containing a small percentage of tin will yield more 
lead to water than will ordinary lead pipe, especially if free carbonic 
acid is present. 
A new lead surface will yield more than an old one, as is shown by 
Professor Mason, who found that the same water, stored for three and 
a-half months in contact with new and old lead, yielded 58.10 and 
3.65 parts per million respectively. 
Hot water is more corrosive than cold, and in the case of either the 
solvent power is increased by pressure. 
The result of the continuous ingestion of minute amounts of lead 
may be nil or the production of greater or less marked manifestations 
of chronic lead poisoning. From the fact that lead pipe is in very 
general use for house-mains and distributing pipes and that chronic 
lead poisoning is, comparatively speaking, a not very common trouble, 
it seems reasonable to conclude that with the great majority of persons 
the metal is eliminated with sufficient rapidity to prevent accumula- 
tion and cumulative action. In Massachusetts, seventy-one munici- 
palities reported to Mr. H. W. Clark, in response to inquiries concern- 
ing the extent to which lead service pipes are used, that both lead and 
lead-lined pipes were in use ; seven reported that lead was used ex- 
clusively, and fourteen that fifty per cent, of the service pipes were of 
lead. Notwithstanding this, it appears that in but four of these places 
has there been any marked prevalence of lead poisoning. These four 
places, Kingston, Lowell, Milford, and Fairhaven, and others, where 
occasional poisoning has been reported, are all supplied with ground- 
water. 
In the report referred to above Mr. Clark says : 11 Our investigations 
so far made in the towns and cities having surface-water supplies have 
failed to reveal any cases whatever, although many of these waters at- 
tack lead, the amounts found in some samples not being inconsider- 
able, and the lead, taken in this manner into the systems of many of 
the inhabitants of these cities and towns, may cause mild or unrecog- 
nized cases of lead poisoning." 
Occasionally, fatal lead poisoning is caused. In one such case, re- 
ported by V. Schneider,1 the water was very soft (hardness 1.40) and 
contained 0.95 mgr. lead per liter. After three months' use of the 
water, a young girl of seventeen died with all the characteristic symp- 
toms of poisoning. Analysis of the organs yielded lead to the extent 
of 7.5 mgr. from the oesophagus, stomach and duodenum, and 24.7 
mgr. from the kidneys, liver, and spleen. 
Action on Iron.-Corrosion of iron is favored by the presence of 
nitrates, nitrites, ammonium compounds, mineral and organic acids, 
chloride of magnesium, oxygen, and carbonic acid. The latter is es- 
pecially active, as has been shown by Professor Leffman and by R. 
Petit. The latter,2 investigating the cause of the destructive action 
1 Gesundheits-Ingenieur, March 31, 1897. 
2Comptes rendus, 1896, p. 1278. 350 
WATER. 
of water rich in this gas and poor in lime, placed a certain amount 
of iron filings in each of three vessels, one of which contained ordi- 
nary water, the second containing water through which a stream of 
carbonic acid was conducted for several minutes, and the third filled 
with water to which enough caustic lime had been added to bind the 
dissolved carbonic acid and to give an alkaline reaction to phenolph- 
thalein. After a time, the iron in each specimen was determined with 
the following results, which prove the great influence of the gas. 
1. 3.15 mgr. per liter. 
2. 200.60 mgr. per liter. 
3. Only traces. 
Both cast-iron and wrought-iron pipes may be rapidly acted upon 
unless their inner surfaces are covered by some protective coating such 
as asphaltum, and even then at the joints where the protecting surface 
is not continuous or becomes detached. Some surface-waters form a 
protecting layer of vegetable matter on the surface of the pipe, and this 
is far more efficient than artificial applications and possesses the addi- 
tional merit of imparting no unpleasant taste. 
The rust formed in iron pipes is, under favorable conditions, dis- 
charged in the flowing water, but it is often deposited in bends and 
near joints and may cause obstruction, amounting sometimes to com- 
plete occlusion. 
Action on Zinc.-On account of the action of water on plain iron 
pipes, pipes of galvanized iron, that is, iron coated within and with- 
out with metallic zinc, have been recommended. This lining is, how- 
ever, very easily corroded, especially if the water contains oxygen, 
carbonic acid, ammonia or nitrates, and the water is made milky by 
the oxide and carbonate in suspension. 
Whether or not the zinc compounds occurring in water can be pro- 
ductive of harm, is a point on which authorities differ. But at least it 
must be admitted that they may cause chronic and obstinate constipa- 
tion, even when present only in small amounts, and that zinc is not a 
cumulative poison. Dr. John C. Thresh 1 mentions a case of obstinate 
constipation in a child, due to the use of drinking water which passed 
through a half mile of galvanized pipe. Relief followed the discon- 
tinuance of the supply. 
Analysis of water drawn from galvanized pipes has often revealed 
very large amounts of zinc. Messrs. J. A. and E. W. Voelcker2 
record an interesting case in which the hot-water pipes of a house, 
supplied by water piped a half mile through galvanized iron, were 
completely blocked by a deposit of zinc. The water was very pure 
and soft and contained but six grains of total solids per gallon. The 
deposit contained 64.32 per cent, of basic carbonate and 21.96 per 
cent, of oxide of zinc. 
Zinc is sometimes a normal constituent of water. Myelius3 found 
1 Water and Water Supplies, London, 1896. 
2 The Analyst, July, 1896. 
3 Ibidem, IV., p. 51. BACTERIA IN WATER. 
351 
about half a grain per gallon in the water supply of Tutendorf, and 
Carl T. Mbrner1 has reported the presence of 0.015 part of zinc car- 
bonate per million in the water of a well near Upsala. This well, 
which was. but about fifteen feet deep, had been in use for over a year. 
The water was submitted for analysis solely on account of its peculiar 
taste, and beyond the fact that it yielded zinc, the source of which 
coidd not be determined, the results of the analysis were very favor- 
able. No unpleasant effects had been noted among those who used 
the water. Two springs in Missouri, according to Hillebrand2 yield 
much larger amounts. In both, the zinc exists in the form of sul- 
phate. The yield amounts to 120.5 and 132.4 parts per million, re- 
spectively. 
Action on Tin.-It is commonly supposed that tin is unaffected 
by water, but such is far from being the case. Tin is attacked by 
water to quite a considerable extent, though not so readily as the 
other metals mentioned. But the compounds formed are, so far as we 
know, quite incapable of causing the slightest injury to the system, 
and this metal is highly recommended as a lining for iron pipes. Its 
cost alone prevents it from supplanting lead for house-mains and dis- 
tributing pipes. 
Bacteria in Water. 
The ordinary water bacteria are of the harmless and beneficent 
kinds, which, depending upon dead organic matter for sustenance, bring 
about its conversion into simple chemical substances. How many 
species of these saprophytic organisms exist in water cannot be said, 
but about two hundred varieties have thus far been described. They 
may be present in small or in enormously large numbers without being 
necessarily of any hygienic significance, although usually their existence 
in large numbers indicates the presence of an abundance of organic 
matter, and yet they may thrive and multiply enormously in water 
containing almost no organic food materials. Indeed, multiplication 
occurs more rapidly in pure than in polluted water, but diminution in 
number is also more rapid. In impure water, they multiply slowly, 
but their grow'th is persistent and, under ordinary natural conditions, 
sudden marked diminution in number does not occur. 
Besides those forms whose natural habitat is water, others are often 
present whose natural habitat is the bodies of man and animals, and 
which, in water, are, therefore, in an unnatural medium. These 
forms, which include the pathogens, probably do not increase in num- 
ber in water, whether the latter be pure or extensively polluted. They 
live for a certain time, retaining their virulence in undiminished de- 
gree, and then tend to become modified in this respect and rapidly to 
disappear. The germs of cholera have been found in Seine water in 
an active state after seven days, and in ordinary drinking waters as 
long as twenty days after addition. The typhoid fever organism will 
1 Upsala Lakareforenings Forhandlingar, 1898, Vol. III. 
2 United States Geological Survey, Bulletin No. 13. 352 
WATER. 
live for greater or less periods of time, according to circumstances ; it 
lias been found in very pure water after more than seven weeks, while 
in badly polluted water its life is quite short. Sunshine and tempera- 
ture appear to have very decided influence upon its vitality. The in- 
fluence of sunshine is modified by the depth of the water in which the 
organism is suspended. Buchner1 has shown that the rays of the sun 
will kill cultures of the typhoid bacillus at a depth of about five feet 
in four and a-half hours, while at double that depth their effects are 
hardly perceptible. 
While it is true that this organism survives longer in cold than in 
warm weather, it cannot be said definitely that the reason lies in any 
inherent greater resistance to the influence of cold than to that of heat, 
and, indeed, it seems more probable that the true explanation of the 
fact is to be found in the fact that in warm weather the conditions are 
more favorable to the growth of the common species of water bacteria 
which are believed to secrete substances which exert a toxic influence 
on pathogens and cause them to disappear. The belief that such toxins 
are secreted is strengthened by the researches of Frankland,2 who 
shows that waters which do not favor bacterial multiplication are 
changed in this particular on being boiled. He found that while an- 
thrax spores were much diminished in number or actually destroyed 
in a short time in unsterilized water, their numbers were not reduced 
and their virulence remained unimpaired after upwards of seven months 
in sterile water. 
These toxic substances are presumably not secreted by all forms of 
water bacteria, but only by certain species which may or may not be 
present in any given water, and it is regarded as most likely that they 
are not inimical to the same extent to all varieties of pathogens, but 
that substances harmless to one kind may act fatally on another. In 
general, it may be stated that those pathogens which form spores retain 
their vitality and virulence longest in any kind of water. 
The ordinary water bacteria are found in much greater abundance 
in surface-waters than in those derived from the soil. Indeed, many 
observers, including Koch and Fraenkel, have maintained that waters 
from the unpolluted subsoil are practically sterile. This, however, 
has been shown by Sedgwick and Prescott3 to be not the case. Using 
improved methods of investigation and paying special attention to the 
nature of their culture media, these observers demonstrated conclu- 
sively that wholly unpolluted springs, wells, and tube wells may yield 
considerable numbers of bacteria and sometimes a greater abundance 
than is contained in some surface-waters. 
In their paper they state " that the plates are remarkable not only 
for the slow growth of the species present, but also for the absence of 
liquefying colonies, and, in many cases, for the abundance of chromo- 
genic varieties. These facts are especially important as indicating 
1 Centralblatt fur Bakteriologie und Parasitenkunde, XI., p. 781. 
2 Journal of State Medicine, January, 1894. 
3 On the Bacterial Contents of Certain Ground Waters, Including Deep Wells. 
Report of the State Board of Health of Massachusetts for 1894, p. 435. WATER AND DISEASE. 
353 
the total absence of contamination by ordinary surface-water, and, as 
far as they go, they strengthen the confidence with which well-pro- 
tected ground-waters may be regarded as sources of public water sup- 
plies." Their conclusions and results have been confirmed a number 
of times by other competent investigators elsewhere. Ground-waters, 
when brought to the surface and exposed to the air, soon become rich 
in the ordinary forms of bacteria, which find in them the conditions 
necessary for extraordinarily rapid multiplication. 
Surface-waters vary very much in their bacterial content according 
as the conditions present at any one time favor or retard growth and 
accessions. Sunshine, influx of food material or of substances inimi- 
cal to bacterial life, sedimentation, and growth of higher organisms 
act for or against increase. Suspended matters in their descent carry 
down with them the bacteria that have gathered upon them or have 
been entangled by contact. The diminution in their number by this 
means is more marked in still waters than in rivers with rapid motion. 
The growth of algae and other water plants causes diminution by re- 
moval of the nutrient materials upon which the bacteria depend, and 
probably through some other influence not yet discovered. The in- 
crease in bacteria, sometimes noticed during the colder months, is ex- 
plained by Frankland1 by the fact that in winter much water runs in 
over the surface from manured fields. 
There is one form of microscopic organisms, belonging to the class 
of fungi, which merits special mention : Crenothrix Kuhniana. This 
is a small filamentous plant with cells no larger than the ordinary 
bacteria. It grows chiefly in ground-waters which contain organic 
matter and iron, the latter of which ingredients it fixes in the form of 
ferric oxide in the gelatinous sheath of its filaments, which thereby be- 
come yellow, yellow brown, or brown in color. It causes great trouble 
by the rapidity with which it grows in water pipes, the lumen of which 
is not infrequently completely occluded. This can occur more readily 
where the surface presents roughness and imperfections to which the 
growths may attach themselves. When the filaments are broken off 
and become disseminated through the water, the latter is rendered unfit 
for laundry use on account of the iron-rust. Sometimes, it gives rise 
to disagreeable odors and an inky taste. 
It may be very troublesome within the tubes of driven wells or in 
the reservoirs, as well as in the distributing pipes. Sometimes, it may 
be seen in large aggregated masses floating about on the surface of 
stored water. By its extensive growth in pipes, it may seriously affect 
a whole public supply. 
Water and Disease. 
The use of impure water for drinking and other domestic purposes 
may be a direct cause of disease, and it is supposed also to act upon 
the system in such a way as to lower the resistance of the body to the 
action of infectious matters ; but it must be borne in mind that the 
1 The Bacterial Purification of Water, London, 1897. 354 
WATER. 
nature of the polluting material is of far greater importance than its 
mere amount. To maintain that water containing any considerable 
amount of organic matter, regardless of its character and source, will 
inevitably tend to produce a general impairment of health, is as great 
an error as to underrate the danger possible to arise from a small 
amount of specific contamination. It is quite as improbable, for in- 
stance, that the amount of dissolved vegetable matter necessary to 
yield albuminoid ammonia in what may be designated " considerable " 
amount can do any great injury, even when constantly ingested, as that 
an infusion of tea, which, by the same process of analysis, would yield 
results which would be startling in comparison, could of itself conduce 
to the development of an infectious disease. 
Alarmists may reject as unsuitable for household purposes a water 
containing an amount of vegetable matter sufficient to give a yellow- 
brown color, and accept as sufficiently pure another containing less 
organic matter and less mineral matter, but with it the micro-organisms 
of infectious disease. They go to the extreme of saying that organic 
matter in solution must " lower the tone " and must, therefore, be 
avoided, and if asked why this is so, fall back on " general principles " 
and " common sense," upon which so much illogical unexplainable 
theory is based. As a matter of fact, we know that water which is in 
a sense impure, but not specifically polluted, may be used year in and 
year out without injury. We know, further, that water containing 
much less organic matter, but infected with bacteria of certain kinds, is 
likely to cause disease in at least a part of those who use it once, oc- 
casionally, or habitually. We know also that a water once specifically 
polluted may, under similar conditions, be again polluted, and in the 
interval may be of good quality. 
We know that water containing large amounts of dissolved vege- 
table matter in process of decomposition or of a definitely poisonous 
character may produce disturbances of a very serious nature; that an 
abundance of minute water plants, as algje, and animal organisms, as 
infusoria, may produce ill effects ; that decomposing animal matters 
sometimes yield toxic substances of great potency, and that excessive 
mineral matter in suspension or solution is not without its deleterious 
effects. 
Therefore, it may be laid down as a general rule, regardless of the 
fact that all impurities do not necessarily breed disease or undermine 
the health, that all water containing or likely to contain domestic 
sewage, abundant growths of minute vegetable and animal organisms, 
decomposing matter of animal origin, dissolved vegetable matter of an 
inherently toxic nature or undergoing decomposition, or excessive 
amounts of mineral matter should not be accepted as fit for human 
consumption. Especially must we bear in mind that polluted water 
which is quite free from disease organisms and toxic matters to-day may 
contain them in abundance to-morrow. 
Disorders Connected with Mineral Matter.-It is very commonly 
noticed that when one changes suddenly from the use of a soft water 355 
DISORDERS CONNECTED WITH MINERAL MATTER. 
to another that is quite hard there follows a temporary disturbance of 
the functions of the digestive apparatus. The most marked effect is 
usually constipation with occasional diarrhoea. Loss of appetite and 
slight nausea are not uncommon. The effects are due to the influence 
of the salts causing permanent hardness. Change from hard to soft 
water is quite as likely to cause unaccustomed looseness of the bowels 
from the withdrawal of this influence on the intestinal secretions. Just 
how much of any one of these salts can be said to be distinctly in- 
jurious to health is a matter of doubt, but from 10 to 15 parts in 
100,000 of water are commonly regarded as undesirable. 
It has been asserted that the use of hard water is one of the chief 
causes of stone in the bladder, but such a connection is extremely 
improbable. How the use of carbonate and sulphate of calcium can 
bring about a deposit of uric acid or of oxalate of lime or of phosphates 
in the bladder can hardly be explained. The fact also that stone is 
very common in some districts where the water is soft, and quite rare 
in others where it is hard, suggests that the cause is to be looked for 
rather in the individual himself-his food, his metabolism, his habits 
of life, and, perhaps, hereditary predisposition. 
Suspended mineral matter, as clay and marl, will often cause diar- 
rhoea in persons not habituated to its use, and not infrequently in those 
who are. 
The disease most commonly connected with mineral matters in water 
is goitre. That this disease can be produced by drinking water, can 
hardly be doubted, for it is a well-known fact that in Switzerland and 
France, for instance, there are wells which yield waters which are 
successfully used for the intentional production of the disease with the 
view to escape compulsory military service. The enlargement is not 
necessarily a permanent disfigurement; disuse of the water may be 
followed by disappearance of the swelling, but oftentimes the disease 
thus intentionally acquired is not to be shaken off. 
The exciting cause has been attributed to the presence or absence of 
certain mineral substances, but the wide variety of the supposed agents 
is of itself strong evidence of the poor foundation upon which the 
mineral matter theory rests. It is noticed, for instance, that in some 
districts where the disease is especially prevalent, the soil is largely 
magnesian limestone, and that, as might be supposed, the ground-water 
is rich in lime and magnesium salts. Therefore, it is reasoned, magne- 
sian limestone must be the cause; but there are many such districts 
where goitre is unknown. More than that, the disease is endemic in 
some quarters where the water is soft and almost free of lime and 
magnesium salts. Again, it has been attributed to the presence of 
certain salts of iron, but this theory also cannot bear the test, for these 
may be present where no goitre is seen, and may be absent where the 
disease prevails. Absence of iodine is another explanation based on 
nothing worthy of credence. 
The most probable cause is now believed by some to be an organism 
which flourishes in the water. The first to promulgate this theory 356 
WATER 
were Italian observers who, in 1890, reported facts of interest bearing 
on the question, since which time, other observers, particularly in India, 
have contributed further evidence of its probable truth. 
The most striking facts have been presented by Surgeon-Lieutenant 
E. E. Walters,1 whose observations were pursued in a district in India 
two thousand feet above sea-level, with extremely porous soil and 
a water supply containing but slight amounts of organic and mineral 
matter and but minute traces of iron. 
The inhabitants, who live under the same climatic conditions, but 
with different occupations, may be divided into two classes: the 
native Bhutias and the Sepoy troops from the northwest provinces. 
The former are carriers and coolies; they are omnivorous, but, by 
reason of poverty, mostly vegetarians. Their chief diseases are goitre, 
syphilis, and malaria. The temporary inhabitants, the Sepoys, are 
all vegetarians, and are a healthy lot, practically free from syphilis, 
and living under excellent hygienic conditions. They had been in the 
district twenty months. Examination of 169 Bhutias showed that 
over 75 per cent, had goitre; nearly 90 per cent, of those over twelve 
years of age were afflicted. Of 380 Sepoys examined, 54 per cent, had 
goitre. The Bhutias say that their goitres increase during the rainy 
season, and this is borne out by the out-patient register and regimental 
admission book for 1895. All the British officers, too, had suffered 
from enlarged thyroids during the preceding rainy season. Their 
drinking water was passed through a Pasteur filter; all other water 
used was taken as tea or soda. 
Taking up the several conditions which have been alleged as the 
cause of the process, he shows them to be not at fault in this particu- 
lar district. Iron is present in the water only in very minute quanti- 
ties, and the highest degree of permanent hardness was but three and 
a-half. As to lime as a cause, it appears that many of the Bhutias 
without goitres are great lime eaters, while of the Sepoys, who never 
touch it, over 50 per cent, had developed goitres within twenty months 
after arrival. 
The theory that the disease is due to carrying heavy loads up and 
down hills might satisfy in the case of the Bhutias, but not in that of 
the Sepoys, who, though not carriers, yet have goitre. Further, as to 
age, it appears that 55 per cent, of the children under twelve had no 
goitres after living there all their lives, or about the same percentage as 
developed them among the Sepoys after a visit of only twenty months. 
He believes the disease to be due to an organism of the amoeba type 
with a selective power against the thyroid or its secretion. For a 
time the system opposes it, and sometimes successfully, but when it 
overpowers the phagocytic resources of the system, the thyroid en- 
larges in the effort to combat the poison. Under thyroid feeding (two 
five-grain tabloids daily) the records show a weekly diminution of a 
quarter to half an inch in the circumference of the Sepoys' necks, and 
when the treatment ceases, the gland again increases in size. That is 
1 British Medical Journal, September 11, 1897. DISORDERS CONNECTED WITH ORGANIC POLLUTION. 
357 
to say, additional resisting power is administered in the shape of thy- 
roid tabloids which keep the poison in check and allow the gland to 
recover its normal size, but on withdrawing the accessory agent, there 
is diminished resistance and again an increase in size. 
Disorders Connected with Organic Pollution.-Ordinary vege- 
table matter in suspension and abundant growths of algae and other 
water plants will sometimes cause diarrhoeal troubles, but, so far as is 
known, cannot cause specific disease. Peaty matters in solution have 
now and then appeared to be connected in some way with intestinal 
derangement, but we have no absolute knowledge that they actually 
have been or can be a cause of such trouble. 
We know only two diseases which we can say with certainty can be 
carried by water, and they are cholera and typhoid fever, but it is 
commonly said that water is a great factor in the spread of diphtheria, 
yellow fever, malaria, and dysentery. In the case of diphtheria, the 
weight of evidence is certainly against its being a water-borne disease. 
There is some evidence of its spread through the use of a common 
water supply, but in these cases there is usually a common drinking 
vessel, and probably a preexisting case of the disease among the drink- 
ers. The diphtheria organism cannot long survive in water which is 
not very extensively polluted. 
As to yellow fever, the connection is only suspected : there is no 
evidence whatever. 
Outbreaks of dysentery have occurred which seemed to be due to 
the use of water contaminated with fiecal matters, but though it can, 
perhaps, be an occasional cause, it certainly is not a common one. 
There is plenty of evidence, such as it is, that water from certain 
marshes may cause outbreaks of fever of a malarial character, and among 
the strongest cases are those in which large numbers of persons, as 
soldiers, have been taken at about the same time after using a water 
of this sort. But it must not be supposed that all marsh water will 
produce fever nor that all water from a malarial district will do so, 
for many communities use marsh water with no harmful result, and 
the water of a malarial country may be used some distance away as a 
public supply with perfect impunity. Such, for instance, is the case 
with part of the supply of Rome. 
One of the strongest cases showing possible or probable connection 
between water and malaria is reported by Laveran, and it shows also 
the action of the stomach at rest and at work. A detachment of sol- 
diers drank at a certain well and then enjoyed a hearty meal; another 
detachment ate first, and later drank from the same well. Of the for- 
mer, all became sick with malaria ; of the latter, none were affected. 
The difference in the results was thought to be due to the fact that 
those who escaped took no water until the gastric juice was called out 
in the process of digestion. 
Quite a number of cases are recorded in which men on shipboard 
have used the water of certain casks which others have declined, the 
former becoming sick with malaria and the latter escaping. 358 
WATER. 
There is more or less evidence that certain animal diseases may be 
spread by water containing the necessary organism. Hog cholera and 
anthrax have certainly been spread by water into which bodies of 
those that had died of these diseases had been thrown, and glanders 
may be spread from horse to horse by the use of a common drinking 
trough. 
The diseases of greatest interest in connection with drinking water 
are the two which we know can be spread by infected water-cholera 
and typhoid fever. The first-mentioned happens, with us, to be one of 
minor interest, inasmuch as it is a most uncommon visitor; the other, 
however, is always with us, and we have, therefore, constant oppor- 
tunity for observation of the influence of polluted water in its 
causation. 
The strongest proof of the value and efficiency of the purification of 
water by filtration through sand is the drop which occurs in the mor- 
tality from typhoid fever when a community abandons the use of un- 
treated polluted water and adopts this method of improving the quality 
without changing the source of supply. The city of Lawrence, Mass- 
achusetts, for example, prior to and including part of the year 1893, 
used the unfiltered water of the Merrimac River, into which is poured 
the sewage of a succession of large cities and towns having an aggre- 
gate population of several hundred thousands. In the year mentioned, 
the process of filtration was adopted and the good results were almost 
immediately evident. Following are the death-rates from typhoid 
fever per 10,000 of population for the four years immediately preced- 
ing and for the same period following the change : 
Preceding change. 
Year of change. 
Following change. 
1889.... 
... 12.7 
1893 8.0 
1894.... 
... 4.7 
1890.... 
....13.4 
1895.... 
....3.1 
1891.... 
....11.9 
1896.... 
....1.9 
1892.... 
....10.5 
1897.... 
....1.6 
It is but fair to add that about half the deaths from the disease in 
1894 and 1895 were of persons who persisted in drinking unfiltered 
water directly from the canals. 
The city of Hamburg adopted filtration in May, 1893, after a most 
devastating epidemic of cholera in the preceding year. Typhoid fever 
had always claimed a very large number of victims annually, and dur- 
ing the four years, 1890-1893, the death-rate from the disease was 
2.6 per 10,000. But in the next two (1894-1895), it fell to 0.75. 
Comparison of typhoid death-rates of cities using polluted waters 
with those of others using pure or purified waters is most convincing 
both of the efficiency of filtration and of the disastrous results of neg- 
lecting to protect the public from the dangers of impure supplies. 
From among large cities having a population of between one and two 
millions, Chicago and Berlin may be selected for comparison. These TYPHOID INFECTION OF WATER SUPPLIES. 
359 
two cities have about the same number of inhabitants. Chicago takes 
its water from Lake Michigan, into which vast volumes of sewage are 
poured at various points, and uses it without purification. Berlin is 
supplied by two lakes, Tegel and Muggel, which are protected as far as 
possible from pollution, but, nevertheless, every gallon used is filtered. 
During the years 1890-1894, the death-rates from this one disease 
averaged 84 per 100,000 at Chicago, and but 8, or less than one-tenth 
as high, at Berlin. Between 1889 and 1893, Chicago suffered unusu- 
ally from typhoid, and in 1891, the typhoid mortality reached 159.7 
per 100,000. At this time, the intake was situated but a few hundred 
feet from the shore, and in consequence of the ravages of the disease, a 
tunnel was built, extending the intake four miles into the lake. The 
result of this extension was an immediate marked fall in the number 
of cases, but nothing comparable to what might reasonably be expected 
had the water been subjected to filtration. 
During the twelve months ending March 31, 1891, the cities of 
Lawrence and Lowell with a combined population of 123,000 people, 
using polluted river water, recorded 228 deaths from typhoid fever, 
while Boston with about four times that number of inhabitants, using 
well-protected but unfiltered surface-water, had but 159 deaths from 
the same disease. 
The recent experience of Philadelphia furnishes a most instructive 
example of the danger of using polluted water. During the first six 
months of the year 1899, out of a population of over a million, 7,038 
cases of typhoid fever with 800 deaths were recorded. This outbreak 
served finally to incline the public authorities to favorable consider- 
ation of the necessity of instituting a filtering plant. 
Typhoid Infection of Water Supplies.-Typhoid infection of a 
water supply may be direct or indirect. Direct infection occurs 
through the entrance of ordinary sewage containing the essential or- 
ganism, or of faeces or urine discharged along the banks of a river or 
lake, for example, by persons suffering with or convalescent from the 
disease. Indirect infection occurs from discharges deposited in or upon 
the soil and thence washed by rain into bodies of water or downwards 
into wells. Ordinary sewage pollution is not sufficient to bring about 
an outbreak of the disease, nor will specific pollution necessarily always 
be followed by the occurrence of cases. The specific organism has 
only a limited tenure of life, and in the absence of conditions favorable 
to its existence, it may perish before it reaches the consumer. More- 
over, the number present may be very small and the effects pro- 
duced so slight as to occasion no great notice. It is to be borne in 
mind that not every mouthful of a polluted supply contains the organ- 
ism and that not every person to whose system it gains access must 
necessarily come down with the disease. 
Until quite recently it has been supposed that the infecting organ- 
isms had their origin only in the faeces of preexisting cases, but it is 
now know that this is far from being the case and that they exist in 
the faecal discharges during only the early stages of the disease or up 360 
WATER. 
to the twentieth day or, perhaps, even somewhat later. Petruschky 1 
has shown that the urine may contain millions of living bacilli in each 
cubic centimeter and that they may be found for many weeks and even 
after convalescence is well established. They may appear as early as 
the fifteenth day, when, perhaps, they are no longer demonstrable in the 
faeces. Dr. Mark W. Richardson2 found them in very large numbers 
and in practically pure culture in the urine of nine out of thirty-eight 
patients. They appeared late in the course of the disease and continued 
to be eliminated in several of the cases after discharge from the hos- 
pital. 
These observations of Petruschky and Richardson have been fully 
confirmed by other bacteriologists. It appears, then, that an appar- 
ently well person is capable of infecting a water supply to a greater 
extent and with less optical evidence, or none at all, by a discharge of 
urine into a water-course than an evidently sick one by a deposit of 
his faeces into it or upon its banks. 
Whatever the mode of infection of a public water supply, the re- 
sults, if any, are seen in an increase in the number of cases ordinarily 
occurring in the community supplied, and except in those instances 
where the disease is spread by infected shellfish or other foods, any 
considerable augmentation of cases points unmistakably to the con- 
sumption of polluted water, even though the system of filtration is 
followed. In the latter instance, investigation will almost certainly 
show some defect in the filters or that their capacity has been 
overtaxed. Even after the subsidence of the outbreak, the disease 
may continue to be more prevalent than usual for some little time, es- 
pecially in the absence of a proper system of sewerage. 
Influence of Introduction of Public Water Supplies on Typhoid 
Rates.-Contrary to what might be expected, the highest death-rates 
from typhoid fever in thickly settled countries are, generally speaking, 
not in the crowded cities, but in the towns which have no public water 
supplies. In Massachusetts, for example, the five towns highest in 
this respect had, during the eighteen years prior to 1890, an average 
typhoid death-rate of 12.82 per 10,000 of population, while the aver- 
age of the five highest rates for cities with public supplies was but 
7.65, and of all the cities of the Commonwealth only 4.62. In the 
town with the highest mortality, Ware, the average for fifteen years 
prior to 1886 was 16.5 in 10,000; in that year a public supply was 
introduced, and at the expiration of four years the mortality had di- 
minished 60 per cent. 
In 1870, only 20 cities and towns in Massachusetts had modern pub- 
lic supplies; at the end of 1896, all of the 32 cities and 127 of the 
322 towns, comprising 89.8 per cent, of the entire population were 
thus provided, and but three towns with populations exceeding 3,500 
had none; at the end of 1898, but 9.7 per cent, of the entire popula- 
tion of two and a-half millions were without public supplies, but this 
1 Centralblatt fur Bakteriologie und Parasitenkunde, 1898, XXIII., No. 14. 
2 Journal of Experimental Medicine, May, 1898. INFLUENCE OF PUBLIC WATER ON TYPHOID RATES. 
361 
small percentage was made up of small towns with scattered inhabi- 
tants, where the introduction of public works would be beyond the 
financial possibilities. 
As a result of this very general introduction of a common supply in 
place of that derived from individual wells, largely of the open variety 
and situated in close proximity to sources of pollution, a very decided 
decline in typhoid fever has been noticed. This result is by no means 
peculiar to Massachusetts, but is found to be the consequence wherever 
the selection of the source is made with judicious care and measures 
are taken to protect it from avoidable pollution. 
It is not to be supposed, however, that the mere introduction of [a 
common supply without the observance of this necessary precaution 
will best serve the interests of the public health. In the following 
table, compiled by Mr. Hiram F. Mills,1 is shown the change in the 
typhoid death-rates per 10,000 in each of the cities of Massachusetts 
which introduced water within the years 1869 to 1877. 
Cities. 
Yearly number 
of deaths by 
typhoid fever 
per 10,000,1859 
to 1868. 
Date of intro- 
duet'n of water 
supply. 
Yearly number 
of deaths by 
typhoid fever 
per 10,000 1878 
to 1889. 
Percentage of 
deaths in the 
latter period 
are of those in 
the former. 
Holyoke 
6.73 
1873 
8.93 
133 
Lawrence 
8.34 
1875 
8.33 
100 
Lowell 
6.16 
1872 
7.63 
124 
Fall River 
7.78 
1874 
6.32 
81 
Springfield 
9.67 
1875 
5.29 
55 
Taunton 
6.12 
1876 
5.02 
82 
Northampton 
10.98 
1871 
4.04 
37 
Lynn 
9.06 
1871 
3.87 
43 
New Bedford 
7.77 
1869 
3.80 
49 
Newton 
6.57 
1876 
3.65 
56 
Malden 
8.04 
1870 
3.54 
44 
Fitchburg 
10.59 
1872 
3.16 
30 
Woburn 
8.29 
1873 
2.95 
36 
Somerville 
4.28 
1867 
2.95 
69 
Chelsea 
5.97 
1867 
2.89 
48 
Waltham 
8.12 
1873 
2.42 
30 
It will be noticed that of these sixteen cities there were three which 
showed no improvement, and two of these were worse off than before. 
The reason for this is very clear. All three are manufacturing cities 
situated on rivers polluted by sewage. At Holyoke, while the public 
supply is but slightly liable to contamination, the operatives in the fac- 
tories used water from two other sources, subject to gross pollution ; 
namely, from the canals, the entrance of one of which is situated close 
to the outlet of one of the main sewers of the city, and from wells 
indirectly supplied by the canals. 
Comparison of the death-rates from typhoid fever among those of 
different occupations brought out the fact that the operatives in the 
mills which used canal water suffered from the disease three times as 
1 22d Annual Report of the State Board of Health of Massachusetts, 1890, p. 534. 362 
WATER. 
much pro rata as all other persons. Lowell and Lawrence, at the 
time mentioned, were using the polluted water of the Merrimac 
River. Lowell took its supply fourteen miles below the point of en- 
trance of the sewage of Nashua, N. H., and consumed it without 
treatment. Lawrence drew upon the same supply, after its enrichment 
by the sewage of Lowell, at a point but nine miles below the outfall of 
the latter's sewage. In 1891, Lowell suffered unusually from typhoid 
fever by reason of the additional contamination by fseces of typhoid 
patients discharged into Stony Brook, a small tributary of the Merri- 
mac, only three miles above the intake of the water-works. 
The conditions of all three places have since been changed. At 
Holyoke, warnings were posted for the benefit of the operatives ; 
Lowell abandoned the river in favor of ground-water in 1893, and 
in the same year Lawrence instituted filtration. In all of the three 
cities the expected happened; namely, a marked diminution in the 
death-rate. 
Examination of the above table reveals the fact that in most of the 
sixteen cities the reduction in the typhoid death-rate was most pro- 
nounced. In some of them, the diminution has proceeded to a much 
greater extent than is here shown. In 1896, three cities with an ag- 
gregate population of 70,000 showed less than one death per 10,000 
from this disease, and in one of them, Woburn, there was none at all. 
Classification of Cities According to Typhoid Fever Death- 
rates.-The position held by water as a causative factor in the spread 
of typhoid fever is such that, paraphrasing a familiar quotation, the 
student of sanitary matters may well say : " Show me a city's statistics 
of the disease and I will tell you the character of its water supply." 
Pure supplies and high typhoid rates are quite incompatible, and the 
endemicity of the disease in communities of any large size makes equally 
incompatible the use of sewage-polluted water and low morbidity and 
mortality. In no way can this fact be more clearly illustrated than 
by comparing the death-rates of the disease in the leading cities of the 
world and noting the source and nature of the water with which they 
are supplied. From the admirable work of Mr. John W. Hill,1 the 
following table is compiled : The rates given are those reported for 
the year 1896 per 100,000 of population. 
City. 
Population. 
Source of Supply. 
Rate. 
Amsterdam 
489,496 
Haarlem dunes, and River Vecht, filtered 
3 
Munich 
406*000 
Spring water from Mangfall Valley; 37 miles away 
3 
The Hague 
187,545 
Sand dunes, filtered 
4 
Dresden 
342,340 
Filtered wells and gallery by River Elbe 
4 
Berlin 
1,695*313 
Filtered water from Lakes Tegel and Muggel 
5 
Vienna 
1'526*623 
Springs in the Schneeberg 65 miles away 
5 
Hamburg 
625,552 
Filtered water from the River Elbe 
6 
Stockholm 
267,100 
Lake and well water 
6 
Copenhagen 
333*714 
Filtered water from wells and springs 
7 
Breslau 
377,062 
Filtered water from the River Oder 
8 
1 The Purification of Public Water Supplies, New York, 1898. TYPHOID FEVER DEATH-RATES. 
363 
City. 
Population. 
Source of Supply. 
Rate. 
Paris 
2,511,629 
Rivers Seine, Marne, and Vanne, Ourcq Canal, 
artesian wells, and springs 
11 
Rotterdam 
276,338 
Filtered water from the River Maas 
12 
Altona 
148,934 
Filtered water from the River Elbe 
13 
Trieste 
161,886 
Kent wells, and filtered water from the Rivers 
13 
London 
4,421,955 
1,140,000 
Thames and Lea 
14 
Brooklyn 
Impounded water, and open and driven wells 
15 
Lawrence 
55,000 
Filtered water from the River Merrimac 
15 
Edinburgh 
276,514 
Impounded and filtered water from Pentland 
16 
1,934,077 
Hills 
Mew York 
Impounded water from Croton and Bronx Rivers.. 
16 
Milwaukee 
257,500 
Lake Michigan 
18 
Brussels 
518,387 
18 
St. Louis 
570,000 
Mississippi River 
19 
Buffalo 
350,000 
Niagara River, at head 
20 
Detroit 
279,000 
Detroit River 
20 
Davenport 
35,000 
Mechanical filter, Mississippi River 
20 
Sidney, M.S. W 
423,600 
Impounded water from Upper Nepean River 
20 
Newark, N. J.1 
230,000 
Impounded water from Pequannock River, filtered 
21 
Glasgow 
705,052 
Loch Katrine 
23 
Manchester 
530,000 
Lake Thirlmere 
23 
Turin 
344,203 
Driven wells 
24 
Dayton, O 
85,000 
25 
Quincy, Ill.2 
42,000 
Mechanical filters, Mississippi River 
26 
Venice 
163,254 
Impounded water 
27 
Providence 
150,000 
Pawtuxet River 
27 
Rome 
473,296 
Eontanadi Trevi, Aqua Felice, and Paoli 
27 
Prague 
364,632 
Lake Ontario 
28 
Toronto3 
196,666 
28.5 
Buda-Pest 
579,275 
Ground-water 
29 
Chattanooga4 
40,000 
Mechanical Filters, Tennessee River 
30 
San Francisco 
330,000 
Impounded water from mountain springs 
31 
Boston 
508,694 
Lake Cochituate, Sudbury River, and impounded 
Covington 
50,000 
water 
32 
Ohio River 
32 
Knoxville 
37,000 
Mechanical filters, Tennessee River 
32 
Liverpool 
632,000 
Lake Vyrnwy 
32 
Christiania 
182,856 
33 
New Orleans 
275,000 
Drinking water from tanks and cisterns 
33 
Philadelphia 
1,188,793 
Schuylkill and Delaware Rivers 
34 
Baltimore 
507,398 
Gunpowder River, Lake Roland. 
37 
Indianapolis5 
165,000 
Driven wells and White River 
41 
Lowell6 
85,700 
Driven wells 
42 
Cleveland 
330,279 
Lake Erie 
43 
Louisville 
211,100 
Ohio River. 
45 
Dublin 
349,594 
River Vartry, impounded water, filtered 
45 
Chicago7 
1,619,226 
Lake Michigan 
46 
Moscow 
753,469 
Mytschia springs and ponds, Moscow and Yanza 
46 
Cincinnati 
341,000 
Rivers 
Ohio River 
48 
Washington 
278,150 
Potomac River 
51 
Nashville 
87,754 
Filter gallery, Cumberland River 
55 
Milan 
441,948 
Mechanical filters, Chattanooga River 
55 
Atlanta8 
110,000 
60 
1 Average rate, 1890-1896, 38.1 ; reduced 45 per cent. 
2 Average rate, 1890-1896, 53.6 ; reduced 51.5 per cent. 
3 Average rate, 1890-1896, 49.5 ; reduced 42.2 per cent. 
4 Average rate, 1890-1896, 68.2 ; reduced 56 per cent. 
5 Average rate, 1890-1896, 64.5 ; reduced 36.4 per cent. 
6 Average rate, 1890-1896, 77.6 ; reduced 45.9 per cent. 
7 Average rate, 1890-1896, 71.2 ; reduced 35.4 per cent. 
8Average rate, 1890-1896, 85.1 ; reduced 29.5 per cent. 364 
WATER. 
City. 
Population. 
Source of Supply. 
Rate. 
Brisband1 
93,657 
Allegheny River 
60 
Pittsburg 
280,000 
61 
Denver 
150,000 
South Platte River and Marston Lake 
61 
Jersey City 
187,098 
Passaic and Pequannock Rivers 
61.5 
Newport, Ky 
30,000 
Ohio River 
63 
Alexandria2 
231,396 
River Nile by canal 
89 
Cairo3 
374,838 
River Nile by canal 
141 
St. Petersburg4 
954,400 
Filtered water from River Neva 
142 
It will be noticed that the cities with the lowest rates treat their 
water before use or go long distances for pure spring supplies, while 
those afflicted with the greatest amount of the disease take the nearest 
available water and use it without treatment, or with such as cannot 
deserve the name. Among the cities with the worst showing are sev- 
eral which, in one wTay or another, filter their water; this conjunction 
of incompatible facts indicates in each case either very imperfect filtra- 
tion, or the introduction of an unusual amount of disease from without, 
or the occurrence of infection through the use of polluted milk, oysters, 
or other food. 
Examples of Typhoid Fever Epidemics and of Limited Out- 
breaks Traced to Infected Water.-For the purpose of illustrating 
to what an extent specifically polluted water can, under favorable con- 
ditions, bring about a sudden outbreak or explosion, the following 
cases have been selected from the many which are to be found in the 
literature of hygiene. 
Epidemic at Lausen, Switzerland.-This best known and most often 
quoted of epidemics of typhoid fever was practically the first one of 
any considerable extent to be traced undisputably to the use of spe- 
cifically polluted water, although many outbreaks, large and small, 
had been ascribed to the use of water " containing considerable organic 
matter " and only supposedly infected. 
Up to 1872, this village of 780 inhabitants had not been visited by 
typhoid fever, even in sporadic cases, for sixty years. On August 7th, 
with no previous warning, ten persons were seized, and during the 
next ten days nearly sixty more. The number of cases increased from 
day to day until 130 persons, or one-sixth of the entire population, had 
been seized. So large a percentage of involvement pointed to some 
common cause, and the immunity enjoyed by the inmates of a group 
of houses not connected with the public water supply directed atten- 
tion to the latter, which was derived from a spring at the foot of a 
ridge about 300 feet high, between the village and the Fuhrler valley. 
In this valley, at a point between one and two miles distant from 
Lausen, was an isolated farm where dwelt a man who, on June 10th, 
shortly after his return from a visit, was taken sick with typhoid fever. 
'Average rate, 1890-1896, 29.7 ; increased 102 per cent. 
2 Average rate, 1890-1896, 143.4 ; decreased 38 per cent. 
3 Average rate, 1890-1896, 168.3 ; decreased 16.2 per cent. 
4 Average rate, 1890-1896, 77.2 ; increased 84 per cent. EXAMPLES OF TYPHOID FEVER EPIDEMICS. 
365 
Before the end of July, three more cases developed in the same house. 
The discharges of all four were thrown into a brook in which the 
family washing was done and which served to irrigate the meadows 
below. Whenever it was dammed up for this purpose, the volume of 
the water supply beyond the ridge was noticeably increased. Between 
July 15th and the end of the month, the meadows had been submerged 
by this process, and in three weeks from the beginning of the operation, 
the explosion occurred in Lausen. 
The sequence of events was, then, the appearance of the initial case 
on June 10th and of three more in the same house before the end of 
July, the daily pollution of the water of the brook, the damming of the 
brook in the middle of July, and the appearance of the first cases in 
Lausen on August 7th. Everything pointed to direct connection be- 
tween the impounded water and the spring a mile or more distant on 
the other side of the ridge, and its existence was established by dump- 
ing about a ton of salt into the brook and noting its speedy appearance 
in the Lausen spring. As a very large amount of flour, deposited at 
the same place, gave no evidence of its appearance, even in traces, it was 
proved that the water passed through a coarse filtering medium rather 
than through an open underground passage. 
The Plymouth, Pa., Epidemic.-The town of Plymouth, Pennsylvania, 
had, at the time of the epidemic in 1885, a population of about 8,000 
people. The general water supply was derived from a mountain 
brook which was dammed at intervals so as to form a series of im- 
pounding reservoirs, but a large part of the population was supplied 
by individual wells. A citizen who spent the Christmas holidays at 
Philadelphia returned in January to his home ill with typhoid fever 
and had a very long sickness. During the entire period, his excreta, 
which were in no way disinfected, were thrown upon the snow and ice 
on a slope not forty feet away from the brook, at a point midway be- 
tween two of the dams. At this time the brook was frozen over, and 
it remained so until the approach of spring. 
During the last third of the month of March, there was a sudden 
period of warmth, and the snow and ice began to melt. Shortly after- 
wards, the warm spring rains began and the ice and snow and frozen 
excreta upon the slope were melted, and the entire accumulation was 
washed into the brook and thence into the water mains. Within three 
weeks thereafter, cases of typhoid fever by the score made their ap- 
pearance throughout the town. On some days, more than a hundred 
new cases were reported, and on one, the number reached nearly two 
hundred. The total number of seizures has been variously stated, the 
lowest estimate being 1,000 and the highest 1,500. The number of 
deaths was not less than 114 and has been placed as high as 150. 
It was discovered that the epidemic was limited practically to those 
whose houses were supplied by the town mains, and to those who, 
while supplied at home by wells, drank of the public supply while 
absent from home during working hours. This distribution was par- 
ticularly emphasized in one street, where the houses on one side all had 366 
TER. 
one or more cases, while those on the other had none at all. The 
former were supplied by the town mains and the latter depended upon 
wells. 
A somewhat similar outbreak on a much smaller scale is reported 
by Dr. Dupard1 as occurring at a small village in the Alps, the de- 
tails of which are as follows : 
Outbreak at Uvernet.-In October, 1898, a detachment of 157 in- 
fantry soldiers were quartered in four houses in the village, each house 
sheltering approximately a fourth of the men. In one, where 37 were 
quartered, there appeared within a few weeks 22 cases of typhoid fever, 
six of which terminated fatally. At the time of seizure there were no 
other cases in the village, nor did any appear in any other house than 
this one. Investigation revealed the fact that a few days before the 
arrival of the troops, a child of ten years had been taken ill with the 
disease in another house situated on higher ground, about 400 feet away 
from the house in question. Where the child lay ill, there was no 
privy, and his excreta were thrown upon the ground in a neighboring 
field. His soiled clothes were washed in the spring nearby. 
At the time of the soldiers' arrival, a number of heavy rains oc- 
curred, by which the surface impurities of the soil in the neighborhood 
of the house where the child lived would, by reason of the inclination 
of the ground, be washed toward the house occupied by the soldiers. 
This was supplied by water from a small stream through a rude main 
constructed of worm-eaten hollow logs laid in a shallow depression in 
the surface of the soil. There could be no question of the probability 
of contamination of this supply by the faecal discharges thrown upon 
the ground in the near vicinity, and in the absence of any other cases 
and with the high percentage of seizures in the one house, no other ex- 
planation appears to be possible. 
Epidemic at Ashland, Wisconsin, in 1893-94.-This outbreak is one 
of peculiar interest in that in addition to serving as an excellent illus- 
tration of the danger of using the same body of water as a place for 
the disposal of sewage and as a source of drinking water, it was made 
the basis of an action at law which established the liability of water 
companies and municipalities in case of sickness and death caused by 
the distribution and use of infected water. 
The city's supply is derived from an arm of Lake Superior, Che- 
quamegon Bay, upon which the city is situated. This bay, which is 
about twelve miles long and of an average width of five, varies from 
eight to thirty-six feet in depth. North of the city, and extending 
outwards in a northwesterly direction, is a breakwater, constructed for 
the protection of the harbor against northerly gales; and between it 
and the city, the mouth of the water intake is located about a mile 
from the shore. (See Fig. 35.) The sewage of the city is discharged 
further to the west and south. The currents in the bay follow the 
course indicated by the arrows in the figure, and carry the sewage 
toward the breakwater and over the mouth of the intake. This con- 
1 Lyon Medical, Jan. 1, 1899, p. 5. EXAMPLES OF TYPHOID FEVER EPIDEMICS. 
367 
dition of affairs was brought to the attention of the company by the 
health boards of the city and state repeatedly, but without results. 
That the water was polluted, was evident on mere ocular inspection, 
for it was often cloudy or markedly turbid. During the winter of 
1893-94, typhoid fever made its appearance in the city, and from the 
initial cases a disastrous epidemic developed, which led to the estab- 
lishment of a model filtering plant. 
The action at law referred to above was brought by the widow of 
one of the victims. In evidence, it was shown that he lived continu- 
ously in Ashland and drank no water other than that supplied by the 
Fig. 35. 
CHEQUAMEGON BAY 
Conditions obtaining at Ashland, Wis., prior to the epidemic of 1893-94. 
water company; that previous to his seizure the disease had prevailed 
in the city, and that the discharges from the antecedent cases had 
passed into the waters of the bay by way of the city sewers. The 
court found for the plaintiff in the sum of $5,000. 
Epidemic at Liineburg in 1895.-The ancient town of Luneburg, 
with a population of 22,000, has a system of sewers which empty at 
two points into the small River Ilmenau. The public water supply is 
in the hands of a number of separate corporations, which had their 
origin in mediaeval guilds ; and as the two principal ones supply the 
same parts of the town, it happens that their mains run through the 
same streets, and that not alone adjoining houses, but even different 368 
WATER. 
stories of the same building are supplied by either one according to 
circumstances. The Raths company furnishes a ground-water which 
is perfectly good, except for its rather high content of iron, which has 
sometimes caused more or less trouble. 
The other large corporation, known as the Abts Company, obtains 
its water from the Ilmenau, usually at a point above the town ; but be- 
tween July loth and 20th, it drew it from a place in the middle of the 
town, opposite the pumping station, where the water was extremely im- 
pure. Previous to these dates, typhoid fever, which was always present 
in some amount in the town, had begun to appear to an unusual extent, 
and in the first half of August, there was a sudden and remarkable in- 
crease in the number of cases. On the termination of the outbreak, 
205 cases had been reported, 169, or 82.44 per cent., of which were 
among families supplied with the water of the river. 
It was proved that for a period of some days, which included the 
dates above mentioned, the diarrhoeic discharges of a young girl, very 
sick with typhoid fever, were thrown, without being disinfected, into 
the river at a point about 300 feet above the intake and on the same 
side. In addition to this one source of the causative agent which pro- 
duced such a sudden rise in the curve, it was known that the river had 
been polluted by the discharges of another patient in May, and that the 
epidemic had its real beginning in June. It is conceivable that in a 
town where the house supplies are so complicated that different stories 
have different kinds of water, a fair percentage of the victims of an epi- 
demic may acquire the disease through neighborhood visiting, though 
their own domestic supply is of the proper quality. In this whole 
outbreak, only 17.56 per cent, of the cases were among people whose 
premises were supplied by the other companies. 
Epidemic at Zehdenick in 189 7.-This was a local outbreak traced 
to the contamination of a well by the discharges of a child sick with 
typhoid fever. The water was used by the inmates of the houses in 
the immediate vicinity, and the disease was limited to them alone. 
Of 303 persons making up the 29 households of the neighborhood, 94, 
or nearly a third, were seized within a short period, while not another 
case was known in the town. The inmates of nine houses within the 
infected area, who obtained their water from another source, were un- 
touched. 
Limited Outbreak Among Soldiers.-An infantry regiment, returning 
from the autumn manoeuvres, passed through a small village where 
typhoid fever existed, and halted for water. Two days afterwards, three 
men were seized with great suddenness, and within two weeks, 36 men 
were down with the disease. They had been exposed to no other 
source of infection, and other troops who passed through the same vil- 
lage without stopping for water were unaffected. Knowing the day 
when the infection occurred, and since in every case the onset was 
marked by very acute symptoms, Dr. Emil Jauchen1 was able to de- 
termine the exact period of incubation. Three were seized on the 
1 Wiener klinische Wochenschrift, July 7, 1898. ASIATIC CHOLERA. 
369 
second day, seven on the third, six on the fourth, four on the fifth, 
four on the sixth, five on the seventh, and seven between the ninth and 
the fourteenth. The short periods are explainable by the fact that the 
men were in a state of exhaustion at the time of drinking, and all took 
copious draughts. 
Asiatic Cholera.-This disease, which is endemic in India, whence 
it makes periodical excursions to other parts of the world, sometimes 
most widespread and with the most disastrous results, is, perhaps, more 
exclusively than typhoid fever, a water-borne disease. Since the dis- 
covery by Koch of the exciting cause and the detection of the same 
in drinking water during epidemics of the disease, the older the- 
ories of its method of spread have been abandoned save by the few 
remaining adherents of the " localist " theory, whom not even the facts 
revealed during and after the great epidemic of 1892 can move from 
their dogged attachment to the creed of their revered teacher. 
During the course of the widespread devastating epidemic of 1892, 
which in its journey from the valley of the Ganges through Persia 
claimed 20,000 victims in Teheran alone, and in its course through 
Russia destroyed 215,157 more, and which extended through Ger- 
many, Austria, France, Belgium, Holland, and even to the harbors of 
the Western Hemisphere, no more instructive example of the connection 
between the disease and polluted water and of the immunity conferred 
by the use of a pure supply could have been yielded or desired than 
the experience of Hamburg, Altona, and Wandsbeck. These three 
cities adjoin one another so closely that there is no visible line of de- 
markation, and in a geographical sense might be regarded as one place. 
In one important respect, however, the three places differ very 
materially ; namely, their public water supplies. Wandsbeck was sup- 
plied with filtered water from a lake but little subject to pollution ; 
Altona drew upon the Elbe at a point below the entrance of the sewage 
of Hamburg, but filtered the water through sand; Hamburg used 
unfiltered water from the Elbe above the city. During the summer of 
1892, or between August 17th and October 23d, Hamburg, with a 
population of 640,000, had nearly 17,000 cases of cholera, of which 
slightly more than half terminated fatally; Altona, with a population 
about a quarter as large, had but 500 cases, or only one-thirty-fourth 
as many (400 of these are supposed to have come from Hamburg), and 
Wandsbeck had practically none. 
Very noticeable was the fact that where Hamburg and Altona come 
together, the Hamburg side was plentifully springled with cases, while 
the other was comparatively free (see Fig. 36), and this was still more 
particularly remarked along a certain street that for a distance formed 
the boundary line, in which the houses on the Hamburg side had 
plenty of cases and those opposite had none. Almost as though in- 
tended for the purpose of marking more sharply yet the distribution 
of the two kinds of water, it happened that a group of tenement houses 
on the Hamburg side of the boundary was supplied with water from 
the Altona mains, and in these houses, densely peopled by the laboring 370 
TEA TFT?. 
class, not a single case occurred, while in neighboring houses the disease 
was raging. 
Thus we have a most eloquent instance of the value of sand filtra- 
tion and of the danger of using polluted supplies. Hamburg's un- 
filtered water came from above the city, while Altona had to depend 
upon water which, before being filtered, had received the entire sewage 
of over three-quarters of a million people. The initial specific pollu- 
tion of the river water was traced back to Russian emigrants, herded 
in barracks on one of the wharves pending their embarkation for the 
United States. At the time of the outbreak, there were, on an average, 
about a thousand of these people on hand all the time. Many of them 
came from districts in Russia which had been and were then suffering 
severely from cholera, and all were well supplied with dirty clothing 
and blankets, some of which they washed while they were being de- 
tained. It is believed that among the thousands that had arrived, 
Fig. 36. 
ALTONA 
side of the boundary. 
HAMBURG 
side of the boundary 
Portion of the boundary line between Hamburg and Altona. The dots indicate cases of cholera. 
there must have been some mild cases of the disease or at least some 
convalescents with cholera germs still in their evacuations two or 
three weeks after recovery. All the sewage matters of every descrip- 
tion from these people were discharged directly into the river at the 
wharf. 
With the exception of a few straggling cases, there was no cholera in 
either of the two cities from October 23d to December 6th, when a 
small outbreak occurred in Hamburg. This reached its culminating 
point, five cases in one day, on the 26th, and then the disease be- 
gan to reappear in Altona, but under very different conditions from 
those which characterized the epidemic in August. Of the 500 cases 
which then occurred, about 400 were connected in one way or another 
with Hamburg, but in the later outbreak, most of the patients were of 
the well-to-do class of workmen whose occupation did not call them to 
Hamburg-women, young children, inmates of hospitals and others ASIATIC CHOLERA. 
371 
having no reason to go there. Consultation of the records of bac- 
teriological examination of the Altona filtered water showed an in- 
crease in the first week of December and again in the last days of that 
month and at intervals in January, which indicated that some disturb- 
ance must have occurred in the working of the filters. 
Investigation showed where the fault lay and also its nature : the 
surface of the sand had been frozen under the mud layer and had 
thawed over only part of its area, so that the whole work of the filter 
was thrown upon a part. The imperfect working in early December 
was not followed by cholera, for at that time the river was practically 
free from the germs. Then came the few new cases in Hamburg, 27 
in number, and reinfection of the Elbe, followed by faulty working of 
the Altona filters and consequent distribution of a small amount of 
infective material through the water mains. The organisms were 
found in the water just below the mouth of the main sewer of Ham- 
burg and also in one of the settling basins of the filter plant, where the 
water stood prior to delivery to the beds. 
The Propagation of Cholera in India.-As has been stated, the home 
of cholera is India, and so long as the natives are faithful to their re- 
ligion and to the observance of old-established customs, just so long 
will that country supply the rest of the world with occasional infection. 
Considering the extreme conservatism of all classes of East Indians and 
the national reverence of the Hindus for all holy places, it may be safe 
to predict that before any marked change for the better is accomplished, 
the rest of the civilized world will have advanced so far in sanitary 
affairs that cholera will be no more feared than varicella. As illus- 
trative of what sanitary reform in India would have to encounter, the 
following extracts from the report of Dr. Simmons, quoted by Profes- 
sor Mason, will be found of use and interest. It may be stated by 
way of explanation that Orissa, below mentioned, is a province cover- 
ing over 24,000 square miles, every part of which is holy ground. 
Every town contains consecrated land and is filled with temples, and 
every little hamlet has its shrine. 
" The drinking water supply is derived from wells, so-called ' tanks ' 
or artificial ponds, and the water-courses of the country. The wells 
generally resemble those in other parts of Asia. The tanks are exca- 
vations made for the purpose of collecting the surface-water during the 
rainy season and storing it up for the dry. Necessarily they are mere 
stagnant pools. The water is used not only to quench thirst, but is 
said to be drunk as a sacred duty. At the same time, the reservoir 
serves as a large washing-tub for clothes, no matter how dirty or in 
what soiled condition, and for personal bathing. Many of the water- 
courses are sacred; notably the Ganges, a river 1,600 miles long, in 
whose waters it is the religious duty for millions, not only of those 
living near its banks, but of pilgrims, to bathe and to cast their dead. 
" The Hindoo cannot be made to use a latrine. In the cities he digs 
a hole in his habitation ; in the country he seeks the fields, the hill- 
sides, the banks of streams and rivers when obliged to obey the calls 372 
WATER. 
of nature. Hence it is that the vicinity of towns and the banks of the 
tanks and water-courses are reeking with filth of the worst description, 
which is of necessity washed into the public water-supply with every 
rainfall. Add to this the misery of pilgrims, their poverty and dis- 
ease, and their terrible crowding into the numerous towns which con- 
tain some temple or shrine, the object of their devotion, and we can see 
how India has become and remains the hot-bed of the cholera epidemic. 
" In the United States official report, the horrors incident upon the 
pilgrimages are detailed with appalling minuteness. W. W. Hunter, 
in his Orissa, states that 24 high festivals take place annually at Jug- 
gernaut. At one of them, about Easter, 40,000 persons indulge in 
hemp and hasheesh to a shocking degree. For weeks before the car 
festival in June and July, pilgrims come trooping in by thousands 
every day. They are fed by the temple cooks to the number of 90,- 
000. Over 100,000 men and women, many of them unaccustomed to 
work or exposure, tug and strain at the car until they drop exhausted 
and block the road with their bodies. During every month of the 
year a stream of devotees flows along the great Orissa road from Cal- 
cutta, and every village for three hundred miles has its pilgrim en- 
campments. 
" The people travel in small bands, which at the time of the great 
feasts actually touch each other. Five-sixths of the whole are females, 
and ninety-five per cent, travel on foot, many of them marching hun- 
dreds and even thousands of miles, a contingent having been drummed 
up from every town or village in India by one or other of the three 
thousand emissaries of the temple, who scour the country in all direc- 
tions in search of dupes. When those pilgrims who have not died on 
the road arrive at their journey's end, emaciated, with feet bound up 
in rags and plastered with mud and dirt, they rush into the sacred 
tanks or the sea and emerge to dress in clean garments. Disease and 
death make havoc with them during their stay; corpses are buried in 
holes scooped in the sand, and the hillocks are covered with bones and 
skulls washed from their shallow graves by the tropical rains. 
" The temple kitchen has the monopoly of cooking for the multitude, 
and provides food which, if fresh, is not unwholesome. Unhappily, 
it is presented before Juggernaut, so becoming too sacred for the 
minutest portion to be thrown away. Under the influence of the heat 
it soon undergoes putrefactive fermentation, and in forty-eight hours 
much of it is a loathsome mass unfit for human food. Yet it forms 
the chief sustenance of the pilgrims and is the sole nourishment of 
thousands of beggars. Some one eats it to the very last grain. In- 
jurious to the robust, it is deadly to the weak and wayworn, at least 
half of whom reach the place of suffering under some form of bowel 
complaint. Badly as they are fed, the poor wretches are worse lodged. 
"Those who have the temporary shelter of four walls are housed in 
hovels built upon mud platforms about four feet high, in the center of 
each of which is the hole which receives the ordure of the household, 
and around which the inmates eat and sleep. The platforms are 373 
ASIATIC CHOLERA. 
covered with small cells without any windows or other apertures for 
ventilation, and in these caves the pilgrims are packed, in a country 
where, during seven months out of twelve, the thermometer marks 
from 85 to 100 degrees Fahr. Hunter says that the scenes of agony 
and suffocation enacted in these hideous dens baffle description. In 
some of the best of them, thirteen feet long by ten feet broad and six 
and one-half high, as many as eighty persons pass the night. It is 
not, then, surprising to learn that the stench is overpowering and the 
heat like that of an oven. Of 300,000 who visit Juggernaut in one 
season, 90,000 are often packed together for a week in 5,000 of these 
lodgings. In certain seasons, however, the devotees can and do sleep 
in the open air, camping out in regiments and battalions, covered 
only by the same meagre cotton garments that clothe them by day. 
11 The heavy dews are unhealthy enough ; but the great festival falls 
at the beginning of the rains, when the water tumbles in solid sheets. 
Then lanes and alleys are converted into torrents or stinking canals, 
and the pilgrims are driven into the vile tenements. Cholera invari- 
ably breaks out. Living and dead are huddled together. In the 
numerous so-called corpse-fields around the town as many as forty or 
fifty bodies are seen at a time, and vultures sit and dogs lounge lazily 
about gorged with human flesh. In fact, there is no end to the recur- 
rence of incidents of misery and humiliation, the horrors of which, 
says the Bishop of Calcutta, are unutterable, but which are eclipsed 
by those of the return journey. Plundered by priests, fleeced by 
landlords, the surviving victims reel homeward, staggering under their 
burdens of putrid food wrapped up in dirty clothes, or packed in 
heavy baskets or earthenware jars. Every stream is flooded, and the 
travelers have often to sit for days in the rain on the bank of a river 
before a boat will venture to cross. 
"At all these points the corpses lie thickly strewn around (an En- 
glish traveler counted forty close to one ferry), which accounts for the 
prevalence of cholera on the banks of brooks, streams, and rivers. 
Some poor creatures drop and die by the way ; others crowd into the 
villages and halting-places on the road, where those who gain admit- 
tance cram the lodging-places to over-flowing, and thousands pass the 
night in the streets, and find no cover from the drenching storms. 
Groups are huddled under the trees; long lines are stretched among 
the carts and bullocks on the roadside, their hair saturated with the 
mud on which they lie ; hundreds sit on the wet grass, not daring to 
lie down, and rocking themselves to a monotonous chant through the 
long hours of the dreary night. 
"It is impossible to compute the slaughter of this one pilgrimage. 
Bishop Wilson estimates it at not less than 50,000. And this descrip- 
tion might be used for all the great Indian pilgrimages, of which there 
are probably a dozen annually, to say nothing of the hundreds of 
smaller shrines scattered through the peninsula, each of which at- 
tracts its minor hordes of credulous votaries. So that cholera has 
abundant opportunities for spreading over the whole of Hindostan 374 
WATER. 
every year by many huge armies of filthy pilgrims ; and the country 
itself well deserves the reputation it universally possesses of being the 
birthplace and settled home of the malady." 
Parasites and Drinking Water. 
There is abundant evidence of the agency of drinking water in the 
spread of certain of the animal parasites, but with respect to certain 
others the danger is much over-rated (tape-worms), or, indeed, imag- 
inary (trichinae). 
Round worms, Ascaris lumbricoides, are undoubtedly spread in part 
by water. The female deposits enormous numbers of eggs in the 
small intestines, and these are expelled in the faeces. Whether the 
freshly discharged eggs are capable of reproducing the worm, is a mat- 
ter of doubt, but it seems probable that the intervention of another 
host is necessary. Wherever this parasite is known to prevail exten- 
sively, the people use polluted water for drinking. 
Pin worms, or seat worms, Oxyuris vermicularis, are probably spread 
by water. They locate in the caecum and upper colon, where the fe- 
male deposits eggs in large numbers, which, reaching a water supply 
after being discharged through the bowel, may be taken into the stom- 
ach, where the envelope of the embryo is disintegrated by the gastric 
juice. The larvae develop in the small intestines and come to maturity 
in about four weeks. 
Guinea worms, Dracunculus medinensis, are said to invade the body 
through the skin during bathing or through the stomach in drink- 
ing water; the evidence of the latter method is definite. In the 
stomach, the embryos are rapidly developed, and soon the impregnated 
female proceeds from the alimentary canal to the subcutaneous tissues 
in various parts of the body, where she finally breaks through the skin 
and escapes. The living embryos which are then liberated, finding 
their way into fresh water, enter the bodies of the common fresh-water 
flea, Cyclops quadricomis, which acts as the intermediate host and 
conveys the organism to the human stomach. 
In a case reported by Dr. John Patterson,1 the patient had an ab- 
scess on the upper part of the left tibia, from which, when it was ex- 
cised, a portion (four inches) of a worm was removed. Later, he had 
an abscess and sinus of the left calf, followed by a swelling back of the 
inner malleolus, and in this a portion of a worm, twenty-five inches in 
length and devoid of a head, was found. 
Whip worms, Trichocephalus dispar, which are said to be extremely 
common in Paris and some other places outside the tropics, are spread 
wholly by water, without which the embryo cannot develop within the 
the egg. Taken into the stomach, the envelope is dissolved and the 
liberated larva attaches itself to the wall of the intestine, where it 
proceeds very slowly to develop. It does not reach full maturity until 
about a year has elapsed. 
1 Medical Record, Oct. 7, 1899. ICE. 
375 
Filaria sanguinis hominis, the parasite which produces chyluria, haema- 
tochyluria, and elephantiasis, finds its way into the system through 
water contaminated by mosquitoes which have sucked the blood of 
persons suffering from the parasite. The adult female produces an 
enormous number of minute embryos, which pass into the blood; and 
when these are taken into the stomach of the mosquito, they wander 
to other parts of the insect, where they become further developed, and 
later are transferred to the water, through which they pass into the 
human stomach, where the cycle is completed. This parasite is not 
confined wholly to the tropics and is occasionally seen in our southern 
states. 
Bilharzia hsematobia, the cause of a peculiar hsematuria common in 
parts of Africa, is believed by many to be transmitted by drinking 
water contaminated by the urine of persons suffering with the disease. 
The embryos probably enter the system of some other organisms, 
which play the part of intermediate hosts and advance their develop- 
ment one stage. 
Anchylostomum duodenale, the cause of anaemia observed in the 
workmen of certain mines and in the men engaged in driving the St. 
Gothard tunnel, is probably disseminated chiefly by polluted water. It 
produces extreme anaemia, digestive disturbances, and hemorrhages, 
and is the cause of considerable mortality in Egypt, Brazil, the West 
Indies, especially Porto Rico, and in some parts of Italy and other 
countries. The parasite is a minute worm which attaches itself, some- 
times in enormous numbers, to the villi of the upper part of the small 
intestine, through which a constant drain is made on the blood. The 
eggs are discharged from the intestine in the faeces, and are taken into 
the system of new victims through the drinking water. According 
to Dr. Carl Tinus,1 the larvae are regularly found in the dung of horses 
used in the mines at Brennberg in Hungary, and also in great numbers 
on the timbering in the mines, near the ore passages where the work- 
men put their hands to steady themselves. This suggests the possi- 
bility of direct infection through food conveyed to the mouth by un- 
washed hands. 
Another parasite, Rhabdonema intestinale, which causes intense 
anaemia and enteritis with persistent diarrhoea, is very common in the 
West Indies, Brazil, Italy, and other tropical and subtropical coun- 
tries. It is frequently associated with Anchylostomum duodenale. 
The female in the intestine produces enormous numbers of eggs, 
which hatch in the intestinal canal and are discharged to the extent of 
thousands every day. 
ICE. 
It is a common idea that ice is necessarily pure, because, in freezing, 
" water purifies itself." Ice may, however, be quite as impure as the 
original water or very pure, according to circumstances. The first for- 
mation is quite likely to contain impurities, such as the dust and other 
1 CEsterreichische Sanitatswesen, 1898, No. 42. 376 
WATER. 
matters floating on the surface. Under ordinary conditions the im- 
purities will be limited to this layer, for in the growth of the ice from 
above downwards, all but traces of dissolved substances and practically 
all of the suspended matters are excluded. 
Ice may become impure in several ways. If snow falls upon it and 
becomes wet either by rain or by water from below and then freezes 
and becomes part of the ice, it will contain all the impurities which have 
been washed out of the air. If while the ice is thin, holes are cut so 
as to permit flooding from below, it will contain all the impurities of 
the water. Cut from shallow ponds, it will be pure or impure accord- 
ing to the quality of the water and the depth to which it freezes. Water 
from such ponds, if polluted by surface washings or sewage matters, is 
likely to yield ice which, when melted, will give off offensive odors. 
It is a common belief that bacteria are killed in ice, but many 
varieties will retain their vitality in it for a very long time. As early 
as 1871, Burdon Sanderson showed that even the purest ice is likely 
to contain them in some degree. Chantemesse and Widal proved in 
1882, Prudden in 1887, and Riche, Frankel, and others at different 
times, that pathogenic bacteria may maintain their vitality to a sur- 
prising degree in ice, and that the bacillus of typhoid fever is particu- 
larly resistant. Prudden1 showed that ice, made from water which 
contained them to an innumerable extent, yielded at the expiration of 
103 days no less than 7.348 per cubic centimeter. 
Not alone are bacteria resistant to the ordinary low temperature of 
ice, for Pictet and others have proved that even the extraordinary cold 
of liquefied air, - 315°, is not sufficient to destroy them. 
Clear ice contains fewer organisms than that which contains air 
bubbles, and snow ice contains them in greatest abundance. 
Artificial ice is frozen in blocks of the size and shape of the tanks 
in which the water is held. As the entire mass of water in each tank 
is frozen it naturally must contain in its inner portion, which is the 
last to freeze, all of the matters originally contained. Unless the water 
used is pure and colorless, the ice will not be of good quality, and, par- 
ticularly in the center, will not be of good appearance. When colored 
or impure water is used, it is a common trick to remove the impurities 
and coloring matters by tapping the center before the freezing process 
is completed, and drawing off the liquid in which they have become 
concentrated. On account of the possible retention of part or all of 
the contained impurities and bacteria of the water from which it is 
made, artificial ice should be manufactured only from distilled water 
or from natural water of the highest degree of purity. 
As an illustration of the danger of using infected ice in water or 
other beverages, the following case 2 may be cited. The officers of a 
French regiment stationed at Rennes gave a dinner, at which the cap- 
tains and superior officers drank only beer, while the younger men, the 
lieutenants, sitting together, drank champagne cup made with ice cut 
from the river Vilaine at a point below the town, where the water 
1 Medical Record, March 26, 1887. 
2 Revue d'Hygiene, April, 1898. CHEMICAL EXAMINATION OF WATER. 
377 
was extensively polluted by sewage from a district in which there had 
been a number of cases of typhoid fever. After the usual period of 
ncubation, eight of the lieutenants, but none of the other officers, were 
seized with typhoid fever. As the food served was the same for all, 
and as the disease was limited to those who drank of the champagne 
cup, the outbreak may be attributed in all fairness to the ice from the 
infected locality. 
CHEMICAL EXAMINATION OF WATER. 
Collection of Samples.-In taking samples of water for chemical 
analysis, great care is necessary in order to secure specimens which 
shall be fairly representative of the supply under investigation. They 
should be taken only in clean glass bottles or demijohns of from half 
a gallon to a gallon capacity, and never in stone jugs, tin cans or 
wooden kegs. The best form of bottle has a glass stopper, but a per- 
fectly clean cork is quite unobjectionable. In spite of directions most 
carefully given, one often sees specimens sent'in stone jugs stopped 
with wooden plugs wrapped with old cotton rags or pieces of news- 
paper to secure a tighter fit, and sometimes smeared with shoemakers' 
wax, pitch, or even tallow. Analysis of such specimens is likely to 
give results of no value whatever, for it must be remembered that we 
are dealing with exceedingly small amounts of ammonia and other 
products, and that anything short of absolute cleanliness of receptacles 
introduces error. 
The bottle, supposedly clean at the start, should be thoroughly 
rinsed with the water to be sampled, then filled to the neck and se- 
curely stoppered. If the sample comes from a pump, the barrel of 
the latter must be completely emptied of the water which has been 
standing in it for any length of time ; if from a pipe, the water should 
be allowed to run to waste, until the whole of the original contents 
have escaped ; if from a pond or other body of water, the bottle 
should be plunged sufficiently far beneath the surface to avoid the en- 
trance of floating matters, and sufficiently far from the banks to avoid 
matters which hug the shore. 
After the sample is secured, as little time as possible should elapse 
before beginning the analysis, because of the rapidity with which 
changes occur in the organic matters, ammonia, nitrites, and nitrates. 
Determination of Free Ammonia and Albuminoid Ammonia. 
Solutions Required: 1. Standard Solution of Ammonium 
Chloride.-Dissolve 3.138 grams of pure dry ammonium chloride 
in one liter of distilled water free from ammonia. One co. of this solu- 
tion represents 1 mgr. ammonia. 
2. Standard Dilute Solution of Ammonium Chloride.- 
Dilute 10 cc. of the strong solution up to a liter with water free from 
ammonia. One cc. of this solution represents 0.01 mgr. ammonia. 378 
WATER. 
3. Solution of Sodium Carbonate.-Dissolve 200 grams of pure 
sodium carbonate in one liter of water free from ammonia. 
4. Alkaline Potassium Permanganate.-Dissolve 8 grams of 
potassium permanganate and 200 grams of caustic potash in 1,500 cc. 
distilled water and boil down to a liter to get rid of any free ammonia 
present. Fifty cc. of this solution are required for each analysis. 
The author finds it convenient to omit the boiling-down process when 
the solution is prepared and to take 75 cc. and boil down to 50 at the 
time of analysis. This insures freedom from ammonia when used, and 
avoids the bumping which is so likely to occur when the cold solution 
is added during the process of distillation. 
5. Nessler's Reagent.-Dissolve 35 grams of potassium iodide in 
150 cc. of distilled water. Dissolve about 16 grams of corrosive sub- 
limate in 300 cc. of distilled water. Add the latter to the former, 
Fig. 37. 
Distilling apparatus used in determining the ammonias in water. 
both solutions being cold. Then add 200 grams of caustic soda, dis- 
solved in a half liter of distilled water, and mix thoroughly. Next 
add, with constant stirring, a saturated solution of corrosive sublimate 
until the precipitate which forms is permanent; then dilute the whole 
to a liter. Let stand until clear, when the supernatant liquid should 
have a pale straw color. 
6. Ammonia-free Water.-This may be obtained by distilling 
water made slightly acid with sulphuric acid. The first 25-50 cc. of 
distillate should be rejected, and the next 50 cc. should be tested with 
Nessler's reagent. If no color appears, the distillate is ammonia-free, 
and the operation may then be continued until the contents of the re- 
tort are reduced to very small bulk. Should the test show traces of 
ammonia, successive portions should be tested until a negative result 
is secured. It is well to prepare a goodly supply and keep it on hand 
in glass-stoppered bottles. CHEMICAL EXAMINATION OF WATER. 
379 
Apparatus Required. Distilling Apparatus.-Some analysts prefer 
glass retorts; others, distilling flasks with side tubes. Whichever is 
used, the connection with the Liebig condenser must be tight. The 
author prefers a distilling flask with a side tube of such a size that it 
enters the condenser tube easily, but without making a loose joint. A 
bit of clean rubber tubing on the side tube may serve to make the joint 
more perfect at the point of entrance. The mouth of the flask should 
be closed with a rubber stopper with a single perforation, carrying a 
funnel tube which reaches to the bottom of the flask. 
The flask or retort may be heated either by a rose burner or by the 
free flame of a Bunsen lamp. In laboratories where water analysis is 
conducted on a large scale, it is found convenient to have the distilling 
flasks, arranged in the form of batteries, connected with block tin con- 
densing tubes which pass through a common cooling-tank fed by a 
single tap. 
In Fig. 37 is shown the form of apparatus which the author finds 
convenient for ordinary work. 
Nesslerizing Tubes.-For making the determination of ammonia by 
the colorimetric method, tubes of colorless glass, about 12 J x f inches, 
with a mark at the 50-cc. point are required. 
Determination.-The flask and condenser are rinsed with ammonia- 
free water, a half liter of the water and 5 cc. of sodium carbonate solution 
are introduced into the flask, and heat is applied. The distillate is col- 
lected either in the Nessler tubes or in 50-cc. flasks, from which it is 
transferred to the tubes; and when three portions of 50 cc. each have 
been collected, all of the*free ammonia in the sample will have passed 
over. 
On beginning the distillation, 75 cc. of the unconcentrated alkaline 
permanganate solution are heated in a small flash and boiled down to 
50 cc., and on the completion of the distillation for free ammonia, the 
hot reagent is added through the funnel tube, and boiling is continued. 
If the reagent has been concentrated in advance, 50 cc. are added. 
The nitrogenous organic matter is now attacked by the permanganate 
solution and more ammonia is evolved. While this in no way differs 
from the free ammonia, it is given the distinguishing name " albuminoid 
ammonia " to indicate its origin. The process is now continued as 
long as any ammonia goes over, but usually no reaction is observed 
after four portions of 50 cc. have been collected. In the laboratory 
of the State Board of Health of Massachusetts, it is the custom to fill 
five tubes and then to cease the distillation. 
To each of the tubes containing the ammonias, 2 cc. of Nessler's 
reagent are added. In the presence of ammonia, a yellowish brown 
color is produced, the depth of which depends upon the amount of 
ammonia present. Some exceptionally rich waters yield such an 
amount of ammonia that a precipitate is formed on the addition of the 
reagent. Then it is necessary to repeat the process and take an aliquot 
part of the distillate and dilute it with ammonia-free water to 50 cc. 
before nesslerizing. Should a precipitate again occur, a smaller part 380 
WATER. 
must be taken, and so on until the proper reaction is obtained. The 
amount in the whole distillate can then be mathematically determined. 
Having nesslerized the several tubes, the next step is to determine 
the amounts p'resent by comparison of colors with a scale made as 
follows : Into a series of tubes, held in a rack, different amounts of the 
weaker solution of ammonium chloride are introduced, then ammonia- 
free water is added to each up to the 50-cc. mark, each tube inverted 
to insure thorough mixing, and finally, 2 cc. of Nessler's reagent added 
to each. A convenient scale is secured by using 0.25, 0.50, 0.75, 
1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, and 5.00 cc., representing 
0.0025, 0.0050, 0.0075, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 
0.040, and 0.050 mgr. of ammonia. 
The first of these will have a very faint yellowish brown tint, and 
the last a very decided reddish brown color, while the intervening 
tubes show a progressive deepening. With these tubes the distillates 
are compared, and the matching of colors gives the desired results. 
If a given tube falls between any two of the scale, a new comparison 
tube may be prepared; but the practiced eye can determine very accu- 
rately without this extra aid. Having read the color of each tube, 
the amounts of those representing the free ammonia are added together, 
and the total multiplied by 2 to get the amount per liter of water; 
the same process is carried out for the determination of the albu- 
minoid ammonia. The results represent parts per million, since a liter 
equals a million milligrams. 
Example.-The three free ammonia tubes show 0.023, 0.006, 0.000: 
total 0.029 mgr.; multiplied by two = 0.058 per liter. By moving 
the decimal point one place to the left, we have 0.0058 part per 
100,000, in which terms the results are ordinarily expressed. 
Precautions.-Since the depth of color caused by Nessler's reagent 
is more or less affected by temperature, and since in all processes of 
comparison the conditions must be the same so far as is possible, the 
reagent should not be added until the distillates and the contents of 
the comparison tubes have the same temperature. Equality in this 
respect is secured without any manipulation or trouble by leaving the 
tubes over night so that all will acquire the temperature of the room. 
It is hardly necessary to point out that the air of the room in which 
the distillation is conducted must be quite free from laboratory fumes 
such as ammonia and sulphuretted hydrogen, which, being absorbed 
by the distillate, would, in the one case, give erroneous results, and in 
the other, react upon the mercury salt in the Nessler's reagent. 
The heat applied to the distilling flask should be so regulated that the 
time required for each portion of 50 cc. will be about fifteen minutes, 
since with more rapid distillation there is likely to be some loss of am- 
monia by imperfect condensation. 
The reading of the tubes should not be undertaken until at 
least five minutes have elapsed after the addition of the reagent. 
The extreme depth of color obtainable is reached somewhat within 
that time. 381 
CHEMICAL EXAMINATION OF WATER. 
The practice of some analysts of distilling the free ammonia out in 
one lot of 150 or 200 cc., collecting the albuminoid ammonia in 
another single portion of 200 or 250 cc., nesslerizing a portion of 
each and calculating the total amount of each by multiplication by 
the proper factor gives correct results; but it has been shown that by 
proceeding in this way, one may lose useful information obtainable 
from a knowledge of the rate at which the ammonia is evolved, since 
organic matter, well advanced in decomposition, yields it more co- 
piously in the first distillate, whereas fresh material yields it more 
slowly and uniformly. 
Some analysts make duplicate distillations of one water at the same 
time, determining the free ammonia in one specimen, and by adding 
the permanganate at the start in the other, determining the total free 
and albuminoid ammonia together. By subtracting the lesser from 
the greater, the amount of albuminoid ammonia is obtained. 
Determination of Other Nitrogen Compounds. Preliminary 
Treatment.-Should the specimen of water have an appreciable color 
due to dissolved vegetable matters, it is necessary, before attempting 
the determination of the above-mentioned substances or of the chlo- 
rides, to decolorize a sufficient volume by means of milk of alumina. 
This is prepared by mixing gradually very dilute solutions of sodium 
hydrate or ammonia and alum or aluminum sulphate ; the resulting 
precipitate is allowed to settle and is then washed several times by de- 
cantation. The water used in washing must be free from chlorides, 
nitrates, and nitrites. If strong solutions are used, the gelatinous 
precipitate soon undergoes change both in appearance and character. 
It becomes chalky and loses its property of removing color. In order 
to remove all coloring matter, a half liter of the water may be shaken 
in a flask with a few cc. of the thick " milk " and then filtered 
through paper. By this means, the most highly colored swamp waters 
can be made colorless in a very few minutes. 
Determination of Nitrogen as Nitrites. Solutions Required.-1. 
Sulphanilic Acid Solution (paramidobenzene sulphonic acid). 
Dissolve 0.50 gram in 150 cc. of acetic acid, sp. gr. 1.040. 
2. Naphthylamine Solution (a-amidonaphthalene). Dissolve 
0.10 gram, in 20 cc. of boiling water, filter, and add 180 cc. of acetic 
acid, sp. gr. 1.040. 
3. Standard Sodium Nitrite Solution.-Dissolve 0.275 gram 
of pure nitrite of silver in pure distilled water and add a dilute solu- 
tion of pure sodium chloride until precipitation ceases. Dilute to 250 
cc. and preserve in the dark in an amber bottle. 
4. Standard Dilute Sodium Nitrite Solution.-Dilute 10 cc. 
of the above to a liter with pure distilled water and preserve in the 
same way. One cc. equals 0.001 mgr. nitrogen as nitrites. 
Process.-To 50 cc. of water in a Nessler tube, or to 100 cc. in a 
tube of larger diameter,'add 2 cc. of each of the two first-mentioned 
solutions. If nitrites are present, a pink to a garnet color is developed 
within a half hour, the intensity of color depending upon the amount 382 
WATER. 
of nitrite present. If no change is observable at the end of a half 
hour, nitrites may be recorded as absent. If, on the contrary, a color- 
ation is produced, the test may be repeated and at the same time one 
or more comparison cylinders prepared. In similar tubes, dilute to 
the mark with distilled water free from nitrites 0.25, 0.50, and 1 cc. of 
the dilute sodium nitrite solution, and add to each the proper amounts 
of the test solutions. At the end of half an hour, compare the color 
acquired by the water sample with the standards, and multiply by the 
proper factor to determine the amount per liter. . 
Since the air of laboratories in which gas is burning is very likely 
to contain traces of nitrites, which are readily absorbed by water, it is 
well to keep the tubes corked or otherwise protected. An open tube 
left some hours is almost sure to develop more or less color. 
The color reaction is due first to the action of the nitrite present on 
the sulphanilic acid, where by a new compound (diazobenzene sulphonic 
anhydride) is produced, which is then acted upon by the naphthyla- 
mine and converted into another (azo-<z-amidonaphthalene-parazoben- 
zene sulphonic acid) which imparts the color. 
Determination of Nitrogen as Nitrates. Solutions Required.-1. 
Phenoldisulphonic Acid.-Heat together for six hours in a water- 
bath 555 grams of strong sulphuric acid and 45 grams of pure phenol. 
Should the resulting compound solidify on cooling, it may be liquefied 
again in the bath and then poured into a number of small bottles pro- 
vided with ground stoppers. Then, as needed, one of them may be 
placed in the bath and the contents liquefied. 
2. Standard Solution of Potassium Nitrate.-Dissolve 0.722 
gram of pure potassium nitrate in a liter of pure distilled water. 
One cc. equals 0.1 mgr. nitrogen as nitrates. 
Process.-Evaporate 10 cc. or more of the water to dryness with 
one drop of sodium carbonate solution in a small porcelain dish. To 
the residue, add 1 cc. of phenoldisulphonic acid which must be brought 
into contact with every particle by means of a glass rod. Dilute with 
water, make strongly alkaline with ammonia or caustic potash, and, 
finally, make up to 50 or 100 cc. with water. Evaporate measured 
volumes of the standard nitrate solution, treat the residues with the 
same amount of the reagent, and proceed in the same way to make a 
comparison scale. The addition of the alkali converts the picric acid, 
formed by the action of the nitrate on the phenoldisulphonic acid, into 
the corresponding picrate, which imparts a bright yellow color, the in- 
tensity of which depends upon the amount of nitrate present. The 
comparison of tints may be made directly in the porcelain dishes or in 
tubes of the same sort as used in the nitrite determination. 
The accuracy of the test is diminished by the presence of chlorides 
in notable amounts, say over 2 parts in 100,000, but not by nitrites.- 
On this account, Mason recommends the addition of corresponding 
amounts of sodium chloride in the preparation of the color scale. 
Determination of Chlorine.-Solutions Required.-1. Standard - 
Solution of Silver Nitrate.-Dissolve 4.7970 grams of pure CHEMICAL EXAMINATION OF WATER. 
383 
silver nitrate in a liter of distilled water. One cc. of this solution is 
the equivalent of 1 mgr. of chlorine. 
2. Solution of Potassium Chromate.-Dissolve 5 grams of 
potassium chromate in 100 cc. of distilled water, add nitrate of silver 
solution, for the removal of any traces of chlorides present, until a red 
precipitate of chromate of silver is formed. Let stand and separate 
the precipitate by decantation or filtration. This solution is to be 
used as an indicator. 
Process.-Place in each of two beakers of similar size 100 cc. of 
water and 5-10 drops of the indicator. The beakers standing side by 
side upom a white surface of porcelain or filter paper, the silver nitrate 
solution is added to one of them from a burette little by little until, in 
spite of stirring with a glass rod, a faint reddish tinge is beginning to 
be perceptible. This is more easily seen by comparison with the water 
in the other beaker. The burette reading is now taken, and then a 
drop or two more of the reagent will, by intensifying the red color, 
show that the end point has been reached. The process depends upon 
the fact that silver has a greater affinity for chlorides than for chro- 
mates, and that, so long as any of the former are present, no permanent 
union will be made with the latter. When, however, all the chlorine 
has combined with the silver, the red chromate begins to form and 
makes its presence known by the change of color. On the completion 
of the process, the amount of the standard reagent used indicates the 
amount of chlorine present, each cc. used representing a milligram. 
Inasmuch as a certain amount of the reagent is required to give the 
beginning tint in 100 cc. of distilled water, a correction must be made 
before setting down the result. This amount differs somewhat with 
different observers, since all eyes are not equally quick to discern the 
appearance of the reddish tint, and hence the best method of fixing 
the amount to be subtracted is for each one to determine it himself by 
experimenting with 100 cc. of distilled water containing the requisite 
amount of the indicator. 
Should the amount of chlorine in a given sample be so small that 
the end reaction appears on the addition of but a few drops of the 
silver solution, it is best to concentrate 250 or 500 cc. of the water to 
100 cc. and repeat the titration. 
Determination of Residue.-Evaporate 100 cc. of water to dry- 
ness in a perfectly clean, dry, accurately weighed, platinum dish. 
When completely evaporated, transfer the dish from the water-bath to 
an air-bath kept at 105° C. and leave it for an hour, at the expiration 
of which time, place it in a desiccator to cool. Reweigh and note the 
gain in weight, which represents the amount of total solids in the vol- 
ume of water taken. The number of milligrams gained represents the 
number of parts per 100,000. The weighing must be done as quickly 
as possible, in order to avoid error due to the absorption of atmospheric 
moisture by hygroscopic matters in the residue. 
In order to determine the amount of volatile substances, the dish is 
next heated to dull redness on a platinum triangle over a Bunsen 384 
WATER. 
lamp. The organic matter, in the process of burning off, gives rise to 
more or less blackening and may also evolve odors which often convey 
some idea of its nature. The blackening may disappear quickly or 
may persist for some time, especially in the case of woody matters such 
as are present in brown swamp waters. Animal matters cause an odor 
like that of burnt horn ; vegetable substances, one suggestive of 
burning peat. The loss in weight represents not only the organic 
matter but also the nitrates, nitrites, ammonium salts, combined car- 
bonic acid, and, if the temperature has been raised too far, part of the 
chlorides. The residue after ignition represents the " fixed solids." 
Determination of Hardness.-For the determination of hardness, a 
number of processes are in use, but for practical utility, that known as 
the " soap method " is to be preferred. 
Solutions Required.-1. Standard Solution of Calcium Chlo- 
ride.-Weigh out 1 gram of pure calcium carbonate, dissolve it in as 
little as possible dilute hydrochloric acid, and evaporate to dryness. 
Add to the residue a little distilled water and again evaporate to dryness. 
Dissolve in distilled water and make up to a liter. One cc. represents 1 
milligram of calcium carbonate. 2. Standard Solution of Soap. 
Scrape about 10 grams from an old dry piece of pure Castile soap free 
from sodium hydrate and carbonate, and dissolve it in a liter of diluted 
alcohol. Let stand over night and filter. This must next be standard- 
ized in the following manner: To 100 cc. of distilled water contained 
in a glass-stoppered bottle of about 250-cc. capacity, run in, from a 
burette, successive small portions of the soap solution until, on vigorous 
shaking, a lather is formed which persists at least two minutes, and 
note the amount used. 
Repeat the operation with 99 cc. + 1 cc. of the standard solution of 
calcium chloride, and then with 2, 3, 4, 5, 6, 7, 8, 9, and 10 cc. of the 
same solution made up to 100 cc. with distilled water, and note the 
amount used in each test. It will not suffice to determine the amount 
necessary to produce a lather with distilled water and with 10 cc. of 
the calcium chloride solution made up to the same volume, and divide 
the difference by 10, since as we go up in the scale a gradual lessening 
of the amount of increase for each degree is noted. In this way we 
obtain a scale of values for the particular lot of soap solution made at 
one time. It will save some trouble if one makes up a number of 
liters, but it is necessary to make occasional tests to see that the strength 
does not deteriorate, or, if it does, to correct the scale. 
Process.-To 100 cc. in the bottle above mentioned, add the soap 
solution in the same manner as employed in making the scale, and 
when the end point is reached, note the amount used, and by reference 
to the scale, ascertain the number of degrees of hardness. Should the 
water be harder than 10 degrees, it is best to take a smaller amount 
and make it up to 100 cc. and then proceed anew, remembering at the 
end to calculate accordingly. 
The result obtained expresses the " total hardness." If it be desired 
to ascertain the temporary, or removable, hardness, 100 cc. of the water CHEMICAL EXAMINATION OF WATER. 
385 
may be boiled five minutes and then allowed to cool. The original 
volume is restored by the addition of the necessary amount of distilled 
water, and then the operation is repeated. The second result indicates 
the permanent hardness, and the difference, if any, is the temporary 
hardness. 
Determination of " Oxygen Required."-All organic substances 
are susceptible of oxidation, but as they are widely variable in character, 
they require very different amounts of oxidizing agents for the attain- 
ment of the same result. The several methods proposed for determin- 
ing the oxygen-consuming capacity of drinking waters have, therefore, 
only a limited value, but in general it may be said that a high require- 
ment indicates an amount of organic matter inconsistent with purity 
when it cannot be accounted for by the presence of ferrous salts. 
Since the amount of organic matter is pretty fairly indicated by the 
ammonia and albuminoid ammonia determinations, the estimation of 
the " oxygen required " serves only as confirmatory evidence. 
Solutions Required. 1. Standard Solution of Potassium Per- 
manganate.-Dissolve 0.395 gram in a liter of distilled water. One 
cc. is equivalent to 0.1 mgr. of available oxygen. 
2. Standard Solution of Oxalic Acid.-Dissolve 0.7875 gram 
in a liter of distilled water. One cc. corresponds to an equal meas- 
ure of the permanganate solution. 
3. Dilute Sulphuric Acid, 1:3. 
Process.-The determination is based on the fact that potassium 
permanganate gives up its oxygen readily to organic matter, especially 
in the presence of acid and with the application of heat. The reaction 
is expressed in the following equation: 
4KMnO4 4- 6H2SO4 = 2K2SO4 + 4MnSO4 + 6H2O + 5O2. 
Thus four molecules of permanganate will yield five of oxygen or, 
differently expressed, 632 parts by weight of the one will yield 160 
parts by weight of the other ; hence, 3,950 permanganate equals 1,000 
oxygen. 
In this operation, cleanliness of vessels is of the greatest importance. 
A porcelain casserole or evaporating dish of sufficient size is made fit 
for use by boiling in it distilled water acidulated with sulphuric acid 
and adding permanganate solution until no further decoloration is 
observed. 
Place 200 cc. of the sample in the dish, add 10 cc. of the dilute 
sulphuric acid and heat to boiling. Add from a burette enough of 
the permanganate solution to cause a very distinct redness, and boil 
again, adding the permanganate as the color tends to fade away, so as 
to keep as nearly as possible the original color. When further boiling 
for 5 to 10 minutes fails to diminish the intensity of the color, oxida- 
tion is complete. Add now 10 cc. of the oxalic acid solution, which 
will discharge the color if the permanganate has not been added too 
freely. Should the color not be discharged by 10 cc., add 10 more. 
Having now a colorless solution, add more permanganate until a slight 386 
WATER. 
pink color again appears. Note the total amount of permanganate 
used, subtract from it that used up by the oxalic acid, multiply the 
number of cc. remaining by 5 in order to arrive at the amount which 
would be consumed by a liter, and divide by 10 to express the result 
in milligrams of oxygen. Inasmuch as any nitrites present are oxi- 
dized to nitrates, a correction must be made for them. This can be 
done very readily, since 16 parts of oxygen are required for 14 parts 
of nitrogen as nitrites. 
Since the permanganate solution is not wholly stable, it should be 
titrated against the oxalic acid solution every time it is used. This 
can be done most conveniently by adding, after the operation is com- 
pleted and the reading of the burette is noted, 10 cc. more of the ox- 
alic solution and titrating again to the same point as before. 
The oxalic solution keeps better, if a few cc. of strong sulphuric acid 
are added when it is being diluted to a liter. 
Determination of Color.-The color of water may be observed by 
viewing a sufficient depth of the specimen in a glass cylinder against a 
white surface. Color may be expressed quantitatively by comparison 
with the standards for the ammonia determinations. 
Determination of Odor.-Place about 200 cc. of water in a 500-cc. 
beaker, cover with a watch-glass and heat to about 40° C. Give the 
beaker a rotary motion so that the water is set in motion, remove 
the watch-glass and with the nose well inside the beaker note the 
character of the odor. Some analysts prefer to heat the water in a 
glass-stoppered bottle, the use of which permits a much more thorough 
agitation of the water before applying the nose. The odor should be 
designated according to the substance which its presence suggests. 
Determination of Reaction.-A most delicate reagent for alkalinity 
in water is a 1-per-cent, solution of toluylene red. Fifty cc. of water 
distinctly alkaline will become intensely yellow on the addition of 2 
or 3 drops. A less degree of alkalinity will cause an orange or pale 
red color. It is so delicate a test that one part of alkaline carbonate 
in a million is revealed by it. 
The presence of acids is shown by another sensitive indicator, lac- 
moid. This is not affected by carbonic acid nor by ferrous and other 
metallic salts which are acid to litmus, but is affected by ferric salts. 
It may be used as a 1-per-cent, solution in diluted alcohol. Phenol- 
phthalein solution, 0.5 per cent., is colorless in neutral and acid so- 
lutions, and pink in alkaline. It is affected by carbonic acid. 
In the determination of reaction, a drop or two of the indicator is 
added to a volume of the water in a long glass tube. A very faint 
change due to acids or alkalies is quite perceptible on looking down 
through the column against a white background. If the reaction is 
acid, the sample should be boiled, then cooled and tested again to 
ascertain if the acidity is due wholly or in part to carbonic acid. 
Acidity and alkalinity are determined quantitatively by titration with 
centinormal solutions of soda and hydrochloric acid, using lacmoid or 
phenolphthalein and methyl orange as indicators. CHEMICAL EXAMINATION OF WATER. 
387 
Detection and Determination of Lead.-Many processes have 
been proposed for both qualitative and quantitative determination of 
this most undesirable contamination. The simplest test, but by no 
means the best, consists in adding a drop or two of ammonium sul- 
phide to a volume of water in a tall glass cylinder and noting the 
character of the discoloration produced. If a darkening occurs, due to 
the formation of a metallic sulphide, the addition of dilute hydrochloric 
acid will distinguish between lead and iron, the sulphide of the latter 
being soluble. To those who have had any practical experience in 
detecting minute amounts of metals in water, this method is far from 
being satisfactory. More or less color is imparted by the ammonium 
sulphide, and more or less turbidity is commonly produced on the ad- 
dition of the acid. Moreover, when unconcentrated water is used for 
the test, no reaction may occur, although the poisonous metal is present 
in minute traces. 
Another simple test, depending upon the formation of lead chromate, 
has been offered by S. Harvey1 who claims that water containing 0.30 
milligram of lead in a liter will show a turbidity from chromate, when 
250 cc. are treated with 0.10 gram of potassium dichromate; and that 
in twelve hours the precipitate will settle and become still more dis- 
tinct. 
Since small amounts of lead sulphide remain in solution and can 
only be separated with great difficulty when the volume of water is 
large, it is best to concentrate the specimen to a very small bulk be- 
fore attempting to precipitate the lead. From this point onward the 
methods employed vary very considerably. Liebrich2 precipitates 
the lead as sulphide in acid solution, converts it to sulphate by treat- 
ment with nitric and sulphuric acids and dissolves this by warming 
with a few cc. caustic potash (1:10). The solution is filtered and made 
up to 20 cc. and 2 cc. of ammonium sulphide are added, whereby a 
brown color is produced, which can be compared with the shades pro- 
duced by similar treatment of the same volumes of distilled water con- 
taining known amounts of a solution of lead sulphate in caustic potash. 
Antony and Benelli3 recommend the addition of mercurous chloride 
before precipitation as sulphides, believing that thereby no trace of lead 
can escape complete separation. The combined sulphides are filtered 
and dried, then heated to such an extent that the mercury salt is 
driven off, leaving the lead as a residue. Mr. H. W. Clark,4 after try- 
ing all known methods, finds most satisfaction in the following process 
devised in his laboratory : 3,500 cc. are evaporated down to 25 or 30 
cc., 10 or 15 cc. of ammonium chloride solution added to assist the 
separation of the sulphides, and a considerable excess of strong am- 
monia. Hydrogen sulphide is then added and the dish allowed to 
stand some hours, after which more ammonia and hydrogen sulphide 
are added. After boiling to expel the excess of hydrogen sulphide, the 
1 The Analyst, April, 1890. 
2Chemiker Zeitung, 1898, XXII., p. 225. 
3 Journal de pharmacie et de chemie, 1898, No. 7, p. 72. 
4 Loco citato, p. 582. 388 
WATER. 
precipitate is filtered off. It contains any lead, iron, copper or zinc as 
sulphides, and other suspended organic and mineral substances. It is 
washed once with hot water and the paper is then boiled in dilute 
nitric acid (1: 5). It is then filtered, and washing is continued as long 
as any acid is removed. 
The filtrate and the washings are concentrated to about 10 or 15 cc., 
cooled, and then mixed with 5 cc. of concentrated sulphuric acid 
(specific gravity 1.84) and heated until copious fumes of sulphuric acid 
are evolved. In the absence of more iron than 0.025 in 100,000, 
acetic acid and ammonia are added directly. It is next boiled and 
filtered, all the iron, dehydrated silica, and insoluble organic matter 
being left on the paper. The filtrate is then used for the colorimetric 
determination of lead by means of comparison of the shade produced 
by the addition of hydrogen sulphide solution with a set of standards 
containing known amounts of lead. 
With more than 0.025 iron in 100,000, the process is somewhat dif- 
ferent ; the lead sulphate is washed into a beaker with alcohol and 
water and allowed to stand over night, and then filtered off and washed 
with 50-per-cent. alcohol until free from iron. It is then dissolved by 
boiling the filter with ammonium acetate in a porcelain dish. Experi- 
ence has demonstrated that this process is extremely accurate and 
reliable. 
The author finds the following process simple, rapid, and accurate. 
Evaporate 3,000-4,000 cc. of water down to about 15-20 cc. in a 
porcelain dish, add, little by little, and with gentle heat, enough dilute 
hydrochloric acid to dissolve any encrustation of salts on the sides and 
bottom and to give a slight acid reaction, then add 5-10 cc. of sulphu- 
retted hydrogen water of good strength. Any lead present is precipi- 
tated in a very fine state, but not so fine but that the entire amount can 
be collected on a Swedish filter. Wash twice and then treat on the 
filter with boiling dilute nitric acid until the black deposit is wholly 
dissolved. Wash with hot water as long as the washings are acid, and 
add them to the nitric acid filtrate. Evaporate to dryness in the 
original dish, add distilled water, and again dry. Dissolve the residue 
in hot distilled water and make up to 50 cc. Take 5-10 cc. and dilute 
to about 80 cc. with distilled water in a glass comparison tube of 100 
cc. capacity, add sulphuretted hydrogen water in sufficient amount, 
make up to 100 cc. with distilled water and mix thoroughly by invert- 
ing the tube a number of times. Compare the depth of color with 
those of a series of tubes containing known amounts of lead as lead 
nitrate, treated with sulphuretted hydrogen in the same way. 
The standard solution is made by dissolving 0.160 gram of pure 
lead nitrate in a liter of distilled water; one cc. represents 0.1 milli- 
gram of lead. A convenient scale is made with 1, 2, 3, 4, 5, 6, 7, 
8, 9, and 10 cc. of the solution in 100 cc. If the sulphuretted hydro- 
gen water is added after diluting to about 80 cc., the result is a series of 
sufficiently clear standards showing very sharp and regular stages of 
color. If the reagent is added before the lead salt has been sufficiently CHEMICAL EXAMINATION OF WATER. 
389 
diluted, the standards are very turbid and are lacking in the very 
essential gradation of color. 
Should the depth of color obtained in the preliminary test be 
greater than that given by No. 10, a smaller amount must be taken 
and the experiment repeated. Should it be very faint, the whole of 
the remainder may be treated and compared. From the result ob- 
tained by matching the colors, the amount of lead in parts per 100,- 
000 is easily calculated. 
Example.-Ten cc. treated as above gave a color reaction midway 
between standards 6 and 7 ; hence, one fifth of the whole contains 
0.65 mgr. lead, and the entire amount contains 3.25 milligrams. The 
amount of water concentrated was three liters. Hence one liter of 
water contains 1.08 milligrams, and 100 cc., or 100,000 milligrams 
of water contain 0.108 mgr. 
Detection of Zinc.-One is reasonably safe in assuming that water 
which has been in contact with galvanized iron will show the presence 
of zinc. This can be determined quantitatively by evaporating a 
quantity of water to a small bulk, heating the latter with a sufficient 
amount of dilute hydrochloric acid in order to take up any oxide or 
carbonate, and then proceeding to the precipitation of the sulphide 
after making alkaline with ammonia. For qualitative purposes, a 
volume of water is made slightly alkaline with ammonia, boiled and 
filtered. The addition of a few drops of test solution of potassium 
ferrocyanide to the filtrate will, in the presence of traces of zinc, cause 
a white precipitate or at least an opalescence, which, however, may 
not be distinct within a half hour. 
Detection of Tin.-Although, so far as we know, tin in water has 
no sanitary significance, it sometimes is desirable to ascertain its pres- 
ence in water and in other substances. For rapid testing for this 
metal, the method recommended by C. Deniges1 may be employed. 
This depends upon the fact that stannous compounds cause a reddish 
violet color with nitrate of brucine. The brucine solution is made by 
dissolving 0.5 gram of brucine in 5 cc. of nitric acid, diluting to 250 
cc. with distilled water and boiling for fifteen minutes, and after cool- 
ing, making up the volume to 250 cc. again. 
The water is evaporated to dryness with a little hydrochloric acid. 
The residue is dissolved in a very little water, and to it is added 1 cc. 
of the brucine solution. If so little as the twentieth part of a milli- 
gram of tin is present, the color change will be distinctly shown even 
in the presence of iron and copper. 
Detection and Determination of Iron.-This very common and 
frequently troublesome constituent of water is very easily detected by 
concentrating a sufficient volume of the sample to a small bulk, con- 
verting the iron present from the ferrous to the ferric form by boiling 
with a little nitric acid, and adding a few drops of a solution of 
potassium sulphocyanate, which causes a deep red coloration. By 
means of a scale made with known amounts of ferric iron treated with 
'Revue Internationale des Falsifications, VIII., p. 98. 390 
WATER. 
the same volume of test solution, the amount of iron can be quite ac- 
curately determined. A standard solution of iron may be made by 
dissolving 0.10 gram of pure metallic iron in aqua regia and diluting 
to a liter with distilled water; one cc. represents 0.10 milligram of 
iron. The comparison scale is made by diluting progressively increas- 
ing volumes with distilled water up to nearly 100 cc., adding a few 
cc. of a 5-per-cent. solution of potassium sulphocyanate and then 
making up to 100 cc. 
For other determinations of a strictly technic character the reader is 
referred to the many excellent treatises bearing on the subject. 
Inferences as to Character of Water from the Results of Sani- 
tary Chemical Analysis. 
It is impossible to fix any absolute standards by which to pass upon 
the potability of water without reference to its origin, for surface- 
waters cannot be judged by the same standards as ground-waters, and, 
moreover, those which apply to waters of either class from one local- 
ity may be wholly inapplicable to those from another. A surface- 
water, for instance, may without prejudice yield an amount of albu- 
minoid ammonia which would be most suspicious in the case of a 
ground-water, while the latter may contain, under some circumstances, 
an amount of free ammonia quite inconsistent with purity in the case 
of the former. Again, an amount of chlorine which in a water from 
near the sea would be normal, would indicate in another from far in- 
land the presence of sewage matters. 
Ammonia may be expected in some amount in any water ; it is 
characteristic of decomposition of organic nitrogenous matter of inno- 
cent character as well as of sewage, and it may be present in consider- 
able amounts in both normal and polluted waters. Furthermore, it 
may be present in higher amounts in a water from an uncontaminated 
deep-bored well or in stored rain, than in polluted water that has 
undergone chemical change. Albuminoid ammonia may be yielded in 
equal amounts by a water contaminated by sewage, and by one quite 
free from it, but rich in dissolved vegetable matter derived from leaves. 
Richness in mineral matter may be present equally in normal and pol- 
luted waters. A pure water may be rich in nitrates, while a sewage 
water may have lost them by reduction. Either may be colored or 
not, clear or turbid, and odorous or odorless. 
There is one constituent, however, the presence of which in more 
than measurable quantity is a tolerably sure indication of pollution, 
that is to say, the nitrites, but their absence is not a guarantee of 
purity, for in grossly polluted waters they may be wholly wanting. 
In general, however, it may be set down as a safe rule, that nitrites 
and high free ammonia together mean recent pollution ; occurring 
continuously, they indicate constant pollution, and with chlorine fairly 
above the local normal, ordinary sewage contamination. High am- 391 
RESULTS OF SANITARY CHEMICAL ANALYSIS. 
monias with nitrites, but with no marked increase in chlorine, may in- 
dicate contamination by matters from manured farming land. 
The results obtained in the chemical analysis of a specimen of water 
are often quite sufficient for the formation of an opinion of its suit- 
ability or unfitness for general domestic purposes, but more often a 
knowledge of the source and the surroundings thereof is necessary for 
their intelligent interpretation. They maybe such as to indicate that, 
whatever its source, the water which yielded them is very good or 
distinctly bad, but, on the other hand, they may be such that full knowl- 
edge of all the facts is imperatively necessary for the formation of 
a correct judgment. A water yielding the following results, for in- 
stance, may be unhesitatingly pronounced to be of undoubted purity 
so far as chemistry can determine, quite irrespective of source. 
The figures express parts per 100,000. 
Free ammonia 0.0002 
Albuminoid ammonia 0.0018 
Nitrogen as nitrates 0.0240 
Nitrogen as nitrites 0.0000 
Chlorine 0.07 
Volatile residue 1.25 
Fixed residue 1.60 
Total residue 2.85 
Hardness 1.00 
Appearance, clear and bright. 
Color, absent. 
Odor, absent. 
Changes observed on ignition of residue ; no blackening. 
In this case the figures indicate almost total absence of organic mat- 
ters and but slight amounts of mineral constituents. There is no sug- 
gestion of contamination of any kind, and the only conclusion that can 
be drawn is that the water is pure and soft and suitable for all domestic 
purposes. 
On the other hand, the following results may in the same way be 
sufficient for unqualified condemnation. 
Free ammonia 0.4750 
Albuminoid ammonia 0.0585 
Nitrogen as nitrates 4.600 
Nitrogen as nitrites 0.054 
Chlorine 4.27 
Volatile residue 11.10 
Fixed residue 23.30 
Total residue 34.40 
Hardness 14.00 
Appearance, clear and bright. 
Color, absent. 
Odor, foul after heating. 
Changes on ignition of residue ; slight blackening. 
These results, which are actual ones obtained from a specimen sent 
to the author with a simple request for an analysis, but with no state- 
ment of origin, warranted a report of gross pollution, regardless of 
source, for the presence of sewage matters was most undeniable, and 
under no circumstances of geographical location could any other report 392 
WATER. 
be made. Inquiry concerning the origin of the water brought the in- 
formation that the well from which it came was located at no great dis- 
tance from a leaching cesspool and was only used when the usual source 
of supply, a spring, ran dry. Repeated attacks of illness, of no great 
seriousness as to results, had been noticed whenever, during the past 
two or three years, this water had been used. 
These two may serve as good examples of undoubted purity and ex- 
tensive pollution. Both are ground-waters, and what is not without 
interest, they came from one and the same small inland town. 
Such results as the above require no long consideration ; they speak 
for themselves. But it very commonly happens that even a single in- 
gredient may cause suspicion of sewage pollution to arise when infor- 
mation as to the location of the supply is withheld. Thus, the amount 
of chlorine may be very considerably higher than the lowest normal 
commonly observed inland, and yet well under the amount which 
excites no adverse comment in a water from the coast. Thus, 3.85 
parts in a well water from an island in Boston Harbor and 1.35 in 
another from the borders of Long Island Sound may be regarded as 
fairly low, while if found in springs in the Green Mountain range they 
would be most abnormally high and of much significance. 
Again, such an amount might come in connection with fair yields 
of the ammonias, and then under one class of conditions the organic 
matter would appear to be of vegetable origin and in another to be a 
part of sewage. 
It is also impossible to draw sharp dividing lines between small, 
considerable and high amounts of the ammonias, but in general terms 
it may be stated that up to 0.005 or 0.006 part per 100,000 may be 
regarded as low, from thereabouts to 0.015 or 0.020 as considerable, 
and beyond as high. Measurable amounts of nitrites are most signifi- 
cant, while nitrates may run up to several whole parts per 100,000. 
Thus, it may be readily understood that in the majority of cases the re- 
sults must be considered in conjunction with all material facts connected 
with source, surroundings, and opportunity for receiving pollution. 
Bacteriological Examination of Water. 
The bacteriological analysis of water may be divided into quanti- 
tative and qualitative determinations. The former is commonly ex- 
tended over long periods of time and has for its object the determina- 
tion of the normal bacterial content of a given water supply and the 
observance of any unusual variation therefrom, while the latter is pur- 
sued for the purpose of determining the nature of the organisms and, 
more particularly, whether they are such as are to be found in the 
excreta of the body. The finding of such does not mean necessarily 
that the use of the water will inevitably produce disease, but it indi- 
cates the possibility and probability that water containing non-patho- 
genic organisms from this source may, if not to-day, to-morrow or BACTERIOLOGICAL EXAMINATION OF WATER. 
393 
later be infected with others from the same source, capable of acting 
as the exciting cause of grave disaster. 
As is the case with chemical analysis, it is impossible to fix any 
standard of safety based on the mere amount expressed by the quan- 
titative results, since it is the nature and not the amount of the con- 
taminating matters which determine the question of potability. But 
sudden deviations from the seasonal normal suggest unusual access of 
contamination and serve as warnings of possible danger. 
The isolation and systematic study of the various species of bacteria 
in a given water to determine whether or not they may be pathogenic 
involves much labor and an intimate knowledge of bacteriological 
technic which can be acquired only by thorough training in a bac- 
teriological laboratory. Familiarity with the methods of preparing 
culture media and making cultures, of isolating species and studying 
their characteristics is, therefore, a necessary qualification for the pur- 
suit of bacteriological examination of water, and anything more than a 
brief outline of special methods employed in this particular field of re- 
search would be quite beyond the scope of a work of this character. 
Collection of Samples.-In taking samples, it is, of course, necessary 
to observe the most rigid precautions against the introduction of ex- 
traneous organisms. All vessels must, therefore, be absolutely clean 
and sterile. Collection may be made either in small bulb tubes, drawn 
out into a point and sealed by closure in the lamp flame, or in small 
bottles of about 200-cc. capacity with ground stoppers. The bulbs are 
very easily made by anybody who has had ordinary experience in 
qualitative analysis. By the application of the heat of the lamp im- 
mediately before sealing, or by vaporizing a drop of contained water 
by the same means and sealing just as the last of the steam is escaping, 
they will contain but little air, and when used are easily filled through 
the influence of the partial vacuum. 
In taking the sample, the point is introduced below the surface of 
the water and then broken off with sterile forceps. The bulb is partly 
filled almost immediately, and then the broken point is again sealed 
as before by the application of heat from a gas flame or alcohol lamp. 
If bottles are used, they should first be washed on the outside in the 
water to be sampled, then plunged beneath the surface. The stoppers 
are then withdrawn and when filling is completed, they are replaced. 
If any considerable time must elapse before the cultures can be made, 
the samples should be packed in ice in order to retard the multiplica- 
tion of the contained bacteria; and since very low temperatures have 
no harmful influence on the life of the organisms, the addition of a 
small amount of salt to the ice may be of advantage, though freezing 
must not be permitted, on account of the danger of bursting the con- 
tainers. 
Planting the Samples.-If possible, the planting should be accom- 
plished on the spot, on account of the multiplication which is inevitable 
with delay. If this is not possible, no greater delay should be per- 
mitted than is absolutely necessary. 394 
WATER. 
For qualitative determinations, two sets of plates should be made ; 
one on gelatin to be kept at 18-22° C., and one on agar-agar to be 
incubated at 37-38° C. When working on a water of unknown 
character hitherto unexamined, different amounts of the sample, 1, 2, 
3 and more drops, should be used, since one can have no definite idea 
of its bacterial richness. 
In quantitative work, the amounts taken must be measured with the 
greatest accuracy, especially when preliminary determinations have 
shown such a number of organisms as to make great dilution with 
sterile water necessary, for any departure from absolute accuracy in- 
troduces an error which will be multiplied according to the degree of 
dilution. 
When bulb tubes are used, their contents are expelled with the aid 
of gentle heat, which causes the small amount of contained air to ex- 
pand and force the liquid through the stem, which is broken at the 
point by pressure from sterile forceps. The expelled water is received 
in a sterile tube from which it can be withdrawn in a sterile graduated 
pipette. 
Quantitative Determination.-The value of quantitative determi- 
nations lies in the comparisons which one is enabled to make from a 
series of periodical examinations of the same water, for the information 
to be derived from a single examination has very limited utility. By 
means of periodical counts, one is enabled to form an idea of the con- 
ditions normally present under different circumstances and to note at 
once any disturbing influence. Quantitative determinations are of 
special value in watching the efficiency of sand filtration of public sup- 
plies. 
Knowing from preliminary tests or from past experience how much 
water should be taken for each plate or roll and the degree of dilu- 
tion necessary, two sets are made, one on gelatin and one on agar- 
agar, and the growths allowed to develop. Gelatin cultures are kept 
at 18-22° C.; the others are incubated at 37-38° C. 
The lower of these two ranges of temperature is much more favor- 
able to the multiplication of ordinary water bacteria than the higher, 
and consequently it will be found that the colonies developing on the 
gelatin will be decidedly more numerous than those on the agar-agar. 
In expressing results, therefore, mention should be made of the cul- 
ture-medium employed, and in making comparisons of one day's results 
with those of another, the importance of limiting them to figures ob- 
tained under like conditions of culture-medium and temperature is too 
obvious to need further mention. 
The counting of the colonies should be undertaken always at the 
expiration of fixed intervals of time, since more and more develop from 
day to day, particularly on agar-agar. For assistance in counting, one 
may employ the well-known Wolffhugel apparatus or one of the sev- 
eral modifications thereof or, what is even more simple, may have the 
bottoms of Petri dishes or under surfaces of the ordinary glass plates, 
whichever'are used, ruled off in square centimeters by means of a writ- BACTERIOLOGICAL EXAMINATION OF WATER. 
395 
ing diamond. The entire number of colonies on the plate may be 
counted, or those falling within a certain number of squares may be 
averaged and the result multiplied by the whole number of spaces 
covered by the culture-medium. 
Drs. W. Hesse and Niedner 1 have proposed a method for quantita- 
tive determinations which does away with the use of nutrient gelatin 
and all the attendant disadvantage due to liquefying bacteria. Their 
most important recommendations are as follows : 
The amount of water planted per plate should be such as will pro- 
duce no more colonies than can be easily and accurately counted ; that is 
to say, not more than a hundred. At least five plates should be pre- 
pared, and if these yield results fairly in agreement, their average 
should be taken ; but if any plate gives figures more than 100 per 
cent, removed from the mean, it should be discarded. These should 
be kept at room temperature and in the dark as long as new colonies 
develop, that is, for 2-3 weeks, at the end of which time one may make 
counts which will have some claim to accuracy. On account of the 
evaporation that occurs during this time, it is necessary to use for each 
plate at least 10 cc. of culture-medium. The most suitable medium is 
made with 1.25 agar-agar, 0.75 albumose, and 98 distilled water. 
Gelatin should be abandoned on account of the rapidity with which 
the plates made with it become useless on account of the liquefying 
colonies which obstruct some growths and dissolve and wash others 
away. The medium above described possesses the advantage that it 
needs no addition of acid or alkali. 
Qualitative Determination.-The chief interest in qualitative ex- 
amination of drinking water lies in the solution of the question whether 
or not intestinal bacteria are present. Plates may be prepared and 
preserved in the same manner as for quantitative work, except that the 
amount of water planted needs no accurate measurement, but on ac- 
count of the usual great preponderance of the common harmless 
varieties of bacteria, it is rarely the case that one can isolate the 
pathogens without recourse to special methods which favor their 
growth and at the same time kill off the others. One such method 
consists in incubating the sample with bouillon for 36-48 hours at 
37-38° and then preparing plates in the usual way. The common 
bacteria are in this way subjected to conditions unfavorable to their 
growth and vitality, while multiplication of the pathogens is promoted. 
Another method, depending upon the resistance of the typhoid organism 
and the Bacillus coll communis to the action of dilute carbolic and 
hydrochloric acids and the powerful influence of these agents on the 
common water bacteria, consists in incubating a few drops of the 
sample in 10 cc. of bouillon containing a few drops of a solution of 5 
parts of phenol and 4 of hydrochloric in 100 of distilled water. The 
bouillon is first incubated with the latter addition for 24 hours at 
37° C., and then receives the sample. 
After further incubation for 24 hours or longer, plates are made in 
' Zeitschrift ftir Hygiene und Infectionskrankheiten, XXIX., p. 454. 396 
WATER. 
the usual way and the resulting growths systematically studied. Still 
another process is that of Professor Theobald Smith,1 who recommends 
the addition of a few drops of the water to bouillon containing 2 per 
cent, of glucose and incubating in fermentation tubes at 37-38° C. for 
36-48 hours, at the end of which time, if gas has accumulated in the 
end of the tubes, plates are prepared in the usual way. By this proc- 
ess it is possible to secure pure cultures of the intestinal bacteria. 
For the detection of the cholera organism, Koch recommends incu- 
bating 100 cc. of the suspected water with 1 gram each of sodium 
chloride and peptone at 37° C. and preparing therefrom at intervals of 
10-20 hours agar-agar plates, from which, if colonies develop, other 
plantings can be made for systematic investigation. 
For the detection of the cholera organism in small numbers in the 
presence of water bacteria, Dr. Arens2 has found caustic potash of 
assistance, and recommends incubating 175 cc. of water with 25 cc. of 
pancreas bouillon containing from 0.10 to 0.16 gram of the alkali, by 
means of which the growth of the organism is favored. Dr. Aufrecht,3 
working on similar lines, found that the development of the organism is 
favored by gelatin containing 1 per cent, of caustic soda. 
Comparative Value of Chemical and Bacteriological Analysis of 
Drinking Water. 
As the science of bacteriology began to develop and take the posi- 
tion to which its importance gave it a title, its disciples conceived a 
strong prejudice against and contempt for any opinion as to the pota- 
bility of a particular water based upon chemical analysis, maintaining, 
quite correctly, that minute amounts of ammonia, albuminoid am- 
monia, and chlorine are quite incapable of acting as the exciting cause 
of infective disease, and that not these substances, but only specific or- 
ganisms not demonstrable by chemical processes, can so act. 
It must be conceded that for a time prior to the discovery of the 
nature of the infective agents the importance of the results of chem- 
ical analysis was grossly exaggerated, and that arbitrary standards, such 
as were established by the Rivers Pollution Commissioners, upon 
which conclusions were based, have, in the light of further experience, 
been abandoned as absurd and untrustworthy. But it must also be 
conceded, even by those who were most caustic in their criticism, that 
chemistry is to-day equal if not superior to bacteriology in indicating 
possible danger from the use of water exposed to contaminating in- 
fluences. 
In the earliei' days, much capital was made by bacteriologists of the 
fact that a sample of water, inoculated with a culture of the bacillus of 
typhoid fever, was reported by a chemist of high standing as of a high 
degree of purity and eminently suitable for domestic purposes. Such 
1 American Journal of the Medical Sciences, Sept., 1895. 
2Miinchener medicinische Wochenschrift, March 7, 1893. 
3 Centralblatt fiir Bakteriologie und Parasitenkunde, March 23, 1893. VALUE OF CHEMICAL AND BACTERIOLOGICAL ANALYSIS. 
397 
a test, however, is unworthy of the slightest consideration, since under 
natural conditions a water showing a high degree of chemical purity 
is not likely to be infected with a pure culture of a pathogenic organ- 
ism, and the submission of a pure water so treated is a mere trap, the 
setting of which is no more praiseworthy than would be the sending 
of a sterile solution of cyanide of potassium or of sulphate of strych- 
nine to a bacteriologist with a request for an opinion from the stand- 
point of his specialty as to its desirability as a beverage. 
Chemical analysis can show the presence of organic and mineral im- 
purity such as accompanies infectious matters from the intestine and 
bladder. It cannot give grounds for a positive assertion that the use 
of a water thus polluted will inevitably cause disease, but it can and 
does serve to point out possible danger. It can detect the presence of 
sewage matters, and while it cannot prove the presence of infectious 
material therein, it can at least point out that the occurrence of typhoid 
fever in the community furnishing the sewage is likely to be followed 
by other cases of the disease in the community which uses the polluted 
water. It cannot distinguish typhoid pollution from any other excre- 
mental contamination, since a healthy body yields the same chemical 
substances as one that is diseased. In the case of waters containing 
no evidence of contamination, it can supply the basis of an opinion as 
to safety, but it cannot furnish any guaranty that the condition is per- 
manent. 
Bacteriological analysis differentiates between pathogenic and non- 
pathogenic contamination, but it is only rarely that it serves to point 
out danger in advance. Even when an outbreak of typhoid fever has 
occurred and attention is thereby drawn to the condition of the water 
supply, the results of bacteriological examination are generally negative. 
The reason for this is two-fold. In the first place, the examination for 
the detection of the specific organism is not ordinarily begun until at- 
tention is drawn to its necessity by an outbreak of the disease, which 
does not appear until about two weeks from the time contamination 
has occurred. Unless the contamination is continuous, by the time the 
examination is instituted, the polluting materials have either passed on 
or the specific organisms have perished. In the second place, even 
though they are present, with our present methods it is not an easy 
matter to isolate them, and we can only determine in most cases the 
probability of their presence. 
It must be borne in mind that the organisms are particulate bodies 
in suspension in great dilution and that their distribution is not homo- 
geneous as in the case with substances in solution, and, therefore, the 
amount of water taken for planting plates may not contain them. But 
in the unsuccessful search, it is not uncommon to find the Bacillus coli 
communis, and where this organism lurks, the other may have been 
present. 
As a rule, bacteriological search for the typhoid bacillus has given 
negative results. Laws and Andrews failed to find it in the sewage of 
London, although it must have been present, and had but slight sue- 398 
WATER. 
cess in the examination of sewage from a hospital where forty cases of 
the disease were being treated. The reason for this may be that 
through absence of suitable food material and favorable temperature 
and by reason of the antagonistic influence of the ordinary sewage 
bacteria they had lost their vitality, or it may be that they were so 
diluted that the volumes used for planting failed, as a rule, to contain 
them. Examination of the water supposed to be concerned in the un- 
usual outbreak at Maidstone yielded absolutely negative results, al- 
though no reasonable doubt can exist that at some time they had been 
present. 
Professor Percy Frankland, who, as is well known, has had a large 
experience in dealing with micro-organisms in air and water, says :1 
" The detection of specific pathogenic bacteria in drinking water is now 
known to be almost beyond the range of practical politics, and the search 
for such bacteria is, in general, only carried on in deference to the spe- 
cial request of the layman, the uninitiated, or the hopelessly ignorant, 
whilst it cannot be repeated often enough that any feeling of security 
which may be gathered from an unsuccessful search for pathogenic 
bacteria is wholly illusory and in the highest degree dangerous. * * * 
By far the most important service which has been rendered by bacteri- 
ology is the means which it affords of controlling the efficiency of fil- 
tration and other purification processes. The slightest irregularity or 
defect in the process of filtration is at once laid bare. Bacteriological 
purity of well waters can also be satisfactorily controlled." 
A positive result, said to be the first instance in which the organism 
isolated responded to every test, including growth on gelatin, potato, 
litmus milk, bouillon and glucose bouillon, agglutination and Pfeiffer's 
test with animals, is recorded by Drs. Kubler and Neufeld.2 
In this case, the cause of the disease lay in the use of water from a 
well infected by the urine of a person sick with the disease. Four 
weeks from the time of the first examination when the bacillus was 
isolated, a second analysis was made, which yielded bacilli which re- 
sponded to all the tests excepting Pfeiffer's, which exception was sup- 
posedly due to modified virulence. 
As a matter of fact, then, from what has gone before, it may be 
said that neither chemical nor bacteriological analysis is infallible. 
Each has its uses, and each may be helped by the other. The value 
of either lies in the skill displayed in interpreting the results, and this 
requires quite as much knowledge as the making of the examination 
itself. 
1 Journal of the Sanitary Institute, October, 1899, p. 393. 
2 Zeitschrift fur Hygiene und Infectionskrankheiten, XXXI., p. 133. CHAPTER V. 
HABITATIONS, SCHOOLS, ETC. 
Section 1. GENERAL CONSIDERATIONS. 
It is essential to health that the houses in which we dwell shall 
be built upon proper sites, free from dampness and organic pollution ; 
they should be provided with adequate means for heating, ventilating, 
and lighting; they should be well supplied with water for general 
domestic purposes and provided with a proper system of plumbing 
for the removal of sewage; they should be constructed with proper 
precautions against dampness from without or below. Heating, venti- 
lation, lighting, and plumbing are considered below under their sev- 
eral headings. 
Aspect.-It is commonly directed that habitations should be placed 
so as to face the south, but unfortunately one is not always in a posi- 
tion to be over-particular in the matter of points of the compass, and, 
indeed, there seems to be no particularly good reason why that side of 
the house in which is located the main entrance should face south and 
the others respectively north, east and west. The southerly side of a 
hill is very much to be preferred to the northerly because of the 
greater amount of sunlight and of protection against the cold winds 
from the north, but in a plain and elsewhere, whichever wall of the 
house faces south, there must be, if the structure be rectangular, one 
to the north. Far better is a location with the corners of the house 
pointing north and south, for in that case every window must receive 
some direct sunlight at some part of the day, whereas with sides fac- 
ing directly north and south, the windows of the former receive no 
direct sunlight and the rooms are dull and cheerless. In large cities, 
aspect is commonly a minor consideration, the desirability of a house 
being determined mainly by other circumstances. 
In general, it may be said that, when possible, a house should be so 
situated as to insure an abundance of light and air with protection 
against the cold winds of winter. 
Construction and Arrangement.-Consideration of building ma- 
terials and the details of arrangement of rooms and division of floor- 
space are beyond the scope of a work of this nature, and it is necessary 
only to call attention to the importance of ensuring dryness, light, and 
air, and such thoroughness of construction as shall not permit a too 
generous amount of natural ventilation with consequent waste of heat. 
Of the very greatest importance is the character of the cellar, that 
part of the house which is most neglected during both construction and 400 
HABITATIONS, SCHOOLS, ETC. 
occupancy. Unless the site is one of unusual dryness, the cellar floor 
should consist of a generous layer of cement impervious to moisture 
from below and to soil air and its contaminations, such as gas from 
leaking mains. The foundation walls should be tight and dry and 
should contain in their upper part a sufficient number of windows of a 
size to admit an adequate supply of light. 
The walls should be made as far as possible proof against wind and 
weather. In exposed positions, it may be that a clapboarded wall is 
far drier than one of brick, for the latter material, if very porous, is not 
uncommonly wet through by driving rain and does not quickly become 
dry again. Sometimes it becomes necessary to cover an entire brick 
wall with a protective coating of paint or even with a sheathing of tin 
plate. For protection against dampness and cold, external walls may 
be built with an intervening air space, which acts like that of a double 
window; the outer and inner faces of the wall are joined at intervals 
by bonding bricks or ties of various materials, including hard non- 
porous bricks, glazed bricks, and iron. 
Roofs should be very tight and protected against the backing up of 
water from melting snow and ice when the gutters are filled with ice. 
As a covering, slate is much to be preferred to shingles, though its 
initial cost is much greater ; it is permanent in character, impermeable, 
and requires but little repairing, while shingles wear out in course of 
time, and, by taking up moisture, lead to rotting of the timbers beneath. 
Tin is tight and impermeable, but is very hot in summer. Tar and 
gravel are well suited to nearly flat roofs, the gravel protecting the tar 
from the action of the sun, and the combination being very durable. 
Care of Habitations.-The proper care of a house and its surround- 
ings is a subject that can hardly be taught; with many, it is a natural 
instinct; with more, very little is required to satisfy the understand- 
ing of the term. A large class distribute house sanitation with an 
uneven hand, insisting upon the perfection of care of those parts which 
they inhabit and in which the outside world is received, and neglect- 
ing those where filth is most likely to accumulate, but to which, per- 
haps, the general overseeing eye never penetrates. In a way, the most 
important parts of a house are the cellar and the kitchen, and these 
should receive more careful attention than the drawing-room, where, 
presumably, organic filth can hardly gain access in appreciable 
amounts. The otherwise careful housekeeper, to whom a burnt match 
on the hearth of an open fire is an abomination, will, perhaps, view 
with placid face the boxes, baskets, and even barrels of rotten fruits 
and vegetables, dirty cans and other refuse brought to the surface from 
the cellar once each year at the time given over to " spring cleaning." 
The perfectly kept house knows no cleaning seasons. 
SCHOOLS. 
Schools, even more than habitations, require the best of situations 
with reference to light and air. Windows should be large and numer- 401 
SCHOOL FURNITURE. 
ous, and, according to the estimates of different authorities, their com- 
bined area should equal from a tenth to a fourth of the total floor area. 
In the arrangement of school furniture, the main consideration lies in 
the direction of the light. The desks are best placed so that the light 
comes from the left of the pupils; coming from the right, it casts 
annoying shadows of pen or pencil in exercises requiring writing; 
cross lighting may cause still greater annoyance by casting double 
shadows. Light from the front is exceedingly trying, as may be 
readily appreciated by attempting to read a clock placed between two 
windows ; from behind, it casts shadows of the body upon the work on 
the desk. 
Cloak rooms should be spacious and well ventilated and provided 
with ample hanging facilities permitting sufficient space between the 
individual garments. 
Water-closets and urinals demand more than usual care, for children 
are prone to carelessness in their use; and since they are commonly 
placed in the basement, they are very likely, if not kept in scrupulously 
clean condition, to pollute the air of the rooms above. 
School Furniture.-School furniture is well known to be one of 
the most important influences in the development of lateral curvature, 
and much careful study has been pursued in improving its construc- 
tion. Desks and chairs should not be supplied with reference to 
age, but according to the size of children, and should be adjustable to 
each child. Common faults of chairs include improper shape of back, 
improper height, too great depth or breadth of seat, too much slope 
from front to back, and improper horizontal distance from the desk. 
Common faults of desks include insufficient or too great height, and 
improper slope of the surface. 
Chairs should be of such a height that when the leg and thigh form 
a right angle the foot shall be squarely on the floor. If too high, the 
child cannot touch the floor and fails to obtain the needed assistance 
from the feet and legs for the maintenance of an upright position ; if 
too low, the position is cramped and awkward and the child is forced 
to extend the legs in one direction or another and contort the body 
accordingly. The seat should be wide enough to support both thighs 
comfortably, but not so wide as to permit the assumption of bad 
postures in which the back is not well supported. It should not be 
too deep from front to back, since then proper attitude is impossible. 
It should slope very slightly from front to back, or be made slightly 
concave, in order that the tendency to slip forward may be counter- 
acted. The back should be curved forward so as to support the child's 
back and be comfortable in whatever legitimate attitude he may 
assume, for he requires changes in position for the relief of downward 
pressure and strain of muscles and ligaments, since any attitude long 
maintained results in fatigue. With chairs of the best form of con- 
struction, faulty attitudes are less comfortable than proper ones. 
Desks should be of such a height that the forearms of the child can 
be rested without causing, on the one hand, stooping, or, on the other. 402 
HABITATIONS, SCHOOLS, ETC. 
raising of the shoulder and curving the spine. If too high for the 
child, the work is brought too near and causes straining of the eyes. 
The top should have a proper slope downward of from ten to twenty 
degrees, and its edge should project slightly over the forward edge of 
the chair so that the body and head may not be inclined forward too far. 
Proper height of seats and desks and correct horizontal distance be- 
tween the two are attained by the adoption of adjustable furniture, of 
which there are many varieties. 
Blackboards should be dull black and never shiny, for if they are 
shiny they reflect light and what is written thereon is difficult to read 
from certain points in the room. They should be kept well cleaned, 
in order that the contrast with the chalk shall be sharp. The chalk 
should be white or yellow ; blue, green, and red chalk marks are 
much more difficult to read. Blackboards should never be placed be- 
tween windows, on account of glare. Copying from blackboards is 
very trying to the eyes, on account of the constant necessary change of 
focus. 
Legislation Concerning Schools.-Many of our States have passed 
laws providing for school sanitation in several particulars. Seventeen 
require expert examination of plans for projected buildings. Sixteen 
provide for fire-escapes and other protection from fire. A number 
provide for proper ventilation, but only two, Massachusetts and Con- 
necticut, have established a standard and require its enforcement. 
Kentucky alone provides standards for lighting, for floor space and air 
space, for proper seating, and for water supply. About one-third of 
the States and Territories compel vaccination, and one-fourth provide 
safeguards in the matter of contagious diseases in general. 
Section 2. VENTILATION AND HEATING. 
We have seen how necessary it is to life that the CO2 given off by 
the blood in the lungs to the inspired air shall be continuously dis- 
charged from the body, and we know that whatever other effects the 
impurities of vitiated air may produce, the effect of undue CO2 in the 
air is to interfere with the function of respiration. 
Therefore, it follows that the air which we breathe must be as free 
as possible from the impurities which we continually discharge into it, 
and that this condition can be obtained only by constant dilution of 
them by a constant supply of fresh air. In the open air, this dilution 
goes on without any artificial assistance and requires no consideration, 
but in confined spaces, we have to a certain extent a reproduction of 
the conditions that obtain in the lung; namely, the presence of a vol- 
ume of vitiated air, separated from the purer surrounding air, and re- 
quiring to be discharged and replaced. In other words, the air in the 
first confined space, the lung, is discharged into the second confined 
space, the room, and thence must be removed to the outside and re- 
placed by an equal amount of normal air. The constant dilution and 
removal of impurities due to the necessities of life, so that their amount VENTILATION AND HEATING. 
403 
shall be so small as to be harmless, is the function of ventilation, which 
may be regarded as the respiration of a building. 
It is, of course, not to be expected that the air of an inhabited room 
can under the usual conditions be maintained in a condition of purity 
like that of the outdoor air, even though but one candle or one per- 
son be present to exchange carbon dioxide and water for oxygen, but 
the impurities can be reduced to a minimum by the introduction of a 
proper amount of fresh air. What shall be considered a proper 
amount of continuous air supply, depends upon what we adopt as a 
limit of permissible impurity, measured by the amount of CO., present. 
For the maintenance of a fair degree of vigor and stability through 
proper oxidation of the blood and dilution of the effete matters dis- 
charged, and for the maintenance of the fullest and most perfect func- 
tional activity, one requires respectively about 30 and 50 cubic feet of 
air per minute. Less than 30 will inevitably produce impaired vital- 
ity ; over 50 can be productive of no gain in improvement so far as the 
effects of the ordinary vitiating matters are concerned. 
At the latter rate, then, an hourly supply of 3,000 cubic feet is 
necessary for the proper dilution of the respired air of each individual 
present in a confined space. Thus, a room of 3,000 cu. ft. capacity, in- 
habited by one person, must receive its full capacity of fresh air once 
every hour. But this renewal must be a continuous process so as to 
prevent an accumulation of impurities which would occur if the air 
were simply replaced in bulk by an hourly aeration by opening win- 
dows for the requisite few' minutes. 
Nor must it be supposed that even with constant fresh supply the 
air of the room can have the same composition as that which enters 
from without, for the impurities of each respiration are not removed in 
separate distinct lots, but are mingled in the general bulk. If the oc- 
cupant's head were in a conduit bringing the constant supply of fresh 
air and carrying away the products of respiration, no such amount of 
air would be necessary and no contamination of the general supply 
would occur. Under ordinary circumstances, with an hourly supply 
of 300 cu. ft. per capita, the amount of CO2 will not range above 6 or 
7 volumes in 10,000, and any system of ventilation that will keep it 
down to this must be called good. 
Other impurities than those of respiration are to be considered in 
all questions of ventilation. The influence of burning illuminating 
material on the composition of air is very great, both as to the con- 
sumption of the oxygen and the production of CO2 and other im- 
purities, and it is not insignificant in its relation to the temperature. 
The impurities from one cubic foot of ordinary illuminating gas are 
such in amount as to require, according to various estimates, from 500 
to 1,800 cubic feet of air for their proper dilution. They include not 
only carbonic acid and water, but carbon monoxide, sulphur acids, 
nitrogen acids, marsh gas, ammonia compounds, unconsumed carbon, 
and other matters. Different forms of burners consume different 
amounts of gas to get the same illumination; ordinarily from three to 404 
HABITATIONS, SCHOOLS, ETC. 
six cubic feet are used per hour, requiring 1,500 to 10,000 cu. ft. of 
air supply for proper dilution of the impurities produced by each 
burner. 
Therefore, on both hygienic and economic grounds, the burner which 
produces the maximum of light from the minimum of gas is the best 
for use, it being understood that a given volume of gas will yield the 
same amount of impurities, whatever the burner employed. 
The impurities from candles and lamps are less in number and va- 
riety, but, measured by the comparative illuminating power, they are 
larger in amount than from gas. For example, the combustion of an 
amount of candle or kerosene oil necessary to produce the same inten- 
sity of light as one cubic foot of gas, will produce from 40 to 160 per 
cent, more impurities, and requires, therefore, proportionately more air 
for their proper dilution. 
The subject of ventilation, involving, as it does, the continuous intro- 
duction of pure air to displace that which has become vitiated by 
whatever cause or heated to such a degree as to be inconsistent with 
comfort; having to deal with buildings and rooms of various sizes, de- 
signed for different uses ; and, as it is chiefly in the colder months that 
its importance is greatest, being intimately connected with the problems 
and cost of heating, is a very complex one which will not permit the 
adoption of any inflexible rules applicable to all cases. 
Amount of Space Required for Good Ventilation. 
If it be agreed that for the most perfect results an adult requires au 
hourly supply of 3,000 cubic feet for the removal of his own effete 
matters, to say nothing of the accessory impurity dependent upon il- 
lumination, the next question is as to the amount of cubic space neces- 
sary per capita, that is to say, through how small a space that amount 
of air can be drawn hourly without disagreeably perceptible draughts. 
The sensation of draught is governed very largely by the temperature 
of the moving air, a cold slowly moving current being more percepti- 
ble than a warm one moving at a greater rate of speed. Draughts 
which are productive of discomfort are more dangerous than the ordi- 
nary vitiation of the air, and, therefore, complete ventilation with 
draughts is worse than partial ventilation without draughts. 
It has been shown by Pettenkofer that with the aid of delicate ap- 
paratus and mechanical power, about 2,500 cubic feet can be passed 
without draughts through a space of 424 cubic feet in an hour ; that is 
to say, through a room 8 feet square and 6.5 high, the air can be re- 
newed six times. 
The minimum space within which one can receive, under artificial 
conditions, six complete changes of air in one hour is, therefore, 424 
cubic feet; but in order to get 3,000 cubic feet in one hour, the air 
would have to be changed seven times, and so the required mini- 
mum space would be 500 cubic feet. In large spaces, however, it is 
possible to obtain morefrequent changes without danger from draughts. NATURAL FORCES IN VENTILATION. 
9 
405 
Thus, in a hall 40 by 20 by 15 feet, 40 persons can be supplied with 
3,000 cubic feet each per hour, and each one will have 300 cubic feet 
of air space. Therefore, in dealing with large spaces, we may assume 
300 cubic feet per capita rather than 500. 
In the ventilation of small spaces, there is, in addition to the possi- 
bility and danger of draughts, the grave difficulty that the inlets and 
outlets are necessarily so near together that much of the air will pass 
directly from the one to the other without having mingled with the 
main body, and without, therefore, doing the slightest service in dilut- 
ing the impurities present. In large air spaces, this objection does not 
apply with equal force, for the opportunity for diffusion is greater, the 
larger the space, though of course here, too, the inlets and outlets may 
be so unfortunately placed as to favor the formation of direct currents. 
In the ventilation of large spaces in which large numbers of people 
gather, as churches, theatres, schools, and lecture-rooms, we are at once 
confronted by the fact that 300 cubic feet of space is a more liberal 
per capita allowance than is often practicable, and that this space is in- 
compatible with a draughtless ventilation by the necessary air volume. 
If, then, the question be asked, how to provide the necessary amount, 
there is but one answer ; namely, that it cannot be done. Fortunately, 
however, the danger from impure air is proportionate to the length of 
time of exposure, an occasional short time spent in a crowded room or 
public conveyance filled with bad air being less harmful than prolonged 
and habitual occupancy of a room in which the air is less vitiated, but 
yet not good. 
In general, it may be said that the importance of ventilation varies 
with the particular air spaces; those which are used only at intervals 
and for short periods of time have much less need of it than those 
which are used uninterruptedly ; those which are not crowded demand 
less than those that are; those used only for the moment need no con- 
sideration whatever, the natural forces at work at all times being suffi- 
cient for their needs. 
To insist upon thorough ventilation of every part of a house at all 
times, as most amateur hygienists do, is to demand a needless waste of 
energy and money, for except in the warm months when the windows 
and doors are left freely open for the sake not alone of ventilation but 
of general comfort, ventilation goes hand in hand with heating and 
divides the expense. 
Nor can one successfully insist upon any rule that each person must 
have at least a thousand cubic feet of air space with renewal of the con- 
tained air once in 20 minutes, for to do so is to urge in the case of the 
poor of large cities an impossibility, since space is costly, and with ven- 
tilation to the proper extent, is beyond their means. 
Natural Forces in Ventilation. 
Before proceeding to the subject of systems of ventilation, we must 
consider the natural forces which are at work in the presence or 406 
HABITATIONS, SCHOOLS, ETC. 
absence of all schemes and systems. These forces are diffusion and 
gravity. 
Diffusion and Gravity.-The rate at which gases diffuse is by no 
means the same for all, the lighter diffusing much more rapidly than 
the heavier. In fact, the rate varies inversely as the square roots of 
their densities. The province of diffusion in ventilation is limited to 
bringing the air to a condition of more or less complete homogeneity 
by causing the gaseous matters to become distributed throughout the 
mass, but in an inhabited room it can do but little towards keeping 
the air at its normal composition. By reason of the law governing 
the rate of diffusion, there must of necessity be a constant, though 
slow, removal of gaseous impurity into the external air, for wherever 
two gases are brought into contact, diffusion will occur, whether the 
meeting place be large spaces, as rooms, or small spaces, as pores in 
the plastering, bricks, mortar, stone, or other material which forms 
the boundaries of that room. This force is, however, very inadequate 
and can be of service only as an assistant to another. Moreover, it 
can affect only gaseous and not suspended matters. 
Of vast importance, however, is the other force, that of gravity. 
Equal volumes of air at the same temperature and under the same 
pressure will have the same specific gravity ; if the temperature of 
one of them be raised, it expands a definite amount for each degree 
and thus has less specific gravity than the other the more it is heated. 
Being surrounded by air which is heavier than itself, it rises or, more 
properly, is forced upwards by the heavier air, which descends to oc- 
cupyjits place, in the same way that a volume of light oil in a cylinder 
is forced upwards when water is poured upon it. If, on the other 
hand, it is cooled, its volume contracts, its specific gravity is increased, 
and it sinks downward through the warmer lighter air below it. In 
this way, differences in temperature cause constant movements in 
bodies of air, and currents are established. 
In an inhabited room this force is always at work, for there must 
necessarily be some source of heat, even though it be only the body of 
the occupant. The air in contact with the body becomes heated and 
is then displaced by the colder air about it; this in its turn is sub- 
jected to the same influences, and the whole of the contained air must 
rise in temperature and be correspondingly expanded. As it becomes 
lighter than the surrounding air, the latter forces itself in and the 
original air out through all the available openings, and thus a certain 
amount of ventilation is accomplished. 
Under the ordinary conditions of occupancy of a house or room, we 
have additional sources of heat in the combustion of fuel and illumi- 
nating materials, and no matter how imperfect the applied system of 
ventilation may be, and in spite of all efforts to exclude the external 
air, a very considerable amount of interchange of air is inevitable. It 
is only in a chamber that is to all intents and purposes hermetically 
sealed that no ventilation will occur when there is a difference be- 
tween the internal and external temperatures. Heated air will escape NATURAL FORCES IN VENTILATION. 
407 
through flues, through cracks around windows and doors, between the 
boards of the floors and of the general structure, and even through 
the interstices of unpainted plastering and mortar, and through the 
pores of bricks. That a large volume of air will pass through cracks, 
needs no demonstration; the passage of air through bricks, plaster, 
and mortar can be easily shown. 
If to the opposite sides of a brick, we fasten by means of sealing 
wax two ordinary glass funnels, and then smear its entire exposed sur- 
face with a liberal coating of the same material, all of the external pores 
excepting those within the spaces covered by the funnels are made 
impervious to air. If now we connect by means of a rubber tube the 
Fig. 38. 
Apparatus for demonstrating the permeability of bricks, etc., to air. 
funnel on one side with a bottle in which air can be compressed by 
means of water pressure, and by the same means the other funnel with 
an inverted test-tube filled with water, and apply pressure, in a few 
minutes, the passage of air through the pores of the brick will be mani- 
fested by the escape of bubbles from the outlet tube upward through 
the water. (See Fig. 38.) 
The passage of air through plastered walls is much impeded by wall 
paper and may be totally prevented by oil paint and moisture. 
Numerous experiments have proved that with varying differences 
between the internal and external temperatures, the air of a room or 
building will be renewed partly, wholly, or repeatedly every hour, 408 
HABITATIONS, SCHOOLS, ETC. 
even when efforts are made to prevent as far as possible the entrance 
of the outside air. The results vary with the difference in conditions, 
the highest effects being produced when the temperature differences 
are wide, the opportunities for leakage great, and the external air in 
active motion. With perfect calm and equal temperature, the result 
will be nil. 
Perflation and Aspiration.-Inequalities in outside temperatures 
give rise to the larger currents of air which we know as winds. These 
have a very great influence on ventilation both by their perflating ac- 
tion and by aspiration. The highest results of perflation are those 
obtained when obstacles to the free admission and exit of wind are re- 
moved, as, for instance, by opening windows in its path. The quick- 
Fig. 39. 
Fig. 40. 
Fig. 41. 
Common forms of stationary ventilating cowls. 
Rotary cowl. 
ness and frequency of renewal of contained air by this means will 
necessarily depend upon the size of the openings and the velocity and 
direction of the wind. The least effects are produced, whatever the 
velocity and direction, when the obstacles to entrance are greatest. 
The aspirating influence of wind is shown by the upward currents pro- 
duced in flues when the internal and external temperatures are equal. 
A current of air, moving swiftly across the outlet of a flue, has the same 
effect on the contents of the flue as that of a common hand atomizer 
has on the contents of the tube. The air in the upper part is. carried 
along mechanically, a partial vacuum is formed, and that which is be- 
low rises to take its place and is in turn carried away. In the case of 
the flue, air from below is constantly drawn up and dissipated; in the NATURAL VENTILATION. 
409 
case of the atomizer, the liquid into which the tube dips is lifted and 
blown into spray. 
This influence is utilized and assisted by various forms of cowls 
placed over outlet flues; some of these, however, though they seem to 
be an aid, are really a hindrance to the outflow, as can be easily demon- 
strated. 
In Figs. 39 and 40, are shown forms of cowls which offer some 
assistance to the aspiratory influence of winds, and in Fig. 41 is shown 
another very popular kind, the rotary cowl, which offers an obstruction 
to the passage of air. As the 
wind causes the top to revolve, 
the impression is made that 
work is being performed ; that 
in its revolutions it is creating 
a suction which causes an up- 
ward current of air. As a 
matter of fact, however, it is 
doing no such work, but is, on 
the contrary, interposing an 
obstacle to the passage of air. 
This can be easily demon- 
strated by measuring by means 
of an anemometer the amount 
of air discharged through the 
flue during a given period 
while the revolving top is in 
place, and again during an 
equal period while it is re- 
moved. The difference be- 
tween the results obtained will 
invariably be in favor of the 
period during which the cowl 
is absent. 
Other forms of cowls, con- 
structed so that their outlets 
are turned by means of a vane away from the wind, are useful in assist- 
ing aspiration. Such a form is shown in Fig. 42. By reversing the 
position of the vane, the mouth of the cowl is turned toward the wind 
so that the flue is converted into an inlet for fresh air. 
Fig. 42. 
Aspirating cowl with vane. 
Natural Ventilation. 
Ventilation that proceeds from the operation of natural forces is 
known as " natural ventilation." For the attainment of the largest re- 
sults, these forces must be assisted to the extent of removal of obstacles 
to their action so far as may be advisable. It is not well to depend 
upon the chance cracks and upon the migration of air through the pores 
of building materials, but necessary openings, both inlets and outlets, 410 
HABITATIONS, SCHOOLS, ETC. 
should be provided. The greater the obstacles to the escape of heated 
air, the less the opportunity for successful natural ventilation. 
The extreme of obstruction to the escape of contained air may be il- 
lustrated by an hermetically sealed metallic box or by a closed glass 
bottle. Suppose we provide one small opening in the side of the box or 
in the stopper of the bottle to act as an outlet and inlet, and observe the 
result. According as the contained air is warmed or cooled, the open- 
ing will act as an outlet or as an inlet, but only to a limited extent. 
The expansion due to heating will cause the escape of a portion of 
the contents ; the contraction due to cooling will cause the indrawing of 
some of the outer air; but in either case, the movement is all one way 
and there is no real interchange. Suppose, however, two openings are 
supplied; then one will be utilized as an outlet, the other as an inlet, 
and a constant inward and outward current will be maintained. 
The more tightly fitting we make our windows and doors, and the 
more impervious to air we make our walls by means of paint and 
sheathing paper, the more do we oppose natural ventilation. On the 
other hand, the intelligent placing of inlets and outlets furthers the ob- 
ject to be achieved. 
In addition to permanently installed inlet and outlet flues, tempo- 
rary openings can be utilized whenever desirable. The most available 
of these is the opened window, which can be so utilized as to avoid too 
voluminous exchange and unbearable draughts. The area of the open- 
ing can be very simply regulated, and the air may be deflected up- 
wards or the current may be broken up by the interposition of fine 
wire gauze, flannel, or other pervious material. 
A very common plan is to place a board lengthwise under the lower 
sash, so as to fill completely the opening made by raising the window 
and thus establish an inlet or outlet where the two sashes overlap each 
other, for the barrier to the movement of air, formed by the juxtaposi- 
tion of the lower border of the upper sash and the upper border of the 
lower one, no longer exists, and the entering current is, moreover, 
given an upward direction. Instead of a board, a frame, over which 
a diaphragm of flannel is fastened, may be used. This arrangement 
is pervious to air but impervious to dirt, which is, therefore, filtered 
out. Movable panes, either sliding or swinging by the side or end, 
are frequently employed, especially in double windows. There are also 
numerous patented devices for window ventilation, all designed with 
the idea of dividing or deflecting the current of admitted air. 
As has been remarked above, the most important force in natural 
ventilation is that dependent upon unequal temperatures of bodies of 
air; in a perfect calm and with equal temperatures, natural ventilation 
would have to depend wholly on the force of diffusion. 
The enormous influence exerted by the heating and lighting of a 
building or room on its ventilation becomes, then, self evident, but it 
is not simply as a motive force that the relation between heat and ven- 
tilation is so close and important, for the incoming air must be raised 
to an agreeable temperature in order that the space may be habitable. NATURAL VENTILATION. 
411 
Thus, a very large share of the cost of heating is chargeable to venti- 
lation, whatever the system of ventilation be. In the matter of ex- 
pense, the amount of leakage through cracks and other small openings 
is, in a certain class of cases, of very great importance. In our dwell- 
ings, it is important that the interchange of air shall proceed continu- 
ously in the inhabited parts, but in buildings which are used only by 
day, and perhaps for only a few hours daily (schools, etc.), it is not es- 
sential that the air shall be constantly renewed at other times ; and 
here it is wise to obstruct the leakage as much as possible by perfect 
construction and by dampers in the flues, so that waste of heat, fuel, 
and money may be prevented. 
For the promotion of the process of natural ventilation, a number 
of " systems " have been devised, many of which can be productive of 
no results other than incomes for their promoters. As a rule, most 
of those noticed in works of this character are either ill-adapted to the 
conditions of our climate or incompatible with our methods of build- 
ing, and will, therefore, not be considered here. 
The only system of natural ventilation worthy of advocacy is that 
which provides proper inlets and outlets and a suitable means of 
heating. 
Inlets and Outlets.-As to the size, location and number of in- 
lets and outlets, no hard and fast rules can be applied for all cases, 
since the conditions are widely varying, and many different circum- 
stances have to be taken into account. But general rules may be laid 
down. 
If several inlets are to be provided in a room, it is essential that 
they should be distributed in such a manner as to insure a thorough 
blending of the admitted air. They should not be so placed, with 
reference to outlets, as to favor the forming of direct currents between 
them, whereby a large proportion of the inflowing air is discharged 
without having fulfilled its function-a not unusual condition, which 
illustrates that the amount of air admitted is not by any means a meas- 
ure of thoroughness of ventilation. Their location is not such an im- 
portant matter as the placing of the outlets, but, in general, an inlet is 
best placed on an inner wall where it shall be most nearly central in 
relation to the outside walls. 
With reference to the floor, if the incoming air is heated, they may be 
placed high or low, but if it is admitted cold, they should be at a higher 
level than the heads of the occupants and provided with arrangements 
for deflecting the current upwards toward the ceiling. This may be 
accomplished by causing the current to impinge upon a surface slant- 
ing upwards. The results of this deflection are that the fresh air be- 
comes mixed with the warmer air and that more time is required for 
it to reach the lower parts of the room, when it will have become suffi- 
ciently warmed not to cause discomfort. The interposition of the de- 
flecting surface also spreads the current radially and reduces its velocity. 
The incoming air becomes mingled with the general supply and 
joins the currents which are constantly in motion. That which comes 412 
HABITATIONS, SCHOOLS, ETC. 
in contact with cooling surfaces, such as windows and outside walls, is 
cooled and, therefore, falls towards the floor, and that which takes its 
place as it falls is cooled in its turn and follows after, so that currents 
are established, which tend to keep the whole bulk in more or less 
motion. As these currents reach the floor, their natural trend is across 
that surface toward the inner warmer walls, where they become heated 
and are inclined toward the ceiling, reaching which, they are pushed by 
the force behind and drawn by the one in front toward the outer walls 
and windows again. In the meantime, some of the air is escaping 
through outlets and diffusion of the impurities is proceeding, so that a 
more or less even character is brought about throughout the air of the 
room. 
Outlets may be placed at the level of the floor, in the ceiling, or at 
any height in the walls, according to the conditions of each individual 
case. If the incoming air is not heated, the outlets should be placed 
high up, for where only unheated air is admitted, the warmest air must 
be the oldest and its location will be in the upper air space. 
If, on the other hand, the air is heated, the outlets may be any where 
so far as height is concerned, but there is some choice in locations with 
respect to inner and outer walls. Outlets placed beneath windows or 
near outer walls will withdraw the falling currents of the only recently 
introduced air before it has had an opportunity to become well mixed 
by passage across the floor to the other side and before it has in any 
proper degree fulfilled its functions; but if its passage through the 
lower strata is not interrupted in this manner, it is enabled to mix 
with and dilute the impurities of the air already vitiated and thus ef- 
fect a large measure of work, and so when it reaches the other (inner) 
side and finds an outlet for its escape, there is no objection to its with- 
drawal, and, indeed, its removal then is highly desirable. Hence, and 
for another reason as will appear, outlets should be placed in inner 
walls rather than near or in outer cooler ones, and near the floor where 
they may intercept the air before it may again become a part of the 
ceiling currents. 
If but one outlet is to be provided, it should be placed with refer- 
ence to the most even movement of the current over the whole area, 
having in mind the fact that the air movement toward it is convergent 
and the direct reverse of the flow from the deflecting and diffusing sur- 
face at the inlet. 
As to size, it may be said, in general, that a single outlet, or the 
aggregate if there be more than one, should be of such size as to insure 
the possibility of removal of such an hourly air supply as the space is 
likely to require under the ordinary conditions of its usual occupancy ; 
that it should not materially exceed this limit, and that the final 
velocity of the outflowing current should not be productive of the sen- 
sation of disagreeable draughtiness. 
As to the shape of inlets and outlets, it is self evident that, with 
equal areas, that which has the smallest periphery will offer the least 
frictional resistance and is, therefore, best adapted. Thus, a circle NATURAL VENTILATION. 
413 
enclosing an area equal to a square foot has a smaller periphery than a 
square enclosing the same area, and a square has a smaller one than an 
oblong rectangle. Take for instance a square foot; it may be included 
within boundaries 
12X12 inches, a square. 
16X 9 " 
18 X 8 " 
24 X 6 " 
36X 4 " 
48 X 3 " 
72 X 2 " 
144 X 1 " 
oblong rectangles. 
With these boundaries, the periphery ranges from 4 feet (the smallest) 
to 24 feet 2 inches. The frictional resistance will, therefore, be greater 
in proportion as the shape varies from the circle and square. 
The shafts communicating with the inlets and outlets must be so 
disposed in the general plan as to offer the least resistance to the inflow 
and outflow of air. Unless they are artificially heated, inlet flues 
must not be located in outer walls, on account of the likelihood of the 
formation of down draughts due to cooling of the air column. Their 
inner surface should be as smooth as possible in order to bring to a 
minimum the loss of movement due to friction, and they should be 
cylindrical, if possible, for the same reason. They should be as free as 
possible from angles, and especially right angles, because of the very 
serious loss of motion which these cause, each right angle diminishing 
the current about half; thus, after passing one right angle, the flow 
would be half; after a second angle, the half would be reduced to a 
quarter, and after a third, to an eighth. The neglect to take into ac- 
count the loss of flow by friction, bends, and angles is responsible for 
the failure of many a plan for ventilation. 
What has been said concerning the impossibility of making general 
rules for the sizes of inlets and outlets applies with equal force to the 
fixing of sizes of flues, for these depend upon the many and varied 
conditions which, even under the best favoring circumstances, affect the 
rate of flow. 
In planning inlet and outlet shafts, it is to be borne in mind that 
something more is necessary for their proper working than the dictum 
that this one is for fresh air and that one for foul, for natural forces 
have no respect for mere names and plans, and the current in a flue 
will be upward or downward, inward or outward, according to natural 
laws. Outlet shafts may become considerably cooled by low external 
temperatures; they may be invaded by rain and snow, the evaporation 
of which causes cooling and, therefore, increase in gravity; or there 
may be an insufficiency of inlet air, so that a partial vacuum is formed 
by the current of one large outlet flue, which thereby causes a reversal 
of that of a smaller one, so that one flue draws against another. It is 
from any one of these causes that a chimney may fail to discharge 
smoke upwards-a circumstance noticed more often in summer than in 
winter. 414 
HABITATIONS, SCHOOLS, ETC. 
Mechanical Ventilation. 
Mechanical ventilation consists in the propulsion or extraction of air 
by means of blowers or exhaust fans driven by steam or electricity. 
That in which the air is propelled by the action of a blower is known 
as the " plenum " system, and the other, in which it is withdrawn by an 
exhaust fan, is known as the " vacuum " system. 
In the plenum system, the air is drawn into a box, in which the re- 
volving blades of a fan are located, and it is then driven into a central 
conduit and from there through appropriate shafts to the spaces for 
which it is intended. When it is desired, the air may be received from 
or blown first into a chamber where it can be heated. The air supply 
can be very easily regulated by diminishing or increasing the number 
of revolutions per minute, but it should always be in slight excess over 
the real need, in order to produce a slight outward pressure, which will 
prevent inward leakage. 
In the vacuum system, the air is extracted from the various rooms 
through pipes leading to a central shaft, where it is drawn into the fan 
and discharged outwardly. This system has among other disadvan- 
tages that of great inequalities in draught in the different discharge 
tubes, and that the vacuum condition favors the inward leakage of cold 
air through cracks, walls, and about windows, and tends to cause cold 
floors and disagreeable small draughts about windows. In consequence, 
more fuel is needed for the maintenance of a proper temperature, and 
the system is, therefore, a source of greater expense. 
The advantages of artificial ventilation lie in the fact that the object 
sought is attainable in any and all conditions and variations of weather, 
and that less space is required for shafts than in the case of natural 
methods. 
Mechanical ventilation on a comparatively small scale is commonly 
employed in crowded offices and other spaces by means of small ex- 
tracting fans run by the aid of electricity (connection being made with 
the electric light system) in specially provided locations connected with 
outlet flues, or directly in a space made by removing window panes. 
Artificial Heating in Its Relations to Ventilation. 
First, for the proper understanding of the subject of heating in its 
bearings on ventilation, it is necessary to consider the different ways 
in which heat is imparted. These are three in number : radiation, 
conduction, and convection. 
Radiation.-Radiant heat passes from its source through the air to 
bodies by which it can be absorbed, transmitted, or reflected. Air, 
being "transparent " to heat, is not materially affected, and the drier 
the air, the less heat it will retain. It passes directly from its source 
in waves, like the waves of light, to the object upon which it falls, and 
the amount reflected or absorbed varies with the nature of the object, 
its color, the character of its surface, and its temperature. Its in- ARTIFICIAL HEATING IN ITS RELATIONS TO VENTILATION. 
415 
tensity varies inversely as the square of the distance between the 
source and the object upon which it falls; thus, the amount received 
by two objects 1 and 5 feet respectively distant, will be inversely as 1 
and 25; at 1 and 10 feet, inversely as 1 and 100; at 5 and 10 feet, 
inversely as 25 and 100 ; that is, the nearer will receive in the first in- 
stance 25 times; in the second, 100 times; and in the third, 4 times 
as much as the farther object. 
As an instance of radiant heat, we may take that which proceeds 
from an open fire. The heat passes in direct lines through the air to 
the walls, floor, ceiling, furniture, and other objects in its path, and these 
absorb some and reflect the rest to other parts of the room. It directly 
warms only that surface of an object that is directly opposed to it. 
The objects by which it is opposed then disseminate it in two ways : 
by conduction and convection. 
Conduction.-Conducted heat is that which passes from one par- 
ticle of matter to another in direct contact, that is from one particle to 
another of the same object, or from one object to another which it 
touches. Conduction acts through all solid substances, but by no 
means to the same extent, some being good, some indifferent, and 
others bad conductors. The best conductors are metals, and these 
vary within very wide limits ; copper, for instance, is a very much 
better conductor than iron or zinc. Wood is a poor conductor, and 
woven and felted materials and asbestos are very bad. Through 
liquids and gases, heat is conducted only to a very limited extent, but 
there is no substance known that is absolutely non-conducting. 
Good conductors permit a rapid flow of heat through their sub- 
stance ; bad ones, only a slow transmission. Good conductors relin- 
quish their heat rapidly to their colder surroundings, whether air or 
anything else, and withdraw heat from bodies which are warmer than 
themselves. 
Convection.-Convection is the process by which heat is communi- 
cated to gases and liquids, acting through their mobility which permits 
those parts which have been expanded by reason of becoming heated 
to be displaced upwards by cooler portions, which, in their turn, re- 
ceiving heat, give way to others, until the whole mass becomes raised 
in temperature by continued application of heat and consequent main- 
tenance of circulation. 
Every warm body with which air comes in contact communicates its 
heat to those portions in its immediate vicinity; these expand and are 
forced onwards by the cooler heavier parts nearest them; these in 
their turn give way to others, and convection currents are established 
to such an extent that the air of a room takes on a very complicated 
state of activity. 
Convection currents are established by every person in a room so 
long as the temperature is below that of the body. They are estab- 
lished by the warmed walls, floor, furniture, hot-water pipes, steam 
radiators, close stoves and other warm objects and in this way the air 
becomes heated. The air which enters rooms through shafts com- 416 
HABITATIONS, SCHOOLS, ETC. 
municating with the air chambers of furnaces and " indirect radiation " 
apparatuses are convection currents in the largest sense. The direct 
rays of the sun, passing through windows and absorbed by the floor, 
walls, and other objects which they strike, also cause upward convec- 
tion currents. 
Methods of Warming.-The principal methods of heating houses 
and rooms are: 1. Open fires. 2. Stoves. 3. Furnaces. 4. Hot- 
water pipes. 5. Steam pipes. The method most applicable in any 
particular case will depend upon the size of the room and the number 
of rooms in the building. In general, it may be stated that the smaller 
the space, the more simple the method. For a single room, an open 
fire or a stove will be quite sufficient; for a small house, stoves or a 
furnace; for a large one, one or more furnaces or hot-water or steam 
apparatus ; and for large buildings-office buildings, for instance- 
"direct" or "indirect" steam. 
1. Open fires.-Practically the whole of the heat supplied by an open 
fire is radiant. If the fuel is held in a grate, there is, of course, a cer- 
tain amount of conduction from the bars, and of convection currents 
in the air in its immediate vicinity. But this conducted and convected 
heat does not get out into the room, because it is immediately carried up 
the flue by the draught of the chimney. The radiant heat is absorbed, 
reflected, and distributed in the manner already described, but reaches 
directly only those surfaces which are opposed to its source-which ac- 
counts for the saying that, in a cold room with an open fire, " one side 
roasts while the other freezes." 
Only a small part of the total heat of the fuel consumed is avail- 
able for heating, since most of it, about seven-eighths, is carried at 
once up the chimney. An open-fire stove such as the old-fashioned 
" Franklin," which stands out in the room and is connected with the 
flue by stove piping, yields a large amount of its heat, since the ma- 
terial of its construction is heated by conduction and then gives it off 
to the air by convection. 
Open fires cause the introduction and removal of large volumes of 
air, but these are by no means always well mixed with the whole mass 
of contained air. Nevertheless, a large measure of ventilation is ac- 
complished, a certain amount of heat, perhaps sufficient for immedi- 
ate needs, is given off, and there is also an unmeasurable addition to 
the general cheerfulness. They may cause too much draught and 
they are certainly not economical, but as accessories to other heating 
methods they may be most useful. 
2. Stoves.-Close stoves have more direct results in heating and 
less in ventilating than the open fire, for more of the heat produced is 
available, and they discharge into the chimney only the air volumes 
that have passed through them. The materials used in their construc- 
tion, iron, soapstone, brick and fireclay, conduct the heat and give it 
off to the air with varying rapidity ; cast-iron yields it about as rapidly 
as it is received, soapstone and brick give it off only gradually, but for 
a longer period. ARTIFICIAL HEATING IN ITS RELATIONS TO VENTILATION. 
417 
When cast-iron becomes red-hot, it may be decidedly objectionable 
for two reasons : first, that the organic dust particles in its immediate 
vicinity become charred and yield odors ; and second, that it absorbs and 
transmits considerable carbon monoxide from burning coal. Stoves 
may be so arranged as to act not alone as heaters, but as ventilating ap- 
paratuses, and this fact is of very great value in the case of small school 
buildings in the country districts. The stove, standing out in the 
room, may be surrounded by a cylindrical jacket from the floor up- 
ward, leaving a sufficient air space between the two. Through the 
floor within the enclosure, is an opening into an air duct communicat- 
ing with the outdoor air. The heat of the stove is communicated 
to the air between the latter and the jacket, and an upward current is 
formed, which draws upon the fresh-air conduit so that a constant 
current of warmed pure air is thrown into the room. (See Fig. 43.) 
Fig. 43. 
Jacketed ventilating stove. 
It goes without saying, that here, as elsewhere, the incoming air must 
be taken from points where its impurity cannot be interfered with by 
local conditions. 
Gas stoves and oil stoves have the advantage over others that 
they are more prompt in results, more easily controlled, and more 
quickly put out of use. They have the disadvantage, however, that 
the products of their fuel combustion are discharged directly into the 
air of the room. In the case of the oil stove, this is not such a serious 
matter, since the perfect combustion of good oil results in carbonic 
acid and water, but with gas the products are more numerous and 
varied and include some that are irritating and poisonous. With 
proper ventilation, however, in the case of both, no harm will be done. 
3. Furnaces.-Hot-air furnaces are not only of very great importance 
as heaters, but of enormous influence in ventilation. In their use, the 
cold outdoor air is brought in by a conduit, the " cold-air box," to a 418 
HABITATIONS, SCHOOLS, ETC. 
chamber in the upper part of the furnace, above and surrounding the 
" dome," where it comes in contact with the very hot surface and is 
heated by convection. Thence it passes upwards through separate tin 
tubes to the several places for its discharge. In a house which is un- 
provided with special inlet and outlet flues for ventilation-and most of 
our houses are so constructed-a furnace of ordinary heating capacity 
performs an amount of ventilating work quite sufficient for all needs, 
and for which it rarely receives any credit. 
It discharges into the various rooms a constant supply of warmed 
fresh air. Where and how it all escapes, is a matter of only secondary 
interest and importance, for it gets out wherever it can find its way. 
4. Hot-water Pipes.-Hot-water heating depends upon the circula- 
tion of water by convection currents through a system of pipes which 
may extend all through a large sized building. The water is heated 
in a boiler below and passes through a main, leading from the upper 
part thereof. As one portion of water comes in contact with the heat- 
ing surface and expands, it is moved along, and the circulation be- 
comes established just as with air. The "main" gives off branches 
where needed, and these at their extremities turn back and become 
" returns," which eventually connect with each other and form the 
" main return," which, conveying the cooled water, enters the boiler 
at its lowest point. 
The first part of this system may be compared with the arteries, 
and the "returns," with the veins of the body. Vents are provided 
for the escape of dissolved air liberated from the water, and " cut- 
offs " are inserted for the shutting out of any part of the system as 
desired. It is very necessary that air should not be allowed to ac- 
cumulate in the pipes, since it will stop the flow. In low pressure 
systems, a small cistern is provided to allow for the expansion of the 
water and to prevent its overflow. The hot-water system may be of 
either high or low pressure. With high pressure, the pipes are smaller 
and necessarily stronger, and the water is heated to a considerably 
higher temperature (300° F.) and hence circulates more rapidly. With 
the low-pressure system, the water does not go much, if any, above 
212° F. 
With the hot-water system of heating, the air is heated mainly by 
convection, though from polished pipes a certain amount of radiation 
occurs. With high pressure, the air may be quite easily overheated. 
5. Steam Pipes.-In steam heating, the system is very like that of 
hot-water heating, except that steam is the circulating medium instead 
of water. With steam, and, indeed, with hot water, heat may be dis- 
tributed by the " direct " or " indirect " methods. In the " direct " 
method, the pipes are distributed within the space to be heated, and the 
air of each room is heated separately. In the " indirect " method, the 
heating surfaces are all concentrated in the basement and are enclosed 
in galvanized iron conduits, which receive and conduct the air just as 
in the case of the hot-air furnace. The two methods, it will be noticed, 
vary widely in the matter of assisting ventilation ; the direct brings REGULATION OF TEMPERATURE. 
419 
in no air, but heats that which is at hand ; the indirect brings in large 
volumes of heated fresh air and thus insures change of air. 
In conclusion may be mentioned the considerable heating and 
circulating influence of burning illuminating gas. By means of suit- 
able outlets above the burners, gas may be made not only to discharge 
the products of its own combustion, but to send out large volumes of 
otherwise vitiated air as well. Nor is the heat of the sun so insignifi- 
cant that it may be passed by without notice in the planning of sys- 
tems of ventilation. Inasmuch as the difference in temperature of the 
outside air on the north and south sides of a house averages about five 
and may reach ten degrees, just that amount of advantage may be 
gained by taking the air for ventilation from the warmer side. In 
gravity ventilation, the inlets should be where they may face the pre- 
vailing winds. 
In carrying out any scheme of efficient ventilation, it is necessary 
to guard against overheating, which may not be noticed until it be- 
comes so marked that it cannot help attracting attention. When such 
is the case, the common practice is to cause a lowering of the tem- 
perature to the desired point as soon as possible by opening win- 
dows to let in the colder air. The consequence is the production 
of a distinctly cold atmosphere,. more so than is ordinarily shown 
by the thermometer, which does not react very promptly to sudden 
changes. This produces chilly sensations which call for a return to 
the original condition. In the meantime, a lot of heat has been 
wasted and the foundation for a cold has, perhaps, been laid. If 
windows are left open in the upper stories, as often happens in over- 
heated buildings, there is constant outflow and waste of heated air with 
a corresponding inflow of unwarmed air below, which requires the ex- 
penditure of additional fuel in order that the lower stories shall be 
properly warmed. In overheated buildings, there is also the additional 
loss from outward leakage through all possible outlet channels. 
To prevent waste of heat in properly heated buildings, we have 
recourse to double glazing and double windows. Double glazing is 
accomplished by fitting two panes into each space instead of one, with a 
space of a quarter or a half inch between them. By this means, the 
loss of heat occurring through ordinary windows is reduced about one- 
third, which means a saving of considerable fuel, since the loss of heat 
by conduction through glass windows is very considerable. 
Double windows are still more efficient as heat savers. Here the 
outer window is made to fit as accurately and closely as possible by 
the use of listing, and we have between the two windows a fairly deep 
space filled with air, which is a very poor conductor of heat. It is on 
the same principle that we use loosely woven woolen goods and furs, 
which hold within their meshes and hairs a large amount of this 
poor conductor. The loss of heat through walls is lessened when a 
similar air space exists within them ; a solid wall will conduct a very 
Regulation of Temperature. 420 
HABITATIONS, SCHOOLS, ETC. 
large amount of heat and waste it, while the same amount of building 
material, or considerably less, can be so disposed as to bring this loss 
down to a minimum. 
Loss of heat is caused also by dampness of walls, for a continual 
evaporation goes on from their surface, and this requires heat and pro- 
duces cooling. Every ounce of moisture so vaporized requires the 
consumption of extra fuel. 
Necessity of Providing Moisture. 
Concernina- the need of insuring a normal amount of moisture in the 
air of heating buildings, there is more or less difference of opinion, but 
the weight of evidence from a medical standpoint and from our own 
sensations points to the advisability of introducing an amount of mois- 
ture sufficient to bring the relative humidity of the air to 50 or 55 per 
cent. 
The lower the temperature of a body of air, the less the amount of 
moisture it can hold, and what would be saturation at a low tempera- 
ture would be but a very low relative humidity at a high one. For 
instance, a volume of air at 0° F., containing its fullest possible amount 
of aqueous vapor, admitted to the cold-air box of a furnace and then 
heated to 85° F. before being conducted to the rooms of a house, will 
have at its new temperature but a .very small relative humidity. It 
will be so much drier than any outside air, that that of the driest cli- 
mate in the world will be moist in comparison. The great majority 
of U. S. Signal Service Stations have a mean relative humidity of 65 
to 75 per cent.; only 24 show below 60 or over 80, and the very 
lowest is in the hottest part of Arizona, where newspapers crack when 
handled, glued furniture falls apart, and the skin becomes hard and dry. 
At this place, Fort Yuma, the mean relative humidity is 35 per cent. 
When outdoor air is heated so as to maintain an even temperature 
of 70° F., but with no addition of watery vapor, its capacity for ab- 
sorbing moisture is very much increased and it will take it up from all 
moist objects with which it comes in contact. It will take it from the 
skin, from the mucous membranes of the mouth, nose and respiratory 
tract; from furniture made from wood which, in the process of kiln- 
drying, was never brought to such dryness; from the leather bindings 
of valuable books, causing them to crack and fall to pieces; and from 
plants which, in consequence, wither and die. It thus causes more or 
less dryness of the skin, irritation of the throat, and cough. It causes 
also need of a higher temperature to give the same sensation of warmth 
and comfort than is the case with air containing a normal amount of 
moisture. 
It is on account of the disagreeable and destructive effects of extreme 
dryness that water holders are attached to furnaces and stoves so as to 
give moisture to the heated air. But even when any attention is paid 
to keeping them full, which is not often, they are very inadequate for 
the purpose. NECESSITY OF PROVIDING MOISTURE. 
421 
Air at 25 I., saturated with moisture and then heated to 70°, would 
need over a half pint of water in every thousand cubic feet to give it a 
humidity of 65 per cent., and this is far in excess of the capacity of the 
ordinary waterpot of the furnace, as is seen when we reckon what half 
a pint per thousand cubic feet 
means in the course of a day. 
Moisture can be imparted 
to the air by exposing pans or 
porous vessels of water to the 
heated current, or by means of 
the " humidifier/' which ex- 
poses to the air passing 
through the registers a surface 
of cotton wicking communicat- 
ing with a reservoir of water. 
(See Fig. 44.) With this de- 
vice, Dr. H. J. Barnes, of 
Boston, reports that he is able 
to keep his office at 53 per 
cent, relative humidity by 
evaporating an average of four and a-half quarts of water per day. 
At the same time, he finds a temperature of 65° to be perfectly com- 
fortable where before he had required 70 or 71°. 
On a larger scale, water may be vaporized into the air in the form of 
steam from a boiler. In the building of the American Bell Telephone 
Co., in Boston, a building having a cubic capacity of 450,000 cubic 
feet and a day-time population of over 450 persons, the air, which is 
distributed by the mechanical system, is drawn into the building at the 
rate of 26,000 cubic feet per minute, heated to about 100° F. in the 
stack room, and moistened so as to contain about 50 per cent, relative 
humidity. For the production of this condition, no less than 675 gal- 
lons of water in the form of steam are given to the air in 10 hours, or 
about one and a-half barrels per hour. Certain parts of the building 
which, before the adoption of this process, had been heated with some 
difficulty, are now made more comfortable, and in the whole building 3° 
less heat are required for the maintenance of an agreeable temperature. 
According to Mr. C. J. H. Woodbury,1 under whose direction the 
plant was installed, 11 another feature indicating the greater comfort of 
the building was the absence in winter of the coughing by those em- 
ployed there, a cough of the bronchial kind or from the larynx, a cough 
which ends with a squeal, which is so prevalent in New England dur- 
ing the winter, especially in those employed in offices." 
Filtration of Air.-Here may be given an instance of the benefit 
derived from filtering large volumes of air introduced into a building 
for purposes of ventilation. In the building above mentioned, the air 
is drawn into and through a system of large cotton bags 30 feet in 
length, in which all dirt and dust must be retained. About a peck per 
Fig. 44. 
Humidifier. 
1 Transactions of the New England Cotton Manufacturers' Association, Vol. 63. 422 
HABITATIONS, SCHOOLS, ETC. 
month is separated in this way from the air, which is drawn not from 
the street level, but far above it. An analysis, chemical and micro- 
scopical, made in April, 1897, showed 22.67 per cent, of organic and 
77.33 of inorganic matter. The material consisted of all manner of 
animal, mineral, and vegetable substances ordinarily present in the dust 
of large cities. 
Determination of Rates of Ventilation. 
The estimation of the amount of air entering and leaving a room 
through inlet and outlet flues is a very simple matter, but the results 
may not be accepted as an indication of the efficiency of ventilation, 
since it so often happens that much of the effluent air has failed to per- 
form its full duty in diluting the impurities arising from respiration and 
combustion. Nevertheless, such a determination may yield important 
indications. 
In order to ascertain the volume of air passing through an opening, 
whether inlet or outlet, it is necessary to know the area of the opening 
and the velocity of the current. The former is easily calculated 
arithmetically; the latter can be found only by the use of an anemom- 
eter, an instrument of very delicate construction, which registers the 
distance traveled by a current of air in any period of time during 
which it is exposed. 
A current of air, passing through an opening, has not the same ve- 
locity at all points of its cross section. It moves in the same man- 
ner as a river-faster at its center, where it is least subject to the influ- 
ence of friction. Therefore, the velocity must be taken at different 
points and the mean of the results accepted as its true rate of move- 
ment. The anemometer is held for a given time, say half a minute, 
at a point at the periphery of the opening, and then moved along a 
short distance and held for an equal period, and so on, from point to 
point, until the whole area has been fairly traversed. The reading of 
the instrument is then noted, and the distance indicated is divided by 
the number of points where stops have been made. The quotient 
equals the distance traveled by the whole current during the unit of 
time employed. 
It will be found most commonly that the movement at the periphery 
is very slow, and that as the center is approached, the velocity becomes 
greater and greater, the maximum being attained at the center. 
Knowing the average movement in feet or meters, the volume is calcu- 
lated by multiplying this by the area in square feet or square meters, 
the product being the volume in cubic feet or cubic meters passing 
during the unit of time. From this result, the volume per hour is 
easily made known. 
Example.-The size of the opening is 2 by 3 feet; the area is, 
therefore, 6 square feet. The anemometer, held at 24 points for 15 
seconds each, registers 228 feet. The mean of this is 9.5 feet, and the 
current is moving, therefore, at the rate of 38 feet per minute. The DETERMINATION OF RATES OF VENTILATION 
423 
cross section of the current being 6 square feet, the volume discharged 
in a minute equals 6x38, or 228 cubic feet, and in an hour, 13,680 
cubic feet. 
By determining the rate of discharge through all inlets and outlets 
in this manner, an idea is obtained of the amount of ventilation occur- 
ring through means provided, but, as has been stated, not of its effi- 
ciency. The sum of the inlet discharge will almost never agree with 
that of the outlet, since much air enters and leaves a room through 
other openings. Knowing the capacity of the room, we learn from the 
amount of inlet air the number of times the air of the room has been 
replaced. 
The full measure of ventilation and its efficiency can be very closely 
determined by methods originated by Pettenkofer. One of these con- 
sists in first creating an unusual degree of impurity either through 
respiration of a large number of persons, as, for instance, by children 
occupying a schoolroom, or by burning a? number of candles, or by 
other chemical processes, then, after taking a specimen of the air for 
analysis, keeping the room closed for an hour or two. At the expira- 
tion of the allotted time, a second sample is taken, and from the results 
of the two analyses, the rate of ventilation is ascertained by means of 
Seidel's formula, which is as follows : 
(7 = 2.303 m. log 
. Pi - a 
in which C = amount of air which has entered. 
2,303 is a constant. 
m = capacity of the room. 
p{ = amount of CO2 originally present. 
Pi - amount of CO2 at the end of the experiment. 
a - amount of CO2 in the external air. 
Example.-The air of a schoolroom of 500 cubic meters capacity, 
accommodating 34 children, contains at the end of the session 18.5 cc. 
CO2 in 10,000, or 0.00185 :1. At the end of an hour, a second analy- 
sis shows 8.5 cc. CO2 in 10,000 or 0.00085 :1. The outer air contains 
3.5 cc. CO2 in 10,000 or 0.00035 :1. 
Then 
c-2 303 V 500 V w 
0 - 2.303 X 500 x log o.OOo85-0.00035 
0.0015 
= 1151.5 Xlog^5 
= 1151.5 X log 3 
= 1151.5 X 0.4771213 
= 549.4 cubic meters of air in an hour. 
Thus, the air of the room is renewed but once and a tenth per hour, 
and the result shows that the per capita ventilation is about a fifth of 
what it should be. 
The other method consists in imparting to the air of a room a contin- 
uous supply of carbonic acid by means of burning candles, and making 
periodical analyses of the contained air. He employs candles of pure 424 
HABITATIONS, SCHOOLS, ETC. 
stearin, one gram of which yields 1.404 liters of the gas. A prelimi- 
nary analysis of the air is made and then a number of the candles, the 
combined weight of which is noted, are placed about the room and 
lighted. At stated intervals, the room is entered, and after the air 
has been well mixed by vigorous fanning, samples are taken for analy- 
sis. At the end of the experiment, the candles are put out and re- 
weighed, and from their loss in weight and the results of the analyses, 
the amount of ventilation is calculated by means of a most complicated 
formula devised by Hagenbach. 
Other methods have been proposed by Recknagel, Petri, and others, 
but they present no advantages and are, in general, so complicated 
that in the hands of other than expert physicists they are quite useless. 
Section 3. LIGHTING. 
Natural Lighting.-In natural lighting, the light enters the room 
directly or by reflection through the windows, and is then reflected to 
different parts of the interior, which receive different amounts of light 
according to circumstances. Thus, white and light colored walls, floors, 
and articles of furniture reflect and disperse the light, while dark walls, 
draperies and other objects absorb it. Large rooms having but small 
window area and all rooms, however generously provided therewith, 
Fig. 45. 
Room u/ith ordinary 
window. 
Room with ordindry 
window. 
Room with window of 
prismatic ydass. 
Action of prismatic glass in projecting light. 
looking on narrow alleys or streets in which the opposite buildings are 
so high that the sky-angle is small, cannot be uniformly illuminated by 
diffused daylight without some assistance. 
The means employed are exceedingly simple, and the discovery of 
their utility for this purpose was due to chance. In order to obstruct LIGHTING. 
425 
the view into factory workrooms from the outside, and to lessen the 
temptation to operatives to waste time in looking out, ribbed glass 
was introduced instead of ordinary glass for use in windows, and it 
was noticed that not only was the desired end attained, but that the 
light from the windows was projected farther into the rooms, and to such 
an extent in some instances, that artificial lights, required before in 
the brightest part of the day, could be dispensed with. Attention be- 
ing thus drawn to the great advantage and saving of expense, a num- 
ber of different kinds of glass with uneven surface have been placed 
upon the market and have come into very extensive use. The best of 
these, which is the most expensive, is known as " prismatic glass " from 
the fact that one surface consists of a series of prisms running horizon- 
tally. The entering light, instead of falling directly to the floor, is 
tipped up and projected toward the opposite sides of the room, as shown 
in Fig. 45. Vertical section of a sheet of the 
glass is shown at A in Fig. 46. 
By varying the angle of the prisms, the con- 
ditions obtaining in any situation can be met and 
light can be projected in any desired direction. 
Naturally, the prisms cannot be used indiscrim- 
inately, for a series adapted to light the entire 
lower part of a room with a certain sky angle 
might, when applied to another, throw the light 
toward the ceiling instead of to the parts where 
it is required. Therefore, to meet all conditions, 
the glass is made with a great range of angles, 
and the particular kind needed in any situation 
is determined by measurement. 
Where the sky angle is very small, canopies, 
hung at the proper angle above the windows, serve 
to throw inward a flood of light. The disadvan- 
tage of prismatic glass is its great cost. 
Ribbed glass is very efficient and much less 
expensive. This is made with 4, 5, 7, 11, and 
21 ribs to the inch and of different thickness and weight, since the fewer 
the ribs, the deeper they must be cut, and the thicker, therefore, the glass. 
Vertical section of a sheet of ribbed glass is shown at B in Fig. 46. 
Artificial Lighting.-The methods of artificial illumination com- 
prise electric lighting and those dependent upon the combustion of oils, 
gases, and hard fats. The oils employed are chiefly of mineral origin, 
but animal and vegetable oils are used to some extent, though not very 
much in this country. Hard fats in the form of candles are used very 
extensively in all countries on account of safety, cheapness, and general 
availability. The gases in common use are derived from coal and 
hydrocarbons. Of late, acetylene gas, obtained by the action of mois- 
ture on calcium carbide, has come into more or less extensive use. 
Luminosity of Flame.-In the combustion of a candle, it will be ob- 
served that the flame consists of four parts, the lowest of which, blue 
Fig. 46. 
Vertical section of pris- 
matic and ribbed glass. 426 
HABITATIONS, SCHOOLS, ETC. 
in color, gives out practically no light. The middle portion, dark in 
color, consists of hydrocarbon gas generated from the substance of the 
candle. Next is the luminous yellow portion ; and outside of this, is 
an almost invisible envelope. 
The atmospheric oxygen, moving toward the inner portion of the 
flame, unites with the carbon escaping outwards from the luminous por- 
tion and forms carbon dioxide; more oxygen passes onward and in- 
ward, meets the hot gas from the central part of the flame, and, being 
insufficient in amount to unite with both the hydrogen and carbon 
constituents, combines by reason of greater affinity with the hydrogen, 
leaving the carbon free, but so much raised in temperature that it be- 
comes incandescent, thus furnishing light during the extremely slight 
interval elapsing in its passage to the outermost portion of the flame, 
where, as has been already stated, it is oxidized to carbon dioxide. The 
same process goes on in the combustion of illuminating gas and oils, 
the luminosity of the flame being due to the incandescent particles of 
carbon in the breaking up of the hydrocarbon compounds into their ele- 
ments. A mixture of gas and air, such as occurs in the use of the Bun- 
sen burner, gives off little or no light, since each particle of carbon is 
provided with enough oxygen to convert it at once into carbon dioxide, 
and so incandescence cannot occur. If the air supply to the interior 
of the flame is shut off, luminosity is at once produced. 
If the area of the outer surface of an ordinary gas flame is so small 
that atmospheric oxygen cannot be taken up sufficiently fast to unite 
with all the carbon arriving at the outer part of the flame, the un- 
oxidized carbon becomes cooled below the ignition point and is given 
off in the form of smoke. Defects in the burner or excessive rich- 
ness in hydrocarbons may cause smoking during combustion, the sup- 
ply of air being too small to consume the carbon. The introduction 
of a cool surface into the luminous portion of the flame causes deposi- 
tion of soot thereon. 
If the area of the flame is made too large by turning on a large 
volume of gas under high pressure, the gas is projected so far that it 
comes in contact with sufficient atmospheric oxygen to burn a large 
part of its carbon and hydrogen simultaneously, and, as a result, the 
excess of gas is consumed without luminosity and wasted. 
Gas Burners.-The best of the burners in commonest use is known 
as the bat's-wing, from the shape of the flame. The tip is hemispher- 
ical and is provided with a single straight slit, through which the gas 
emerges in a thin flat sheet. Another, known as the fish-tail, contains 
in its tip two small orifices, through which the gas issues and then 
spreads out into a flat flame shaped as the name indicates. This burner 
is inferior to the bat's-wing in that its flame is less luminous with the 
same amount of gas, and the orifices are much more easily fouled and 
occluded. 
The Argand burner consists of a hollow ring, provided with a circle 
of small holes and attached by hollow arms, through which the gas is 
supplied, to a socket screwed to the pipe. The gas, issuing from the VARIETIES OF GAS. 
427 
holes, forms a circular flame, which is provided with an abundant air 
supply which passes upward through the perforations of the holder for 
the chimney, which is an essential part of the apparatus, and through 
the central hole of the burner as well. The chimney must be of proper 
diameter and height to ensure an air supply adequate for complete 
combustion of the gas. 
The Welsbach burner, which may be taken as a good representative 
of the class of incandescent lamps, consists of a modified Bunsen burner, 
over which is suspended a mantle composed of incombustible material 
which becomes intensely luminous when heated in the Bunsen flame, 
and thus transforms non-luminous heat energy into luminous light 
radiation. The mantles are made in different ways of different mate- 
rials and are exceedingly fragile. One of the commonest and best sorts 
is made by saturating a delicate network of cotton in a strong solution 
of several earthy oxides (cerium, zirconium, lanthanum, thorium), 
then baking and finally heating it until the cotton fibers are destroyed, 
thus leaving a gauze composed of the oxides alone. No single earth is 
efficient by itself. The flame and mantle are protected by a cylindrical 
glass chimney, which serves also to steady the flame, and the whole is 
commonly enclosed in some form of globe or shade to modify the in- 
tensity of the light. By providing a suitable burner to ensure the 
requisite degree of heat, any kind of combustible gas or oil vapor can 
be used. Lamps are made on the same principle for kerosene burning. 
The incandescent mantle not only gives out much more light than 
an ordinary or Argand flame, but does so at a much smaller expenditure 
of gas. 
Objection is often made that the Welsbach light is very trying to 
the eyes. This is true; but the same objection can be urged against 
the sun and other intensely bright objects when looked at directly. 
The lights should be so placed that they will illuminate those parts 
where light is needed, and if they are likely to try the eyes, they should 
be enclosed in globes designed to soften the glare and diffuse the rays 
uniformly. 
Varieties of Gas. 
Coal-gas is made by heating bituminous coal in fire-clay retorts, in 
which process the compounds of hydrogen and carbon are transformed 
into gaseous and other products. The gas is conducted by pipes to 
condensers and purifiers where it is freed from ammonia, sulphuretted 
hydrogen, tarry matters, and other impurities, and is then carried to 
storage tanks. The purified product consists of about 50 parts of 
hydrogen, 35 of marsh gas, 6 or 7 of carbon monoxide, and the bal- 
ance of ethylene and other hydrocarbons, and nitrogen. 
Water-gas is made from coke or anthracite coal, steam, and petroleum. 
The coke or coal is placed in an air-tight cylinder lined with fire clay, 
and then is ignited and blown up to a white heat by means of a blast 
of air. The air is then shut off and a current of steam is blown 
through. This is decomposed by the great heat into hydrogen and 428 
HABITATIONS, SCHOOLS, ETC. 
oxygen, the former passing on uncombined, and the latter uniting with 
carbon to form carbon monoxide. The resulting mixture is then car- 
ried to a gas holder, from which it is conducted to the u carburetter," 
where it is enriched in order that, when burned, it shall produce a 
luminous flame. This is a chamber of fire-brick kept at red heat. 
Here, vaporized petroleum is injected with the hot gas until the re- 
quisite percentage of carbon in the mixture is attained. The final 
product has much the same odor as coal-gas, but is of very different 
composition and much more poisonous in character, containing about 
30 per cent, of carbon monoxide, 35 of hydrogen, 20 of marsh-gas and 
the balance of ethylene and nitrogen. 
Water-gas can be made also by pumping crude petroleum in a small 
stream into a red-hot gas retort, where it is at once converted into vapor, 
which, with a current of superheated steam, is then driven through a 
long coil of pipe heated to a high temperature. The chemical reaction 
is the same, the carbon uniting with the oxygen of the steam to form 
carbon monoxide, leaving the hydrogen free. 
The poisonous properties of both coal-gas and water-gas are due 
solely to the contained carbon monoxide which, as shown originally by 
Claude Bernard, makes a definite compound with the oxygen carrier 
of the blood, the haemoglobin, which then becomes incapable of per- 
forming its function. This being the case, the vastly greater danger 
attending the use of water-gas is self evident. 
As has been said, the odor of the two kinds is practically the same, 
but in order to have the same value as a warning of danger from leaks, 
that of water-gas should be much more pronounced, since so much less 
of the gas is required to bring the air into a poisonous condition. 
Usually about 0.4 per cent, of carbon monoxide in the air is required 
to produce fatal results, but less may be fatal with long exposure. In 
recovery from poisoning, the carbon monoxide is not oxidized in the 
body, but is driven out of its combination by the oxygen of the inspired 
air; but though after a few hours the blood may be nearly freed from 
the poison, the damage already done to the brain and other tissues 
through the temporary partial deprivation of oxygen may be severe 
and lasting. Recovery is commonly accompanied by severe headache, 
persisting for a long time, often with nausea and vomiting. 
The increased danger of gas poisoning when coal-gas is supplanted 
by water-gas with its high carbon monoxide content is well shown by 
the statistics bearing on the subject at Boston, Massachusetts. In 
1888, when but 1 per cent, of the gas sold was water-gas, there were 
no deaths, suicidal or accidental, from gas poisoning. In the follow- 
ing year, there was but one. In 1890, the percentage of water-gas rose 
to 8, and there were 6 deaths, four accidental and two suicidal. In 
1892, as a result of permissive legislation, 52 per cent, of the gas sold 
was water-gas, and the deaths rose to 15. In 1897, the percentage 
rose to 93 and the deaths to 47, 32 of which were accidental and 15 
suicidal. In the five years ending September 1, 1899, 169 deaths had 
occurred. VARIETIES OF GAS. 
429 
On account of the danger, a commission, appointed in England in 
1899, reported adversely on all illuminating gas containing over 20 
per cent, of carbon monoxide, which proportion corresponds approxi- 
mately to a mixture of equal volumes of coal-gas and water-gas. 
Acetylene gas, C.,H2, is an unstable compound of carbon and hydro- 
gen. It has a strong disagreeable odor. Mixed with air in the propor- 
tion of 1 to 19, it is violently explosive. It is poisonous, but not to 
the same extent as ordinary coal-gas ; an animal exposed to an atmos- 
phere containing it becomes unconscious after a time with no manifes- 
tations of nervous or respiratory excitement, and if removed at once 
recovers in a very short time. Prolonged exposure is fatal. Blood 
will absorb about 0.8 per cent, of its volume of acetylene, but the 
solution gives no characteristic spectroscopic appearance. If any com- 
pound is formed with haemoglobin, it must be very unstable. If a 
high percentage of oxygen be present, animals can survive its action 
many hours. 
It is made from calcium carbide, a reddish brown or gray material 
prepared by subjecting a mixture of lime and coke to very intense 
heat. When this substance is wet with water, a double decomposi- 
tion occurs, the calcium uniting with the oxygen of the water to 
form quicklime, and the carbon with the hydrogen to form acetylene. 
Between four and five cubic feet of the gas are yielded by a pound of 
the ordinary commercial carbide. 
Burned in ordinary gas burners, the flame cannot secure a sufficient 
supply of oxygen for the complete combustion of the carbon, and in 
consequence it smokes and fails to exert its full power of illumination. 
By using a tip with an exceedingly thin slit, and forcing the gas 
through under heavy pressure, the flame is greatly enlarged and is of 
very great brilliancy. Its illuminating power is about 15 times 
greater than that of ordinary gas. 
It can be liquefied at a temperature of 64° F. by a pressure of 1,200 
pounds to the square inch, and can be stored in cylinders of steel. 
Apparatus for its use should not be made of copper or silver, since 
these metals are attacked by it and the resulting compounds are very 
explosive. 
In some apparatuses in use, the water is dropped on to the carbide 
by an automatic arrangement so that the yield of gas is regulated, but 
the gas continues to be evolved after the water supply is shut off, since 
the moistened carbide cannot be prevented from undergoing decompo- 
sition. In others, the carbide is introduced into 10 times its volume 
of water in a vessel connected with a gas holder of sufficient capacity. 
Whether acetylene is likely to have a great field in the future, can- 
not in the present state of development be predicted, but many changes 
and improvements are necessary before it can be looked upon as hav- 
ing any very great practical value. 
Gasolene gas is a mixture of gasolene vapor and air, the function of 
the latter being to dilute the former until the proportion of carbon in 
the mixture is equivalent to that in common gas. Gasolene is a mix- 430 
HABITATIONS, SCHOOLS, ETC. 
tore of light hydrocarbons, a product of distillation of crude petro- 
leum. Its specific gravity ranges from 0.629 to 0.667. It volati- 
lizes slowly at low temperatures and rapidly at 70° F. and above. It 
is exceedingly inflammable. 
Gasolene gas is generated and forced through supply pipes to the 
burners by special forms of apparatus which require but little attention. 
It is well suited to single houses and small groups of houses where no 
public supply exists. 
Impurities Given off in Lighting.-In the combustion of illumi- 
nants of all kinds, considerable amounts of decomposition products are 
given off to the air, and their removal by means of efficient ventilation 
is important. These products are least in amount and importance in 
lighting with candles and oil lamps, being chiefly carbon dioxide and 
watery vapor. The impurities given off in the combustion of gases 
include sulphur dioxide, very variable in amount according to the ex- 
tent of purification ; carbon monoxide, also variable according to the 
completeness of combustion ; carbon dioxide, about half a cubic foot 
for each cubic foot burned ; ammonium compounds, and aqueous vapor. 
Gas Pipes.-Street mains are commonly made of cast-iron pipes of 
rather light weight, which vary much in texture and density and are 
not infrequently perforated with blow-holes of varying diameter or 
otherwise defective. On account of the dangers of extensive leakage 
and of the financial loss due to waste of gas and the cost of making 
repairs, all pipes should be thoroughly tested before being laid. Pipes 
which show no leaks when new may soon be corroded in the soil at 
points where bubbles occur in the walls with but a thin layer of metal 
on either side. Wrought-iron pipes are corroded more quickly in the 
soil, but are more uniform in density and texture than cast-iron and 
require fewer joints in a given distance. Both kinds should be pro- 
tected by a generous coating of asphaltum or other suitable material. 
House pipes are most commonly of wrought iron, though sometimes 
other softer materials are employed. The latter are more expensive 
and possess the additional disadvantage of being easily punctured by 
nails and gnawed by rats and mice. The entire system of distribut- 
ing pipes should be most carefully joined in order that no leaks shall 
occur. When they do occur, the search for their location must be con- 
ducted with all possible precautions against the risk of explosions, 
since mixture of gas and air in the proportion of about 8 per cent, of 
the former are violently explosive if brought in contact with a flame. 
The gas should be shut off at the meter, and the apartments where 
the smell is perceived should be thoroughly aired. The examination 
should then be begun at the meter and its connections, and if defects 
are there found, the meter, if at fault, should be removed, or the con- 
nections put in proper condition with new washers. The fixtures 
should next receive attention, every joint and cock being tested, the gas 
being turned on again at the meter. Smearing the joints with some 
viscid material, such as strong soapsuds, will show small leaks by for- 
mation of bubbles. The examination of the joints of the distributing PL UM BING. 
431 
pipes is a matter of considerable difficulty and may require much dis- 
turbance of structural parts. 
Fixtures should be so located as to avoid hot-air currents from reg- 
isters in the floor and walls, on account of the great annoyance caused 
by flickering of the flame. Flickering is caused also by the presence 
of condensed moisture in sags in the pipes and bends in the fixtures; 
this causes the gas to issue in a series of bubbles with consequent un- 
steadiness of the flame. The remedy consists in interposing drip cups 
and draining off the water. 
The proper arrangement of fixtures is frequently a difficult problem, 
particularly in large rooms. In general, it may be said that they 
should be well distributed rather than clustered in central chandeliers. 
Fairly uniform diffusion can be secured by the use of globes of pris- 
matic glass, which act in the same way as the ribbed and prismatic 
window glass described above. 
Electric Lighting.-Incandescent electric lighting possesses certain 
notable advantages over aM other systems of artificial illumination. It 
requires no oxygen and produces no decomposition compounds, and 
hence in no way alters the composition of the air. It imparts but little 
heat to the surrounding air and hence has but a limited influence in 
causing convection currents and raising room temperature. 
Section 4. PLUMBING. 
Whether we view the subject from the standpoint of possible danger 
of infection through inhalation of sewer air or from that of aesthetics, 
we must recognize the great importance of the removal of all sewer 
wastes from the habitation through a system of plumbing that is so 
perfect that it shall leak neither liquid nor solid matters nor foul air 
and smells. For the attainment of the best results, all large commu- 
nities adopt plumbing ordinances designed to prevent faulty construc- 
tion and the admission of the dreaded " sewer gas/' which, to the lay 
mind, and very generally to the professional mind as well, is a most 
potent cause of disease. 
While the weight of evidence is against the acceptance of the doctrine 
of the transmission of disease through this agency, it must be conceded 
that foul odors, besides being disagreeable, exert on the sensitive indi- 
vidual a decidedly injurious action through the imagination and, more 
particularly, through their effects on the appetite and digestion. Most 
of the foul smells coming from plumbing fixtures are not from the 
sewer at all, and hence may not properly be called sewer gas or sewer 
air; they are due to decomposing organic matters within the pipes or 
traps or in some other part of the fixture which, with ordinary use, 
does not become thoroughly cleansed. Thus, it is often found that the 
odor from a wash-basin is due to decomposing soapy matters and other 
deposits in the horn leading from the overflow holes, but it is difficult 
to convince the timid that such is the fact, except by ocular and other 
demonstration. 432 
HABITATIONS, SCHOOLS, ETC. 
The most perfect system of plumbing needs careful supervision, for 
no pipe or other part subjected to frequent contact with filthy matters 
can be kept permanently clean unassisted, and any such surface not 
cut off from contact with the free air of the room must inevitably, un- 
der certain conditions, give rise to a certain amount of nuisance. The 
reduction of these possibilities for nuisance to the lowest limits is one 
of the main objects of the many ingenious plumbing appliances of one 
kind and another that are almost daily increasing in number and variety. 
Broadly speaking, plumbing may be divided into two classes ; good 
plumbing and bad plumbing. The former costs more in the begin- 
ning ; the latter, in the end ; the former is installed by the capable and 
honest plumber; the latter, by the trickster who has given his calling 
such a bad name that he finds it more to his liking to hide behind the 
more pretentious title of " sanitary plumbing engineer," just as some 
barbers become " tonsorial artists." 
The better class of plumbers, in undertaking the installation of a 
system of plumbing, attempt to attain such a degree of perfection that 
repairs are only occasionally necessary ; the other class, either intention- 
ally or because of inability to do good work, produce a system requir- 
ing constant repairs and consequent expenditure. This class of work- 
men also are quick to take every advantage of loosely drawn or am- 
biguous specifications, whereby the owner suffers eventually more than 
the original financial injustice. But the responsibility for poor plumb- 
ing is not by any means always to be placed upon the plumber, for an 
owner unwilling to pay the price of good work can hai'dly blame the 
plumber for unwillingness to provide labor and first class material at 
less than cost, and gets cheap material and cheap workmanship in re- 
turn for his inadequate appropriation. 
A good system of plumbing calls for sound materials, absolutely 
tight joints, thorough ventilation, and a plentiful water supply to en- 
sure thorough flushing without wastefulness. It should be so planned 
that the various fixtures ou each floor shall be in relatively the same 
locations, thus avoiding unnecessary and expensive extensions of waste 
and supply pipes. The wastes should be easily accessible and are best 
run in full view so that any leakage can be detected at once. When 
hidden from view, leaks may exist undetected until much damage has 
resulted. Open plumbing, furthermore, ensures good workmanship 
and makes repairs simpler and much less expensive. The pipes need 
not be a disfigurement to a room, for they may be neatly painted or 
bronzed, and will then have no worse appearance than those used in 
steam heating. If they must be placed in recesses or within walls, 
they may be concealed by boards or panels fastened by screws and 
easily removable. 
The important fixtures, such as bathtubs and water-closets, should be 
placed where ventilation can be secured and where dependence upon 
artificial light is not altogether necessary. The ideal place is in an 
outer room with a window through which the sun's rays and fresh out- 
door air may enter. THE SOIL PIPE AND MAIN DRAIN. 
433 
The Soil Pipe and Main Drain.-The soil pipe receives at various 
points, through the several waste pipes, the contents of wash-bowls, 
sinks, bathtubs, urinals, water-closets and other fixtures, and conducts 
them to the drain, by which they are carried on to the sewer or cess- 
pool as the case may be. In this country, the material almost univer- 
sally used for soil pipe is cast iron, but in England, lead is preferred. 
The advantages of iron over lead are many; it is lighter, stiffer, 
stronger, cheaper, and more durable, and is not subject to accidental 
perforation by driven nails and gnawing rats. Lead pipe of large 
diameter sags by its own weight, and it is difficult to secure it strongly 
wherever its weight is borne by the fastenings. It is very easily 
corroded, dented, flattened, and perforated. 
Cast-iron soil pipe is made in two grades ; light, or " standard," and 
"extra heavy." Only the latter should be employed, the former being 
much too thin and flimsy. The walls of the extra heavy grade should 
not be less than an eighth of an inch in thickness. The pipe is made 
in lengths of 5 feet, exclusive of the socket, or hub, which is an enlarge- 
ment of one end for the reception of the spigot end of the next length, 
so that no irregularities shall be caused in the calibre of the pipe where 
joints occur, but, on the contrary, that the inner surface shall be flush 
throughout. Each length should be of uniform wall thickness 
throughout and free from flaws, sand holes, and other imperfections, 
and should be subjected to strength tests at the place of manufacture. 
The inner surface should be perfectly smooth. 
In joining the lengths together, the spigot end of one is inserted as 
straight as possible into the hub of the next, and a gasket of oakum is 
inserted into the intervening space by means of a caulking tool, and 
rammed hard so as to fill about half the depth of the hub. The object 
of the gasket is to prevent the entrance of any of the molten lead used 
in the next process to the bore of the pipe. 
The next step is the filling of the rest of the space with molten lead 
from a ladle. Since this metal shrinks on cooling and since moisture 
and dirt prevent its adherence to the iron, it is necessary next to ex- 
pand it and drive it down by mechanical means. This process requires 
much care and involves much risk of fracture, since the blows of the 
caulking tools must be quite heavy; in fact, much heavier than the 
lighter grade of pipe can withstand. Against this form of pipe and 
its jointing, certain objections are urged, not the least of which is the 
opportunity given for botch-work and fraud. Instances of filling the 
space with mortar, sand, putty and other material have been not un- 
common. Some unscrupulous plumbers gloss over the fraud with a 
thin layer of lead; some make the joint properly and neglect to caulk 
it; some make as perfect a joint as possible in places where ocular in- 
spection is easy and probable, and omit to caulk or even to insert the 
oakum where the joints are hidden, but without forgetting to make the 
usual charge. In a large dwelling very expensively plumbed, the 
author once found no less than fourteen absolutely uncaulked and open 
joints in the several soil pipes. 434 
HABITATIONS, SCHOOLS, ETC. 
Another objection to this form of joint is the possibility of its be- 
coming loose through alternate expansion and contraction due to changes 
in temperature. The expansion is unequal, especially when due to hot 
water in the pipe, and the spigot expands more than its surrounding 
socket and compresses the interposed lead, which, when equilibrium 
becomes reestablished, does not resume its original shape, but remains 
in its new form. In this way, it is possible, but not very probable, that 
a minute space may be created all about the spigot, and that through 
this space, leakage of liquid, but more especially of air, may occur. In 
an upright pipe, leakage of liquid is most unlikely to occur, since the 
hub end of each joint is uppermost. 
Still another objection is the great difficulty encountered in unjoint- 
ing when, for any reason, it is necessary to remove a length of pipe 
Fig. 48. 
Fig. 47. 
Fig. 49. 
Improper bends in soil pipe. 
Proper bends in soil pipe. 
Y-braneh to soil pipe. 
in making repairs and alterations. The usual and easiest course to 
pursue in such a case is to break the pipe and remove it in pieces. 
To meet the several objections to this form of pipe, the Sanitas 
flanged pipe was devised by Mr. J. Pickering Putnam of Boston. 
This makes a joint which is described as an adjustable flanged joint 
with lead washers or gaskets for packing. The gaskets, which are 
star-shaped in cross-section, are squeezed between the flanges of the two 
adjoining pipes and crushed to half their original thickness by screw- 
ing up the bolts set in square recesses in the flange ears. These are 
screwed simultaneously, so that the pressure on either side is equalized 
and the gasket is uniformly compressed. The gasket for a 4-inch pipe 
weighs a half pound. For this joint are claimed cheapness and security. 
The time required to make it is reckoned in seconds as against minutes, 
the amount of lead consumed is much less, and the unjointing is 
simple and involves no breakage. THE SOIL PIPE AND MAIN DRAIN. 
435 
The diameter of a soil pipe should ordinarily not exceed 4 inches, 
but in very large buildings, in which are numerous water-closets and 
other fixtures, 5-inch pipe is sometimes used. 
Soil pipes should run as nearly vertically and with as few deviations 
from a straight line as practicable. When these are necessary, right- 
angled bends, such as shown in Fig. 47, must be avoided, and instead 
thereof, obtuse-angled elbows, as in Fig. 48, should be employed. 
Where waste pipes and branches connect, the junctions should be made 
with Y-branches and not at right angles. (See Fig. 49.) These 
junctions are differently made when a lead pipe is to be connected with 
an iron one. The lead pipe must first be " wiped " on to a brass ferrule 
by means of solder, and the ferrule is then caulked into the hub. 
With the flanged Sanitas pipe, the connection is more easily and cheaply 
obtained ; here the lead pipe is flanged out and bolted to the iron by 
means of cast-iron rings with ears and bolt- 
holes corresponding to those on the pipe. 
Each soil pipe should be extended in full 
size through the roof for about two feet, and 
its outlet should not be obstructed by a cap 
or cowl as is commonly done. The cap 
serves no useful purpose, and the passage 
for air is so narrow that in winter, when 
the warm moist air ascends, a coating of 
frost is formed all over the inner surface of 
the exposed pipe, and this may grow in 
thickness so as to occlude the outlet com- 
pletely, as is shown at A in Fig. 50. In 
all cases, one must make provision for the 
expansion and contraction of the column of 
metal, for while the movement either way 
is slight, its force is very great; therefore, 
the fastenings must not be too rigid, but 
must allow a little play. 
The soil pipe must be very firmly sup- 
ported at the bottom, and its junction with 
the main drain should be made with a bend 
of as large a radius as possible. The best support is either a brick pier'or 
a wooden post or other firm and unyielding structure. The connection 
must under no circumstances be at a right angle, but with an elbow 
bend supported on a foot as in Fig. 51. If the pipe must be carried 
along a cellar wall, it should be supported either by a shelf or by 
wrought-iron pipe-hooks. 
From the point where the soil pipe departs from the perpendicular 
and tends toward the sewer or cesspool, it is commonly known as the 
drain, whether other soil pipes enter it or not. The drain should con- 
sist of iron as far as a point well away from the foundation of the 
house and from all danger of fracture due to settling. Under no cir- 
cumstances should an earthenware drain pipe be employed within the 
Fig. 50. 
Occlusion of outlet of soil pipe by 
frost. 436 
HABITATIONS, SCHOOLS, ETC. 
house or beneath the foundation or through a soil in which a well of 
drinking water is situated. The main drain may be carried along the 
wall of the cellar in the manner above described, or it may be suspended 
by wrought-iron hangers from the joists of the floor of the first story, 
Fig. 51. 
Fig. 52. 
Elbow bend and support. 
Intercepting trap. (Running trap.) 
or, if there are water-closets or other fixtures in the cellar, it may run 
below the floor. In the latter case, it should be easily accessible. 
The drain should have all the fall that can be conveniently given, 
and this should be as nearly uniform as possible throughout its length. 
No part of it should run flat or sag. The greater the pitch, the more 
completely the pipe is scoured out by each passage of water. It should 
have a fall of at least a quarter of an inch to the foot or, preferably, 
more. 
Fig. 53. 
Objectionable arrangement of intercepting trap and ventilating pipe. 
Before the drain passes beneath the foundation wall or, if this is 
impossible, at a point outside in a manhole, an intercepting trap is 
placed, provided with clean-out holes covered with air-tight covers. 
This trap, known sometimes as the running trap and main trap, is of THE SOIL PIPE AND MAIN DRAIN. 
437 
the same diameter throughout as the drain itself. This kind of trap 
is manufactured in an immense variety of forms, one of the best of 
which is shown in Fig. 52. This has an inlet and an outlet for sew- 
age, an inlet for fresh air, and a clean-out and inspection hole on the 
outfall side. The sewage enters by the inlet at the left, which is 
slightly higher than the outfall at the right. The uppermost opening 
is for the fresh air inlet. The latter is for the purpose of insuring a 
complete circulation of fresh air throughout the entire length of the 
drain and soil pipe, and communicates with the external air by means 
of a pipe of the full diameter of the drain, running from the house side 
of the trap to some point outside. 
In Fig. 53 is shown an arrangement very commonly adopted, but 
open to serious objections. Here, the filth may be thrown up against 
Preferable arrangement of intercepting trap and ventilating pipe. 
the entrance of the fresh-air pipe F at A and form an accumulation. 
The floor of the drain and of the outlet 8 are at the same level, as is 
shown by the two sides of the water seal L, and there will be, there- 
fore, not enough head to force all light solids easily beneath the dip of 
the trap. 
A much better arrangement is that shown in Fig. 54. In this, the 
inlet of the fresh-air pipe F is situated at a point some distance away 
from and on the house side of the trap, where splashing and accumu- 
lation of filth cannot occur. At A, the entering sewage falls through 438 
HABITATIONS, SCHOOLS, ETC. 
a distance of about two inches at L, and can force any solid matter 
under the dip and onward through S. It will be noted by the direc- 
tion of the arrows in both figures that the normal direction of the air 
current is inward, but under some conditions of internal and external 
temperatures, as, for example, in summer, the direction is likely to be 
reversed. In winter, owing to the higher temperature of the house, 
the movement in the soil pipe is naturally upward and outward, and 
in the pipe F, is downward and inward. 
Waste Pipes.-The pipes connecting fixtures with the soil pipe are 
known as waste pipes. They are commonly made of lead, though cast 
Fig. 55. 
Sags in an improperly laid pipe. 
iron, wrought iron, and galvanized iron are also employed. The ad- 
vantage of using lead is that it is more easily run, especially in 
places where bends and angles are necessary, and requires, therefore, 
a smaller number of joints. TIiq disadvantages are the liability to 
perforation by nails carelessly driven and by gnawing rats, and the 
possibility of the formation of air-locks through sagging of a pipe 
improperly laid. These occur sometimes when a pipe is not prop- 
erlyjsupported or where high points and low points occur in a crooked 
run. This is shown in exaggerated form in Fig. 55. Here we see a 
Fig. 56. 
Flush fittings with screw couplings. 
series of low points, in which water will stand and where sediment may 
accumulate, and a corresponding number of high points containing air. 
These impede the flow of water onward, and if the pressure is low, a 
series of them in a single run may stop it altogether. 
Iron pipes possess whatever advantage attaches to rigidity, and 
while they are not so easily adapted to crooked runs and require more 
joints, it must be said that the latter are quickly and easily made 
when screw couplings are employed. Some joints are made by screw- TRAPS. 
439 
ing directly into hubs and some by means of ordinary couplings, the 
result in either case, as shown in Fig. 56, being perfectly flush 
fittings. 
Waste pipes need ordinarily be not larger than 1.5 inches in diameter 
nor heavier than three pounds to the foot. In those cases where the 
supply pipes deliver a heavy stream of water under large pressure, it 
may be necessary to use a larger size, in order to ensure the removal 
of all the water without danger of overflow. Too large pipes and too 
small pipes are equally bad. If too small, the overflow is retarded 
and they are easily choked; if too large for the fixture from which 
they lead, they cannot possibly be thoroughly flushed, but are soon 
coated with grease and other filth and eventually become completely 
occluded. Thus, a 2-inch waste pipe, attached to a fixture by a 1.25- 
inch joint, would be quite too large and out of place. 
Lead waste pipes can be joined to iron soil pipes in the manner 
already described, and to wrought iron by brass screw nipples wiped 
Fig. 57. 
Running trap. 
on to the lead with solder and screwed with red lead into the thread 
of the fitting. Lead should always be joined to lead by wiped solder 
joints and never by cup or " copper bit " joints, excepting when the 
operation of wiping is clearly impossible. 
Traps.-Each separate fixture connected with the soil pipe, that is 
to say, each water-closet, wash-bowl, bathtub, etc., must be provided 
with some form of trap situated as near it as possible. A good trap 
will wholly prevent the passage of all air or gas or odor from the 
waste pipe or soil pipe backward into the air of the house, while per- 
Fig. 58. 
Forcing of seal of running trap. 
mitting the free passage of liquids and suspended solids toward the 
sewer. It should be of such construction as will admit of ready in- 
spection and cleaning, and under ordinary circumstances should be 
self-cleansing. Improperly trapped or untrapped fixtures are as much 440 
HABITATIONS, SCHOOLS, ETC. 
to be avoided as leaks, the result in either case being the same so far 
as the passage of offensive odors is concerned. 
The simplest form of trap, called running trap, consists of a down- 
ward bend in a horizontal pipe, as shown in Fig. 57. When water is 
discharged through such a pipe, the depressed portion will be found to 
stand full of water when the discharge ceases, and this body of water 
will prevent the passage of air in either direction. But if sufficient 
pressure is exerted on either side to force the level of the water on that 
side down to the lowest point of the bend, air may be forced through, 
as is shown in Fig. 58. The water between the water level and the 
lowest point of the upper internal surface of the bend is known as the 
seal, and this should never be less than 1.5 inches in depth. In Fig. 
57, the seal is that which lies between the two dotted lines. 
This form of trap is one of a class called round-pipe traps, and to this 
class belong a number of forms, five of which are shown in Fig. 59. 
Fig. 59. 
Forms of round-pipe traps, 
These are the S-trap (A), the Half-S (B^, the Three-quarter-S (0), the 
Running, already described, (D), and the Double-S, or Hunchback, (E 
These several forms are in all cases of the same size throughout and, 
therefore, will pass anything which can gain entrance. With proper 
flushing, they are easily kept clean, but they are quick to lose their seal 
by a sudden flow of water through them or by disturbance of atmospheric 
pressure produced by the sudden discharge of water through pipes 
with which their own pipes are connected. The means for the pre- 
vention of this occurrence are considered below. 
Another class of simple traps includes all those known as Bottle or 441 
TRAPS. 
Pot traps. In one form of the bottle trap, the principle of which is 
shown in Fig. 60, the end of the inlet pipe dips several inches into the 
pool of water. In order to drive air backward through the inlet pipe 
A, it would be necessary to exert pressure sufficient to force the water 
within the chamber B upward through A until its 
level is brought down to the lower end of A. Under 
ordinary circumstances, such a pressure would be quite 
impossible. To drive air in the other direction through 
A into B is less difficult, but this will require a pres- 
sure sufficient to depress the water standing within 
A down to the outlet of the pipe. 
In Fig. 61 is shown a trap of this kind, in which 
there are two inlets ; the principal one, the pipe I, and 
the second, which connects with the overflow of the 
fixture, the pipe B. The arrows indicate the direc- 
tion of movement of the sewage through the pot. As 
the level rises, the excess runs off through the outlet 
0 and discharges downward. The upper portion of 
the pipe marked V connects with the ventilating pipe, 
in which free circulation of air is maintained. The 
object of this is explained below. This form of trap is 
made to lose its seal only with great difficulty, though a part of it may 
be lost by siphonage. The objection to this form of trap is the likeli- 
hood of the accumulation of filth, for unlike the round-pipe trap, they 
Fig. 60. 
Fig. 61. 
Fig. 62. 
Two forms of ventilated bottle traps. 
are not self-cleansing, since the whole contents are not set in motion 
each time the fixture is used. 
Another, simpler, form of pot trap is that shown in Fig. 62. Here 
the inlet tube I is not immersed in the liquid, but communicates directly 
with the lower part of the chamber ; the outlet 0 starts from the upper 
part of the chamber, and the communication with the ventilating pipe 442 
HABITATIONS, SCHOOLS, ETC. 
has its exit at the crown. It will be observed that in both these forms, 
the seal is quite deep. The undue accumulation of filth in these traps 
must be guarded against, and for this purpose clean-out holes, closed 
with metallic screw caps, are provided. A large accumulation of filth 
in one of these traps 
makes siphonage of the 
seal more easily brought 
about. This class of trap 
is used only under sinks, 
basins, baths and wash tubs; 
never under any circum- 
stances under water-closets. 
Among the traps de- 
pending upon mechanical 
devices to assist the water 
seal, the Ball trap may be 
taken as a type. In this 
form (shown in Fig. 63), 
the up-cast limb of the trap consists of a chamber considerably 
broader than the inlet branch, and contains a ball, the specific gravity 
of which is slightly greater than that of water. This, when the 
contents of the trap are at rest, rests on its seat and makes a gas- 
tight joint. When liquid is discharged into the trap, the ball B is 
thrown upward into the position indicated by the dotted line, and when 
Fig. 63. 
Ball trap. 
Fig. 64. 
Bell trap. 
the flow ceases, it drops back again into its original position. It can- 
not escape from the chamber, since there is not space enough for it to 
pass between the lip of the pot and the top of the cover. 
This form of trap cannot be siphoned out, because of the size of the 443 
GREASE TRAPS. 
pot, but with disuse, it may lose its seal by evaporation. In such an 
event, however, the ball retains its seal and closes the joint. The great 
objection to this trap is that, even though nothing which should be other- 
wise disposed of is thrown into the fixture, as, for instance, matches and 
other objects, the seat of the ball is likely to become the point of 
deposit for hair, bits of cotton, linen fiber, and sponge, and then a 
gas-tight joint cannot be made with the ball. As a matter of fact, 
indeed, all mechanical devices in traps are much inferior to the ordi- 
nary water seal. 
Another form of trap, much used in kitchen sinks, is known as the 
Bell trap. (See Fig. 64.) In this, the delivery pipe D projects for 
some distance upward into the reservoir; the inlet consists of a strainer 
S to which is attached the bell B, 
which dips into the pool of water 
in the reservoir and encloses the 
outlet of the pipe D. There is, 
it will be seen, no direct commu- 
nication between the air contained 
within the bell and that above. 
The waste reaches the reservoir 
through the holes in the strainer, 
and as the level of the liquid 
rises, it escapes through D. This 
form of trap is quite likely to be 
choked by deposits of small bits 
of food material and other sub- 
stances forced through the holes 
of the strainer with the aid of a 
sink brush. It is also easily 
siphoned, and, furthermore, being 
easily removed, it very commonly 
happens that the fixture is utilized by lazy servants for the disposal 
of waste matters which should be deposited elsewhere. 
Grease traps are devices for preventing the choking of drains by 
grease, which, discharged in the liquid state with hot water, solidifies 
when it comes in contact with the cold surface of the waste pipe and 
adheres thereto with great tenacity. The coating which it forms be- 
comes thicker and thicker through successive applications, and eventu- 
ally may occlude the pipe so completely that the trouble must be at- 
tacked from the outside, the remedy requiring sometimes the removal 
and incidental destruction of an entire length of pipe. Grease traps 
may be located beneath the sink or, preferably, in a place provided 
therefor outside the house. 
A common type of this device is shown in Fig. 65. The greasy 
water runs into the reservoir through the inlet I, and the liquid grease, 
being lighter than the water, rises to the surface and forms a scum, 
which, when cold, solidifies into a cake. The outlet 0 of the trap dips 
far beneath the surface and so discharges none of the accumulated 
Fig. 65. 
Grease trap. 444 
HABITATIONS, SCHOOLS, ETC. 
grease. Air is admitted through V and can circulate thence through 
the inlet pipe I, as indicated by the arrows. The accumulated grease 
must be removed periodically through the clean-out, which is closed 
by the cover C. A larger and more complicated apparatus is shown in 
Fig. 66. Here the chamber is enclosed in jacket A B, through which 
cold water is allowed to circulate. The dirty water enters through I 
and discharges from the upper branch 0, which is vented through V. 
The grease accumulates at G and is removed through the top, which is 
closed by the hinged cover C. 
There are many other forms of grease interceptors, but none is per- 
fect, for under the most favoring circumstancs, some grease will escape 
and may congeal on the surface of the waste pipe or drain. All 
Fig. 66. 
Jacketed grease trap. 
grease traps must be attended to at short intervals, else they may become 
almost completely filled with solid grease. 
Loss of Seal.-Traps may lose their seal in various ways : by 
siphonage, by evaporation, by back pressure, by leakage, by accumu- 
lation of sediment and by capillary attraction. The most important 
of these is siphonage, for the prevention of which, two methods are 
commonly employed. In one, the up-cast limb of the trap is widened 
so that it becomes a pot or reservoir. A large reservoir will resist 
siphonic action much more successfully than a small one; an 8-inch 
pot cannot be siphoned through a pot of ordinary size, a 4-inch pot 
resists only when its seal is unusually deep, and anything less than 4 
inches is inadequate. 
This form of trap, however, offers decided objection. In the first 
place, it is likely to accumulate much sediment, and in the second, it 
constitutes a miniature cesspool, the presence of which in a system of LOSS OF SEAL. 
445 
plumbing cannot be countenanced, since sewage matter should be dis- 
charged in as fresh a condition as possible and not in a state of putre- 
faction, which, if cesspools are employed, will inevitably be brought 
about. Moreover, this form of trap is very expensive and bulky. In 
the other method, the up-cast branch is connected with a ventilating pipe 
by a branch from its upper portion. Unless one or the other of these 
two methods is adopted, the contents of the trap, particularly in the 
case of a round-pipe trap, are likely to be siphoned over when its 
fixture is used or when a large volume of water is discharged from 
some other fixture into the soil pipe and in its descent causes a partial 
vacuum. In the former case, the trap is self-siphoned ; in the latter, the 
partial vacuum draws the water over and breaks the seal. 
If the trap communicates with a ventilating pipe, this disturbance of 
equilibrium cannot occur, since the descending mass of water causes a 
downward suction of air through the vent pipe to satisfy what would 
otherwise be a partial vacuum. In Fig. 67, the diagram on the right 
Fig. 67. 
shows the condition after siphonage has occurred; the greater part of 
the water has been drawn over until air can be sucked through, and 
that which remains has fallen back into place. The result is that a 
free communication exists between the fixture above and the soil pipe 
below. The diagram on the left shows the condition of the seal if the 
trap is connected with a ventilating pipe through F. 
In venting traps in this way, the position of the vent pipe is of con- 
siderable importance. Ordinarily, it is placed as shown in the figure. 
The objection to this procedure and the proper method are shown in 
Fig. 68. If the pipe enters in the middle of the bend, each discharge 
of sewage into the trap causes a projection of the liquid upward into 
the pipe F, and after a time an accumulation is likely to occur at A. If 
Effects of ventilation and non-ventilation of traps. 446 
HABITATIONS, SCHOOLS, ETC. 
the pipe is situated farther to the right, as in the drawing on the right, 
this accumulation is not likely to occur and the sewage and the air take 
the directions indicated by the arrows. The vent pipe is more easily 
joined to the trap, however, in the manner to which objection is made. 
The ventilating pipes from the different traps of a system of 
plumbing connect with a main ventilating pipe, which may be joined 
to the soil pipe, alongside of which it runs, at a point in its upper 
part, before its projection through the roof. It is important that the 
junction of each vent pipe with the main shall be at a point above the 
fixture, since in case of an obstruction in the soil pipe below, the 
water may back up through the trap and discharge through the vent 
pipe into the main vent, as shown in Fig. 69. Here, the soil pipe S' has 
Fig. 68. 
Improper and proper positions of vent pipes 
been obstructed at a point just below the entrance of the waste~pipe 
from the fixture, and water has accumulated throughout the entire 
length of waste pipe and is discharging into the main ventilating pipe 
at V. If the point V were higher than the upper margin of the 
bowl, this could not occur, since the bowl itself would fill and over- 
flow into the room and thus call attention to the obstruction. 
Non-siphoning Traps.-A number of traps known as non-siphoning 
have been devised to obviate the necessity of back-venting. Among 
these may be mentioned the " Sanitas," invented by Mr. J. Pickering 
Putnam, and the " Hydric." 
The Sanitas trap, shown in Fig. 70, is made proof against siphonic 
action by a deflecting partition within the chamber, which permits the 
passage of air above the water and throws back a volume of water 
sufficient to maintain a seal over three inches in depth, which resists 
evaporation for a long time and cannot be destroyed by capillary at- NON-SIPHONING TRAPS. 
447 
traction. \v hen attached to fixtures with large outlets and quick dis- 
charge, it is also self-cleansing, even when ashes and similar unusual 
constituents of sewage are thrown into it. In the figure, the several 
parts are shown separately; the main structure, the chamber, and the 
deflecting partition. 
The Hydric trap, shown in Fig. 71, contains no deflecting partition 
or other mechanical device, but depends upon the action of the upper 
surface of the body of the trap in deflecting and throwing back the 
water during the sucking of the air 
through the chamber and over the 
water. When the siphoning action 
is finished, a sufficient volume of 
water remains to form a permanent 
seal. 
Evaporation of the seal does not 
commonly occur except with long 
Fig. 69. 
Fig. 70. 
Improper junction of vent pipe with main vent. 
Sanitas trap (taken apart). 
disuse. It is favored by trap ventilation, since when a current of air 
comes in constant contact with a body of water, constant absorption 
is in process. In order to prevent loss by evaporation in case of long 
disuse, two processes are in vogue. One is to employ a trustworthy 
person to visit the premises weekly during the absence of the occu- 
pants and flush each fixture. The other and, on the whole, the more 
economical, is to pour into each fixture a sufficient amount of glycerin, 
which, being hygroscopic, will take water from rather than yield it to 448 
HABITATIONS, SCHOOLS, ETC. 
the atmosphere, or of oil, which will float on the surface of the water 
and prevent its absorption by the air. 
Back pressure is a force which is not much to be feared. In former 
times, when it was not customary to ventilate the soil pipe, back pres- 
sure was not uncommonly caused by winds and the action of tides, so 
that the air in the whole plumbing system was compressed and the seal 
forced backward. Sometimes, a trap situated near the bottom of a tall 
stack is forced by back pressure, brought about by the descent of a 
column of water pressing the contained air ahead of it. 
Leakage as a cause of loss of seal is too evident to require explana- 
tion. Accumulation of sediment may be so extensive as to replace the 
water in great part and thus render siphoning much easier. Capillary 
attraction is a not infrequent cause of loss of seal when accumulations 
of hair, threads, and other like substances occur in a non-scouring trap 
Fig. 71. 
Hydric trap. 
at the outlet and drain away little by little the fixture side of the seal 
into the outfall. 
It is hardly necessary to say that nothing should be thrown into 
traps excepting those matters which are recognized as constituents of 
normal sewage, that is to say, neither matches, nor rags, nor broken 
china, nor wads of newspaper, nor stiff writing paper not easily dis- 
integrated by the action of water. All such substances are likely not 
only to clog traps and spoil the seal, but to form obstructions in the 
soil pipe, particularly where bends occur. 
The extremists who cling to the sewer-air theory of transmission of 
disease are not always satisfied with ordinary trapping, feeling sure 
that the water in one branch of the trap will absorb disease germs 
from the sewer air and discharge them on the fixture side. To avoid 
this, a system of double trapping has been advocated, with which assur- 
ance is made doubly sure. With this arrangement, we have two traps 
in immediate succession, so that the waste from the first must pass 
through the second; thus we have two seals, and any poison absorbed 
from the further one and disengaged backwards will then meet with 
a second obstruction. 449 
WATER-CLOSETS. 
Besides the manifest absurdity of such extreme precaution, there is a 
decided objection to this arrangement, since the solid matters are likely 
to lodge in the second trap and cause it to be obstructed. While the 
head of water may be sufficient to drive the waste through one trap, 
it is by no means certain that it will be strong enough to drive it 
through two, and, as a matter of fact, it usually is not sufficient. 
Moreover, between the two traps an air lock is likely to form, and 
that in itself is a decided objection, as has been already explained. 
Water-closets.-By reason of the fact that their general employ- 
ment is a matter of comparatively recent times, it is very commonly 
believed that water-closets are 
the invention of the last half 
century. They date back, 
however, many centuries, for 
in a somewhat simpler form 
they were in use in ancient 
Rome and Pompeii, and prob- 
ably even earlier in Asia and 
Africa. These primitive forms, 
however, were devoid of the 
mechanical appliances, flushing 
tanks, etc., of the closets of the 
present day. It is said that the 
prototype of the present closet 
was in use in France and Spain 
before the sixteenth century, 
but so far as is known, no dia- 
grams of their construction are 
extant. In England, the first 
water-closet with a flushing 
apparatus was constructed un- 
der the direction of Sir John 
Harington at his country seat 
at Kelston, near Bath, and de- 
scribed by him in a satirical, 
semi - political work, " An 
Anatomy of the Metamorphosed Ajax," printed in 1596, from which 
work Figs. 72 and 73 are taken. Fig. 72 shows the details of the 
apparatus described by him as follows : 
" Here are the parts set down with a rate of the prices, that a 
builder may guess what he hath to pay. 
Fig. 72. 
Reduced facsimile of the oldest known (1596) draw- 
ing showing details of a water-closet. 
' 'A the cistern ; stone or brick. Price 
s 
6 
d 
8 
b, d, e the pipe that comes from the cistern, with a stopple to 
the washer 
3 
6 
c a waste pipe - 
1 
0 
f, g the stem of the great stopple, with a key to it 
1 
6 
h the form of the upper brim of the vessel or stool-pot 
m the stool-pot, of stone 
8 
0 450 
s d 
n the great brass sluice, to which is three inches current to send 
it down a gallop into the Jax 10 0 
i the seat, with a peak devant for elbow-room. The whole 
charge thirty shillings and eight pence : yet a mason of my 
masters was oflered thirty pounds for the like. Memorandum. 
The scale is about half an inch to a foot." 
HABITATIONS, SCHOOLS, ETC. 
Fig. 73 shows the apparatus set up and during flushing. " Here is 
the same all put together; that the workman may see if it be well. 
A the cistern. O'the little washer, c the waste pipe. D the seat 
board, e the pipe that comes from the cistern. / the screw, g the 
scallop shell, to cover it when it is shut down. II the stool pot. i the 
stopple, k the current. I the sluice, m, N the vault into which it 
falls : always remember that ( ) at noon and at night empty 
it, and leave it half a foot deep 
in fair water. And this being 
well done, and orderly kept, your 
worst privy may be as sweet as 
your best chamber." 
We have evidence that even 
among peoples not classed among 
the highly civilized, the use of 
water-closets is by no means of 
recent date. Thus, Ogilby in his 
elaborate work on Africa, pub- 
lished in 1670, describing the city 
of Fez, says, on page 187 : " The 
River Fez which Paulus Jovius 
calls Rhasalme, passes through the 
City in two Branches; one runs 
Southward towards New Fez, and 
the other West; each of these 
subdividing into many other clear 
running Channels through the 
Streets, serving not onely each pri- 
vate House, but Churches, Inns, 
Hospitals, and all other publick 
Places to their great convenien- 
ces. Round about the Mosques 
are a hundred and fifty Common-Houses of Easement, built Four- 
square and divided into Single-Stool-Rooms, each furnished with a Cock 
and a Marble Cistern, which scoureth and keeps all neat and clean, as 
if these places were intended for some sweeter Employment." 
The water-closets of the present day may be divided into two classes ; 
those having movable internal mechanism and those having none. To 
the former class belong the plunger, or plug, closet, the pan closet, and 
a number of others ; to the latter belong the hopper closet, the various 
wash-out closets, the siphon closets, and the siphon jet closets. To 
attempt to describe all the different forms on the market would be a 
Fig. 73. 
Companion to Fig. 72 showing parts put together. WATER-CLOSETS. 
451 
tedious and useless task, for the patented devices alone run up into the 
hundreds. Therefore, in the following pages, only those which may 
be taken as types of the worst and best will be described. First will 
be described those of distinctly objectionable construction. These in- 
clude a number which, while they are no longer introduced in com- 
munities having modern plumbing regulations, exist in thousands of 
houses, into which they were introduced at a time when they were re- 
garded as absolutely perfect. 
The Pan Closet.-The principle of this apparatus is shown in Fig. 74, 
which is a vertical section of the working part of the closet, free from 
the cabinet work in which it is usually enclosed. It consists of a 
hopper II, provided with a flushing rim and closed at its outlet by 
means of a hinged pan P, which is released by a mechanism which it 
is unnecessary to illus- 
trate or explain. When 
the pan is in the horizon- 
tal position, it is partly 
filled with water, into 
which the excreta are dis- 
charged, though ordi- 
narily they come in 
contact first with the 
surface of the hopper 
above the water level. 
The closet is emptied 
by pulling a knob or 
handle which releases the 
pan, which then takes the 
position shown in the 
figure by the dotted lines. 
The contents are thus 
thrown into the lower 
chamber, and fall into the 
trap below. The mecha- 
nism which releases the 
pan also starts a flush of water through the flushing rim over the sur- 
face of the hopper. This flush is supposed to scour the interior and to 
be sufficiently voluminous to drive the excreta over the bend of the trap 
and forward toward the soil pipe. When the pan is brought back to 
its original place, the flush continues until the pan is filled to the same 
level as before. 
As a matter of fact, the flush of these closets is ordinarily little 
better than a mere dribble. The front wall of the receiving chamber, 
against which the excreta are thrown by the pan in its descent, is in- 
variably in a filthy condition, which cannot be improved by any amount 
of such flushing as the apparatus is capable of giving. The conse- 
quence is that each time the pan is dropped, a volume of foul air is dis- 
placed upward into the room. The inlet side of the trap is commonly 
Fig. 74. 
Pan closet. 452 
HABITATIONS, SCHOOLS, ETC. 
a miniature cesspool, since the flush has so little head that it is unable 
to drive objects of lighter specific gravity than that of water through 
the trap. In the illustration, $ represents what is known as a "safe" 
to catch all drippings from any source, and from this, the pipe s con- 
ducts them to the bend of the trap. This whole contrivance, formerly 
the pride of the plumber's craft, is now generally and justly regarded 
as an abomination. 
The Plunger, or Plug, Closet.-This apparatus, shown in Fig. 75, is 
far less objectionable than the pan closet. It consists of a receiver B, 
in which a large volume of water can be retained when the plunger, or 
plug, A, is in place. When A is lifted, the contents of B escape down- 
ward into the trap, which is vented at K The plunger A not only 
controls the emptying of the receiver, but also acts as a standing over- 
Fig. 75. 
Plunger closet. 
flow, for should the water in the reservoir rise higher than the upper 
level of the plunger, it will flow over into A, and from it through C 
into the trap. This fixture requires a large amount of water in order 
to obtain a proper flush, for unless the flush is generous, bits of paper 
and other material may adhere to the edge of the outlet, so that when 
the plunger is in place the valve is not tight. Naturally, with a loose 
joint, the contents of the receiver will ooze away and leave it in a dry 
condition. 
These two forms suffice as illustrations of the objectionable class of 
closets, and it may be said, in general, that all closets depending upon 
internal, mechanical, movable parts are objectionable, and all of them 
are likely to become exceedingly foul. 
A properly constructed water-closet must have a flush of water 
which will wash the whole of the interior surface of the bowl most WATER-CLOSETS. 
453 
thoroughly, carry onward all the filth and other material beyond the 
trap, and leave the bowl filled to the proper height with clean water. 
It must be so thoroughly cleaned every time it is used, that no filth 
can remain deposited at any point, and it must be quite free from any 
disagreeable odor. 
Hopper Closet.-The simplest form of non-mechanical closets is 
known as the Hopper, which is shown in Fig. 76. The illustration 
hardly needs explanation, the device consisting simply of a hopper 
connected with a simple S-trap, ventilated in the usual way. Hoppers 
are known variously as short and long. The long variety presents no 
advantage over the short and is much less easily kept in proper con- 
dition. The long hopper has its trap beneath the floor; the short hop- 
per, above it. The short hopper is 
less likely to become foul, on ac- 
count of the smaller surface pre- 
sented and because the level of the 
water in the trap is nearer the seat. 
The hopper must be provided with 
a generous flush from a flushing rim, 
for otherwise it is likely to become 
foul, since from the shape of the 
receiver, fouling of its posterior 
interior surface is inevitable. This 
is more marked with the long than 
with the short hopper. Unless the 
flush is a generous one, it is neces- 
sary to pour down an occasional 
pailful of water and also to apply the closet brush at least daily. 
Open Wash-out Closets.-The open wash-out closet is designated 
variously as front or back or side wash-out, according to the direction 
which the contents of the bowl take toward the trap. In Fig. 77 is 
shown a •front wash-out in vertical section. The bowl, provided with 
a flushing rim F fed by the supply pipe P, holds a pool of water, into 
which the excreta are projected. The greatest depth of this volume 
should not exceed If inches. In use, the contents of the bowl are 
swept by the water from the flushing rim into the trap S, which is 
ventilated at Fin the usual manner, and the flow is sufficiently volu- 
minous to force the excreta down and under the partition. 
If the volume of water in the bowl is deeper than above stated, it is 
possible that the flush may sweep beneath any floating excreta, which, 
in consequence, may be retained. If no pool at all or only a very 
much shallower one be kept, the excreta may adhere to the basin with 
such tenacity that they are not easily dislodged by a single flush. For 
the wash-out closet, it was intended to secure the combined advantages 
of the hopper and the plunger closets, that is, the advantage of a large 
surface of water in the bowl in addition to that in the trap, without 
the intervention of any mechanical contrivance. The objections to the 
wash-out closets are : (1) that the principal office of the flush is the 
Fig. 76. 
Hopper closet. 454 
HABITATIONS, SCHOOLS, ETC. 
cleansing of the basin ; (2) that after each using, the excreta and paper 
are likely to remain in the inlet side of the trap until the fixture is 
Fig. 77. 
Open wash-out closet. 
used again; and (3) that the surface against which the excreta are 
thrown during the flushing is likely to become fouled and remain so 
until cleaned mechanically by means of a brush or other appliance. 
Fig. 78. 
Siphon jet closet. WATER-CLOSETS. 
455 
Another form of wash-out closet has the basin so constructed as to 
form a trap. Closets of this class are much like the hopper, but hold 
a much greater depth of water. They are known more commonly as 
"wash-down" closets. In both the wash-out and the wash-down 
closets, the lip of the trap should dip not less than one and one-half 
inches beneath the water level; less than that increases the risk of loss 
of seal by evaporation, and more requires a larger flush than is ordi- 
narily obtainable to force the excreta, etc., downward and onward. 
Siphon Closets.-Another type of wash-down closet is known as the 
siphon jet. In this, the contents of the receiver are drawn out by 
siphonage, and at the same time are propelled by a jet of water from 
the front. In Fig. 78, one of these closets is shown. Here the 
chamber is divided into two sides of a trap by the partition & As 
the flush is brought into play, a jet of water comes down with some 
force through A and pushes the contents of B over into the chamber 
C, and as the flush continues, the chamber C becomes the long leg of 
a siphon, so that when the flush ceases to act, the siphon continues to 
suck out the contents of the receiver until the water level is brought 
down to the point S, when air is 
admitted and the siphon becomes 
thereby broken. The after-flush 
raises the water level again to its 
original point. 
Another form of siphon closet 
which acts without the assistance of 
a jet is known as the Dececo. This 
is a very simple and efficient fixture, 
invented by the late Col. George E. 
Waring, Jr. The receiver is very 
deep and maintains several inches of 
seal. The apparatus is shown in 
Fig. 79. To assist in charging the 
siphon, a weir-chamber, situated 
below the receiver and just beneath the floor, is employed. When the 
flush is set in action, the water in the basin overflows and falls into 
the weir-chamber below. This has a constricted outlet which is very 
quickly closed by the descending water, and thereby the entrance of air 
from the soil pipe side is prevented. As the water rushes into the 
long leg of the siphon, it pushes the contained air onward, the leg is 
soon filled with water, and the siphon is completed. When the con- 
tents of the bowl have been sucked down to the lower border of the 
partition, the siphon is broken by the admission of air at that point, 
and the bowl is then refilled by the after-flush. 
Still another efficient form of closet is the Sanitas, shown in Fig. 80. 
In this apparatus, invented by Mr. J. Pickering Putnam, the flush is 
accomplished by the pressure of water in the supply pipe. This pipe 
enters the bowl below the normal water level and stands permanently 
full through its entire length up to the cistern. The water is held in 
Fig. 79. 
Dececo closet. 456 
HABITATIONS, SCHOOLS, ETC. 
the pipe by atmospheric pressure. The upper end of the pipe is closed 
by the cistern valve, and the lower end by the water beneath the water 
level of the receiver. The lower portion of the supply pipe is perfo- 
rated at two different points, 
through the first of which, water 
is supplied to the flushing rim, 
and through the second, a jet is 
set in action, as in the ordinary 
siphon jet closet. 
When the flush is set'in opera- 
tion, the cistern valve is opened, 
and the water descends and 
escapes through the two outlets ; 
through the upper, the passage 
leading to the flushing rim is 
filled, and through the lower, the 
water is projected from the bottom 
of the receiver up into the siphon. The action is very quick and 
practically without noise. When the cistern valve is again closed, the 
water ceases to escape through the openings, and that in the flushing 
rim and passages leading thereto falls back into the bowl and restores 
the normal level. 
Flushing Apparatus.-The object 
of a flushing apparatus is the thorough 
removal of all adhering excreta from 
the sides of the fixture and its propul- 
sion through and beyond the trap. The 
flushing rim is connected with a supply 
pipe of about 1.25 inches diameter, 
connected with the cistern. Through 
this pipe, the water is delivered with a 
rush, and is spread out by the flushing 
rim in small jets against the sides of 
the bowl. With some forms of flushing 
cisterns, the flush continues as long as 
the lever which opens the valve is held 
down or until the cistern is completely 
emptied. 
Another form of flushing cistern 
is known as the siphon tank, the 
valve of which is shown in Fig. 81. 
This consists of a double tube, A 
and B, the inner tube A being the 
longer, and the two tubes forming 
a siphon. The lower end of the long leg of the siphon A rests on 
a rubber ring at C, and forms the valve. The siphon is started in 
operation by lifting the valve off its seat by means of a chain fastened 
to the ring in the cap E. The water rushes downward through the flush 
Fig. 80. 
Sanitas closet. 
Fig. 81. 
Valve of siphon tank. WATER-CLOSET CONNECTIONS. 
457 
pipe F, sucks the air out of A, and fills the siphon with water. The 
valve is then dropped back, and the discharge continues flowing into 
the siphon at D, and downward through A, as indicated by the arrows. 
The discharge continues until the level of the water is brought down 
to the point D, when, air being sucked in, the siphon is broken. With 
this apparatus, the flush tank is emptied every time the fixture is used, 
and the valve needs to be opened only long enough to start the siphon 
in motion, which object is accomplished in a few seconds. 
Still another form of flushing apparatus is shown in Fig. 82. This 
is employed to furnish a large flush and a small after-flush, by means 
of which the bowl of the fixture may receive water after the main 
flushing has been accomplished. The tank is divided into two cham- 
bers, A and B. The valve V, worked by chain and lever, is 4 inches 
in diameter. When opened, it discharges water more rapidly than it 
can flow through the pipe B, and, in consequence, the surplus fills the 
Fig. 82. 
Flushing tank. 
chamber B. When the valve is closed, the main flush ceases, and a 
smaller flow continues until the chamber B is emptied. At the point 
O, is the overflow for the chamber A into B. 
A flushing tank should contain not less than 4 gallons, and except 
in the case of the Sanitas closet, should be not less than 6 feet above 
the closet bowl. 
Water-closet Connections.-The ordinary method of connecting a 
modern water-closet with the soil pipe branch is by means of what is 
known as a brass floor-plate joint. The soil pipe branch is fastened by 
means of solder to the brass flange, which is screwed to the floor. The 
closet flange is set upon an intervening rubber gasket, and the two are 
then screwed or bolted together. The common putty joint should not 
be used, for although it may not leak water, it is usually'pervious to 
air and odors. In screwing up the porcelain branch, great care must 
be taken to avoid breakage. Some closets are made in two pieces, the 458 
HABITATIONS, SCHOOLS, ETC. 
bowl being of porcelain, and the trap of iron or other metal with a 
porcelain lining. With these, the danger of breakage is reduced to a 
minimum. 
Urinals.-The urinal is a fixture which should not be tolerated in a 
private house, since, with the best of care, they are almost inevitably 
offensive and, with ordinary care, are sure to be a decided nuisance. 
They are necessary only in large buildings, and there they require 
abundant and frequent flushing and constant care. The waste pipe is 
commonly coated on the interior as far as the trap with a deposit de- 
rived from the urine and does not yield it readily to flowing water. 
The application of washing soda or of solution of ordinary potash is 
ineffective, but hydrochloric acid in 10-per-cent. strength, followed 
shortly by a generous flush of water, will remove it. Weak sulphuric 
acid, about 2.5 per cent., is also efficient. 
Wash Basins.-Wash basins are made of metal, as copper, enam- 
elled and galvanized iron, and of earthenware and porcelain. Most 
commonly, they are of glazed earthenware. In shape, they are either 
circular or oval. The latter form is generally preferred, as it affords 
more space for free action of the arms than a circular one of the same 
Fig. 83. 
Fig. 84. 
Wash basin with^overflow. 
capacity. Some bowls are made with 
a flushing rim at the top, through 
which hot and cold water are intro- 
duced together on all sides, and thus 
the entire surface of the bowl is more 
easily kept clean. In the upper part of the commonest form of basin 
(see Fig. 83) a number of perforations (S) communicate with the over- 
flow horn (IF) connected with the waste pipe. Ordinarily, these outlet 
holes are unable to deliver water as rapidly as it enters through a faucet 
with moderate head, and consequently too much dependence should 
not be placed on them in the prevention of overfilling of the basin. 
In some bowls, the entire overflow horn is an integral part of the fix- 
ture, opening just beneath the plug, as is shown in Fig. 84. Where 
the horn does not so extend, its junction with the waste pipe is not in- 
frequently wrongly made; sometimes, it is connected below the trap; 
sometimes, at the crown of the trap, into or near the vent pipe. The 
overflow horn, especially with long use of the fixture, is very likely to 
become foul, on account of the soap and filth which become deposited 
along its inner surface. In fact, the odor which is commonly ascribed 
Wash basin with overflow horn discharging 
beneath plug. WASH BASINS. 
459 
to " sewer gas " comes from the horn and from the waste pipe between 
the bowl of the trap. 
Another source of odor of much less importance is the chain at- 
tached to the plug. This gradually collects within its links the same 
Fig. 85. 
Wash basin with standpipe plug and overflow. 
kind of deposit, which is completely removed only with some diffi- 
culty and much scrubbing with a brush. On account of the fouling 
of the chain and the inconvenience of having it in the way of the 
hands, some forms of basins are equipped with a standpipe, which acts 
as plug and overflow at the same time. In Fig. 85 such an arrange- 
Fig. 86. 
Improved standpipe overflow. 460 
HABITATIONS, SCHOOLS, ETC. 
ment is shown ; the bowl presents no irregularities of surface, not even 
a plug. The standpipe p, enclosed in the pipe P, acts as a valve when 
it is dropped into place, and the surplus water, rising between P and 
p, escapes through the holes in the upper extremity of p. The device 
is lifted by a knob and is kept off the seat by means of a bayonet 
catch. In the illustration, the plug is off the seat. 
The principal objection to this form of waste valve is that the out- 
let is situated at a considerable distance from the outlet of the bowl, 
and the entire surface between these two points is bound to become 
foul. Furthermore, small bits of lint and hair are likely to be de- 
posited near the seat and cause it to leak so rapidly that the bowl 
cannot hold water for any length of time. A better form is shown in 
Fig. 86. Here the standpipe overflow has its seat directly in the out- 
let of the basin and can be easily got at and cleaned. 
Bathtubs.-Bathtubs are made of various materials in a number of 
forms. The finest grade of tubs are made of porcelain or of fine 
Fig. 87. 
Porcelain or iron bathtub. 
earthenware with a heavy enamel of porcelain. They are made in 
various shapes and are very commonly somewhat ornately decorated. 
They are very heavy and quite expensive. The plainest varieties 
Fig. 88. 
Vertical section of commonest form of bathtub. 
have most commonly the shape shown in Fig. 87. They are usually 
set upon slabs of marble. Tubs of iron with a lining of porcelain BATHTUBS. 
461 
enamel are also made in this form. These are open to the objection 
that the enamel is very easily chipped off. Within recent years, a 
cheap form of tub in this shape, made of ordinary tin plate, has been 
introduced. In spite of the iron frame with which it is surrounded, it 
is very flimsily constructed. 
The commonest form of bathtub used in this country is made of 
tinned and planished copper, weighing from 10 to 24 ounces to the 
square foot. In Fig. 88, this form of tub is shown in vertical section. 
Inasmuch as the copper is to all intents and purposes the lining of a 
box, it is necessary, for the sake of appearances, to have an outside casing 
of cabinet work. The ordinary tub is provided with a waste plug, 
Fig. 89. 
Standing overflow and waste pipe. 
chain, and overflow as shown in the figure. The chain and plug are 
not uncommonly supplanted by an ordinary pipe of the desired length, 
which fits into the outlet of the tub and thus acts both as plug and 
overflow. In some of the tubs of more elaborate construction, a stand- 
ing overflow and waste pipe, shown in Fig. 89, is used. In this, the 
overflow passes over and into the pipe B and escapes through the 
bottom. When the tub is to be emptied, the tube is lifted, and thereby 
the perforations at the bottom of the inner tube A are exposed. On 
the whole, this form is in no way superior to the ordinary standing 
overflow, but possesses certain disadvantages which do not apply to 
that device, which can be completely removed from the outlet each 
time the tub is emptied. 462 
HABITATIONS, SCHOOLS, ETC. 
Other forms of baths, including the sitz-bath, foot-bath, shower-bath, 
douche and needle-bath, and bidets are found ordinarily only in the 
very elaborately fitted bath-rooms of the very wealthy. As plumbing 
appliances pure and simple, they present nothing of any especial hy- 
gienic interest, the matter of waste pipes, trapping, etc., differing in no 
essential respects from what has been already described in connection 
with other fixtures. The shower-bath, which consists mainly of a 
large sprinkler from which water is delivered downward in fine 
streams, is very commonly set above the ordinary bathtub, with a 
screen of wood or curtain of rubber cloth or other suitable material to 
prevent splashing the floor. Smaller arrangements, consisting of a 
sprinkler such as is attached to the nozzle of a watering pot and a 
rubber tube to connect with the faucet of the bathtub, are very com- 
monly used. If desired, the rubber tube can be attached to a mixing 
pipe, which in its turn is attached to both cold and hot water faucets, 
and thus the temperature of the shower can be regulated. 
Sinks.-Under sinks are included pantry sinks, kitchen sinks, and 
slop sinks. These are made of various metals, including cast iron, 
enamelled iron, steel, copper, soapstone, slate, earthenware, and porce- 
lain. Cast iron is easily kept clean with ordinary care, but on account 
of danger of the breaking of dishes and other articles which are washed 
or otherwise handled in them, a grating of wood is not uncommonly 
laid on the bottom. This easily becomes foul, particularly if it is al- 
lowed to stand in the wet sink when not in actual use. All such grat- 
ings should be kept scrupulously clean, and when not actually needed 
in the sink, should be hung up in the air. 
Enamelled iron is much more desirable than plain iron and presents 
a much better appearance. Unfortunately, however, the enamel is very 
easily cracked and detached. Steel sinks are not as durable as ordi- 
nary cast iron, but they are light and cheap. They are very com- 
monly enamelled, and then they are necessarily open to the objection 
above mentioned. Tinned and planished copper is much used for 
pantry sinks, which are commonly made with rounded, but better, with 
perfectly flat bottoms. The copper should have a weight of not less 
than 18 to 24 ounces per square foot. 
In some quarters, soapstone is the favorite material for kitchen 
sinks. Ordinarily, it is quite durable, particularly if it has been sub- 
jected to a preliminary oiling, but some specimens show a tendency 
to disintegrate very rapidly and to become so pitted as to present a 
honey-combed appearance. Earthenware sinks are thick and heavy 
and present no advantages over soapstone. Porcelain is expensive 
and, if thin, is easily broken. It is not extensively used in ordinary 
sinks. 
All sinks should be provided with a not too fine strainer over the 
outlet. Kitchen and pantry sinks are best connected with a grease 
trap. The common practice of constructing cupboards or closets be- 
neath sinks should be discouraged, since these spaces are commonly 
maintained as clutter-holes in which to store unwashed pots, kettles, HOUSE SERVICE TANKS. 
463 
and other utensils, which, in unclean condition, would not be tolerated 
in positions where they are open to inspection. 
House-maids' sinks, commonly known as slop sinks, are generally 
located in small, dark, unventilated closets in the upper story. This 
form of fixture is made rather deeper than an ordinary sink, and is 
sometimes shaped like a hopper. They are best made with a flushing 
rim which will assist in keeping the entire surface clean and free from 
odor. On account of the nature of the refuse poured into these recep- 
tacles, and because of the great probability of the occurrence of splash- 
ing when vessels are emptied, these sinks are often extremely foul, and 
the closets in which they are placed are then always necessarily offen- 
sive. The greatest care is necessary to insure cleanliness. 
Laundry Tubs.-Laundry tubs are made of practically the same 
materials as sinks. The cheapest kind are made of stout planking 
with well-fitting joints drawn tight by iron bolts. This form is not 
very durable, since the alternate drying and wetting soon ruins the 
joints and causes the wood to decay. Those made of porcelain and 
earthenware are very heavy and expensive, but are very durable and 
easy to keep clean. The soapstone tub is generally regarded as the 
most satisfactory, but must be made of material of the best quality, 
since otherwise they are liable to chip and crack off from constant 
contact with hot water. All enamelled tubs are likely to lose their 
enamel, which is easily separated from the metal and chipped off. 
House Service Tanks.-With most plumbing systems, it is essential 
that in the upper part of the building, above the highest fixture, there 
shall be a service tank to feed the hot-water boiler and the various flush- 
ing cisterns connected with water-closets and other fixtures. These 
tanks are commonly placed in positions where access to them is not easy, 
and, in consequence, they are, as a rule, examined very infrequently. 
No matter how carefully they are covered and regardless of the kind 
of water that enters them for storage, they accumulate more or less 
dust and dirt and organic matter and other sediment. All this adheres 
to and accumulates on the bottom, forms a slimy coat upon the sides, 
and there remains until removed by some external force. 
It is hardly necessary to say that this condition should not be per- 
mitted. The tank should be periodically inspected and thoroughly 
cleaned. Fortunately, it is neither necessary nor customary in ordi- 
nary dwellings to use water from the service tank either for drinking 
or for cooking, since the cold water service pipes connect directly with 
the street main and are tapped at intervals with faucets and terminate 
at the tank, where their delivery is regulated by means of ball-cocks. 
Inasmuch as the water from the tank is not used for drinking and cook- 
ing, excepting in houses not connected with the public supply but 
served from a tank filled periodically by pumping, it makes no very 
great difference from a hygienic standpoint of what material the tank 
is built. A very good tank is made of riveted iron plates lined with 
cement of proper quality. Wooden tanks are much used, and give 
satisfaction if they are kept full and clean. 464 
HABITATIONS, SCHOOLS, ETC. 
The tank which, on the whole, is most satisfactory is constructed of 
wood, with the sides secured to the ends by long bolts, and lined with 
tinned copper of good weight. Lead forms a poor lining, for it is very 
easily corroded by water. Galvanized iron and sheet zinc also make 
poor lining material. In large office buildings in which all the fix- 
tures, including those from which water for drinking is obtained, are 
supplied from a main tank in the upper story, it is advisable that the 
lining of the tank should be of tinned copper and under no circum- 
stances should it be of lead. 
Service Pipes.-The method of installing the water service is of 
very minor interest to the hygienist and requires no discussion, the 
nature of the pipes having been considered in another chapter; but 
there is one minor trouble connected with them which may be a cause 
of great annoyance, especially to persons of nervous or irritable nature. 
This trouble is commonly known as water hammer and is something more 
than an annoyance, since its occurrence has a weakening effect on the 
entire pipe system. This is the quivering and rattling that occur from 
end to end when the current of water within them is suddenly checked 
by the quick closure of a cock or valve. In order to prevent this, it 
is necessary to make some provision for a cushion, particularly where 
the water pressure is very great. This not infrequently runs as high 
as a hundred pounds to the square inch and even higher. To cushion 
the blow, an air chamber, commonly made by turning the pipe upward 
for a foot or two above the cock, is used. This extension will from 
the outset contain a volume of air, which, on being compressed by the 
force of the water, makes an elastic cushion. 
Sometimes, however, the air originally contained becomes gradually 
absorbed and taken out by the water which is driven into the chamber, 
and thus it becomes replaced by water and the cushion is destroyed. In 
such an event, it is well to shut off the water and empty the pipes so 
that air may again fill the chamber. Another form of air chamber 
recommended is made by extending the pipe with a piece of larger 
diameter, covered at the top with a tightly fitting screw cap. Within 
this extension, may be placed two or more rubber balls, upon which the 
force of the blow of the water hammer may be expended. 
Water hammer of a most annoying and persistent kind is often oc- 
casioned by the too easy movement of a light ball-cock controlling a 
current of high pressure in a small tank. For example, the water in 
the tank becomes lowered through the use of some fixture below, the 
ball, floating on the surface, opens the valve of the cock, and water is 
admitted to take the place of that which has been drawn off. The 
water, entering with much force, sets the whole contents in motion. 
The ball is thrown up and shuts off the water with great suddenness 
and falls again ; another jet of water is thrown in, and thus, with alter- 
nate quick jets and movement of the ball, the hammering continues 
until finally the level of the water has been restored to its original 
point. 
Testing Plumbing.-Tightness of joints throughout a system of 465 
TESTING PLUMBING. 
plumbing may be determined in several ways. For testing the joints 
of soil pipes and main drains, a most important and searching test is 
that known as the water-pressure test. This is applied before any 
fixtures have been joined to the wastes and soil pipe. All outlets are 
closed with appropriate plugs, made for the purpose and kept in place 
by means of bolts, and then the entire pipe with its branches is filled 
with water. Should there be any leaks in any part of the system, the 
fact will be made manifest by the sinking of the water, and the points 
of escape can be easily found on inspection. 
The other methods applicable to the entire system include the smoke 
test and peppermint test. In the smoke test, the system is filled with 
smoke by means of a device known as an asphyxiator. If leaks exist, 
the fact will be made evident in two ways : first, to the sense of smell; 
second, to the sense of sight. Besides the asphyxiator, a number of 
other devices, including the smoke rocket, have been invented. The 
common method of testing plumbing in this country is known as the 
peppermint test. For this test, the presence of two persons is neces- 
sary ; one to apply the peppermint, and the other to detect its presence 
in the air of the building. About two ounces of oil of peppermint are 
used for each stack of soil pipes. This very pungent oil must be car- 
ried through the house in very tightly corked vials in order that no 
odor shall be given off in transit. 
The vent openings are first closed with plugs, and the oil of pepper- 
mint is then poured into the soil pipe and followed by a quart or two 
of hot water to assist its volatilization. The outlet is then securely 
closed. On account of the clinging quality of the odor, the person who 
empties the peppermint must remain on the roof, with the scuttle closed, 
until thorough inspection of the premises has been made. The very 
pungent volatile oil permeates all parts of the soil pipe and its connec- 
tions, and in case of defective seal or any other imperfection in the 
system, it escapes and makes its presence known in the rooms through 
its effect on the sense of smell. During the examination, it is impor- 
tant that no water-closet be pulled and that no bowl, bath, or sink be 
used, since thereby the whole of the peppermint might be driven out 
of the system into the sewer. CHAPTER VI. 
DISPOSAL OF SEWAGE. 
The composition of sewage varies according to the character of the 
community by which it is produced. To the lay mind the word 
conveys the idea of a mixture of urine and faeces, paper and burnt 
matches, with waste from baths, wash-stands, laundries, and kitchen- 
sinks ; this is ordinary domestic sewage, and may be taken as the type 
of sewage of districts that are purely residential. But the sewage of 
a large community in which all manner of manufacturing is carried 
on is necessarily of a most complex character, containing, as it does, in 
addition to domestic waste, that which is inseparably connected with 
the various industries. Moreover, it is ever changing with increase 
and diminution and changes of all kinds in manufacturing activity. 
Establishments like paper mills, tanneries, dye-houses and woolen- 
mills produce enormous amounts of sewage. In fact, a single one is 
quite capable of producing as much as that of a fairly large town, and 
such manufacturing sewage often contains much more organic and 
other matters than domestic sewage, which, in purely residential dis- 
tricts, is of fairly constant composition, and where the water sup- 
ply is abundant, contains but a small fraction of 1 per cent, of organic 
matter. But it is in this very small percentage that the capacity for 
producing mischief resides, for the most important constituents of sew- 
age are those which in any way may be the cause, direct or indirect, of 
injurious effects on health-that is, organic matters connected with in- 
fective diseases and hence mostly to be found in ordinary domestic 
wastes. Industrial sewage is of secondary, but, nevertheless, in many 
ways, of great importance, for its nature may be such as to make sep- 
arate treatment necessary, because of its action on the life of fish in 
rivers and of the organisms which bring about purification by methods 
to be described. It may contain all manner of chemicals, dyestuffs, 
and other matters, and be repugnant to sight and smell. 
The importance of removal and disposal of filth needs no elucida- 
tion. Removal must be speedy and final disposal so thorough as to 
remove completely the possibility of injuriously affecting health. It 
should not be stored on the premises in cesspools, as is so commonly 
the practice both in small and in many large and densely populated 
places, whether these be of the leaching sort which drain their con- 
tents constantly into the subsoil, or the far less objectionable, but, 
nevertheless, objectionable tight pits with cemented sides and bottoms, 
in which the contents are always in a condition of putrefaction. The 
use of this sort necessitates more or less frequent emptying, which, DISPOSAL OF SEWAGE. 
467 
unless done by the " odorless excavation " suction apparatus (and 
sometimes even then), gives rise to intolerable stench, not confined to 
the immediate neighborhood, but disseminated over a wide area. 
As will be later shown, fresh sewage may be disposed of so as to 
lose its character completely, without undergoing the processes which 
we designate collectively as putrefaction. Its organic constituents are 
seized upon by micro-organisms which work in the presence of air, 
and they are converted to inoffensive harmless products which possess 
the additional property of being invaluable plant foods, such, for in- 
stance, as the nitrates of potassium and sodium. But when filth is 
conserved in pits so that only its upper surface is exposed to the oxy- 
gen of the air, its decomposition is effected by a variety of organisms 
of a different class, which work without air and produce entirely dif- 
ferent chemical compounds, including sulphuretted hydrogen and other 
noisome bodies. Although sewage which has undergone putrefactive 
changes can yet be acted upon by the beneficent nitrifying organisms, 
it is best to get rid of it before such changes become advanced. 
Before proceeding to the consideration of the various methods of 
disposal of excreta and other wastes, it may be well to look into the 
matter from an economic standpoint. It is very commonly the case 
that the question of methods to be adopted is largely influenced by 
the hope of gain, for it is axiomatic in the minds of many that muni- 
cipal sewage is possessed of such immense manurial value that its dis- 
posal without previous treatment for the purpose of reclaiming its 
valuable constituents is sinful wastefulness. This idea has doubtless 
never been more forcibly expressed than by Victor Hugo in the fol- 
lowing passage :1 
" Paris casts twenty-five millions of francs annually into the sea; 
and we assert this without any metaphor. How so, and in what way ? 
By day and night. For what object? For no object. With what 
thought? Without thinking. With what object ? None. By means 
of what organs ? Its intestines. What are its intestines? Its sewers. 
Twenty-five millions are the most moderate of the approximative 
amounts given by the estimates of modern science. Science, after grop- 
ing for a long time, knows now that the most fertilizing and effective 
of manures is human manure. The Chinese, let us say it to our shame, 
knew this before we did; not a Chinese peasant-it is Eckeberg who 
states the fact-who goes to the city but brings at either end of his 
bamboo a bucket full of what we call filth. Thanks to the human 
manure, the soil in China is still as youthful as in the days of Abraham, 
and Chinese wheat yields just one hundred and twenty fold the sowing. 
There is no guano comparable in fertility to the detritus of a capital, 
and a large city is the strongest of stercoraries. To employ the town 
in manuring the plain would be certain success ; for if gold be dung, 
on the other hand our dung is gold. 
"What is done with this golden dung? It is swept into the gulf. 
We send at a great expense fleets of ships to collect at the southern 
1 Les Miserables, part 5, book 2. 468 
DISPOSAL OF SEWAGE. 
pole the guano of petrels and penguins, and cast into the sea the incal- 
culable element of wealth which we have under our hand. All the 
human and animal manure which the world loses, if returned to land 
instead of being thrown into the sea, would suffice to nourish the world. 
Do you know what those piles of ordure are, collected at the corners 
of streets, those carts of mud carried off at night from the streets, the 
frightful barrels of the night-man, and the fetid streams of subterra- 
nean mud which the pavement conceals from you? All this is a flow- 
ering field, it is green grass, it is mint and thyme and sage, it is game, 
it is cattle, it is the satisfied lowing of heavy kine at night, it is per- 
fumed hay, it is gilded wheat, it is bread on your table, it is warm 
blood in your veins, it is health, it is joy, it is life. 
" So desires that mysterious creation, which is transformation of earth 
and transfiguration in heaven; restore this to the great crucible, 
and your abundance will issue from it, for the nutrition of the plains 
produces the nourishment of men. You are at liberty to lose this 
wealth and consider me ridiculous into the bargain : it would be the 
masterpiece of your ignorance. Statistics have calculated that France 
alone pours every year into the Atlantic, a sum of half a milliard. 
Note this ; with these five hundred millions, one quarter of the expenses 
of the budget would be paid." 
Concerning the fertilizing value of human excreta, there can be no 
doubt; but when these are diluted to such an extent that their organic 
constituents amount to less than a thousanth part of the whole, it natur- 
ally follows that to reclaim them in concentrated form involves an 
expense which may be far in excess of their value. A substance 
which, in hand, is of intrinsic value, may be so situated that its acqui- 
sition by ordinary known means cannot be justified because of the 
attendant pecuniary risk, and then, and until other better means are 
devised, it is practically worthless. For example, many districts 
abound in rocks containing silver, gold, and other metals, but in such 
small amounts that they cannot be worked with profit; therefore, 
so far as increasing material wealth is concerned, these ores might as 
well be at the bottom of the sea. But in the case of sewage, the diffi- 
culty is still further increased by the fact that the manurial product is 
not usable on the spot, but must undergo transportation, which is costly 
in proportion to the distance. 
A fair estimate of the value of the manurial matters contained in a 
ton of crude sewage of average composition places it at somewhat less 
than four cents, an amount so small as to appear worse than ridiculous 
when we consider that it is diluted by a volume of water equal to about 
six barrels. The value of the sewage of cities with a very abundant 
water supply is even less than this. Thus, that of Boston has been 
estimated by the Massachusetts State Board of Health to be about one 
cent per ton, and that of New York is said to be even smaller. To 
separate this small amount, the employment of some chemical is neces- 
sary. The resulting compound, known as sludge, has a certain value 
in agricultural operations, but that that value is not such as to warrant DISCHARGE INTO THE SEA. 
469 
the cost of handling and transportation, is most evident when it is stated 
that as a rule it finds no market at any price. In London, for in- 
stance, thousands of tons of wet sludge are produced every day, over 
2,000,000 yearly, and anybody who wants it can have it free of 
charge; but nobody cares enough for it to transport it, and hence it 
has to be carried far out to sea to Barrow Deep, fifty miles away, 
and dumped. 
In considering sewage disposal, it must be borne in mind, therefore, 
that it is a positive public necessity as much as police and fire patrol, 
that it costs money, and that it cannot be a source of income over ex- 
penditure. No community expects a pecuniary return on an invest- 
ment for steam fire-engines and hose carriages, or for revolvers and 
police stations : such are needed for the protection of life and property. 
So, too, a system of sewerage and sewage disposal is necessary for the 
protection of health and is not to be treated as though primarily in- 
tended as a source of public revenue, though, of course, any return 
which may be possible, either from sale of sludge or crude sewage, may 
be regarded as a welcome diminution in the cost of maintenance. 
The methods of disposal of excreta and sewage include, 
1. Disharge into the sea or other bodies of water. 
2. The " dry method," or pail system. 
3. Chemical treatment. 
4. Irrigation, or " sewage farming." 
5. Filtration. 
6. Other biological systems. 
1. Discharge into the Sea.-In communities on and near the coast, 
it is a comparatively easy matter to get rid of sewage by discharging 
it into the ocean and having it carried away by the outgoing tide. If 
it be discharged in a fresh condition, it becomes so enormously diluted 
in a very short time that only under exceptional circumstances can it 
ever be a nuisance in any way. This, of course, presupposes a reason- 
able rise and fall of the tide and does not contemplate such slight dif- 
ferences as a foot or so. With slow movement, less than one and a- 
half miles per hour, deposits are more than likely to be formed, and 
nuisance thus caused must of necessity increase with time, and espe- 
cially with increase of sewage due to growing population. Thus it 
happens that even on the seaboard it may be necessary to purify sew- 
age before discharging it, and the problem of successful and econom- 
ical purification may be one of the most difficult and important in the 
whole range of sanitary science. 
In inland communities situated on rivers of considerable size, delivery 
at a point below the outskirts is the easiest method of sewage disposal; 
but other communities farther down may properly object on more than 
one ground to such action, for the sewage itself maybe a nuisance, and 
the river may be the source of the public water supply. Here, again, 
and where the flow is sluggish and the volume small, treatment before 
discharge is necessary. Where the water into which the sewage is de- 
livered is to be used below for the public drinking supply, the process 470 
DISPOSAL OF SEWAGE. 
of purification must be such as to give the most perfect results possible ; 
that is, must give an effluent which will not affect the quality of the 
water injuriously. 
In both rivers and harbors, in order to prevent nuisance from un- 
treated sewage, the current must be sufficiently voluminous and strong 
to afford large dilution and prevent deposition. 
2. The Pail System.-This is limited in its application to the dis- 
posal of excreta in pails containing dry earth, peat powder, or other 
material, and although it is in operation in several places of consider- 
able size in England and on the Continent, it is better adapted to the 
needs of isolated houses and small villages. It was the natural out- 
growth of the very extensive adoption of the earth closet, a device 
invented by the Rev. Henry Moule, in which the solid excreta are re- 
ceived in a receptacle of suitable size and covered after each addition 
with dry earth, peat powder, or ashes. As often as necessary, the pails 
are collected and emptied, and their contents removed to a distance, 
treated or not with chemicals according to circumstances, and buried 
or used as manure. From the fact that the collection is made at night, 
arose the common term night-soil, and later, from this one, another 
to designate an important part of house plumbing, the soil pipe. 
It is a primitive sort of system, but it has points in its favor as well 
as against. It is not expensive, there is no pollution of streams, and 
the manorial value of faeces is not wasted. But it requires the collec- 
tion, drying, and storage of a large amount of earth, or other material, 
not always easy to obtain; the emptying of the pails must necessarily 
be accompanied by the escape of more or less odor; it may possibly 
give rise to a nuisance at or near the place of final disposal; and ad- 
ditional provision must be made for the removal of liquid refuse. 
The materials used in the pails are chiefly dry earth and peat, 
both of which substances are very absorbent. The earth is ordinarily 
either simply dried or thoroughly baked, but drying is preferable to 
baking because the influence of the saprophytic bacteria of the soil 
is not destroyed. The late Colonel Waring demonstrated most con- 
vincingly the very great power of air-dried soil to dispose of the 
organic constituents of faecal matter so nearly completely that but an 
insignificant amount remains. He kept two tons of dry earth for a 
long time, using it repeatedly in earth closets and storing it after each 
period of use in a dry well-ventilated cellar. It was estimated that by 
the time it had been used ten times, no less than 230 pounds of nitro- 
gen had been added to it, but analysis showed that but 8 pounds re- 
mained, the balance having been restored in gaseous form to the at- 
mosphere. The same fact has been observed by Professor Vollcker, 
who found that earth after being dried and used three times contained 
practically no more nitrogen than it did originally. 
Peat has not only remarkable power of absorption, but also very 
marked bactericidal properties. It will absorb and retain from nine 
to eighteen times its weight of water, it acts as a deodorant in 
the same manner as charcoal, and it retains ammonia in apparently CHEMICAL TREATMENT. 
471 
unchanged condition. The resulting manure is found to decompose 
rapidly and to be especially suited to sandy and light loamy soil. 
Experiment has shown that neither the typhoid nor cholera organisms 
can retain their vitality in contact with peat longer than a very few 
hours, and the same is true of many other varieties of bacteria. 
Sawdust also is recommended for use in earth closets and as an ab- 
sorbent for urinals where there is no water supply. Experiments 
conducted by Dr. G. V. Poore 1 with various materials proved its 
value for the latter purpose and yielded interesting results. A flannel 
bag, two and a-half feet long and a foot broad at the bottom, contain- 
ing six pounds of dry sawdust, received in the course of two months 
thirty-nine pounds of urine ; after about a year, forty-five pounds more 
were added during a period of three months. Notwithstanding that 
the bag had become so rotten as hardly to hold together, the contents 
were not in the least offensive and had never given off any offensive 
odor. Of the eighty-four pounds of urine added, only six pounds 
had filtered through, while the rest had evaporated or been retained. 
The filtrate was dark brown in color, thick, and of high specific 
gravity, but never offensive ; nor had it shown, after lying about for 
months, any tendency to putrefy or become offensive. Filtration 
through earth, old stucco, and peat moss gave identical results. With 
fresh earth, fresh stucco, and fresh ashes, the filtrate was almost color- 
less and odorless, but the power of ashes to give this result is short- 
lived. 
The pail system, whatever may be said in its favor, has had its day 
in large communities, and where it still obtains, is being gradually 
superseded by systems more suitable and satisfactory. 
3. Chemical Treatment.-Sewage disposal by chemical treatment 
has for its object the separation of the suspended matters and the pre- 
cipitation and consequent separation of the putrescible matters in 
solution. The larger masses of the suspended substances may, of 
course, be removed by being entangled in the coagulum produced from 
the soluble matters by the addition of chemical precipitants. The 
effluent must be clear and should contain a minimum of organic matter 
capable of undergoing putrefaction. Whatever the precipitant used, 
the process requires constant and careful supervision in order to achieve 
the best results and to keep the expenditure down to as low a figure 
as is consistent with efficiency. The screened sewage, deprived of its 
coarser matters, is treated and thoroughly mixed with the chemicals in 
large tanks, and is then passed into other tanks where the precipitate 
is allowed to separate by subsidence. The sludge is removed and 
then disposed of in its natural state or after treatment in hydraulic 
presses for the removal of the water. The sewage must be treated in 
as fresh condition as possible and before putrefactive processes have 
begun, since when the latter have got well under way, the results are 
never satisfactory. 
The substances most used as precipitants are alum, lime, and ferrous 
1 British Medical Journal, Aug. 31, 1895. 472 
DISPOSAL OF SEWAGE. 
sulphate, but which of these and others is the best suited for the work, 
is a question concerning which there is no general agreement. Alum 
and other soluble salts of aluminum have moderate disinfectant prop- 
erties, are not poisonous in the general sense of the word, and when 
used in excess impart no color to the effluent. In the presence of lime 
or ammonia, they yield a very bulky gelatinous precipitate which en- 
tangles the suspended matters and bacteria present and carries them 
down, leaving a clear supernatant liquid, which is without color or odor 
and practically sterile. 
With excess of alum, the effluent is acid in reaction and thus 
capable of injuring aquatic life, but it does not form unsightly com- 
pounds with sulphur as do iron and other substances which form 
black sulphides. Lime in the form of milk of lime is extensively used 
both alone and in connection with ferrous sulphate or alum. When 
used alone, it gives a very much more bulky sludge, which has but very 
slight value as a fertilizer. The amount necessary for treatment of a 
million gallons of sewage is generally stated at one ton, but may be 
much less. At the precipitation works at Worcester, Mass., for in- 
stance, during the year ended Nov. 30, 1895, the average daily 
amount of sewage treated was 16,000,000 gallons and the average 
amount of lime used per million gallons was but a trifle over 1,200 
lbs., while the sewage of Lawrence, Mass., was found, in the experi- 
ments conducted by the State Board of Health,1 to require 1,800 lbs. 
for the same amount. As a matter of fact, the amount necessary de- 
pends upon the character of the sewage, that is, upon the amount of 
carbon dioxide in it, for it is this which acts upon the lime to cause a 
precipitate to be formed. Hence it may be said that the amount nec- 
essary is that which will exactly neutralize the contained carbonic acid. 
Ferrous sulphate is very rarely employed alone, but generally with 
lime, the two being used in such amounts that no great excess of either 
is left in the effluent; and these amounts can only be determined by 
actual experiment with the sewage to be treated. On this account, 
precipitation by ferrous sulphate is likely to be somewhat complicated, 
but when it is properly carried out, it appears to give very good results. 
The experiments conducted by the State Board of Health at the station 
at Lawrence led to the conclusion that sulphate of iron alone acts best 
among chemical precipitants. According to Mr. W. J. Dibdin,2 how- 
ever, who, as is well known, has made extensive experiments on this 
subject, the combination with lime constitutes the most economical and 
most efficient agent. An excess of iron in the effluent may lead later 
to an unsightly deposit of ferrous sulphide along the banks of the 
stream into which it is eventually discharged. 
Certain other chemical processes have been exploited in this country 
and elsewhere, but none of them appear likely to be adopted extensively. 
Among them may be mentioned the "Amines" process, in which the 
sewage is treated with lime and amines, chiefly trimethylamine, in the 
1 Report on Purification of Sewage and Water, 1890. 
2 Journal of State Medicine, Jan., 1895. ACTION OF SEWAGE EFFLUENTS ON FISH LIFE. 
473 
form of herring brine. While it gives very satisfactory results, it has 
certain drawbacks, among which are the difficulty of securing a suffi- 
cient supply of the brine, its offensive odor, its deterioration on storage, 
and its possible influence on fish life. 
Another, sometimes known as the "Woolf" and sometimes as the 
" Hermite " process, depends upon the action of chlorine compounds 
produced by electrolysis of salt in sea water or in the sewage itself. 
The organic matters are attacked and somewhat diminished in amount, 
but the principal influence is exerted in the direction of sterilization. 
The precipitating agent is ferrous hydrate formed by the action of 
the electric current on iron plates in the tanks. In the so-called A. 
B. C. process (alum, blood, and clay), a mixture of clay and charcoal 
is first added to the sewage, and next a solution of alum and sulphate 
of magnesium. It is an expensive and troublesome process and yields 
a large amount of sludge. 
In all processes of chemical treatment, a more or less complete tem- 
porary sterilization is effected, and this of itself is often a very serious 
objection, since, although the effluent when discharged may be sterile, 
this condition is not lasting, and the organic matter still present is 
bound sooner or later to decompose and, perhaps, become a serious 
nuisance. The objection to sterilization of sewage does not extend, of 
course, to the pathogenic bacteria of infected faeces and urine, which 
should be destroyed before entrance to the main body of sewage, but 
wholly to the saprophytic organisms which eventually destroy the or- 
ganic matters and convert them to simple harmless compounds. 
There is always more or less organic matter in the effluent, however 
clear this may be, and this, being putrescible, is certain to undergo 
change. This has been demonstrated wherever chemical treatment 
has been adopted, and it is generally admitted that the effluent cannot 
be admitted to water courses without injury to the quality of the water 
both so far as fish life and wholesomeness for drinking are concerned, 
unless it is first further treated by some biological process and thereby 
made clean and harmless. In the words of Professor L. P. Kinni- 
cutt,1 who has made an exhaustive study of chemical purification at 
Worcester, Mass., and elsewhere in America and in Europe, "We 
believe we have proved in America * * * that by chemical precipita- 
tion alone, even with the greatest care, and at an excessively high cost, 
a filtrate cannot be obtained sufficiently pure to turn into a water 
course unless the minimum dry weather flow of that water course is at 
least ten times, and, better, fifteen times the average flow of the sewage." 
Action of Sewage Effluents on Fish Life.-It may be broadly stated 
that " purified " sewage, when discharged into a water course, 'will 
cause more harm to fish than will ordinary crude sewage, for while all 
chemical precipitants will either cause the water to act as a poison or 
withdraw its dissolved oxygen so that it will not sustain life, the 
elements of crude sewage may be greedily taken up by the fish as 
valuable food material. 
1 Journal of the Sanitary Institute, Jan., 1900, p. 662. 474 
DISPOSAL OF SEWAGE. 
Much depends, of course, upon the nature of the precipitant (some 
of them being more poisonous than others), and also upon its amount, 
but even when extensively diluted, its action is distinctly harmful. 
Lime is supposed to act by being precipitated in the gills as car- 
bonate, thus diminishing the respiratory area. Chlorine, in a free 
state or as chlorinated lime or soda, exerts, even in extremely dilute 
condition, as less than one part in 100,000 of water, a very fatal in- 
fluence. Iron salts act not only as poisons, but the ferrous forms take 
up the dissolved oxygen and become ferric; then these become reduced 
and again absorb it, and continue in this way to rob the water of its 
power to sustain the respiratory function. But, on the other hand, 
while fresh sewage of ordinary composition is sought for by many 
species of fish as a desirable food, putrefying sewage will either act in- 
juriously on fish or make the water so repugnant to them as to drive 
them away. 
4. Sewage Irrigation.-In the " broad irrigation " or " sewage 
farming" system, sewage is utilized in the growing of crops which 
take up and dispose of much of the water and dissolved solids, while, 
at the same time, oxidation processes in the interstices of the soil destroy 
the bacteria and convert the remaining organic matter to simple harm- 
less products. For the disposal of large volumes by this method, 
very large sewage farms are required. The necessary area will depend 
upon the nature of the soil, its permeability and water capacity, and 
upon the amount of annual rainfall. 
This method has been very extensively adopted in England, where 
there are hundreds of sewage farms, and in Germany, France, India, 
America, and elsewhere, and everywhere it has been found that no hard 
and fast rules as to area per thousand of population can be followed. 
In England, the idea obtains very generally that every hundred of 
population will require one acre of sewage farm, but this, it must be 
remarked, while it may apply in England, which is a rainy country 
and one where domestic sewage is likely to amount to many more 
gallons per capita than on the Continent, owing to the more general 
habit of daily bathing, is much in excess of actual need where the soil 
is more suitable for the purpose, where the rainfall is less in amount, 
and where domestic sewage per capita is produced in smaller quantities. 
According to Waring, each acre of a well-regulated plant will, under 
ordinary conditions, absorb and purify the sewage of 250 to 500 per- 
sons, and if the soil be of porous fine sand and the question of crops 
be put in the background, that of 1,000 to 1,500. As the population 
grows, the plant must be enlarged, and hence it is necessary to hold 
land in reserve to meet future demands. 
Of the very first importance is the selection of a suitable tract of 
land for the establishment of the plant. This, of course, is not always 
possible, for sometimes no land is available, and again such as is at 
hand may be quite unsuited to the purpose. It must be neither too 
permeable nor too close. If too coarse, it will permit the passage of 
the sewage so rapidly that no purification, or at most imperfect puri- SEWAGE IRRIGATION. 
475 
fication, will occur, and the effluent will be unfit to be discharged from 
the underdrains into a water course; if too close, as would be the case 
with a very dense clay, the imbibition of water will be so slow that it 
will fall far below the amount of loss by evaporation. The very best 
soil for the purpose is one of sandy loam with fine interstitial spaces 
which will permit not too rapid percolation, and wherein the processes 
of nitrification can go on most thoroughly. Very dense clays may be 
rendered suitable by the admixture of sand or lime and by tile under- 
draining, and then will perform its office in a satisfactory manner. 
With a proper plant and intelligent supervision, the purified sewage 
makes a clear, bright, and practically sterile effluent. 
In order to carry out the scheme so as to achieve the best results, the 
farm should be divided into three parts, not necessarily of equal area 
but of equal absorbability, each of sufficient capacity for the disposal 
of the entire sewage of a single day. Then each third can be worked 
in its turn, receiving sewage one day and resting two, but the capacity 
of none must be overtaxed, lest the soil become swampy and filthy and 
cease the work of oxidation. 
The farm is laid out in broad ridges and furrows, the latter receiv- 
ing the sewage at regular intervals ; the crops grow on the broad ridges 
between. It should be naturally or artificially underdrained at a dis- 
tance of about six feet, so that the purified filtered water may be re- 
moved and allowed to discharge into any convenient water-course. 
The amount of daily dose per acre varies very widely according to 
pore-volume, permeability, and rankness of vegetation. On a close soil 
in a cold climate, but a few thousand gallons per acre can be discharged, 
while on an open soil in a hot country with rank vegetation, as in 
Madras, for instance, as much as 75,000 gallons daily will not be ex- 
cessive. The chief crops grown are cabbages, mangolds, timothy, rye 
and other grasses ; in short, such as can bear heavy flooding of the soil. 
As regards profit, it may be said that this system is the only one 
which can possibly yield a revenue, but this is not due to the supposed 
value of the manurial constituents of the sewage, but to the water itself, 
which puts the crops outside the danger of drought and beyond the 
need of rain. In some climates, crop follows crop the year round and 
the annual yield is large ; in others, the season is so short in comparison 
that the yield is much less. At the Berlin farms, a yearly yield of 25 
tons of grass per acre, equal to five of hay, is regarded as large and 
satisfactory, while at Krishnampett in Madras, where eight crops per 
year are harvested, the output, according to Dr. J. N. Cook,1 was in 
one year 69 tons per acre, equal to about 23 of hay and worth nearly 
two hundred dollars. The city of Berlin purchased and set aside 20,000 
acres of land for its sewage farms, and notwithstanding an outlay of 
more than 13,000,000 dollars for the entire plant, receives a yearly profit 
of 60,000 dollars from its operation, the labor costing nothing except 
for maintenance of the men engaged, these being condemned thereto 
for various minor misdemeanors. 
1 Indian Medico-chirurgical Review, Dec., 1895, p. 676. 476 
DISPOSAL OF SEWAGE. 
Whether there be a profit or not, this aspect of the question must 
ever be kept in the background and the primary object ever in view. 
When the farms are let out to contractors, it is always advisable and 
even necessary that they be under the supervision of municipal 
authority to insure that the public good is not subordinated to private 
gain. 
Influence of Sewage Irrigation on Health.-Concerning the influence 
of sewage farms upon the health of those dwelling on and near them, 
the evidence is entirely on one side and in opposition to what would nat- 
urally be supposed to be the case. It is the same from Berlin, Paris, 
Edinburgh and the hundreds of other places where the system is in use, 
and all to the effect that in no way is it injurious. It is true that not 
infrequently the sewage gives rise to more or less disagreeable odor, 
especially if it be stored too long, but the fields themselves are gener- 
ally quite free of nuisance, and even though odor be present, it produces 
no harm. At the Berlin works, in a population of more than 1,500, 
there was one death from typhoid fever in five years, the general death- 
rate was very low, and the zymotic death-rate exceedingly so; in fact, 
during one year it was nil. 
Complete freedom from infectious disease is by no means unique, 
but is, indeed, a common condition in the experience of sewage farm- 
ing. At the farms at Gennevilliers, where the sewage of Paris is re- 
ceived, the population is constantly increasing, the general health is 
excellent, and the general death-rate is low and continually decreasing. 
An extensive epidemic of typhoid fever in Paris would be supposed to 
be the forerunner of another of greater comparative severity where its 
sewage, containing all the bowel discharges and urine of sick and 
well alike, is treated, but experience has demonstrated that such is by 
no means the case, for in 1882, for instance, when Paris was the 
victim of an unusually extensive outbreak of that disease, there was 
not a single case at Gennevilliers. 
So far as is known there is as yet no proof that sewage irrigation 
has ever been in any way responsible for the occurrence of any exten- 
sive outbreaks of typhoid fever, dysentery, or cholera, or, indeed, of 
entozoic trouble. Nor is there any reason to look askance upon the 
products of the farms, despite assertions to the contrary based on 
surmise and inexperience, for the facts show that grass and other 
crops are of good quality, make good fodder, and bring good results in 
milk and butter when fed to cows. 
Ferre1 has, it is true, reported an outbreak of typhoid fever in a 
girls' boarding-school at Jurangon, which was presumably due to vege- 
tables from a garden watered with the contents of an infected cesspool; 
and another localized outbreak of the same disease due to infected 
celery has been reported by the State Board of Health of Massachu- 
setts. This occurred in September, 1899, at the Insane Asylum at 
Northampton, in which, prior to September 10th of that year, but four 
cases had occurred during ten years. Then cases began to appear, and 
1 Annales d'Hygiene et de Medicine Legale, Jan., 1899, p. 23. 
A THE WARING SYSTEM OF IRRIGATION. 
477 
in fifteen days the number had reached thirty-nine, and later a few 
more. Investigation proved beyond any reasonable doubt that the 
outbreak was due to celery grown in beds which received the sewage 
of the institution. The method of banking employed in the cultivation 
of the plants made them a favorable medium for transmitting the dis- 
ease. It will be noted, however, that neither of these outbreaks was 
due to produce from a large farm receiving the diluted sewage of a 
distant municipality. 
Aside from local considerations of health, what are the results at- 
tained? This question can be answered in a few words. The organic 
matters of the sewage are completely destroyed by the saprophytic 
bacteria, which also dispose of their pathogenic brethren; the greater 
part of the water is taken up by growing vegetation and evaporated 
into the atmosphere, and the balance in practically sterile condition 
sinks into the subsoil or is carried away by the underdrains and dis- 
charged into a stream. The effluent at Gennevilliers, for example, is 
organically purer than the original water before it becomes sewage. 
The Waring System of Irrigation.-Irrigation on a small scale, 
known in this country as the "Waring system," is very commonly re- 
sorted to for the treatment of sewage of single houses and small settle- 
Fig. 90. 
Field flushing tank. 
ments. As begun by the Rev. Mr. Moule, the inventor of the earth 
closet, it was a scheme for the disposal of the liquid wastes which 
could not be cared for by his closets. The plant consisted of an open- 
jointed tile drain laid a little below the surface of the ground, parallel 
with and close to a row of grapevines. It was next enlarged by Mr. 
R. Field by the addition of a reservoir or flushing tank, shown in Fig. 
90, by means of which the whole drain could be flooded throughout 
and intermittently. Brought to the notice of Colonel Waring, he 478 
DISPOSAL OF SEWAGE. 
adopted the system for his own house and proceeded to improve it in 
several directions and to bring it into common use. Under him, the 
system was brought to its present state of perfection. 
The plant consists of a reservoir into which the sewage runs, a wire 
screening basket to separate the paper and other matters not easily 
oxidizable, an automatic siphon by which complete discharge is se- 
cured as often as the reservoir becomes filled, and a gate-chamber by 
means of which the flow is diverted to any of the three outlets which 
lead to a miniature sewage farm. The drain pipes are laid, with open 
joints, not over ten inches below the surface, and the ground where 
they discharge may be used for grassplots or gardens. The results 
are most satisfactory in any way; the organic wastes are oxidized by 
the soil bacteria, and the water which sinks into the subsoil is incapa- 
ble of causing pollution such as occurs when cesspools with open bot- 
toms below the zone of saprophytic bacteria are employed. 
Within recent years, the tendency has been to do away with the 
drains where sufficient land is available, and to discharge the sewage di- 
rectly upon the surface ; and in 1896, it was predicted by Colonel War- 
ing,1 that before the end of the century "the use of the underground 
tiles will have become exceptional." Fresh sewage thrown upon 
grass is quite inoffensive, except to the sight, unless deposited in such 
amounts in the same place as to cause miring of the ground, cessation 
of oxidation, and consequent putrefaction. It is, of course, necessary 
that the screened matters be removed frequently and buried or burned, 
and that the reservoir be cleansed at regular intervals. 
5. Sewage Filtration.-The method of intermittent filtration of 
sewage is the same in principle as the process described in the chapter 
on water. Like that, it is more than a mechanical separation of sus- 
pended matters : it is a process of screening, oxidation, and eventually 
almost complete purification, much like sewage irrigation. As early 
as 1836, Bronner, of Heidelberg, endeavoring to learn the reason 
why the constituents of fertilizers in solution failed to reach the 
deeper layers of the soil, filled a bottle, having a small hole in the 
bottom, with sifted garden soil and poured in gradually a thick stink- 
ing manure juice and observed the character of the effluent, which 
he found to be almost odorless and colorless, and devoid of fertilizing 
properties. 
But the system of sewage purification by this means had its begin- 
ning within recent years at the experiment station at Lawrence under the 
direction of the engineering department of the State Board of Health of 
Massachusetts, and is now in actual use by many municipalities in this 
country and abroad. The filter beds are best made of sand, not finer 
than 0.2 mm. grain size, and gravel. Ordinary loams, clays, and peat 
are practically useless as filtering materials, on account of the difficulty 
with which water passes through them. The purifying agents are the 
bacteria which are soon established within the interstices, and these 
can act only with the assistance of atmospheric oxygen, and so the 
1 Yale Medical Journal, Nov., 1896. SEWAGE FILTRATION. 
479 
application of the sewage must alternate with thorough aeration of the 
bed. Unless the application be intermittent, the wrong form of bac- 
terial life is encouraged and the process fails. Where sand of the right 
sort is not obtainable, many other materials as coke, burnt clay, coal 
dust, and cinders, have been used as substitutes. 
It is unnecessary to disturb the main body of the filter after the 
process has been started, but on account of the tendency of solid ma- 
terials, such as paper, etc., to accumulate in the upper layers, it is found 
necessary to rake or dig over the surface as often as the indications 
point out. According to Mr. X. H. Goodnough,1 of the Engineering 
Department of the State Board of Health of Massachusetts, the beds 
of four of the filters at the Lawrence station, after ten years' continu- 
ous operation, required only a weekly raking and a semi-annual spad- 
ing to a depth of six to eight inches. In five years, it had not been 
necessary to remove any of the clogged sand for renewal of the sur- 
face. During the tenth year, more than 90 per cent, of the organic 
matter of the very strong Lawrence sewage was removed, and also 
more than 99 per cent, of the contained bacteria. 
It has been shown by the experiments at Lawrence that 100,000 gal- 
lons of crude sewage per day can be purified during all but the colder 
months of the year by each acre of filter underdrained at a depth of 
three to five feet. And even in winter, there is no great difficulty in 
disposing of almost as large volumes if the beds are properly looked 
after, and provided the sewage is delivered in large volumes at a time. 
With delivery of small quantities, there is more danger of freezing. 
It must be borne in mind that the sewage of many kinds of manu- 
facturing establishments is not suited to sand filters or other processes 
which depend for their efficiency on micro-organisms, because of con- 
taining chemicals which will destroy the life of these necessary agents. 
Thus, in the single industry of tanning, at least two substances are 
used which interfere with bacterial growth. In the first place, green 
skins are quite likely to be preserved by means of chemical disinfec- 
tants (sulfonaphtol), and, next, when the skins are soaked preparatory 
to having the hair removed, large quantities of chemicals, such as 
arsenic sulphide and lime, mixed together, are used to facilitate the 
process. Sewage containing these substances in sufficiently large 
amount, if applied directly to a sand filter, will quickly interfere with 
its efficiency by destroying the nitrifying organisms. Sewage from 
this industry contains, in addition, such a very large amount of organic 
matter in suspension, that if applied directly to a sand filter, it will 
cause clogging very quickly. 
Hence this and other industrial sewage of objectionable character 
must be submitted to sedimentation or other treatment, according to 
its nature, as a preliminary to sand filtration. It has been found that 
arsenic, for instance, can be completely removed by passing the sewage 
through coke breeze. " The removal is probably due to a combination 
of the arsenic with the iron in the coke and the formation of an insol- 
'Journal of the Massachusetts Association of Boards of Health, July, 1898. 480 
DISPOSAL OF SEWAGE. 
uble double salt of iron and arsenic, which is retained in the coke." 1 
Filtration through coke has also been found to be efficient in removing 
the organic matters, even when the sewage is applied at the rate of 
250,000 to 300,000 gallons per acre daily. Other kinds of industrial 
sewage may contain other objectionable substances which may tend to 
clog the filter, as grease, soap and other materials, and these may re- 
quire special treatment. The importance of guarding against injury 
to the nitrifying organisms by special sewages must be borne in mind, 
and also that if the process be stopped in winter, it cannot be renewed 
until the return of warm weather. 
6. Other Biological Processes: Dibdin's "Bacteria Bed." 
Cameron's " Septic Tank."-As an outcome of experiments in the 
further purification of the effluent of chemically treated sewage, sprang 
the method known as that of Dibdin's bacteria filter. With the idea 
that purification in a filter bed is not wholly brought about at the 
surface, but that the whole body of the filter is concerned therein, ex- 
periments were made to determine the result of filling a bed and re- 
straining the outflow for different periods of time, thus giving the 
organisms throughout the bed the same opportunity for action. When 
the contents were allowed to run off through the underdrains, the in- 
terstices of the bed became filled with air by inspiration, and after 
standing thus for a time, the process of filling, standing, and emptying 
was repeated continuously for six days, and then an interval of twenty- 
four hours was allowed for complete aeration. 
The results obtained were most promising. During the first month, 
running at the rate of half a million gallons daily, the purification, 
measured by the albuminoid ammonia, ran between 70 and 80 per cent., 
and after a full month reached 83 per cent. The effluent was then so 
pure that fish, placed in it, lived many weeks. Later on, the plan 
adopted comprised two hours for filling, one for standing full, and five 
for emptying, so that the cycle was completed in eight hours. Passing 
filtrate at the rate of a million gallons a day for eight weeks, the bed 
was found to show 78 per cent, of purification. The good results 
were observed to be yielded even when the weather was so cold that 
ice formed on the surface. From these experiments it appears, there- 
fore, that the purifying capacity of a filter may be expressed in terms 
of cubic as well as of surface measure. 
In consequence of the favorable results of these experiments, Mr. 
Dibdin recommended similar treatment for crude sewage, and in No- 
vember, 1896, the process was instituted at Sutton. An average of 
29,165 gallons per day, equal to 773,000 gallons per acre per day, 
was treated with good results, the purification amounting to 66 per 
cent. The effluent was further treated on other beds, and thus a total 
reduction of 86.5 per cent, was brought about. The effluents were 
nearly inodorous and suggested nothing worse than freshly turned 
garden soil. During the 76 days of observation, the suspended solids 
disposed of by bacterial agency amounted to the equivalent of over a 
1 Report of the State Board of Health of Massachusetts for 1896, p. 430. OTHER BIOLOGICAL PROCESSES. 
481 
ton of sludge daily, so that not only was purification effected much 
more simply and cheaply than by chemical treatment, but the annoying 
and expensive matter of sludge disposal was entirely done away with. 
For the disposal of a million gallons of sewage per day, Mr. Dib- 
din 1 recommends as follows : Before being passed on to the beds, the 
sewage should be screened in order to remove mechanically as much 
of the suspended matters as possible, and these may be burned or buried. 
The finer solids " if placed upon a filter constructed in the ordinary 
manner with a stratum of fine material upon the surface, will at once 
form a layer of slimy mud, impeding the progress of the water into 
the pores of the filter, and preventing the entrance of air so necessary 
for the healthy life processes of the bacteria, with the result that in a 
short time the whole mass becomes putrid, aud the ' filter ' is a failure. 
" The first set of bacteria beds should, to be on the safe side, have 
a collective capacity of 160,000 cubic feet, divided into, say, nine par- 
titions. These beds should be filled with either coke, burnt ballast, or 
other suitable substance which has been rejected by a half-inch mesh 
in order to exclude dust and small stuff, and thus lessen the chance of 
clogging from the accumulation of sludge and the zooglea form of 
bacteria, which by its gelatinous character, under favorable conditions 
might develop to a sufficient extent to assist materially in rendering the 
filter water-logged. * * * In addition to this set of beds filled with 
coarse stuff, a second series of the same capacity should be constructed 
at such a level that they can be filled without pumping from the first. 
These should be filled with the fine coke or ballast passed by the sifting 
in the first instance, but the fine dust should be rejected. 
" If it should be desired to obtain a still more perfect effluent, and 
thus to realize the ideal of perfection, namely, an approach to drinking 
water, another set of filter beds of the same area as the foregoing may 
be provided in those cases where the levels permit, and filled with 
very fine breeze or fine sand, such as that used by the water com- 
panies." The beds of each series are to be filled in order, and when 
No. 8 is filled, No. 1 is ready for its second charge, and so on. Allow- 
ing one hour for filling, two for resting full, one for emptying, and 
three for resting empty, each bed can receive three charges in twenty- 
four hours. The ninth bed is to be held in reserve to replace any one 
which may be thrown out of action, and " it would be a useful arrange- 
ment to systematically throw one tank out of action each day, thus 
giving them all a day's rest once in nine days." The efficiency of the 
various beds may be determined occasionally by testing the filtrate for 
nitrates, the presence of which in fairly regular amount is evidence of 
unimpaired activity. 
According to Dr. Clowes,2 the first effluent of the experimental coke 
beds at Crossness for the treatment of London sewage is of such a 
character that fish can live in it for months. The whole of the sus- 
pended matter and 51.3 per cent, of oxidizible and putrescible matters 
1 Purification of Sewage and Water, London, 1897, p. 129. 
2 Bacterial Treatment of Sewage. Second Report. London County Council, 1899. 482 
DISPOSAL OF SEWAGE. 
are removed by a single treatment. Double treatment raises the per- 
centage from 51.3 to 69.2. The deposition of cellulose in various 
forms, as cotton, paper, woody matters, straw, and chaff, which matters 
do not appear to be acted upon to any extent by bacteria, causes con- 
siderable clogging of the interstices and hence reduces the capacity of 
the filter. It was estimated that the reduction amounted to about a 
third in ten months. 
At Sutton, it must be said, there is a catchpit to intercept the 
heavier matters and a very efficient screening machine, and since the 
sewage comes down in so fresh a condition that neither the paper nor 
the solid faeces have had a chance to disintegrate, a very large percent- 
age of organic matter never reaches the filter at all. 
The Cameron " septic tank " process is one in which the anaerobic 
bacteria are first utilized for the purpose of hastening the decomposition 
of the organic matters. Contrary to the general opinion that sewage 
ought always to be treated before the beginning of putrefaction, in this 
system the sewage is kept in storage tanks out of contact with light 
and air until the organic matter is broken down, and then is passed on 
to bacteria beds where the aerobic forms continue the work. While 
the treatment of sewage in large volumes by this process is of recent 
date, the principle is not new, for in 1881, a patent was granted in 
France to M. Louis Mouras for a cesspool which appears to be the 
same thing as the Cameron tank on a small scale. In fact, any tight 
cesspool is nothing less than a primitive septic tank. 
The first attempt at purification of town sewage by this system was 
instituted at St. Leonard's, a suburb of Exeter, England, by Mr. 
Donald Cameron, whose initial plant consisted of a large, underground, 
covered tank, sixty-four feet long, eighteen feet deep, and of an average 
depth of a little over seven feet, and five Dibdin bacteria beds filled 
with coke breeze and clinkers. The crude sewage, before entering the 
tank, passes first into a grit chamber, which is three feet deeper than 
the tank, and in this the heavy matters fall and are detained, but may 
be removed without interruption of the process in operation within the 
tank. The sewage is not screened in any way, and enters the tank, 
after passing the grit chamber, by inlets placed five feet below the sur- 
face. These are so placed for several reasons : the screen floating on 
the surface is not disturbed, gases from the tank cannot escape back- 
wards, and air cannot enter the sewage. 
In the tank, the sewage undergoes putrefaction, the organic matters 
being broken up into simpler soluble forms and in great part converted 
to carbon dioxide, sulphuretted hydrogen, ammonia, nitrogen, and 
other gases. The flow through the tank is continuous, and the effluent 
passes off through outlets located at the further end at the same level 
as the inlets. 
In the center of the tank, an inspection chamber of brick and thick 
plate glass is constructed, and from this the processes going on can be 
observed. At the surface of the liquid, a scum about two inches in 
thickness, consisting of flocculent matter in various stages of decompo- 483 
OTHER BIOLOGICAL PROCESSES. 
sition, is formed, much of it brought up from the bottom by gases 
formed in the process of decomposition. Throughout the tank, count- 
less small masses are seen rising through generation of gases and falling 
by their own weight. Every time a particle rises or falls, it loses in 
volume, and finally it disappears. 
The effluent from the tank, brownish yellow in color and offensive 
in odor, is next admitted to the bacteria beds, where the nitrifying 
organisms perform their share of the work. In its journey to these 
beds, it passes in a thin layer over the sides of troughs closed at both 
ends, and thus becomes aerated by contact with the air. By an auto- 
matic arrangement which regulates the flow, one bed remains full while 
another is being filled, and after a certain time is allowed to empty. 
Four beds are kept in use, the fifth resting for a week. Each bed, 
then, is in operation four weeks out of every five, and after its week 
of rest, takes the place of the one which has been longest in use. The 
accumulation of sludge in the tank is very slight. It amounted to but 
fifteen inches at the end of ten months' trial, during which time over 
seventeen million gallons of sewage were treated. 
Analysis has shown that the organic matters in solution are reduced 
in amount nearly a third and the suspended matters more than a half 
by bacterial action within the tank, and that, after passing through both 
the tank and the bacteria beds, the sewage loses practically all of the 
suspended matters and over 80 per cent, of the oxidizable organic sub- 
stances in solution. The effluent from the beds is fairly clear and suf- 
ficiently pure to warrant its discharge into a water-course. It is even 
claimed that it is fit to drink. 
The advantage of the tank lies in the reduction in the amount of 
suspended matters, whereby less clogging of the surface of the bed oc- 
curs, and in relieving the beds of much of the work of disposing of or- 
ganic matter by nitrification. The cost of working is, moreover, very 
slight, inasmuch as the apparatus, by reason of its ingenious system of 
automatic gears, requires little supervision. It is claimed that, with 
this system, as much as 363,000 gallons per acre of bacteria beds can 
be disposed of daily without nuisance. CHAPTER VII. 
DISPOSAL OF GARBAGE. 
Garbage comprises all manner of waste material and its disposal 
is of very great economic and sanitary importance. The daily 
accumulation in towns and cities is very great and its removal at regu- 
lar intervals is a matter of great concern to municipal administration. 
From a hygienic standpoint, the proper disposal of kitchen waste and 
other decomposable material far outweighs in importance the removal 
of such matters as waste paper, ashes, discarded boots and shoes, tin 
cans, bottles, and other rubbish, which in no way can affect the public 
health, but which for various reasons may not be allowed to accumulate 
in the household. In rural districts, the disposal of garbage in general 
is exceedingly simple, but in crowded communities it entails great ex- 
pense and is usually a very complicated problem. Since this work is 
concerned solely in matters of sanitary interest and not in economics, 
the consideration of this subject will be restricted to the methods of 
disposal of those matters the retention of which on occupied premises 
may be regarded as detrimental to health, namely, those known as 
kitchen refuse, or swill. 
The methods of disposal of these matters comprise those which may 
be carried out by the individual householder on the spot, and those 
adopted by municipal authority after house-to-house collection. 
In many households, they are disposed of by burning in the kitchen 
fire with or without a preliminary process of drying, for which a num- 
ber of simple apparatuses have been devised. A very efficient arrange- 
ment in common use consists of an enlargement in the lower part of 
the stovepipe, forming a chamber into which, through a doorway in the 
end or side, the refuse, in a suitable metallic holder with perforated 
sides and bottom, is introduced. Through this the hot air, gases, and 
smoke from the fire pass on their way to the chimney flue, and thus 
complete drying and partial carbonization are brought about. The 
dried residue is finally disposed of by burning in the stove, where it 
serves a useful purpose as fuel. 
In country and suburban districts, kitchen waste is advantageously 
disposed of by feeding it in a fresh and sweet condition to swine and 
poultry, and depositing in the soil such matters as they will not eat. 
Burying in the soil is a simple and effective method of disposal, entail- 
ing but little labor, since it is best not to deposit it very deeply. 
Near the surface, decomposition occurs quite rapidly, and so a covering 
of earth a few inches in depth is quite enough to prevent contamina- 
tion of the atmosphere with noisome odors. DISPOSAL OF GARBAGE. 
485 
The methods adopted by municipal authorities comprise dumping 
into the sea, disposal to farmers for swine-feeding, utilization as food for 
herds of swine kept for the purpose, and reduction and incineration in 
furnaces of special construction, known as destructors. Dumping into 
the sea is open to the objection that, under favoring conditions of 
winds, tides, and currents, much material may be washed ashore and 
become a nuisance and eyesore to the immediate neighborhood. Dis- 
posal to farmers involves cartage over miles of road in wagons, 
which, if not leaky for liquid matters, at least permit the escape of 
nauseous odors, to the annoyance of dwellers and travelers along the 
route. It involves, also, storage for at least a short time after collec- 
tion, unless the garbage wagons can be themselves sent into the coun- 
try, a proceeding which can hardly be regarded by the taxpayers as 
consistent with the proper management of municipal revenues. This 
period of storage is, in effect, a continuation of that which has, perhaps, 
extended already through several days or a week before collection, 
during which time, various fermentative processes have been at the 
work of decomposition with production of simpler compounds of offen- 
sive character. 
Incineration at special stations for the destruction of swill and all 
other combustible rubbish is being widely adopted by large communi- 
ties, and, in many places, has proved to be not only the most econom- 
ical method of disposal, but even a source of gain. To such a station 
are brought the daily collections of garbage, which at once undergo a 
process of sorting. Paper and pasteboard are utilized in the furnaces 
as fuel or are sold to be used in the manufacture of the cheaper grades 
of paper and cardboard ; old shoes and boots are disposed of to the 
makers of artificial leather, and rubbers and overshoes to the manu- 
facturers of rubber goods ; tin cans are heated to recover the solder; 
pieces of unconsumed coal are collected and used or sold for fuel; 
broken furniture, boxes, barrels, and other wooden objects are split up 
into kindling, and excelsior stuffing is utilized in the furnaces. In 
short, almost every kind of rubbish can be utilized in some way to ad- 
vantage. The late Colonel George E. Waring, Jr., experimenting in 
New York with a long traveling belt, on which the combustible waste 
from a district containing 200,000 people was deposited and picked 
over, found that 90 per cent, of it was salable and but 10 per cent, 
remained to be destroyed by fire. 
In some establishments now in operation, a long, travelling, endless 
belt of steel plates is employed, the carts dumping upon it at one 
place. As the material passes along, it is quickly sorted over by men 
on either side, and what is left is conveyed onwards to a bin, from 
which, in time, it passes to the furnace to serve to destroy the kitchen 
waste. 
It would be impossible, even if it were not quite unnecessary, to 
give in detail a description of the many varieties of machines and fur- 
naces which have been invented for the incineration of refuse. In 
general, it may be said that a destructor consists of a furnace with a 486 
DISPOSAL OF GARBAGE. 
chamber, provided with grate-bars, in which the dry or partially dried 
offal is burned, and a second chamber, in which it is subjected to the 
preliminary process of drying. This second chamber is placed behind 
the front compartment, which receives the dried garbage and other 
combustible material serving as fuel. In the best forms, two fires are 
maintained : one at the forward end and the second at the stack end of 
the furnace, the latter being designed to ensure complete combustion 
of vapors and dust before entrance to the chimney, from which, other- 
wise, they might issue in such a form as to create serious nuisance, not 
alone to the immediate neighborhood, but even for considerable dis- 
tances away. 
The burning of the smoke and fumes is very essential, and failure 
to provide therefor, or the unsuccessful operation of the fume cremator, 
has caused the abandonment of many plants, which, with better instal- 
lation, should have worked successfully and to the public satisfaction. 
In many English cities, destructor furnaces have been in operation for 
years in close proximity to dwellings, schools, and hospitals without 
causing any offense. At Ealing, for example, the furnace is located 
at a distance of 180 yards from two hospitals; in Whitechapel, within 
a very few yards of dwelling houses in the midst of a very populous 
district; at Leicester, but a very few yards from a large school and 
immediately adjoining a considerable number of dwellings. 
The fume cremator consists of a reverberatory arch with rings of 
firebrick, placed in the direction taken by the gases. Projecting ribs 
deflect the vapors to the top of an intensely hot fire, in which they are 
destroyed. Provision is made for rapid removal of ashes and for 
drafts of air at needed points to keep up a continuous very high tem- 
perature of above 2,000° F. The heat produced is commonly utilized 
in the production of steam for the engine which does the necessary 
hoisting and other work and drives the shafting connected with the 
endless belt and other appliances. Another most useful and econom- 
ical application is the utilization of the great store of energy for main- 
taining electrical light plants for lighting the premises and even the 
public streets. In New York and Boston, the surplus energy is util- 
ized, but at most other plants in the 54 cities and towns of this country 
which, in 1899, were using the process, the heat is wasted. 
At the beginning of 1899, 81 communities in Great Britain were 
employing incineration as the chief means of disposal of refuse, and 76 
of them turned the developed heat to some useful purpose. About a 
third of the number use the power for electric lights for the works or 
streets or both together; nearly two-thirds maintain mills for grinding 
materials for mortar and clinkers for pathways; six employ the steam 
for the purpose of public disinfection ; several, for pumping sewage, and 
others, for various useful purposes. In one city, 3,000,000 gallons of 
sewage are pumped through a twenty-foot lift, the works are lighted 
by electricity, the shops and forges of the municipal service are sup- 
plied with power, and other work also is performed. 
Reduction.-In the reduction process, the kitchen garbage is stored REDUCTION. 
487 
in tanks which permit the draining away of most of the water, which 
is conducted directly to the sewer. Next it is dried in cylindrical 
steam-jacketed chambers, into which hot air and superheated steam 
are conducted, the process requiring about 6 hours. The material 
loses about three-fourths of its weight, which passes off in the form of 
aqueous vapor and is condensed and discharged into the sewer; the 
non-condensible stinking vapors are disposed of in the vapor cremator 
connected with the boilers in which the steam is generated. The 
dried residue is next introduced into tanks of naphtha, and the whole 
is heated by steam coils until all grease has been removed, when the 
naphtha solution is separated. This is then distilled, the naphtha 
passing over and being reclaimed for repeated use, and the fat remain- 
ing behind as a valuable product. The extracted residue is dried 
again and worked up into fertilizer. 
Reduction methods are applicable only to large cities, and since it is 
almost impossible to conduct the works without creating a nuisance, 
these must be located at such a distance from a community that the 
value of property may not be impaired and the daily enjoyment of 
life may be in no way sensibly abridged. If the amount of collectable 
kitchen waste is sufficiently large, say that from a population of at 
least 150,000, and if the works can be so placed as to cause no 
nuisance and, at the same time, not to necessitate a long and ex- 
pensive haul of the material, reduction has been found to fulfill both 
the sanitary and the economic requirements, the yield of grease and 
fertilizer having considerable value, thus reducing materially the 
cost of disposal. But as in the case of sewage, it must be borne in 
mind that the removal and disposal of waste is a sanitary measure and 
should not be viewed too much from the standpoint of profit-making. 
If the quantity of garbage collected is too small to warrant treatment 
by reduction processes, it may be burned to advantage in destructors. 
A combination of the two methods, reduction and cremation, would seem 
to be the most advantageous for large communities producing a very 
large daily amount of general wastes. But the possibility of nuisance 
from all reduction works, a nuisance which has already caused the 
abandonment of the great majority of the plants which have been in- 
stalled in this country, must ever be borne in mind, even though the 
nuisance be limited to a small percentage of the population, who, if they 
complain, are regarded by the rest as unduly sensitive, prone to mag- 
nify small discomforts and give them a factitious importance, and in- 
considerate of the general welfare, which, even if true, can not deprive 
them of their right to appeal to the courts for the abatement of the cause 
of their discomfort. CHAPTER VIII. 
DISINFECTANTS AND DISINFECTION. 
Disinfectants, or germicides, are agents which bring about the de- 
struction of bacteria in general and, more particularly, of those that 
act as the exciting causes of disease. While they are all to be classed 
as antiseptics, the latter, as a class, are by no means necessarily disin- 
fectants, since many of them act simply to delay or prevent the action 
of fermentative agents, without exerting any destructive influence upon 
them. Cold, for example, is a most efficient antiseptic, but while it 
may inhibit growth and activity of micro-organisms, it does not neces- 
sarily deprive them of vitality. 
Deodorants are agents which remove or mask disagreeable odors, 
but they are not necessarily disinfectants. Some deodorants are effi- 
cient disinfectants, but not all disinfectants are efficient deodorants. The 
latter are largely substances which, being of strong peculiar odor, are 
used to overcome or supercede disagreeable odors, but without exerting 
any influence upon the causes thereof. Odors may or may not be a 
concomitant of infectious matter according to circumstances, and when 
so, the mere fact of their being overwhelmed by a more powerful rival 
smell has no influence on the vitality of the bacteria present. Some 
deodorants remove smells without the creation of another and without 
exerting any action upon their causes; thus, charcoal and ordinary 
earth. 
The function of disinfectants is the destruction of morbific agents so 
that they shall not spread infective diseases. They are not curative 
of the infected person, but are preventive of the spread of the disease 
from that person to others. An efficient disinfectant for general pur- 
poses must possess the property of killing not this and that species of 
bacteria, but one and all and their spores as well. Some pathogenic 
bacteria have a tolerance for certain disinfectants and can acquire one 
gradually for certain others. Such agents cannot, therefore, be in- 
cluded among the efficient class for general use. For special work in 
destroying the infective agents of certain diseases, disinfectants which 
have been proved to exert a destructive influence on the particular or- 
ganisms may be used, although they have failed to show an equal power 
against other, more resistant, varieties. 
Disinfectants may be divided into two classes, namely : 1. Physical 
agents. 2. Chemical agents. 489 
PHYSICAL AGENTS. 
PHYSICAL AGENTS. 
The physical agents are : 1. Light. 2. Heat. 
Light.-Direct sunlight is one of the most important disinfectants 
known. It retards the growth of many organisms and, after a vary- 
ing number of hours of exposure, completely destroys the vitality of 
a number of the most important pathogenic bacteria, including some 
generally recognized as highly resistant. Diffused daylight and elec- 
tric light are also effective, but in a much diminished degree. Koch 1 
announced, in 1890, that the bacillus of tuberculosis is killed by direct 
sunlight in from a few minutes to several hours, according to the 
thickness of the layer of material in which it is exposed, and by dif- 
fused light in from 5 to 7 days. Dr. Franz Migneco 2 exposed tuber- 
culous sputum on linen and woolen fabrics to direct sunlight and 
found that, provided the layer was not too thick, the bacilli could not 
resist longer than from 24 to 30 hours. The virulence was observed 
to diminish gradually after 10 to 15 hours and to disappear completely 
after 24 to 30 hours. 
Janowski,3 experimenting with the typhoid fever bacillus, discovered 
that that organism failed to grow when planted in bouillon and ex- 
posed for 6 hours to direct sunlight, and that in bouillon, exposed 8 
hours out of every day to diffused light and kept in the dark the rest 
of the time, its development was much delayed; but in the same 
medium, kept wholly in the dark, cloudiness was observed in from 16 
to 20 hours. That this action is not due to increase in temperature, 
was first shown by Saverio,4 who exposed gelatin cultures of the or- 
ganisms of typhoid fever, anthrax, and cholera, and Staphylococcus 
pyogenes aureus to sunlight and electric light for from 2 to 47 hours, 
and made careful observations of the temperatures within the tubes. 
He discovered that the most energetic action was not coincident with 
high temperatures, though the latter hastened the beginning of the 
process. The action of electric light was much less energetic than 
that of the direct sunlight. Anthrax spores were destroyed almost as 
quickly as the bacilli, and after a certain length of time their virulence 
progressively diminished. The red and infra-violet rays appeared to 
exert no bactericidal properties. 
Geissler5 found that direct sunlight exerts a more powerful influence 
on cultures of the bacillus of typhoid fever than an electric light of a 
hundred-candle power at a distance of a meter and advanced the propo- 
sition that the effects on the bacteria are due in part to changes brought 
about in the character of the culture media. That the action of sun- 
light is chemical, is shown by the differences in the capacity of the 
1 Vortrag auf dem zehnten internationalen medicinischen Congresse, 1890. 
2Archiv fur Hygiene, XXV., p. 361. 
3 Centralblatt fur Bakteriologie, VIII., No. 6. 
4Annali dell'istituto d'igiene sperimentale della reale universita di Roma, II., 
Serie 2, p. 121. 
5 Centralblatt fur Bakteriologie, XI., Nos. 6 and 7. 490 
DISINFECTANTS AND DISINFECTION. 
different rays for producing results, the ultra-violet being endowed 
with the greatest power. 
This change in the character of the culture media has been noted also 
by Kruse,1 who found that liquid media,containing complex nitrogenous 
substances, are so altered by the influence of light that they take on 
antiseptic properties against the bacteria, and that the change is pro- 
portionate to the intensity of the light and the duration of the exposure. 
It is directly due to the atmospheric oxygen, which, according to 
Momont,2 is simply assisted by the light, which by itself would have 
but little effect. But it is not alone through changes in the media that 
bacteria are killed, but through changes brought about within them- 
selves as well. And, indeed, it has been demonstrated that not alone 
bacteria, but their toxins also, are affected. According to Fermi and 
Celli,3 the toxin of tetanus, diluted with distilled water and exposed to 
direct sunlight at temperatures between 40 and 50° C., is rendered 
inert in 8 hours, and at 37° C., in 15 hours. In dried condition, it 
loses its power after 4 hours. 
Moisture and access of air are also important factors, as has been 
shown by Momont, who found that anthrax bacilli in a moist state were 
killed in 2.5 hours with free access of air and survived over 50 hours 
when air was excluded. Dry bacilli were killed with access of air in 
5 hours; dry spores, exposed in glass without air, were virulent after 
110 hours and proved to be more resistant than others in a moist 
state. 
The rapidity of action of sunlight is influenced also by the num- 
ber of bacteria present-the greater the number, the longer the time 
required for the bactericidal effect to be instituted. 
The sterilizing influence of sunlight on the bacteria of drinking 
water and sewage has been demonstrated by Procaccini, Buchner and 
Minck, and others to be very considerable, especially at and near 
the surface. Procaccini4 obtained positive results at a depth of from 
26 to 30 centimeters. Minck and Buchner5 found that water con- 
taining 100,000 B. coli communis to the cubic centimeter was ren- 
dered sterile in an hour. The bacilli of typhoid fever and cholera, 
and B. pyocyaneus also were found to be destroyed. Cultures of 
Bacillus typhi, exposed at a depth of about 5 feet, were sterilized in 
four and a-half hours, but at twice that distance beneath the surface 
the action virtually ceased. Buchner6 found, further, that diffused light 
has a strong influence, even as late in the year as November, on B. 
coll communis and B. pyocyaneus. The action of light is considerably 
interfered with by particles in suspension, but with fairly clear water 
the effects are quite perceptible at a depth of about 6 feet. The action 
1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XIX., p. 313. 
2 Annales de 1' Institut Pasteur, 1892, p. 28. 
3 Centralblatt fur Bakteriologie, XII., No. 18. 
4 Annali dell'istituto d'igiene sperimentale della reale universita di Roma, III., 
p. 437. 
5Centralblatt fiir Bakteriologie, etc., XL, p. 781. 
b Archiv fiir Hygiene, XVII., p. 177. PHYSICAL AGENTS. 
491 
of sunlight on bacteria in the presence of water is believed by many to 
be due to the production of hydrogen peroxide. 
The obvious disadvantages of relying upon sunlight for practical 
disinfection are that its supply is quite beyond 'control, and that, even 
on the brightest days, it is impossible to apply it to all parts of a house. 
Nevertheless, its beneficent action may, under favoring conditions, be 
taken advantage of in the treatment of furniture, hangings, and deco- 
rations, often the most troublesome objects to disinfect, especially in a 
country practice. 
Heat.-For purposes of disinfection, heat is employed as " dry 
heat," i. e., hot air, and " moist heat," i. e., steam and boiling water. 
Steam is employed under various pressures in both the saturated and 
superheated conditions. In both conditions it is actually dry, although 
as very commonly understood, saturated steam is associated with the 
idea of moisture. "Wet" steam is partially condensed saturated 
steam and contains suspended particles of water. The temperature at 
which steam is formed depends upon the pressure; and whatever the 
temperature and pressure, as ebullition begins and proceeds, the water 
is maintained at that temperature, and is constantly converted into 
steam, in which the heat employed becomes latent. Until all the 
water has become converted, the resulting steam is said to be saturated, 
since any vapor in the presence of the liquid from which it originates 
and in thermal equilibrium is necessarily saturated. In the saturated 
state, it can neither do work by expansion nor be cooled without un- 
dergoing partial condensation. 
When saturated steam is further heated, its temperature rises and it 
is then known as superheated ; and then, having a temperature higher 
than the condensing point corresponding to its actual density and vol- 
ume, it can be cooled and can do work by expansion without being 
condensed. When very much superheated, it behaves more and more 
like a perfect gas, while saturated steam differs, as a rule, considerably 
in its properties from a perfect gas. If water at the temperature of 
superheated steam be mixed with the latter, some of it will be vapo- 
rized and taken up; but mixed with saturated steam at the same tem- 
perature, no such action will occur. 
According to Rideal,1 the first recorded experiments in the sterilizing 
of organic matter by the application of heat were those of Needham, 
made prior to and during the year 1743, and the first application of 
this agent to disinfection on a large scale was made in 1831 by Dr. 
Henry, F.R.S., who treated infected clothing with hot air and showed 
that the clothing of scarlet fever patients, subjected to a temperature of 
200° F. for two to four hours, would not propagate the disease if worn 
by other healthy persons. The first use of direct steam as a disinfect- 
ant was made under the direction of Dr. A. N. Bell, U.S.N., in the 
case of the steamer Vixen and schooner Mahones, which were infected 
with yellow fever while on service in the Mexican war in 1848. 
Knowing of this use and its observed results, at the Quarantine and 
1 Disinfection and Disinfectants, London, 1898, p. 20. 492 
DISINFECTANTS AND DISINFECTION. 
Sanitary Convention held in Boston, Mass., in June, 1860, the com- 
mittee recommended that " steam generators and steam jackets or 
vats be provided for the disinfection of all personal, hospital, and 
ship's clothing and bedding, together with such other infected goods 
or things as may properly be subjected to high steam heat." 1 
In 1862, according to Dr. Bell, the U. S. Transport Delaware was 
disinfected by steam at the New York Quarantine Station on account 
of yellow fever, this being the first disinfection of a vessel at that 
station and probably the first at any of the port quarantines. Accord- 
ing to the same authority, Commander Ralph Chandler of the U. S. S. 
Don from Santa Cruz, W. I., reported to the Navy Department that 
his vessel had been infected with yellow fever in its worst form (23 
cases with 7 deaths), and that he had successfully disinfected the ward 
room and berth deck by means of steam. He recommended that ves- 
sels destined for service in the West Indies be provided with means 
of steaming the lower decks and holds. 
Dry Heat.-Dry heat is much less effective than moist heat, even at 
much higher temperatures and with longer exposure. Thus, hot air 
at 300° F. requires three or four times as long to accomplish the same 
work as steam at 212° and possesses the additional disadvantage of in- 
juring fabrics and other objects exposed to it. Most fabrics of cotton, 
linen, and silk will withstand an exposure of several hours to dry 
heat at 230° F., but beyond this point, evidence of impaired tensile 
strength is soon manifested. Even at 302° F. (150c C.), dry heat was 
found by Koch and Wolffhugel2 to be not always effective, even after 
two hours, while boiling water and streaming steam at 212° F. were 
found to produce the desired results in a very short time. Owing to 
its lack of penetrating power, dry heat is, moreover, only a surface dis- 
infectant, unless means are employed for the withdrawal of the cold air 
held in the interstices of fabrics and within their folds. On account 
of its inferiority to steam and its aptness to injure fabrics, it is now 
but little employed as a disinfectant. 
Steam.-Although steam had been recommended and used for pur- 
poses of disinfection as early as 1848, and although Pasteur, Tyndall, 
Cohn, and others had demonstrated in a number of extensive scientific 
investigations the sterilizing action of moist heat on putrefactive bac- 
teria and other micro-organisms and Tyndall had shown the necessity 
of discontinuous boiling for the sterilization of spore-bearers, the first 
investigation of the action of steam on the vitality of the bacteria asso- 
ciated with infective diseases was that conducted by Koch, Wolffhugel 
and their associates, the results of which were published in 1881. They 
demonstrated the very great superiority of steam over much hotter air 
and showed that the most resistant spores are destroyed within a few 
minutes. They studied its effects on the different kinds of articles, 
such as clothing, bedding, furniture, and other objects, which in sanitary 
practice may require to be disinfected, showed its applicability to all 
1 The Sanitarian, June, 1897. 
2 Mittheilungen aus dem kaiserlichen Gesundheitsamte, I., p. 301. PHYSICAL AGENTS. 
493 
excepting a limited number, such as furs, leather, and veneered furni- 
ture, and led the way to the installation of public disinfecting plants 
for municipalities, hospitals, and quarantine stations. 
A variety of apparatuses, both fixed and portable, have been devised, 
and their use is steadily on the increase not alone in large communities, 
but, especially in Europe, in thinly settled districts as well. For the 
latter, the portable apparatus on wheels is especially adapted, for it is 
beyond the limits of reason to expect small towns in which, perhaps, 
infective diseases of the kinds that call for thorough disinfection are 
only occasional visitors, to establish and maintain public stations, 
whereas a number of such communities may have joint ownership in a 
portable machine which can be despatched on demand to the point 
where its services are required. 
The general plan of the stationary and portable machines is essen- 
tially the same. They consist of one or more chambers of sufficient 
size to admit objects as large as or larger than a rolled mattress, and 
a boiler for the generation of steam, which is admitted through pipes 
controlled by valves. The most approved machines are so constructed 
that, after the objects have been introduced and the doors closed, the 
contained air can be withdrawn and a partial vacuum of about 20 
inches produced, the object of which will be explained later. This is 
best produced through the agency of a steam jet rather than by a 
pump, since the latter is much slower in achieving the same result and 
exerts no disinfecting action on the germs that are contained in the air 
withdrawn. The best machines are also provided with a steam jacket, 
which assures a more uniform diffusion of heat in the chamber walls 
and a lessened opportunity for condensation, and a non-conducting 
outside casing of asbestos or asbestos-magnesia composition to prevent 
loss of heat. 
The apparatus in use at the New York Quarantine Station may be 
taken as a type of the most approved construction. It consists of a 
chamber of steel, the inside dimensions of which are 4 feet by 3 feet 
3 inches by 7 feet 2 inches, with an outer shell of the same material 
and an intervening space of 2 inches. The outer shell is encased in 
a layer of asbestos-magnesia, 1.5 inches in thickness, for the prevention 
of loss of heat. At each end is a door, made to fit air-tight, swung 
on a crane, and fastened to the chamber by means of turn-buckles. 
Within the chamber is a movable track so arranged that the car, 
made of 1.5-inch angle-iron and No. 6 galvanized iron netting, for 
the reception of articles to be disinfected can be withdrawn at either 
end. 
The steam from the boiler enters the chamber through a 2.5-inch 
pipe at a pressure of 15 pounds to the square inch or at such other 
pressure as may be desired. By means of a steam exhauster, controlled 
by valves, a vacuum can be produced in one minute either in the 
chamber or in the space between the two steel shells. A fresh-air in- 
let, consisting of a 1.5-inch pipe provided with a valve by which it is 
opened and closed, and with a fine brass netting for the exclusion of 494 
DISINFECTANTS AND DISINFECTION. 
matters which otherwise might gain entrance, connects the chamber at 
its upper part with the external air. 
The apparatus is so disposed that the two ends of the chamber open 
into rooms having no communication with each other, one being for 
the reception of infected articles and the other for their delivery after 
they have been disinfected.1 The articles to be treated are placed in 
the car in the special room for their reception, the door is then bolted, 
and a vacuum of 20 inches is obtained by the steam exhauster. This 
removes the air from the chamber and also the air and moisture from 
the material to be treated, which, forming a cushion, would prevent 
the proper entrance of the steam. Steam is then admitted very rapidly 
and a temperature of 230° to 240° F. is attained within three or four 
minutes. After 15 minutes' exposure, the steam exhauster is again 
brought into play and a vacuum of 20 inches is again secured. The 
fresh-air inlet is then opened, and a current of air is drawn through 
the chamber and its contents by means of the steam exhauster for eight 
or ten minutes. The door communicating with the second room is 
then opened and the articles are removed, unrolled, and exposed for 
three or four minutes, at the expiration of which time they are com- 
pletely dry and can be taken away. 
According to Dr. Doty, " The degree of improvement in the drying 
process, which is the result of the combined action of the steam ex- 
hauster and the fresh-air inlet, can only be appreciated by one who has 
waited two or three hours or more for this same result. * * * The 
importance of the rapidity with which this work is now performed and 
the material dried is especially appreciated in the treatment of mail " 
in which a letter unsealed or partly unsealed is very rarely, and with 
the superscription affected is never, found. This satisfactory result is 
due to the rapid action of the heat, the rapid drying, and the preven- 
tion of the spreading of the ink and of the unsealing of the package. 
The value of the vacuum in steam disinfection lies in the fact that 
confined air in the chamber causes great delay in the attainment of the 
desired temperature and interferes much with the penetrating action of 
the steam. In Doty's experiments with and without the assistance of 
the vacuum, self-registering thermometers, placed within packages of 
newspapers, sheets, blankets, and rugs, showed differences ranging from 
nothing to a hundred degrees (F.) after three minutes' exposure, the 
higher temperature in each case being reached in the experiment with 
vacuum, and the smaller differences occurring when the articles were 
loosely wrapped. With longer exposure, the differences were consider- 
ably smaller. 
When no appliance for securing a vacuum is a part of a steam dis- 
infector, the contained air may be driven out through a vent controlled 
by a valve which is opened for a time, while the steam is being ad- 
mitted, and then closed. 
1 The foregoing description of the apparatus and the following account of the 
method of operation are abstracted from Assembly document No. 58, "Disinfection by 
Steam," by Dr. A. H. Doty, Health Officer of the Port of New York. PHYSICAL AGENTS. 
495 
Another point in favor of the vacuum is the lessened opportunity 
for condensation of the steam in the interior of bundles and in the 
interstices of fabrics. It has been found to be advantageous to fill the 
chamber several times at short intervals with a fresh charge of steam, 
and when the vacuum appliance is at hand, the time required for this 
series of operations is materially lessened. 
The penetrating power of steam is greatly dependent upon the 
amount of pressure; the lower the pressure, the less the penetration. 
With machines in which low pressure steam-a pound or two, for 
instance-is employed, penetration is, therefore, very slow and un- 
certain, and when bulky articles, such as rolled carpets and bedding, 
are treated, the results are quite likely to be unsatisfactory. For such 
articles, it is generally agreed that a pressure of at least 20 pounds 
is none too great. With whatever pressure employed, penetration can 
be much assisted by arranging the contents of the chamber so that too 
solid packing is avoided. This is secured by the interposition of 
wooden slats and gratings which leave spaces between the different 
layers, through which the steam is more readily distributed. 
With low pressure steam, condensation is much more likely to be 
troublesome than when high pressures are employed, but ordinarily 
even then but little, if any, injury is suffered by even the most delicate 
fabrics, beyond a slight impairment of gloss or the imparting of a slight 
yellowish tinge. 
In the arrangement of pub- 
lic disinfecting stations, it is 
essential that infected and 
disinfected articles shall be 
kept strictly apart and that 
means shall be at hand for the 
proper treatment of articles 
not suited to disinfection by 
steam. As an example of 
simple, convenient, and effi- 
cient arrangement, may be 
cited the first public station 
installed in Berlin, the ground 
plan of which is shown in Fig. 
91? Here the infected arti- 
cles are unloaded at the plat- 
form L and stored in the room 
J, from which they are carried 
into the room Gv between 
which and the room G2, the 
steam disinfectors are installed. They are loaded into the trucks b, b, b, 
which are pushed into the steam chambers a, a, a, the doors of which 
are then securely closed. Steam is admitted from the boilers in room 
Fig. 91. 
Ground plan of public disinfecting station. 
1 Taken from H. Merke's description in Vierteljahrsschrift fur gerichtliche Medicin 
und offentliches Sanitatswesen, XLV., p. 137. 496 
DISINFECTANTS AND DISINFECTION. 
B, and after the proper interval of time, the doors of the chambers 
opening into the room are opened and the trucks withdrawn. 
The disinfected articles are removed and carried into the storeroom 
A, from which they are sent to the platform Jf for shipment, in special 
wagons, back to their owners. A is a repair shop and storeroom for 
coal, C and D are bathrooms and water-closets for the attendants, and 
E is a storeroom for chemicals. No communication whatever exists 
between the rooms in which the infected and disinfected articles are 
stored, nor between and G2 except through the steam chambers, the 
doors of which are never opened at both ends at the same time. The 
work is directed by telephone from the office K, which is completely 
shut off from H and J, a full view of which is obtained through 
windows hermetically sealed. 
Steam disinfectors are used extensively for purposes other than the 
destruction of disease germs ; they are most useful for renovating bed- 
ding and in the treatment of clothing infested with lice, which with 
their eggs are quickly killed by steam at any pressure. 
Boiling Water.-Articles not injuriously affected by boiling water 
may be most conveniently disinfected in the household by being boiled 
for a half hour. This suffices to kill all varieties of bacteria and the 
most resistant spores of pathogens ; in fact, all organisms excepting the 
spores of a number of non-pathogenic bacteria which are not destroyed 
even after very prolonged boiling. This method is particularly ad- 
apted to bed linen and body linen and, in short, to all washable fabrics 
except woolens. It has the disadvantage of fixing stains so that they 
become more or less permanent; therefore, sheets, night dresses, and 
other articles stained with blood or excreta should have a preliminary 
soaking in cold water so that the spots may be removed. 
Cold.-Although cold is a very efficient antiseptic, but not com- 
monly classed as a disinfectant, it appears to have some destructive 
power over certain pathogenic bacteria, but none whatever over cer- 
tain others, even when extremely low temperatures are employed. 
During the cholera epidemic in Germany in the winter of 1892-93, 
Uffelmann,1 experimenting with cholera bacilli, concluded that they 
have considerable power to withstand cold for periods varying with 
the temperature. Renk 2 placed the limit of endurance in ice at 8 
days. Inoculated water, containing 620,000 bacilli, was frozen at 
- 9.6° C. and kept at that temperature for 39 hours; the ice was 
then melted and tested, and the results were negative. Water more 
richly inoculated and kept for a day in a freezing mixture of ice and 
salt yielded negative results. Still richer water, containing countless 
bacteria, was frozen, and after 48 hours yielded 24,400 to the cubic 
centimeter, and after 96 hours gave 12 negative results. In other ex- 
periments in which freezing was interrupted, no organisms were found 
after six and seven days. 
The typhoid organism, as is well known, can survive the action of 
' Berliner klinische Wochenschrift, 1893, No. 7. 
2 Fortschritte der Medicin, May. 15, 1893. CHEMICAL AGENTS. 
497 
cold for a long time. This was well shown in the experience of Ply- 
mouth, Pa., where, in 1885, a most devastating epidemic occurred after 
the thawing out of an accumulation of typhoid excreta situated near a 
brook which supplied the town with drinking water. (See page 365.) 
Prudden 1 has shown that the typhoid bacillus can withstand freezing 
temperatures for no less than 103 days, but that alternate freezing and 
thawing cannot long be withstood. 
Non-sporulating anthrax bacilli have but little resistance to freez- 
ing temperatures and are very quickly killed, but the spores have been 
found by Frankland, Pictet, and others to be not affected by repeated 
freezing and thawing. Novy2 found that a temperature of - 10° C. 
for three days was insufficient to destroy the vitality of Sanarelli's 
Bacillus icteroides, and it has long been known that, although epidemics 
of yellow fever are checked with the appearance of frost, the cause, 
whether or not B. icteraides, has sufficient resistance to withstand the 
cold of northern and even Arctic winters and show undiminished vigor 
on being reconveyed to warm climates. 
The exceedingly low temperature of liquid air, - 3'12° F., appears to 
have no effect on organisms subjected to it for short periods. Ravenel3 
immersed silk threads, bearing anthrax spores, B. prodigiosus, B. ty- 
phosus and B. diphtherice, in liquid air for varying periods and then 
planted them in bouillon. Not only were the bacteria not killed, but 
their growth was in no way inhibited, multiplication being in every in- 
stance as rapid and vigorous as with the controls. The anthrax spores 
were exposed as long as 3 hours, but the diphtheria organism no longer 
than 30 minutes and the other two forms not over an hour. 
Still more conclusive are the experiments of Macfadyen and Row- 
land, 4 who subjected broth emulsions of B. typhosus, B. coli communis, 
B. diphtherice, B. proteus vulgaris, B. acidi lactici, Sp. cholerce Asiaticce, 
Staphylococcus pyogenes aureus, B. anthracis (sporulating), B. phospho- 
rescens, a sarcina, a saccharomyces, and unsterilized milk, hermetically 
sealed in fine quills, to the refrigerating influence of liquid air for seven 
days. At the end of this time, the quills were withdrawn and allowed 
to thaw. Culture experiments proved that the vitality of the various 
micro-organisms was in no way impaired. Every species grew well, 
the photogenic bacteria grew and emitted light, and the milk became 
curdled. 
CHEMICAL AGENTS. 
The list of substances falling under the head of chemical disinfect- 
ants is very long and includes a wide variety of organic and inorganic 
compounds, some of which are gases, some liquids, and others soluble 
salts. While it is very long-for almost any chemical substance pos- 
sesses under one condition or another a certain degree of bactericidal 
power-the number of agents which may be regarded as trustworthy in 
1 Medical Record, March 26, 1887. 
2 Medical News, Aug. 12, 1899. 
3 Ibidem, June 10, 1899. 
4 The Lancet, April 21, 1900. 498 
DISINFECTANTS AND DISINFECTION. 
actual general practice is exceeding small. Many substances which 
have a high reputation for efficiency are found to be actually worthless 
when subjected to modern methods of testing, and others which yield 
promising results in the laboratory are often found to fail when used 
under the conditions which obtain in practice. 
The undeserved reputation of many preparations is based wholly 
upon the apparent influence which they have exerted in limiting the 
spread of infectious diseases, and it has not been impaired by unex- 
plainable failure to accomplish the same result at other times. An out- 
break of an infectious disease occurs, for example, in a boarding-school, 
and during its continuance a number of bottles of some proprietary 
preparation are used; no further cases are reported, and the credit is 
given to the disinfectant. Six months later, perhaps, another outbreak 
occurs, and in spite of the use of the same agent it spreads and the 
school is closed; this result is not charged on the other side of the 
account, but to the inscrutible ways of Providence, and the fame of the 
disinfectant is in no way injured. In many instances, strength and 
peculiarity of odor are the only qualities necessary for the building 
up of a reputation for efficiency, for man is wont to attribute potent 
properties to unusual things. 
Many substances have undoubted germicidal power over certain 
forms of bacteria and are quite inert against others; some will kill 
every known form under some conditions, and yet may wholly fail to 
affect bacteria of slight resisting power protected by mucus or other 
matter, or may even be rendered inert almost immediately by chemical 
union with some other substance accidentally present. 
Chemical disinfectants act in various ways to bring about the de- 
struction of bacteria. Some act directly upon the bacterial protoplasm 
and cause its coagulation; some bring about changes in reaction favor- 
able to life and growth; some destroy nutritive material by chemical 
change; some take up all the available oxygen, thus becoming them- 
selves changed in character while depriving the bacteria of an essen- 
tial element; and others bring in such an excess of this same element 
that the bacteria cannot withstand its action. Some even stimulate 
multiplication and thus act only indirectly by promoting the formation 
of organic compounds which exert a destructive influence upon the 
organisms by which they have been produced. The disinfectant power 
of many of the metallic salts depends partly upon the nature of the 
solvent. 
Different agents produce their best results in different degrees of 
concentration; thus, while one may be efficient in 5-per-cent. solution, 
another may act equally well or better in 0.10-per-cent. solution or 
even less. Some agents, as, for instance, alcohol, are most bactericidal 
at some one point of concentration, and above and below this the 
property progressively diminishes. In applying any agent whose best 
working strength is known, it must be borne in mind that it is not 
enough to use a small volume of solution of that particular strength, 
but that the substance itself must be employed in such an amount that NON-METALLIC ELEMENTS AND THEIR COMPOUNDS. 
499 
it shall be present throughout the whole mass in the proportion re- 
quired. Thus, an agent which is effective in 2-per-cent. solution can- 
not be used in that strength to disinfect an equal bulk of infective ma- 
terial, since the mixture would then contain but 1 per cent. 
Non-Metallic Elements and Their Compounds. 
Oxygen.-The disinfectant property of pure air is due to its oxygen, 
which attacks organic matter under favorable conditions and converts 
it in great part to carbon dioxide and water. Prolonged aeration is 
rightly regarded as a valuable assistant in disinfection, but it must not 
be overlooked that when infected objects are exposed to moving cur- 
rents of outdoor air, they are also subjected to the powerful influence 
of the chemical rays of sunlight and to the possibility of desiccation. 
Oxygen acts most powerfully in the nascent state, as when liberated 
from compounds whose decomposition results in the escape of the gas 
in the free condition. Among these compounds, ozone, the allotropic 
form of oxygen, containing in each molecule three atoms instead of two, 
and hydrogen peroxide may be mentioned as conspicuous examples of 
oxidizing agents which part very readily with the loosely held element. 
Ozone, in the minute amounts in which it exists normally in air, can 
hardly be regarded as an important influence in practical disinfection. 
Produced artificially by means of the silent electric discharge, it is 
found to be possessed of marked bactericidal power and has been 
highly recommended for special work, particularly in the sterilization 
of drinking water. The researches of a number of investigators have 
demonstrated that dry bacteria are not much affected by dry ozone, but 
that in a moist condition they are quickly destroyed by small amounts. 
Krukowitsch, quoted by Kowalkowsky,1 experimenting, in 1882, 
with putrefactive bacteria, found that 3 milligrams of ozone per cubic 
meter of air killed fresh bacteria, exposed on paper, within an hour, 
and 8 milligrams per cubic meter sufficed to destroy the dried organ- 
isms. Later (1888), Lukaschewitsch, experimenting with B. sub- 
tilis, B. anthracis, Sp. cholerce Asiaticce, and certain putrefactive bac- 
teria, obtained results which were less favorable, but in agreement in 
so far as they demonstrated the relatively slower action exerted on dry 
bacteria. Spores of B. subtilis and B. anthracis in a dry state were 
unaffected by 1.50 grams of ozone per cubic meter, and the comma 
bacillus, in a moist condition, was not affected until after 15 hours' 
exposure to the same atmosphere. 
Ohlmiiller2 employed a much greater strength, namely, 15 grams 
to the cubic meter, and conducted the air through distilled water, in 
which his bacteria were suspended. Water containing anthrax spores 
was sterilized in 10 minutes by 89.9 milligrams of ozone, and con- 
taining millions of typhoid and cholera germs to the cubic centimeter, 
in 2 minutes by less than 20 milligrams. River water and sewage 
1 Zeitschrift fur Hygiene, IX., p. 89. 
2Arbeiten aus dem kaiserlichen Gesundheitsamte, VIII., 1892, p. 229. 500 
DISINFECTANTS AND DISINFECTION. 
were found to be much less easily affected, but with only moderate pol- 
lution it appeared probable that in ozone might be found a cheap and 
efficient means of purifying drinking water. Later on, a number of 
processes were devised for this purpose and carried out on a large scale. 
Hydrogen peroxide, H.,O2, is quite stable in the presence of some 
substances, but gives up its loosely combined atom of oxygen very 
readily to others. It is a powerful, odorless oxidizing agent, pre- 
pared by the action of dilute sulphuric acid on barium peroxide. It is 
destructive of bacteria, but has no action on the enzymes of the digest- 
ive juices and in dilute form is neither poisonous nor irritant in the 
human system. 
According to Altehofer,1 in the proportion of one part in a thousand 
of water containing the organisms of cholera and typhoid fever, it pro- 
duces sterility within 24 hours. In 1-per-cent. solution, according to 
Traugott,2 the bacilli of diphtheria and typhoid fever are killed in 5 
minutes, the organisms of erysipelas and cholera in 2 minutes, Strepto- 
coccus pyogenes in 10 minutes, and Staphylococcus pyogenes aureus in 
from 15 to 30 minutes. With half this strength, the typhoid organism 
and Streptococcus pyogenes are destroyed with equal promptness, the 
cholera and erysipelas organisms in 5 minutes, the bacillus of diph- 
theria in 15, and Staphylococcus pyogenes aureus in an hour. It is be- 
lieved by many that the bactericidal effect of sunlight on organisms in 
surface-waters is due to the hydrogen peroxide produced through its 
influence. 
Chlorine, both in the free gaseous condition and in solution in water, 
has very powerful disinfectant and deodorant properties. It decom- 
poses the offensive gaseous products of putrefaction, such as ammonia 
and sulphuretted hydrogen, and in the presence of moisture unites with 
hydrogen, thus liberating oxygen in the nascent state, which is thereby 
enabled to exert its power against organic matter. In the dry state, 
its disinfectant action on dry matter is but slight and highly unreli- 
able, but in the presence of a reasonable degree of atmospheric mois- 
ture, its effect on organic matter is very considerable, as is shown by its 
bleaching action on dyed fabrics. 
The exhaustive research of Fischer and Proskauer3 demonstrated, 
however, that chlorine as a fumigating agent is untrustworthy and that 
its application is attended by serious disadvantages. The test objects 
employed embraced a somewhat wide variety of pathogenic and non- 
pathogenic organisms and were exposed under different conditions of 
moisture and dryness for varying periods of time and to varying per- 
centages of the gas. The results, as a whole, were highly unsatisfactory 
from a practical standpoint, on account of the impossibility of properly 
regulating all the necessary conditions, the absence of penetrating power, 
the destructive action on fabrics and other articles, and the uncertainty 
in achieving the object sought. 
1 Centralblatt fur Bakteriologie, VIII., p. 129. 
2 Zeitschrift fur Hygiene und Infectionskrankheiten, XIV., p. 427. 
3 Mittheilungen aus dem kaiserlichen Gesundheitsamte, II., p. 228. 501 
NON-METALLIC ELEMENTS AND THEIR COMPOUNDS. 
" Chloride of lime," which is a combination of calcium chloride 
and hypochlorite, the result of passing chlorine over dry slaked lime, 
was in use as a disinfectant and deodorant for a long time before the 
development of the science of bacteriology. In 1881, in the course of 
the first real investigation of the properties of what were commonly 
regarded as disinfectants, Koch obtained very unsatisfactory results 
from his tests with this agent, which thereupon to a great extent was 
discarded. In 1885, Sternberg, then chairman of the committee of 
the American Public Health Association to which, in 1884, the subject 
of disinfectants had been referred, took very different ground regard- 
ing this and other hypochlorites and asserted their efficiency in no un- 
certain terms. Since then, the matter has been the subject of many 
investigations by competent observers, and while in some hands the 
results have failed to be uniformly favorable, the work, as a whole, has 
sustained the position taken by Sternberg as a result of his own ex- 
periments. 
Woronzoff, Winogradoff, and Kolesnikoff1 demonstrated that an- 
thrax spores were killed in one minute by a 5-per-cent. solution, 
though in Koch's experiments they had been found still active at the 
expiration of two days. Jaeger,2 in 1889, concluded, after a series of 
tests with a number of species of pathogenic bacteria, that it is a very 
efficient disinfectant, even in weak solutions. Nissen,3 in 1890, after 
a very careful series of experiments, reported that the organisms of 
cholera and typhoid fever were destroyed in 5 minutes when the ma- 
terial in which they were present contained 0.12 per cent, of the agent, 
and in 10 minutes by half the amount. Anthrax bacilli were killed 
in 1 minute by 0.10 per cent., Staphylococcus pyogenes aureus and 
Streptococcus erysipelatis in 5 minutes by 0.12 and 0.15 per cent, re- 
spectively, and in 1 minute by 0.20. Anthrax spores of low resist- 
ance were destroyed in 15 minutes by 5 per cent, and in 70 minutes 
by 1 per cent. Very resistant spores, capable of surviving 4 hours' 
immersion in 0.10-per-cent. corrosive sublimate and 10 minutes' expo- 
sure to streaming steam, were killed in 4.50 hours by 5 per cent. 
Klein,4 experimenting with sodium hypochlorite in 10-per-cent. so- 
lution (1.0-per-cent. chlorine) on the colon bacillus, anthrax spores, 
Staphylococcus pyogenes aureus, B. enteritidis sporogenes and the bac- 
teria of typhoid fever, cholera, and swine fever, found that all were 
killed in 20 minutes and the non-spore-bearers in 10. In one tenth 
as strong solution, all but the two kinds of spores were destroyed 
within 20 minutes. Duggan,5 working according to Sternberg's 
method, reported, in 1885, that his experiments had shown " that a 
solution containing 0.25 per cent, of chlorine as hypochlorite is an ef- 
fective germicide, even when allowed to act for only one or two min- 
1 Centralblatt fur Bakteriologie, 1887, p. 641. 
2 Arbeiten aus dem kaiserlichen Gesundheitsamte, V., p. 247. 
3 Zeitschrift fur Hygiene, VIII., p. 62. 
4 The Lancet, Nov. 26, 1896, p. 509. 
5 Report of the Committee on Disinfectants of the American Public Health Associ- 
ation, Baltimore, 1885, p. 12. 502 
DISINFECTANTS AND DISINFECTION. 
utes, while .00 per cent, will kill spores of B. anthracis and B. sub- 
tilts in two hours." 
The composition of " chloride of lime," or, more properly, chlorinated 
lime, and its mode of action are matters concerning which there is con- 
siderable disagreement. The substance is variously held to be : (1) a 
mixture of calcium chloride and hypochlorite, (2) calcium hypochlorite 
in which one CIO is replaced by Cl, that is, Ca(ClO) Cl, which, in con- 
tac with water, is broken up into calcium chloride and hypochlorite, 
(3) a compound of calcium hypochlorite and oxychloride with 4H2O, 
formed according to the equation 
4CaO,H2 2C12 = CaO2Cl2. Ca,O2Cl24H2O, 
which is split up in water into calcium chloride, hypochlorite, and hy- 
droxide, and (4) a compound of calcium chloride with hydroxide, of 
which one H is replaced by Cl. It is white or whitish in color and 
occurs as a powder or as friable lumps; it should be dry or nearly so 
and should have no more than a faint odor of chlorine, which element 
should be present in available form to the extent of not less than 35 
per cent, to conform to the requirements of the U. S. P. (British 
standard = 33 per cent., German standard = 25 per cent.). 
With keeping, under various conditions, it may undergo decomposi- 
tion in a number of ways. A pasty condition or a strong odor of 
chlorine is evidence of partial decomposition. It is only partially sol- 
uble in water, and its aqueous preparations are best made by triturating 
the requisite amount with water to the consistency of cream and then 
diluting to the desired volume. The addition of acids to the solution 
causes evolution of chlorine, but the carbonic acid naturally present in 
the water or absorbed from the air decomposes the hypochlorite, 
yielding calcium carbonate and hypochlorous acid, the latter of which 
breaks up into active oxygen and free hydrochloric acid. 
The solution known as the " American standard " contains 6 ounces 
of the powder to the gallon. It is largely used in the disinfection of 
discharges and for scrubbing floors and other woodwork. A weaker 
solution is employed for the treatment of infected bed linen and wash- 
able clothing, but on account of its destructive action, these articles 
must, after a not too long immersion, be most thoroughly washed in 
plenty of fresh water. 
Sodium hypochlorite solution, otherwise known as chlorinated 
soda, Labarraque's solution, and liquor sodse chloratoe, is "an aqueous 
solution of several chlorine compounds of sodium, chiefly NaClO and 
NaCl, and containing at least 2.6 per cent, by weight of available 
chlorine " (U. S. P.). It is used, but not so extensively, for the same 
purposes as chlorinated lime. 
Bromine and Iodine have powerful disinfectant properties, but for 
several reasons are not suited to the purposes of practical disinfection. 
In some respects, bromine is superior to chlorine as a germicide, but 
it is disagreeable and dangerous to handle and is considerably more 
expensive. Iodine is less efficient than chlorine and offers neither as NON-METALLIC ELEMENTS AND THEIR COMPOUNDS. 
503 
such nor as the trichloride any advantage over chlorine and the hy- 
pochlorites, but, on the contrary, a number of disadvantages which 
are sufficient to eliminate it from the list of practical disinfectants. 
Sulphur dioxide easily outranks all other disinfectants in point of 
length of service, its use dating back to very ancient times. While it 
has undoubted bactericidal properties, it has been demonstrated by 
Koch, Wolffhugel, and their associates and many others to be wholly 
untrustworthy for general use, and though still very extensively em- 
ployed by public sanitary authorities, is rapidly being abandoned in 
favor of more efficient and reliable agents. It is purely a surface dis- 
infectant under conditions most favorable to its action, and even then 
is effective against only a somewhat limited number of species of 
pathogenic bacteria. 
It is a colorless irrespirable gas, produced by burning roll sulphur 
or " flowers " in an iron vessel, placed as a precaution against the 
danger of fire in a pan of water, or by burning sulphur candles or car- 
bon disulphide, the latter in a lamp. The amount of sulphur em- 
ployed varies, according to the custom of the operator, from one to six 
pounds per thousand cubic feet of air space, but the whole amount is 
never consumed, and, indeed, under ordinary circumstances, combustion 
ceases before a half or even a third has been burned. In order to 
avoid the necessity of burning sulphur, the liquefied gas, contained in 
cylinders, is to some extent employed. 
In the absence of moisture, the action of sulphur dioxide on even the 
least resistant bacteria is practically nil, and even when water is evapo- 
rated in the room beforehand or at the same time and the gas is 
present in the highest percentage possible, the exposed organisms, 
whether of low or high resistance, are quite likely to retain their vitality 
unimpaired. It is true that some experimenters have reported great 
success in the destruction of pathogenic organisms by means of this 
agent, but the adverse reports are so numerous that it must be clear 
that much official disinfection by means of it must be worse than an 
empty form and, by reason of causing a false sense of security, a posi- 
tive danger. Even were it an efficient disinfectant, the many disad- 
vantages which attend its use would suffice to make it undesirable for 
general purposes, especially in view of the fact that the same disad- 
vantages are wholly absent in other processes. 
In the presence of moisture and air, it is to some extent oxidized to 
sulphuric acid, which corrodes fabrics and other objects ; it reduces or- 
ganic matters and destroys organic colors ; it tarnishes brass and silver 
ware, gilt frames and other objects; it leaves a disagreeable odor 
which persists for days and even weeks after thorough aeration ; bed- 
ding and other articles become impregnated with a peculiar highly of- 
fensive odor which renders their use unpleasant and even impossible; 
and it has such little power of penetration that only such organisms as 
are openly exposed are likely to be affected. 
Where sulphur dioxide is the official disinfectant, it is commonly en- 
joined that the room shall be thoroughly cleansed and air freely ad- 504 
DISINFECTANTS AND DISINFECTION. 
mitted for some days after fumigation. The necessity of this supple- 
mentary process is in itself an admission of the inadequacy of the main 
operation, for if sulphur is an efficient disinfectant, the application of 
soft soap, carbolic acid, hypochlorites, and other agents by means of 
the scrubbing-brush and cloths, the removal and replacing of wall- 
papers, the process of white-washing, and other means of renovation 
recommended, are attacks against an imaginary evil. Granted that 
these processes are necessary, the claims of sulphur dioxide as a practical 
disinfectant must fall to the ground ; if not necessary, they should not 
be enjoined. 
Lime and Metallic Salts. 
Lime, quicklime, or calcium oxide, has long been known as an 
agent possessing great power in destroying organic matter and has been 
very extensively used from very early times in connection with dis- 
posal of the dead. Treated with half its weight of water, it is slaked 
to a dry powder, the hydrate, which, mixed with sufficient water, forms 
the well-known " white wash " commonly used for disinfecting, sweet- 
ening and brightening the walls of cellars, rooms, barracks, barns, 
poultry-houses, and other outbuildings. Slaked lime, mixed with four 
volumes of water to the consistency of cream, forms what is commonly 
known as "milk of lime," which is extensively used in the disinfection 
of excreta and privy vaults. 
The scientific investigation of the disinfectant properties of lime by 
Liborius,1 undertaken at the instance of Koch, demonstrated its value 
in the destruction of the bacteria of typhoid fever and cholera, the 
former of which were found to be destroyed in a few hours by lime 
water containing 0.0074 per cent., and the latter within the same time 
by 0.0246 per cent. Cholera bouillon cultures, containing numerous 
coagula of albumin and thus offering unfavorable conditions for the 
action of the disinfectant, such as would be present in cholera dis- 
charges, were completely disinfected within the course of a few hours 
by 0.40 per cent, of pure lime or by 2 per cent, of ordinary crude 
lime. He recommended the employment of the pure dry powder or 
of milk of lime containing 20 per cent, of it. 
Favorable results were obtained also by Kitasato,2 who found that 
the same two species were destroyed by about 0.10 per cent, in from 
four to five hours. Pluhl,3 carrying the experiments somewhat further, 
recommended the use of milk of lime of 20-per-cent. strength, freshly 
prepared from lime of good quality, for the disinfection of loose dejec- 
tions, prescribing that it must be added in sufficient quantity, with 
thorough mixing, until the whole mass is strongly alkaline in every 
part, as shown by testing with red litmus paper. With such treatment, 
he asserted that complete sterilization is accomplished within an hour. 
Extensive researches by numerous other scientists, though differing 
' Zeitschrift fur Hygiene, IL, p. 15. 
2 Ibidem, III., p. 404. 
3 Ibidem, VI., p. 97. LIME AND METALLIC SALTS. 
505 
somewhat in results in certain unimportant particulars, have confirmed 
the conclusions of these earlier investigators as to the great practical 
value of this agent. As to its value in comparison with chlorinated 
lime, there is some disagreement, some authorities favoring the one 
and some the other, but practically all unite in the opinion that which- 
ever is the more efficient, the difference is slight. 
Of great practical importance in the use of any disinfectant on a 
large scale is the item of expense. It happens, fortunately, that this 
valuable aid is exceedingly cheap and that its use with a liberal hand 
in excess of the recommended amount can be urged without promoting 
lavish expenditure of money. In the disinfection of stools it is com- 
monly advised to add at least an equal volume of the milk, or even 
twice as much, and to allow the mixture to stand for two hours or 
longer before final disposal. In camp sanitation, it is much used with 
excellent results ; but for their attainment, constant watchful super- 
vision is necessary. 
It must be borne in mind that air-slaked lime must not be employed 
in the preparation of the milk, and that the latter on standing loses its 
homogeneous character, which must be restored by stirring or shaking 
each time the material is used. The milk is most powerful when 
freshly prepared and should not be used when older than a very few 
days, unless most carefully protected from contact with air. 
Ferrous sulphate and other salts of iron have long been exten- 
sively used both as germicides and deodorants. All scientific investi- 
gations of the disinfectant properties of ferrous sulphate by Koch, 
Sternberg, and others has demonstrated the utter worthlessness of this 
agent. Not only does it fail as a germicide, but, as has been pointed 
out by Foote,1 it has also no claims to be considered as a deodorant. 
Its employment in this capacity not infrequently makes a bad odor 
worse, through chemical action on organic compounds produced in the 
process of putrefaction. 
Ferric sulphate has been shown by Riecke2 to have very marked 
action against the bacteria of typhoid fever and cholera in acid and 
alkaline excreta, when added in an equal volume of 5-per-cent. solution. 
The disadvantages attending its use, however, more than outweigh 
any considerations which can be urged in favor of its employment in 
place of other more efficient and, on all accounts, less objectionable 
agents. 
Ferric chloride, also has some claim to be regarded as a germicide, 
but it is inferior to the sulphate and is open to the same objections. 
On the whole, therefore, the iron compounds may be safely passed 
by in the practice of disinfection. 
Zinc chloride, like ferrous sulphate, was, until subjected to the 
rigid test of bacteriological proof, regarded as a most efficient disin- 
fectant, and to-day, though the original adverse findings of Koch in 
1881 have been confirmed by many careful experimenters, is still very 
' American Journal of the Medical Sciences, XCVIIL, p. 329. 
2Zeitschrift fur Hygiene und Infectionskrankheiten, XXIV., p. 303. 506 
DISINFECTANTS AND DISINFECTION. 
extensively employed and in many places is officially prescribed by 
the local health authorities. Under some conditions, it does occasion- 
ally succeed in destroying some forms of bacterial life, but its place in 
the list of actual and supposed disinfectants is well down toward the 
very bottom. It is, however, somewhat efficient as a deodorant. The 
sulphate and other salts are equally inefficient as disinfectants. 
Aluminum chloride is the chief soluble constituent of a number of 
extremely popular proprietary disinfectants, prescribed by practicing 
physicians and bought with and without advice by the laity. Like 
other aluminum compounds, the sulphate and the alums, for example, 
it is powerfully astringent, even in dilute form. It is cheap, has no 
action on metallic substances, and does not stain or otherwise injure 
fabrics. Its disinfectant action is slight, and herein it agrees further 
with other aluminum compounds. 
A number of proprietary preparations, in which it is present either 
as principal or auxiliary ingredient, examined by the author with Dr. 
R. M. Pearce,1 were found to be quite inefficient. The test objects in- 
cluded cultures of B. anthracis and B. typhosus, typhoid dejecta, diph- 
theritic membranes, and tuberculous sputa. Each of five preparations, 
in the strength recommended, was subjected to 10 tests, and their 
proportions of successful disinfection varied from 20 to 70 per cent. 
Anthrax bacilli were destroyed by one ; one culture of B. typhosus was 
killed by one, another by all, a third by two ; one typhoid stool was 
unaffected by all, a second was sterilized by all, and a third by three; 
one specimen of diphtheritic membrane was sterilized by four, and 
another by only one ; tuberculous sputum was affected by none. 
Potassium permanganate, well known as a powerful oxidizing 
agent, is much used in surgical practice and in other lines of special 
work. Its use in India, during epidemics of cholera, in the purification 
of wells is said to yield valuable results. Enough of the salt to cause 
a slight tinge of color is added to the water. 
In contact with organic matter and oxidizable mineral substances, 
it parts very readily with its available oxygen, and it is to this element 
that whatever disinfectant property it has, is due. Unfortunately for 
its use in general disinfection, a small amount of organic matter requires 
a very large amount of the salt for complete oxidation. Thus, one 
ounce of liquid faeces or of urine can reduce such an amount that it is 
estimated that the sterilization of the total 24 hours' excreta of one 
person would cost about five dollars. It cannot be used in the treat- 
ment of clothing, since it causes stains of a permanent character. 
The readiness with which it is reduced and rendered inert by mat- 
ters associated with bacteria makes its germicidal action uncertain, 
although laboratory experimentation has demonstrated its undoubted 
power, even in weak solution, against bacteria of high resistance. 
Copper sulphate in weak solutions destroys sporeless bacteria in 
great variety within a short time, but in practical work its use is rather 
limited. It has been strongly recommended for the sterilization of 
1 Journal of the Boston Society of Medical Sciences, March, 1899. LIME AND METALLIC SALTS. 
507 
faeces, but its high cost and other disadvantages, not to mention 
its inferiority as a germicide to other cheaper and more available 
substances, make it improbable that its employment will ever become 
very extensive. 
Mercuric chloride, or corrosive sublimate, is beyond question 
the most powerful of all the metallic salts as a disinfectant, since even 
in such dilution as .01 to 0.10 per cent, it is capable of destroying the 
most resistant organisms known, including the spores of anthrax and 
of the hay bacillus. In Koch's oft-quoted experiments, the growth 
of anthrax bacilli was prevented by 1 part in 300,000, and the spores 
were killed in ten minutes by 1 in 20,000 (0.005 per cent.). His 
later investigation, however, caused him to modify his original estimate 
as to its efficient working strength, but did not displace it from its 
position at the head of the list of metallic disinfectants. 
Investigation by others has given results of very variable character, 
some confirmatory of Koch's, others decidedly in contradiction. Thus, 
Nocht, whose results are reported by Behring,1 found an exposure of 
several hours necessary for the killing of anthrax spores by 0.10 per 
cent., and Behring himself found that, with this strength, no action was 
observable until 10 hours had elapsed, and that complete sterilization 
was effected in 24 hours. With the assistance of sulphuric acid in the 
proportion of nine parts by weight to one of sublimate, the same 
strength killed the spores in 6 hours. Other metallic salts in solution 
gave less evidence of activity, the only one which could be compared 
in efficiency with sublimate being nitrate of silver, a salt which, by 
reason of its prohibitive cost, can hardly find a place in the list of 
practical disinfectants. 
Klein 2 found that, when present in nutrient gelatin in the proportion 
of 1 in 10,000, it does not always prevent anthrax spores from germi- 
nating, but even when it fails, it has a certain restraining influence and 
causes a diminution of infectivity. He found that anthrax bacilli are 
killed by 1 in 2,000 ; that their growth is inhibited, as a rule, by 1 in 
3,000 or 4,000; and that in solutions of 1 in 5,000 they grow with 
modified infectivity. 
The widely different conclusions concerning the action of weak solu- 
tions on anthrax spores and other highly resistant organisms are ex- 
plained by differences in nutrient media, in technic, and in virulence; 
and while it has been established that the earlier opinions were far too 
favorable, it has repeatedly been proved that in germicidal action it 
stands far in advance of all other metallic compounds. But it must 
not be understood that under conditions which obtain in practice, the 
same results as are obtained in laboratory experiments, made with 
broth cultures and spores dried on silk threads, are always to be ex- 
pected. In the treatment of tuberculous sputum, for example, the 
innermost bacilli are protected from contact with the disinfectant by 
1 Zeitschrift fiir Hygiene, IX., p. 395. 
2 Supplement, Fifteenth Annual Report of the Medical Officer to the Local Govern- 
ment Board, 1885, p. 155. 508 
DISINFECTANTS AND DISINFECTION. 
the coagulum which forms on the surface of each separate mass. 
Again, in the treatment of other organic matter, the possibility of pre- 
cipitation as albuminate or sulphide or other insoluble compound of 
mercury must be kept in mind. 
Precipitation as albuminate can be prevented by the addition of 
about 5 parts of sulphuric, hydrochloric, or tartaric acid or of 10 parts 
of common salt for each part of sublimate in 1,000, but conversion to 
sulphide cannot be prevented, if the conditions necessary for its forma- 
tion are present. The albuminate has powerful germicidal properties, 
but the sulphide is practically inert. In the disinfection of faeces, for 
which purpose corrosive sublimate is much used, it must be evident 
that, with the usual strength of solution employed, the whole of the salt 
must frequently be precipitated in one form or another very early in 
the process. In surgical practice, it has the advantage of affecting in- 
struments injuriously, and in household disinfection, its corrosive ac- 
tion on plumbing must be considered as somewhat in the light of a 
bar. Because of its many drawbacks, its use, excepting for sterilizing 
the hands and other parts of the person, walls, floors, and other wood- 
work, is not to be recommended. The usual working strength is 1 
in 1,000. 
Other salts of mercury, the potassio-mercuric iodide, the cyanide, 
and the sulpho-carbolate, for example, possess great germicidal power, 
but in this respect are not superior to the chloride. A preparation of 
the sulpho-carbolate, known as "asterol," containing 17 per cent, of 
mercury, is said by Steinmann 1 to lose none of its disinfectant prop- 
erty in albuminous media, to exert a deep penetrating action, and not 
to injure instruments. 
The mineral acids possess, in different degrees of dilution, varying 
disinfectant power against all species of bacteria. In any effective 
working strength, they corrode the common metals and destroy the 
tensile strength of all kinds of fabrics. 
The bactericidal effect of gastric juice on the bacteria of cholera, dis- 
covered by Koch, was ascribed by him to the contained hydrochloric 
acid ; and experimenting with bouillon cultures of this organism, Kita- 
sato2 showed that 0.132 per cent, of hydrochloric or 0.049 of sulphuric 
acid produced sterility within a few hours. This result, so far as it 
concerns sulphuric acid, was confirmed by Stutzer,3 who found that 
0.05 per cent, killed the organisms suspended in distilled water in 15 
minutes. 
The experiments of Boer4 showed that the bacillus of typhoid fever 
in bouillon cultures was destroyed in 2 hours by 0.07 per cent, of hy- 
drochloric acid, and in the same time by 0.12 per cent, of sulphuric 
Mineral Acids. 
1 Berliner klinische Wochenschrift, March 13, 1900. 
2 Zeitschrift fiir Hygiene, III., 1888, p. 404. 
3 Zeitschrift fur Hygiene und Infectionskrankheiten, XIV., 1893, p. 9. 
4 Zeitschrift fiir Hygiene, IX., 1890, p. 479. 509 
ORGANIC SUBSTANCES. 
acid. The cholera organism was killed by smaller amounts, 0.02 per 
cent, of each, within the same time; the bacilli of anthrax were but 
slightly more resistant than the cholera germ ; and those of diphtheria 
succumbed to the same amounts as were fatal to those of typhoid 
fever. Ivanoff1 determined the amount of sulphuric acid necessary 
to sterilize sewage. That of Potsdam, three times as foul as that 
of Berlin and slightly alkaline in reaction, impregnated with cholera 
germs, was disinfected by 0.08 per cent, in 15 minutes. A proprietary 
preparation, containing 0.76 per cent, of sulphuric acid and nothing 
else, tested by the author, sterilized one of two bouillon cultures of 
typhoid bacilli and one of two typhoid dejecta in two hours, and had 
no effect whatever on diphtheritic membrane and tuberculous sputum. 
Organic Substances. 
Carbolic acid, phenol, phenic acid, obtained chiefly from coal, is 
a substance of varying degrees of purity and disinfectant power. The 
highest grade is practically pure phenol, but the commoner qualities 
contain variable amounts of cresols, xylol, and other higher homo- 
logues, all of which have marked bactericidal properties, and tar oils 
which have none. In the opinion of many authorities, the crude acid 
is superior to the highest grades in disinfecting power by reason of the 
presence of the cresols. 
Prior to Koch's work on disinfectants in 1881, carbolic acid was 
generally believed to be one of the most powerful of germicides, a be- 
lief which was doubtless due, in part at least, to its peculiar and power- 
ful odor. Koch's experiments with anthrax spores led him to the 
conclusion that even in 5-per-cent. solution, it was an inefficient agent 
against highly resistant organisms. Then followed a number of in- 
vestigations by others whose conclusions were by no means in agree- 
ment. It was found by some to be a very efficient general disinfectant, 
by others to be very unreliable, and by still others to be well suited to 
some lines of work and not to others. It was very generally conceded 
that in certain respects its use has many advantages over that of cor- 
rosive sublimate and other metallic salts; that it is not destroyed or 
precipitated by contact with albumin, acids, salts and other compounds; 
and that, even in weak dilution, it destroys many of the common patho- 
genic organisms very quickly. 
Behring, Sternberg, and others found it effective against the bacilli of 
typhoid fever and cholera in 1-per-cent, solution, but opposite conclu- 
sions have been reported as to its action against the former, which organ- 
ism is said to flourish in mixed cultures in the presence of even as much 
as 5 per cent., the accompanying species being destroyed. According 
to Vincent,2 the colon bacillus is killed only by solutions containing 
at least 3 per cent. For the disinfection of tuberculous sputum, Schill 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XV., 1893, p. 86. 
2 Annales de 1'Institut Pasteur, IX., 1895, p. 23. 510 
DISINFECTANTS AND DISINFECTION. 
and Fischer1 found it to be reliable in 5-per-cent. solution within 24 
hours. An experiment by the author and Dr. R. M. Pearce,2 in 
which this material was treated with 17 different preparations, pro- 
prietary and otherwise, including a 5-per-cent. solution of carbolic acid, 
was successful with this agent and four others after a 2 hours' exposure. 
With typhoid stools, diphtheritic membrane, and bouillon cultures of 
the typhoid organism, disinfection was not accomplished. Uffelmann 3 
has reported that while the 5-per-cent. solution did not destroy the 
typhoid organism in an hour, sterilization was complete after 24 hours' 
exposure. 
Its disinfectant power appears to be increased by heat and by the 
presence of mineral acids and common salt. Thus, Heider4 found 
that while at ordinary room temperature a 5-per-cent. solution was in- 
effective against anthrax spores under 36 days, at 55° C. it was success- 
ful in 2 hours, and at 75° C. in 3 minutes. The influence of its asso- 
ciation with common salt, which alone in ordinary amounts has but 
slight bactericidal power, is attested by Scheurlen, Beckmann, Romer, 
and others. 
Scheurlen5 demonstrated that while 1-per-cent, solutions had no 
effect against pus cocci during 5 minutes' exposure, the addition of 
common salt in considerable amounts brought about sterility in one 
minute, and that the same agent enhanced its action materially against 
anthrax spores. Beckmann6 showed that though 3 per cent, of salt 
increased the general disinfectant power of a 1-per-cent. solution very 
considerably, no increase in its power against anthrax spores was 
observable until 24 per cent, had been added ; but in this amount, salt 
itself has considerable power, and it would seem reasonable to attribute 
the effect of the mixture very largely, if not wholly, to it. Romer" 
also proved the same thing with respect to the action of a stronger 
solution (3-per-cent.) which, with the addition of 8 per cent, of salt, was 
much more effective against the same organism. 
Similarly it has been shown by Frankel and Laplace that the pres- 
ence of small amounts of the mineral acids is very helpful, but it is to 
be borne in mind that the latter, unassisted, are by no means without a 
very considerable degree of germicidal power. Both authorities, how- 
ever, have proved that mixtures of carbolic and mineral acids are more 
bactericidal than either ingredient in the proportions used, and both, 
and Nocht as well, have also demonstrated the superiority of mixtures 
of the crude acid with mineral acids over combinations of the pure 
phenol with mineral acids in the same proportions. According to 
Epstein,8 carbolic acid in alcoholic solution is more powerful in the 
same amount than in aqueous solution, which finding is endorsed by 
1 Mittheil ungen aus dem kaiserlichen Gesundheitsamte, II., 1884, p. 145. 
2 Loco citato. 
3 Deutsche medicinische Wochenschrift, XVI., 1890, p. 37. 
4 Centralblatt fur Bakteriologie, IX., 1891, p. 221. 
5Archiv fur experimentale Pathologic, etc., XXXVII., 1896, p. 74. 
6 Centralblatt fiir Bakteriologie, 1896, Nos. 16 and 17. 
7 Miinchener medicinische Wochenschrift, XLV., 1898, p. 298. 
8 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIV., 1897, p. 1. ORGANIC SUBSTANCES. 
511 
Minervini.1 On the other hand, in solution in oil, according to Koch, 
it loses its germicidal property completely. 
On all the evidence presented, the conclusion must be drawn that 
carbolic acid, while effective in weak and saturated aqueous solution 
against many of the pathogenic bacteria, is not suited to the purposes 
of practical general disinfection. When used, it is best to employ the 
stronger rather than the dilute solutions. The pure acid is soluble in 
about 11 parts of water, but the commercially pure article is soluble 
in about 20 parts, giving about 5-per-cent. strength. 
The so-called carbolic powders are, as a rule, inert mixtures of min- 
eral matter and waste products of coal-tar distillation. Their strong 
odor appeals to the imagination and promotes their sale. 
The cresols, meta-cresol, ortho-cresol, and para-cresol, which occur 
as impurities of carbolic acid and, according to many authorities, are 
more powerful as germicides and less poisonous to higher organisms, 
are constituents of a large number of preparations which, within 
recent years, have come into extensive use. The cresols are closely 
related to phenol, from which they differ in that CH3 replaces one H 
in the benzol ring, and according to the position of CH3, we have 
meta-cresol, ortho-cresol, or para-cresol. The latter can be made syn- 
thetically from pure para-toluidin. Cresols are practically insoluble 
in water, but solution is brought about by soaps and by cresol salts. 
Laplace2 was the first to draw attention to the fact that crude car- 
bolic acid and strong sulphuric acid, mixed together, form a compound 
soluble in water and of high disinfectant power. He reported that 
the mixture in 4-per-cent. solution destroyed anthrax spores within 24 
hours, while pure carbolic acid in 2-per-cent. solution, had no effect 
whatever. The first extensive study of the action of cresol was made 
by Frankel,3 who showed that the mixture of sulphuric acid and 
crude cresols is not of the nature of a new compound, but that each 
ingredient exists by itself and exerts its own action, and that the acid 
keeps the cresols in solution. Hammer4 investigated the properties 
of cresols dissolved in sodium meta-cresotinate; here, also, no double 
compound is formed, the salt acting merely as a solvent. Sodium 
salicylate acts equally well as a solvent. The various preparations 
containing cresols and solvents of the same are highly recommended as 
substitutes for phenol, on the ground of higher bactericidal power, 
lower toxicity, and of being less irritating in surgical work. They 
can be diluted at will with water, some forming milky emulsions, some 
clear solutions. 
To determine the toxic properties of the cresols, Seybold5 instituted 
a series of experiments with guinea-pigs, into which 2-per-cent. solutions 
of the individual cresols were subcutaneously injected. The most 
poisonous was found to be para-cresol, and the least so proved to be 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXIX., 1898, p. 117. 
2 Deutsche medicinische Wochenschrift, 1887, No. 40. 
3 Zeitschrift fur Hygiene, VI., 1889, p. 521. 
4 Archiv fur Hygiene, XII., 1891, p. 359 ; XIV, 1892, p. 116. 
5Zeitschrift fur Hygiene und Infectionskrankheiten, XXIX., 1898, p. 377. 512 
DISINFECTANTS AND DISINFECTION, 
meta-cresol, which is also much less poisonous than phenol. From a 
study of the comparative disinfectant action of the several cresols and 
of several other preparations, including tri-cresol (prepared synthetically 
from toluene) and phenol, he concluded that of the three isomers, 
meta-cresol is the most powerful, and that the cresols are all superior 
to phenol. Tri-cresol, which is 40 per cent, meta-, 35 per cent, ortho-, 
and 25 per cent, para-cresol, proved to have double the bactericidal 
power of phenol against B. pyocyaneus, B. prodigiosus, and Staphylo- 
coccus pyogenes aureus. Another preparation of cresol, made by another 
manufacturer and examined by Schiirmayer,1 also proved to be far 
superior to phenol and to a number of the more commonly known 
cresol compounds. A proprietary preparation of cresols, examined by 
the author,2 sterilized in 5-per-cent. dilution in 2 hours, cultures of 
B. typhosus, typhoid dejecta, diphtheritic membrane and tuberculous 
sputum. 
Among the more commonly used cresol preparations may be men- 
tioned the following : 
Creolin.-This is a dark brown, thick, alkaline liquid, which con- 
tains about 10 per cent, of cresols, held in solution by soap, and a 
small amount of phenol. Mixed with water, it forms a turbid whit- 
ish emulsion. According to Hunermann,3 it is inferior to carbolic acid 
against anthrax bacilli and pus cocci, but Van Ermengem 4 found it 
very effective in 5-per-cent. solution against pus cocci and the germs 
of typhoid fever and cholera, and Laser5 found that in the same 
strength it disinfects dejecta completely. Others have obtained even 
more favorable results, and the weight of evidence is to the effect that 
it is decidedly superior to phenol. 
Lysol is a brown oily liquid containing about 50 per cent, of cre- 
sols with neutral potash soap, miscible with water in all proportions, 
forming a soapy, frothing liquid, and with alcohol and glycerin. 
Gruber 6 found a 2-per-cent. solution more effective against pus cocci 
than a 3-per-cent. solution of phenol. Buttersack's7 experiments led 
to the same conclusion and demonstrated also its suitability for the 
treatment of sputum. Vincent8 found it to be a valuable agent for 
the disinfection of faeces and vault contents. In 0.5-per-cent. strength 
it destroyed B. typhosus in fifteen minutes, and in 0.35-per-cent., B. 
choleroe in seven minutes. Its action appears to be continuous. It is 
much used in surgical practice with excellent results. 
Saprol.-This is a liquid containing 20 per cent, of mineral oil and 
80 per cent, of crude carbolic acid. It is lighter than water, and when 
thrown into it diffuses over the surface in a thin layer, which gradually 
yields its active ingredients to the strata below, which, in the course 
1 Archiv fur Hygiene, XXV., 1896, p. 328. 
2 Loco citato. 
3 Centralblatt fiir Bakteriologie, V., 1889, p. 650. 
4 Ibidem, VII., 1890, p. 75. 
5 Ibidem, XII., 1892, p. 232. 
6Ibidem, XI., 1892, p. 117. 
7 Arbeiten aus dem kaiserlichen Gesundheitsamte, VIII., 1892, p. 369. 
8 Annales de 1'institut Pasteur, IX., 1895, p. 26. ORGANIC SUBSTANCES. 
513 
of a day, become impregnated to the extent of about 0.34 per cent. 
In this strength, according to Scheurlen,1 it destroys cholera bacteria 
in one hour. For the disinfection of privy vaults, Keiler2 determined 
that it must be added to the extent of 1 per cent, of the entire contents. 
In mixtures containing 5 per cent., the same observer showed that the 
typhoid fever bacillus is destroyed within a few minutes. Pfuhl3 
found it to be much superior as a general disinfectant and deodorant 
to carbolic acid, but not suited to the treatment of vault contents. 
Laser,4 however, found that 1 per cent, will disinfect faeces and urine, 
and Scheurlen5 reported that for the disinfection of vault contents, but 
two other agents are comparable with it, namely, milk of lime and 
crude carbolic acid. 
Solveol is a concentrated aqueous solution of cresols with sodium 
cresotinate, containing over 25 per cent, of cresols. It is highly rec- 
ommended for use in surgical practice, being unirritating and much 
less toxic than carbolic acid. According to Hammer,6 it is more 
powerful in 2-per-cent. solution than creolin, lysol, and carbolic acid 
in 2.5-per-cent. strength. Hammerl7 also found it superior to carbolic 
acid and the other cresol preparations. 
Solutol is a solution of about 60 per cent, of cresols in sodium cresol. 
According to Hueppe,8 it is far superior to creolin, lysol, solveol, and 
phenol, in which conclusion he agrees with Buttersack.9 Hammer10 
also and others have found it to be well suited to the purposes of 
general disinfection. 
Alcohol.-Ordinary alcohol is extensively employed as a perserva- 
tive of organic material in great variety and hence has come to be re- 
garded as a powerful disinfectant as well as antiseptic. Koch's ex- 
periments showed that though the growth of anthrax bacilli was 
inhibited by 1 per cent, and wholly stopped by 8 per cent., the spores 
were unaffected by nearly 4 months' exposure to absolute alcohol, equal 
parts of the same and water, and mixtures of 1 part of alcohol and 2 
parts of water. Sternberg and others have shown that against some 
forms of bacteria it is inefficient as a germicide in any degree of con- 
centration, and that in different strengths it affects other forms to dif- 
ferent extents. Epstein's 11 experiments led him to the conclusion that 
absolute alcohol is devoid of germicidal properties, and that, diluted 
with water to 50-per-cent. strength, it exerts more action than at any 
other strength. Considerably stronger or weaker solutions show much 
diminished power. 
1 Archiv fur Hygiene, XVIII., 1893, p. 35. 
2 Ibidem, XVIII., 1893, p. 57. 
3 Zeitschrift fur Hygiene und Infectionskrankheiten, XV., 1893, p. 192. 
4 Centralblatt fur Bakteriologie, XII., 1892, p. 234. 
5 Archiv fur Hygiene, XIX., 1893, p. 347. 
6 Ibidem, XII., 1891, p. 359. 
7 Ibidem, XXL, 1894, p. 198. 
8 Berliner klinische Wochenschrift, 1893, No. 21. 
9 Arbeiten aus dem kaiserlichen Gesundheitsamte, VIII., 1892, p. 369. 
10 Loco citato. 
11 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIV., 1897, p. 1. 514 
DISINFECTANTS AND DISINFECTION. 
Minervini1 found that at ordinary temperatures, alcohol and its 
aqueous dilutions are quite powerless against spore-bearers, even with 
long exposure, and that against the sporeless bacteria the action is 
variable according to the amount of water present. The most power- 
ful action was exerted by 50- to 70-per-cent. alcohol. Heated under 
pressure in an autoclave, the power increases directly with the percent- 
age of water. Many germicides which are effective in aqueous solu- 
tion appear to lose more or less of their power in alcohol. Minervini 
found 3 per cent, of carbolic acid in strong alcohol to act with undimin- 
ished energy, but observed that corrosive sublimate, nitrate of silver, 
and other agents were more powerful as the percentage of alcohol in 
the solution diminished. According to Epstein, not only carbolic acid, 
but corrosive sublimate, lysol, and thymol are more powerful in 50- 
per-cent. alcohol than in water, but other agents are weaker. 
Lenti2 has reported that while 0.4 per cent, of corrosive sublimate 
in absolute alcohol had no effect on anthrax spores in 48 hours, 0.1 
per cent, in 98-per-cent. alcohol destroyed them in half the time. The 
same results were obtained with 10 per cent, of carbolic acid ; in ab- 
solute alcohol, it was powerless, but in 30-per-cent. alcohol, it killed 
them in 48 hours. 
Essential Oils.-The volatile oils have long been known to possess 
a certain degree of antiseptic power, but bacteriological experimenta- 
tion has failed to demonstrate that they are very active as germicides. 
Those highest in favor are the oils of peppermint, eucalyptus, and thyme, 
which contain respectively menthol, eucalyptol, and thymol. The latter 
was in somewhat extensive use in surgical practice prior to 1870. It 
is only slightly soluble in alcohol, ether, chloroform, and fixed and 
volatile oils. By many it has been regarded as superior to phenol. 
Spencer Wells much preferred it in his extensive experience in ovari- 
otomy. According to Behring,-3 however, it is only about a fourth as 
powerful, and Sauter4 ranks it even below salicylic acid. 
Eucalyptol is practically insoluble in water, but soluble in alcohol and 
other solvents. Concerning this agent, too, there is much diversity of 
opinion, some regarding it as vastly superior to phenol, others as much 
inferior. Lister praised it highly. Behring found it to be about 
equal to thymol. Menthol is sparingly soluble in water, but freely in 
alcohol and other solvents. It has been highly praised as a surgical 
antiseptic and as freely criticised. Omeltschenko5 ranks the oil of 
peppermint above that of eucalyptus, but below that of thyme. All 
three are placed by him below the oils of cinnamon and cloves. 
Aside from the conflicting evidence as to the power of the various 
volatile oils, their cost alone would be sufficient to restrict their 
general use as disinfectants. They are considerably employed in vari- 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXIX., 1898, p. 117. 
2Annali dell'istituto d'igiene sperimentale della reale Universita di Roma, III., 
1893, p. 515. 
3 Zeitschrift fur Hygiene, IX., 1890, p. 395. 
4 Centralblatt fur gesammte Therapie, VI., p. 376. 
6 Centralblatt fur Bakteriologie, IX., 1891, p. 813. ORGANIC SUBSTANCES. 
515 
ous combinations in mouth washes and in a number of decidedly ex- 
pensive proprietary disinfectants, one at least of which, tested by the 
author, has been found to be efficient in the sterilization of tuberculous 
sputum, one of the few uses for which its manufacturers make no claims. 
Soaps.-It is well known that ordinary soaps, both hard and soft, 
are possessed of considerable bactericidal power, investigated first by 
Koch, who proved that potash soap in the proportion of 1 to 5,000 
had a distinct inhibitory effect on the growth of anthrax bacilli, and in 
five times that strength prevented it altogether. This action was ad- 
mitted by Kuisl,1 who, however, asserted that against other kinds of 
bacteria, B. typhosus for example, it was quite inert. In 1890, Beh- 
ring,2 after experimenting with 40 different kinds of soap, proved that 
their disinfectant power was considerable, and concluded that it was 
dependent upon their alkalinity. Koch, however, had already demon- 
strated that, with equal degrees of alkalinity, soft soap was 8 times as 
powerful as potash alone, and Serafini3 has pointed out that the free 
alkali present, even in concentrated soap solutions, is so small in 
amount that it can exert no disinfectant action whatever, and that 
neither the alkali nor the fatty acid, but the combination of the two, 
is the effective agent. 
Nijland,4 experimenting with a potash soap containing 42.7 per cent, 
of water and a hard soap containing 14.5 per cent., found that the 
former in 0.24-per-cent. solution killed cholera bacteria in 10 minutes 
and the latter in the same strength was not wholly effective in 15, but 
in 0.30-per-cent. solution destroyed them within 1 minute. The same 
organism was used by Jolies5 in testing five soaps, all of which proved 
to be inefficient. By 10-per-cent. solutions, the bacteria were destroyed 
within 2 minutes; by 4-per-cent., in 10 minutes; by 2-per-cent., and 
in three instances by 1-per-cent., in 30 minutes. 
In a later series of tests with typhoid fever bacilli, Jolies c tried an 
almost neutral soap, containing but 0.041 per cent, of free alkali, and 
with 1 per cent., sterilized a bouillon culture within 12 hours; with 3 per 
cent, within 2 hours; and with 6 per cent, in 15 minutes. He showed 
that the action was much influenced by temperature. The above re- 
sults were brought about at temperatures between 4 and 8° C., but at 
18° C., the time which elapsed before complete sterilization was accom- 
plished was about double. This result is not in accordance with the 
general rule that disinfectants are more active with increased tempera- 
ture. He obtained practically the same results with other varieties of 
bacteria and reported that, because of its action on the most common 
pathogenic forms, soap is especially valuable and adaptable for pre- 
cisely the kind of work in which it is the most natural agent, that is, 
in washing dirty and infected clothing. 
1 Inaugural thesis, Munich, 1885. 
2 Zeitschrift fur Hygiene, IX., 1890, p. 395. 
3Archiv fur Hygiene, XXXIII., 1899, p. 369. 
4Ibidem, XVIII., 1893, p. 335. 
5 Zeitschrift fur Hygiene und Infectionskrankheiten, XV., 1893, p. 460. 
6 Ibidem, XIX., 1895, p. 130. 516 
DISINFECTANTS AND DISINFECTION. 
Serafini,1 however, is of the opinion that in the ordinary washing of 
clothes, soaps can exert but little disinfection, because of the many in- 
fluences, hardness of the water for example, which cause a diminution 
of their power. He recommends the avoidance of soft soaps on ac- 
count of the presence cf all of the impurities of the fats and alkali 
from which they are made, and advises one to distrust the ordinary 
colored soaps, which are quite likely to contain rosin. If soap is the 
sole reliance, he recommends using it in strong solution at 30 to 40° C. 
(86 to 104° F.), and immersing therein for a number of hours the 
articles to be treated. Even with long soaking, Beyer2 reports un- 
varying failure of soap against pus cocci and the bacilli of cholera and 
typhoid fever on clothing in hospital practice. 
Reithofter,3 experimenting with common soft soap containing traces 
of free alkali and 2.55 per cent, of potassium carbonate, a white almond- 
oil soap perfumed with nitrobenzol and containing 0.062 per cent, of 
free alkali, and a patented potash soap containing 0.031 per cent, of 
free alkali, found that all three, even in 1-per-cent, solution, were 
highly efficient against cholera germs within very few minutes, and, 
therefore, recommends soap as a practical disinfectant for clothing, fur- 
niture, etc., during epidemics of that disease. For washing body and 
bed linen, furniture, wood work, floors, etc., he recommends a 4- to 5- 
per-cent. soap solution as probably efficient under all conditions after 
from 5 to 10 minutes' contact, but suggests care in avoiding the com- 
mon commercial soft soaps, which are frequently of poor quality. 
Experimenting with B. typhosus and B. coli, he proved that here 
again the soaps possessed a high degree of power, though much larger 
amounts were necessary than in the case of B. cholerce. He demon- 
strated that a 10-per-cent. solution was necessary for the destruction 
of the typhoid germs within a minute, and that a 5-per-cent. solution 
required from 3 to 10 minutes according to the kind of soap, the soft 
soap being slowest in action, as was true also against the cholera germs. 
Against the colon bacillus, the action was still slower; 5 per cent, of 
the almond soap required 15 minutes, and the same strength of potash 
soap failed to accomplish complete sterilization in 20. The superiority 
of the almond soap suggested the possibility that its increased power 
might be due to the nitrobenzol with which it was perfumed, and ex- 
periment showed this to be true. 
Against pus cocci, all three agents failed completely; Staphylococcus 
pyogenes aureus was unaffected by 20-per-cent. solutions at the expira- 
tion of more than an hour. For the disinfection of the hands, 5-per- 
cent. solutions were found to be almost immediately effective against 
cholera germs, but longer and more thorough washing is recommended 
in typhoid infection. 
According to Mikulicz,4 tincture of green soap, the German officinal 
Spiritus saponatus, containing 10.2 potash soap, 0.8 olive oil, 1 
1Zeitschrift fiir Hygiene und Infectionskrankheiten, XIX., 1895, p. 130. 
2 Fortschritte der Medicin, 1897, No. 1. 
3 Archiv fiir Hygiene, XXVII., 1896, p. 350. 
4 Deutsche medicinische Wochenschrift, June 15, 1899. 517 
ORGANIC SUBSTANCES. 
glycerin, 43 alcohol, and 45 water, is admirable in undiluted form for 
sterilizing the hands in surgical work. They should be scrubbed for 
5 minutes with the preparation in its full strength. In his experi- 
ments, Staphylococcus pyogenes aureus was killed in a half minute and 
& p. albus in a minute. 
From all the evidence, conflicting though it be in certain respects, it 
must be evident that in soap we have an agent which, with all its limi- 
tations, is entitled to very serious consideration, at least as an auxiliary 
in complete disinfection. 
Medicated Soaps.-In order to increase the disinfectant properties of 
ordinary soaps, various agents, including mercury compounds, carbolic 
acid, and the cresol preparations, are incorporated in them. Compared 
with ordinary soaps, these preparations appear to be of doubtful utility, 
although in the hands of some experimenters they have yielded good 
results. From an extensive investigation of these soaps, Symes 1 con- 
cluded that for all practical purposes most of them possess no added 
value, but that the mercury soaps are useful in the disinfection of the 
hands. A 1-per-cent, solution of the biniodide soap killed pus cocci 
in a minute, while the other soaps failed to do so in 3 hours. Nijland2 
found that the addition of disinfectants to soaps increases their action 
in some cases and diminishes it in others, the latter especially when the 
added substance combines with the ordinary constituents. 
According to his experiments, the most powerful of all is the cor- 
rosive sublimate soap, which, however, has less power than the cor- 
responding amount of sublimate alone. In 0.003-per-cent. solution it 
killed cholera bacilli in water within 10 minutes. Rideal3 asserts 
that the double iodide of potassium and mercury has stronger germicidal 
powers than corrosive sublimate and is easily incorporated in the soap 
stock. He recommends the admixture of 1 to 3 parts each of mer- 
curic and potassic iodide in 100 of soap. " Potassio-mercuric iodide 
has the advantage of being compatible with strong alkalies, * * * 
moreover, it does not precipitate albumin, and is not easily reduced." 
McClintock 4 tried to make an antiseptic soap in which the mercury 
salt should exist unchanged and active and found the double iodide to 
be the most available agent in the proportion of 0.5 to 2.0 per cent. 
A solution containing 1 per cent, of the soap was found to be fatal to 
pus cocci and cholera, diphtheria, and typhoid fever bacilli in one minute. 
The soap attacked neither nickel, silver, aluminum, nor steel instru- 
ments, nor lead pipes, and did not coagulate albumin. 
Concerning carbolic acid and cresol soaps, the weight of evidence is 
clearly in support of the assertion that they are in no way superior to 
common soaps. Many contain no more than enough to make them 
powerful in odor, which is not enough to confer any marked bacteri- 
cidal power. Nocht5 calls attention to the solvent property of soap 
1 Bristol Medico-Chirurgical Journal, Sept., 1899. 
2 Loco citato. 
3 Disinfection and Disinfectants, London, 1898, p. 347. 
4 Medical News, April 17, 1897, p. 485. 
5 Zeitschrift fiir Hygiene, VIL, 1889, p. 521. 518 
DISINFECTANTS AND DISINFECTION. 
on carbolic acid, showing that at 60° C., a 3-per-cent. solution of soap 
will dissolve 6 per cent, and double that strength will dissolve 12 per 
cent, of carbolic acid. He found that a cold solution of soap containing 
1.5 per cent, of carbolic acid was fatal to pus cocci and non-sporing bac- 
teria in half an hour, but recommends the employment of 3-per-cent. so- 
lution of a 5-per-cent. soap for the treatment of clothing, leather articles 
and other objects. Reithoffer 1 found that carbolic acid is weakened 
by the presence of soap, and that a soft soap containing 40 per cent, of 
lysol was no more effective against pus cocci, B. coli and B. typhosus, 
than ordinary soaps, and was much weaker than a solution of lysol 
alone in the same lysol strength. 
In the disinfection of hands by means of medicated soaps, it must be 
borne in mind that the added disinfectant is commonly present in in- 
efficient amounts, and that, as used, the soaps form a very weak solu- 
tion, which, in the time ordinarily given, can have but little, if any, 
effect. 
Formaldehyde.-Formaldehyde, otherwise known as methyl alde- 
hyde and oxymethylen, the simplest known compound of carbon, hydro- 
gen, and oxygen, was discovered by Professor A. W. Hoffmann in 1867, 
but its germicidal properties were in no way recognized until 1886 and 
not put to practical use until 1891. It is a gaseous product of oxidation 
of wood alcohol made most simply by passing a current of the alcohol 
vapor over platinum sponge previously heated; as the vapor comes in 
contact with the incandescent platinum, it is oxidized to aldehyde and 
water (CH3OH 4- O = CH2O 4- H2O). The continuous current main- 
tains the incandescence. On a large scale, it is produced by treating 
the alcohol in copper tubes containing incandescent coke. 
It is soluble in water up to 40 per cent, and makes a neutral solu- 
tion, but the commercial preparations are usually slightly acid in re- 
action from traces of formic acid. Its solution cannot be stronger than 
40 per cent., and attempts to concentrate it or to condense the vapor 
cause it to polymerize to a white indistinctly crystalline solid, trioxy- 
methylen or paraformaldehyde, (C3HGO3), which is almost insoluble in 
water, melts at 171° C., when ignited, burns with a blue flame, but 
when gently heated in an open dish, is converted again to the gaseous 
formaldehyde. When the solution is heated in a closed vessel under 
pressure, polymerization is prevented by the presence of borax or of 
neutral salts, as chloride of calcium. 
Formaldehyde vapor is exceedingly pungent and very irritating to 
the eyes and nose. It has a strong affinity for many organic sub- 
stances and combines with nearly all foul-smelling products of decom- 
position, forming odorless compounds, and thus acting as a deodorant. 
It transforms gelatin in solution to a tough transparent substance in- 
soluble in boiling water, causes blood serum to lose its coagulability by 
heat, combines with the protoplasm of bacteria, and converts egg albu- 
min into a substance insoluble in water and indigestible. With am- 
monia, it forms an inert compound, hexamethylentetramin, which has 
1 Zeitschrift fur Hygiene, VII., 1889, p. 521. ORGANIC SUBSTANCES. 
519 
the odor of neither substance (4NH3+6CH2O=(CH2)6N44-6H2O). 
It has no action on copper, brass, zinc, nickel, silver, iron, steel, or 
other metallic substances, causes no diminution in the tensile strength 
of fabrics, and has no bleaching or other effect on colors, excepting to 
intensify the effect of certain of the coal-tar dyes (fuchsin, saffranin, and 
perhaps others). It may, however, fix blood, pus, and fsecal stains on 
clothing. It has no injurious action on clothing and other woven 
fabrics, furs, articles of rubber, leather, and paper, photographs, paint- 
ings, woodwork, and furniture. 
Its antiseptic properties were first noted in 1886 by Loew and 
Fischer,1 but its value as a practical disinfectant was first made known 
by Trillat2 in a communication to the French Academy of Science in 
1892, and since that time has been the subject of very extensive in- 
vestigation, which has demonstrated conclusively that formaldehyde is 
by far the most powerful and practical chemical disinfectant known. 
In general, it is used in the form of gas generated in different ways 
from methyl alcohol or from the aqueous 40-per-cent. solution, com- 
monly known by the commercial name Formalin, or from the solid 
polymer trioxymethylen, otherwise known as paraformaldehyde and 
by the trade name Paraform. In some processes of disinfection and 
deodorization, it is applied directly in the form of aqueous solution. 
Methods of Use, and Apparatus.-At first the gas was generated di- 
rectly from methyl alcohol, by means of lamps specially constructed for 
the purpose. The first of these was devised by Trillat, who was fol- 
lowed by Gambier, Barthel, Dieudonn6, Kreil, Tollens, and others, who 
presented various modifications and improvements. 
In 1896, Professor Robinson, of Bowdoin College, exhibited at the 
annual meeting of the American Public Health Association a lamp de- 
vised by him, which, it is generally agreed, is the best yet invented. It 
consists of a disk of moderately thick asbestos, closely perforated with 
small holes and platinized with a strong solution of platinic chloride, 
and a cylindrical dish upon which it is superimposed. In use, the dish 
is partly filled with methyl alcohol and the disk, at first removed, is 
wetted with alcohol, which is then ignited. As soon as the alcohol is 
consumed, the disk is replaced and is at a sufficiently high temperature 
to convert the fumes from the methyl alcohol beneath to formaldehyde, 
and as long as the process continues, is maintained at the proper de- 
gree of heat. But this, in common with all other lamps of the kind, is 
open to several objections, among which may be mentioned the small 
yield of formaldehyde, which necessitates the employment of a large 
number of generators; the fact that a large, if not the greater, part of 
the alcohol is converted to carbon monoxide and dioxide, and the dan- 
ger of fire. 
Trillat, recognizing the defects of his own and other lamps, and being 
convinced of the futility of attempting to disengage the gas by evap- 
orating the aqueous solution from open vessels, whereby polymerization 
'Journal fur praktische Chemie, XXXIII., p. 221. 
2Comptes rendus, CXIV., p. 1278. 520 
DISINFECTANTS AND DISINFECTION. 
is caused, attempted to devise an apparatus in which the aqueous solu- 
tion could be employed without the occurrence of this undesirable 
phenomenon. The outcome of his study was the autoclave which 
bears his name. 
This apparatus, shown in Fig. 92, consists of a cylindrical silver- 
lined pot of heavy copper of about a gallon capacity, with a cover rest- 
ing on a rubber gasket and secured by means of turn-buckles. The 
cover carries a pressure gauge, a thermometer, and an outlet controlled 
by a valve and terminating in a narrow brass tube. The pot is sup- 
ported on a tripod, and beneath it is a Swedish lamp, the flame of 
Fig. 92. 
Fig. 93. 
Trillat's autoclave. 
Sanitary Construction Company's 
generator. 
which is fed by vapors from kerosene oil forced out by compressed air. 
In the pot is placed not more than three-fourths nor less than one- 
fourth of its capacity of a mixture of the 40-per-cent. solution of 
formaldehyde and chloride of calcium, the latter for the purpose of 
preventing polymerization under pressure. This mixture, which con- 
tains 150 grams of the chloride to the liter, is known as formo- 
chlorol. The formaldehyde solution used must be practically free from 
methyl alcohol, which, while of no practical interest under ordinary 
circumstances, is an objectionable impurity when the solution is heated 
under pressure, since then it unites with a corresponding amount of 
formaldehyde to form inert methylal. METHODS OF USE, AND APPARATUS. 
521 
The cover is firmly fixed by the turn-buckles, and then the lamp is 
put in operation. When the gauge shows a pressure of three atmos- 
pheres, the outlet tube is introduced into the keyhole of the door of the 
room to be disinfected, and the valve is gradually opened so as to re- 
lease the vapor. The disengagement of the gas is continued until a 
sufficient amount of the liquid, based upon the amount of air space 
treated, is consumed. According to Trillat, in the case of a room of 
ordinary size, say 18 feet square and 10 from floor to ceiling, the op- 
eration should require about an hour. The objections urged against 
Fig. 94. 
Lentz's generator. 
this form of apparatus are its cost, the want of uniformity in the 
amount of gas delivered within a given time, and the danger of explo- 
sion from the possibility of the non-working of the valve, or from ob- 
struction by one cause or another of the outlet tube. 
A number of other apparatuses for the same purpose have been de- 
vised, and to several of them these objections do not apply. One of 
these is the generator made by the Sanitary Construction Company 
and used extensively by public authorities. (See Fig. 93.) It con- 
sists of a copper reservoir, holding about 3 quarts, from the bottom 
of which leads a quarter-inch copper tube, which forms a coil 2 inches 522 
DISINFECTANTS AND DISINFECTION. 
below and then turns upward and extends above the top of the appa- 
ratus, where it is fitted with a rubber tube carrying a fine copper 
nozzle through which the gas is delivered. Beneath the coil is a 
Swedish lamp similar to that used with the Trillat autoclave. The 
formaldehyde solution is admitted to the heated coil through a valve 
and is transformed to vapor, which escapes through the nozzle. 
Neither pressure nor the presence of calcium chloride is necessary, and 
the rapidity of action and amount of solution used can be determined 
by observing the height of the liquid in the glass gauge on the side of 
the reservoir. 
The apparatus is very much cheaper 
than the Trillat and similar auto- 
claves. Another generator which 
meets with favor is that of Lentz 
(see Fig. 94), in which the formalin 
is heated in a retort by means of a 
Swedish lamp, the gas emerging 
through the metallic delivery tube 
connected by rubber tubing with the 
nozzle, which is inserted through a 
keyhole. 
In order to avoid the use of the 
liquid preparation and to employ in 
its place the solid polymer trioxyme- 
thylen, or paraform, the Schering 
lamp was devised, and in 1897 was 
brought into notice by Aronson,1 
after he had made a series of tests 
which yielded good results. This 
very simple and inexpensive appa- 
ratus, shown in Fig. 95, consists es- 
sentially of a metallic shell, not un- 
like an open piece of stovepipe, sup- 
ported on legs and carrying in its 
upper part a basket made of sheet iron and wire gauze, and an alcohol 
lamp carrying 6 or more wicks. For convenience, the paraform is 
supplied in the form of pastilles weighing a gram each, and these are 
placed in the basket to the number of 2 for every 35 cubic feet of 
air space to be disinfected. The lamp is supplied with alcohol to the 
extent of 2 cc. for each pastille. The wicks must project not more 
than about a twelfth of an inch, which is enough to give a flame which 
will heat the basket and its contents sufficiently to cause volatilization 
of the agent with absolutely no danger of its taking fire and thus 
yielding no formaldehyde gas. By the time the alcohol is consumed, 
the pastilles will have been volatilized completely or nearly so. 
Should the space to be treated be of such size that the requisite 
number of pastilles cannot be placed in the basket, more than one ap- 
Fig. 95. 
Schering paraform lamp. 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXV., 1897, p. 168, 523 
METHODS OF USE, AND APPARATUS. 
paratus must be used. This process has the advantage of simplicity 
and economy of time, for when the apparatus is placed in position with 
its lamp burning, it requires no further attention on the part of the 
operator, who then, with other lamps, is enabled to start the process 
elsewhere and thus accomplish much more than another who, operating 
Fig. 96. 
Breslau generator and lamp. 
an autoclave or similar apparatus, is obliged to give it constant atten- 
tion as long as the gas is being generated. 
Still another apparatus is that used in what is known as the " Bres- 
lau method," in which the gas is disengaged in company with an abund- 
ance of aqueous vapor, by boiling dilute formaldehyde solution. The 
apparatus shown in Figs. 96 and 97, 
taken from the description of the 
method by von Brunn,1 consists of 
a copper boiler about 14 inches in 
diameter and 3 in depth at the pe- 
riphery, with an immovable cover 
slightly domed, in the center of 
which is an outlet tube, to which a 
stout rubber tube can be attached. 
The cover is provided also with 
two handles and an orifice closed 
by a screw cap. A flange around 
the upper border of the boiler keeps 
the latter in place when it is put on 
its support, which is a cylinder of 
enamelled sheet iron about 14 inches 
in height, provided in its lower half 
with slits for the free entrance of air, and on its inner side with three 
supports for an alcohol lamp. The lamp is an open dish, through the 
Fig. 97. 
Vertical section of Breslau generator. (Lamp 
in position.) 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXX., 1899, p. 1. 524 
DISINFECTANTS AND DISINFECTION. 
bottom of which in two concentric rings are 20 tubes which project 
upwards as high as the sides of the vessel. 
With this apparatus, 3.5 liters (nearly 4 quarts) of fluid can be 
brought to a boil in 10 minutes, and nearly the whole can be evapo- 
rated in an hour. The amount of alcohol placed in the lamp should 
be about one-fourth of the volume of the solution in the boiler, and 
this will be consumed before the boiler is empty. Like the Schering 
lamp, the apparatus can be left in the room or it can be used outside 
with a delivery tube passing through the keyhole. In order to achieve 
the best results, a dilution of 1 part of formalin with 4 of water is 
recommended. With this dilution, one avoids the polymerization, ob- 
served when the 40-per-cent. solution is heated, which is due to the 
fact that the water is driven off faster than the formaldehyde. 
A somewhat similar apparatus has been devised for the generation 
of steam in connection with the use of the Schering lamp. It consists 
essentially of a circular copper boiler, surrounding the Schering lamp 
and heated by a circular open alcohol lamp which is really a sort of 
gutter into which a measured amount of alcohol is poured. 
In 1897, Rosenberg1 described and attempted to introduce a simple 
form of lamp for the vaporization of formaldehyde from holzin, a dilute 
methyl alcohol containing 35 per cent, of formaldehyde and 5 of 
menthol, the latter being added in order to prevent the formation of 
methylal and to overcome any tendency to explode. The method has 
been tried by a number of experimenters, but the results have not led 
to its extensive employment. 
A number of inventors have devised methods for spraying the for- 
malin itself, among them Lingner, Prausnitz, Flugge, and Czaplewski. 
The latter2 disengages the gas by means of a jet of steam acting in a 
concentrated solution of formaldehyde, and presents figures showing the 
process to be the cheapest of all. 
In 1898, Schlossmann 3 advocated the use of a mixture of formalin 
and glycerin, which, by means of a steam jet from an apparatus of 
special construction, can be disseminated in the air in the form of a 
fine mist, which, being heavier than air, is supposed to settle and carry 
down all the bacteria mechanically. The mixture contains 10 per 
cent, of glycerin and is called glycoformal; the glycerin is supposed 
to prevent polymerization as well as to act mechanically. According 
to Schneider,4 the addition of glycerin is wholly unnecessary and dis- 
advantageous, since this substance is deposited all about in fine droplets 
and makes cleaning more difficult. The process is also too expensive 
and has the additional disadvantage of leaving an odor which is very 
lasting. 
Germicidal Properties.-The first to note the antiseptic effect of 
formaldehyde were Loew and Fischer in 1886, but though Loew con- 
1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIV., p. 1897, 488. 
2Miinchener medicinische Wochenschrift, 1898, No. 41. 
3 Berliner klinische Wochenschrift, June 20, 1898. 
4Archiv fiir Hygiene, XXXVI., 1899, p. 127. 525 
GERMICIDAL PROPERTIES. 
tinned his observations for some months and Buchner and Segall made 
a study of its antiseptic action in 1889, Trillat, in 1892, was the first 
to draw attention to the importance of the agent. Almost at the 
same time came a publication by Aronson.1 Trillat reported that 
bouillon, infected with B. anthracis, was sterilized by 1 part of formal- 
dehyde in 50,000, and that for the prevention of decomposition of 
meat juice, the agent acted as powerfully as corrosive sublimate in half 
the amount. Aronson reported that growth of B. typhosus, B anthra- 
cis and pus cocci in bouillon was absolutely prevented by 1 part in 
20,000, and very much inhibited by 1 in 40,000. Then followed 
other experimenters, and within six years, formaldehyde had been the 
subject of more extensive investigation than has ever been devoted to 
any other germicide. 
With the autoclave, Roux and Trillat2 reported that a number of 
pathogenic bacteria, including anthrax spores, were killed ; B. subtilis 
and B. mesentericus survived. Bose,3 at the same time, reported suc- 
cessful sterilization of a large number of varieties under different con- 
ditions in a large air space (over 25,000 cubic feet), using 3 liters of 
formalin. Staphylococci in the pocket of a pair of trousers were de- 
stroyed, but others more protected escaped, though the colon bacillus 
between the two sides of a folded mattress, apparently still more pro- 
tected, was killed. Out of a large variety of species including anthrax 
spores, B. pyocyaneus, and B. diphtherice, the only exposed organisms 
that escaped were B. subtilis and B. mesentericus. The dust and walls 
were quite sterile. 
Pfuhl4 found that all exposed organisms were destroyed by the 
Trillat method, but that dried Staphylococcus pyogenes aureus, an- 
thrax spores, and B. typhosus under a nurse's apron and others under 
a military overcoat were not affected; but diphtheria bacilli dried on 
threads and a fresh diphtheria agar culture under a woolen blanket 
were destroyed. Fresh typhoid agar cultures under a blanket were 
not killed ; staphylococcus agar cultures were inhibited. Struver,6 with 
a Munke autoclave much like Trillat's, vaporized 800 cc. of formo- 
chorol in a room of about 1,250 cubic feet capacity and, after 12 hours, 
found that all organisms which had been exposed were dead, but that 
anthrax spores and B. typhosus in a tight closet and anthrax spores in 
the folds of upholstery of a chair were not affected. 
With holzin, Rosenberg,6 using about 4 cc. to the cubic foot of air 
space, sterilized all his test objects within 3 hours. These included 
anthrax bacilli and spores, streptococci, and the bacteria of diphtheria, 
cholera, and typhoid fever, all on silk threads wrapped in blotting 
paper, placed in pockets and sleeves and under the collar of a coat. 
Struver,7 with the same agent in the same amount, was not so success- 
1 Berliner klinische Wochenschrift, 1892, No. 30. 
2 Annales de 1' Institut Pasteur, 1896, p. 283. 
'Ibidem, 1896, p. 298. 
4Zeitschrift fur Hygiene und Tnfectionskrankheiten, XXIV., 1897, p. 289. 
s Ibidem, XXVIL, 1897, p. 357. 
6 Loco citato. 
7 Loco citato. 526 
DISINFECTANTS AND DISINFECTION. 
ful. He exposed, for 24 hours, anthrax spores on threads and the ty- 
phoid fever bacillus on pieces of linen ; neither the spores nor the other 
organism protected by several layers of cotton cloth were destroyed. 
In another experiment, using much less holzin, the spores not protected 
by several layers of cloth were destroyed. 
The first experiments with paraform pastilles were those of Aronson,1 
who volatilized 2 pastilles to every 35 cubic feet and at the end of 24 
hours found that his test objects, which included anthrax spores, 
staphylococci, streptococci, B. pyoeyaneus, and the germs of tuberculo- 
sis, diphtheria, and typhoid fever, on gauze, threads, and other ma- 
terial, were destroyed. He repeated the test with but half the amount 
of paraform and again found everything sterile excepting the anthrax 
spores, some of which were still active. Gehrke,2 using 2 pastilles to 
each 35 cubic feet and with practically the same test objects as Aron- 
son had used, found, after 24 hours, that all that had been exposed 
were dead, excepting the anthrax spores. Fairbanks,3 with the same 
amounts, reported similar results; all exposed organisms and some 
which had been lightly protected between pieces of cloth, and, in cer- 
tain instances, others more completely protected by cloth and placed 
between bulky articles, were destroyed. In one series of tests, among 
the protected objects, only the typhoid and diphtheria organisms were 
killed, but, as usual, all the exposed germs were destroyed. 
In a series of experiments by the author at the Pathological Labo- 
ratory of the Boston City Hospital in 1897, 4 as a preliminary test, only 
a fourth of the recommended number of pastilles were volatilized in a 
small room, in which were placed test objects, only one of which (a 
smear of Diplococcus intracellularis meningitidis) was sterile after 18 
hours' exposure. With half the recommended number, the results were 
better, but not satisfactory. The test objects introduced were paper 
smears of anthrax spores, Staphylococeus pyogenes aureus, B. typhosus, 
and a very resistant non-pathogenic spore-bearing bacillus. After 21 
hours' exposure, these were found to be sterile without exception, but 
dust from several places in the room gave growths, though from others 
the results were negative. A surgical dressing, lying in a pail, yielded 
abundant growth before the experiment, but later was found to be quite 
sterile. Two Petri plates, exposed for 20 minutes after the room was 
aired, showed 7 and 4 colonies respectively. 
In the next experiment, the full recommended number of pastilles 
was employed. The test objects were smears of the same organisms 
as before, but they were more numerous and were differently disposed. 
Some were enclosed in cotton bags heavily sized, some in similar bags 
which had had the sizing removed by boiling; some were placed in 
Erlenmeyer flasks, two of which were introduced well into the middle 
of a hair mattress. In addition, a number of moist dressings and wet 
bloody dressings enclosed in cotton bags were employed. 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXV., 1897, p. 168. 
2 Deutsche medicinische Wochenschrift, April 14, 1898, p. 242. 
3Centralblatt fiir Bakteriologie, etc., XXIII., Abth. I., Nos. 1, 3, and 16. 
4 American Journal of the Medical Sciences, Jan., 1898. POWER OF PENETRATION. 
527 
After 20 hours' exposure, cultures were made which showed the fol- 
lowing results. The smears in boiled and unboiled bags and the slightly 
moist dressings, also enclosed in bags, were sterile without exception. 
The wet bloody dressings gave abundant growths. The flasks in the 
mattress agreed in results; the typhoid and staphylococcus smears in 
each were sterile, but those of anthrax spores and the non-pathogenic 
spore-bearer were not affected. The same was found to be the case 
with the smears in a flask lightly plugged with cotton and standing in 
an open closet. All four smears in another open flask placed in a 
closed closet were unaffected. Dust cultures from various parts of the 
room were negative in almost every case. 
Before the lamps were lighted, 3 Petri plates were exposed for 25 
minutes and yielded respectively 86, 124, and 53 colonies, about half 
of which in each case were of Staphylococcus pyogenes albus with a few 
of aureus, and, in one, of citreus. Three more plates were exposed for 
the same length of time after the room was aired, and the result 
was practically negative. Two colonies of mould developed on one 
and nothing whatever on the other two. A repetition of the experi- 
ment a week later with the same number of pastilles, but with only the 
original test objects, gave the same negative results. Preliminary dust 
cultures showed abundant growths; after 20 hours' exposure, all but 
one dust culture, and that from a closed closet, gave negative results. 
Power of Penetration.-Certain of the earlier experimenters and an 
occasional one of the more recent have claimed for formaldehyde a much 
greater penetrating power than can be explained by any law of physics 
or chemistry, but it is now very generally agreed that while this agent 
is beyond doubt the most powerful and practical disinfectant we pos- 
sess for large air spaces and general work, it is, in the gaseous form, 
merely a surface disinfectant which sometimes does and oftener does 
not penetrate beyond. 
In addition to the works already quoted, the following may be cited. 
Abba and Rondelli1 reported that, in the interior of a heap of clothing 
and on objects covered with clothes, no sterilization was effected. Doty2 
says that a careful analysis of reported results shows that it cannot be 
depended upon when deep penetration is required, but for superficial 
disinfection of furniture, clothing, and fabrics which can be freely 
spread out and exposed, it is of undoubted value. It can also be relied 
upon to penetrate letters and other thin packages placed in an air-tight 
chamber. To this last statement are opposed the results obtained by 
Dr. E. K. Sprague, U. S. M. H. S.,3 who, attempting to sterilize cul- 
tures in sealed envelopes with the Kinyoun-Francis disinfecting ap- 
paratus, failed every time. 
Experimenting with ordinary objects in a vacuum chamber heated 
to 90° C., with a vacuum of 15-20 inches, and with much more 
formalin than can be used under ordinary circumstances-360 cc. va- 
1 Zeitschrift fur Hygiene und Infectionskrankheiten, XXVII., 1898, p. 49. 
2 New York Medical Journal, Oct. 16, 1897, p. 517. 
3 Report on Formaldehyd Disinfection in a Vacuum Chamber, Treasury Depart- 
ment, Washington, Government Printing Office, 1899. 528 
DISINFECTANTS AND DISINFECTION. 
porized in 58 cubic feet-he finds that lie cannot recommend it 11 even 
when combined with a high degree of heat, as a disinfectant upon 
which reliance can always be placed for the treatment of articles re- 
quiring much penetration, especially when the exposure is limited to a 
half hour." Wilson's 1 experience led him to report adversely on its 
penetrative power. Organisms protected by the folds of a blanket 
were not killed. Pfuhl2 warns us against expecting more than it can 
perform, and says that it will always be only a surface disinfectant 
not to be relied upon to influence matters only slightly covered or in 
dust which lies in measurable thickness in cracks of floors and walls. 
He demands a less severe test of a disinfectant than the ability to de- 
stroy anthrax spores, and asserts that when formaldehyde in the air 
will kill Staphylococcus pyogenes aureus dried on silk threads, other 
pathogenic organisms which enter into house disinfection, the strepto- 
cocci and the bacteria of cholera, diphtheria, tuberculosis, and typhoid 
fever, will be destroyed. 
It is important to bear in mind the lack of penetrating power of 
formaldehyde gas, since a disregard of this fact will cause much sup- 
posed disinfection to be a positive danger, because of over-confidence 
in the results actually achieved. Therefore, in practice, all obstacles 
to thorough dissemination must be removed as far as is possible. 
Conditions Favoring Action.-Concerning the influence of moisture 
on the efficiency of formaldehyde gas, there is a decided differ- 
ence of opinion. Abba and Rondelli3 believe that dryness helps the 
process. Symanski4 reports that it acts best in dry air with high 
temperatures. Robinson5 regards dampness as a disadvantage. Tril- 
lat also believes that the presence of moisture makes the results un- 
certain. On the other hand, Strehl2 is of the opinion that moisture 
enhances its action, Novy maintains the same view, and Hammerl and 
Kermauner,6 commenting on the use of paraform pastilles, assert that 
the process is effective, if enough moisture is supplied, and recom- 
mend vaporizing four times the amount of water necessary to saturate 
the air at the existing temperature. 
The results obtained by the author in the experiments above men- 
tioned and in other tests with cultures and decolorized fuchsin solution 
in tubes and flasks stopped with absorbent cotton led him to the con- 
clusion that penetration is influenced largely by moisture ; " through 
dry pervious substances, as cotton cloth, absorbent cotton, hair, etc., it 
appears to penetrate more or less easily, but not always in sufficient 
amount to exert germicidal action. * * * In the presence of moist- 
ure the penetrating power is practically nil." 7 With this statement, 
Rideal8 does not agree. He says, " Inasmuch as the vapor is so sol- 
1 Brooklyn Medical Journal, Nov., 1897, p. 741. 
2Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIV., 1897, p. 289. 
3 Loco citato. 
4 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXVIII., 1898, p. 219. 
5 Ninth Report of the State Board of Health of Maine, 1896, p. 180. 
6 Miinchener medicinische Wochenschrift, Nov. 22 and 29, 1898. 
7 Loco citato. 
8 Disinfection and Disinfectants, 2d Edition, London, 1898, p. 333. TOXICITY. 
529 
able in water one would expect that materials previously moistened 
would absorb more of the gas than dry fabrics, and therefore show 
greater efficiency, as I have found in my experiments." But when the 
gas is absorbed by moisture, it can no longer act as a gas, but as a so- 
lution which has influence in situ, and may give off fumes to the parts 
in its immediate vicinity. 
The advocates of the Breslau method, von Brunn, Flugge, and 
others, regard the concomitant liberation of steam as a most essential 
part of the process, on the ground that as the moisture condenses on 
the walls and contents of the room, the gas is absorbed and then acts 
directly on the object in the form of solution. 
It is very generally agreed that a high temperature is most con- 
ducive to good results. Abba and Rondelli, Trillat, Symanski, and 
others whose works have been quoted, and Ivanoff1 are of this mind. 
Brough,2 whose experience in public disinfection is large, reports that 
low temperatures are decidedly detrimental. 
Toxicity.-Formaldehyde is commonly regarded as non-poisonous for 
higher organisms under ordinary conditions, and most experimenters 
who have confined animals in spaces undergoing disinfection have 
reported no permanently injurious effects. Aronson,3 in 1892, noted 
the effects of the gas on guinea-pigs confined for an hour in a strong 
atmosphere of it; they showed great discomfort and uneasiness, but 
on removal soon recovered completely. He reported some results of 
experiments by Zuntz, who determined the fatal subcutaneous dose 
for rabbits to be 0.240 gram per kilogram of body-weight. In Aron- 
son's later experiments,4 guinea-pigs and rabbits, left over night in 
rooms containing an amount sufficient for practical disinfection, were 
found to be alive, and on being killed showed no evidence even of 
serious irritation of the bronchial mucosa. 
Pottevin5 found that a 2-per-cent. solution in subcutaneous doses of 
0.250 gram per kilogram was fatal to guinea-pigs in a few days 
and that the inhalation of the vapors was likewise fatal in 2 or 3 
days. Trillat says that it is toxic only when inhaled many hours, but 
gives no definite number. De Schweinitz exposed a calf for five 
hours; it showed no particular distress and soon recovered completely 
in fresh air. Kobert exposed guinea-pigs for 36 hours without re- 
sults. Fairbanks exposed mice and rabbits ; Pfuhl, white mice ; Doty, 
guinea-pigs, mice, fowls, and insects, and no deaths occurred. Doty's 
time of exposure was from 3 to 15 hours; he noted occasional evi- 
dence of inflammation of the respiratory tract, but nothing more. 
Opposed to these negative facts are positive results observed by 
Brough and the author. Brough6 has repeatedly found that cats and 
dogs, accidentally overlooked in rooms undergoing disinfection, have 
1 Centralblatt fur Bakteriologie, XXII., 1897, p. 50. 
2 Transactions of the Massachusetts Medical Society, 1898. 
3 Berliner klinische Wochenschrift, 1892, No. 30. 
4Zeitschrift fur Hygiene und Infectionskrankheiten, XXV., 1897, p. 168. 
5 Annales de 1'Institut Pasteur, Nov. 25, 1894. 
6 Loco citato. 530 
DISINFECTANTS AND DISINFECTION. 
been unable to survive even until the door was opened. He notes that 
flies are always killed, and bedbugs also, when not protected. 
In an experiment conducted by the author 1 in a room of 7,660 cubic 
feet capacity, in which 650 cc. of formalin were vaporized, two rabbits 
were left over night in a wire cage. Soon after the gas began to be 
generated, both animals showed strong evidence of discomfort, but at 
the end of 15 hours, when the room was opened, neither appeared to 
be much affected. But it will be noted that the amount of formalin 
used was not large for the air space; no more had been converted be- 
cause of the bad working of the generator. On the following day, 
2,150 cc. of formalin were used, and in the morning one rabbit was 
dead and the other alive, but breathing through the mouth with great 
difficulty. He improved noticeably within 2 hours, but died 36 hours 
later. Both animals were subjected to thorough examination in the 
Pathological Laboratory of the Boston City Hospital, from the records 
of which the following description, which evidences the very extensive 
poisonous action of the gas, is taken. 
"No. 1. Section of the tongue shows nothing abnormal. Section of 
mucous membrane of the mouth shows desquamation of the surface 
epithelium with hemorrhage and infiltration, with lymphoid cells in 
the tissue beneath. Section of oesophagus is normal. There is no 
pneumonia. The liver shows marked injection, with granular and 
fatty degeneration of cells around the central veins of lobules. The 
lymphatic gland shows some dilatation of the lymph sinuses with 
hemorrhage. In the kidney there is slight degeneration of the 
epithelium. 
" No. 2. In the liver there is considerable dilatation of hepatic veins, 
with some degeneration of liver cells in the center of the lobules. The 
kidney is congested. The epithelium of the convoluted tubules is 
somewhat swollen and granular, and there is a small amount of coagu- 
lated albumin in the capsular space of the glomeruli. In many of 
the convoluted tubules there is more or less granular and circular 
reticulum, and, in places, desquamation of the cells. The spleen 
shows a slight amount of hemorrhage in the pulp. Pancreas shows 
no change. One of the lymphatic glands shows a marked degree of 
oedema, with formation of fibrin in the lymph sinuses. In the lung 
there is intense bronchitis with consolidation extending into the sur- 
rounding lung tissue. This is more marked in the very smallest 
bronchi. In one place, in the center of a focus, there are numbers of 
short bacilli. The exudation of the alveoli is almost entirely purulent, 
with some large cells mixed with pus. In another place in the tissue 
there were numbers of large bacilli. There is only a slight amount of 
fibrin in the exudation. In another portion of the lung there were 
very much larger foci which were filled with organisms. All the 
blood vessels of the lung are greatly injected. 
11 It is difficult to explain the absence of bacteria in the cultures made 
from the lung in the second case. The general character of the lesions 
'Annates de 1'Institut Pasteur, Nov. 25, 1894. DIS AD VANTAGES. 
531 
in both cases shows the action of a soluble chemical poison on the 
tissues. The changes are much more marked in the second case than 
in the first, but in both they are of the same general character." 
In another experiment in which the volume of formalin vaporized 
was not sufficient to destroy more than a small proportion of the test- 
objects, a lot of roaches in a glass dish covered with wire gauze were 
killed, and in others conducted in a glass cabinet in which small vol- 
umes of formalin were vaporized, flies were very quickly killed. 
Amount Necessary for Room Disinfection.-The amount of formal- 
dehyde necessary to disinfect any given air space depends very much 
upon the thoroughness with which the escape of the gas is prevented 
during the time given for action. Under ordinary conditions and 
with the observance of all reasonable precautions, it is generally agreed 
that for each thousand cubic feet, a pint of formalin or about 60 pas- 
tilles of paraform ought to suffice. Struver1 would use 45 pastilles 
per 1,000 cubic feet against sporeless bacteria, but in practical disin- 
fection one cannot always discriminate. Fliigge2 advises that in small 
rooms containing the usual amount of furniture the number of pastilles 
be increased from 2 to 2.5 per cubic meter, or to 72 per 1,000 cubic 
feet. 
With the Breslau method, it is claimed that less than half a pint of 
formalin (190 cc.) will suffice for 1,000 cubic feet with 7 hours' ex- 
posure. Novy3 also is of the opinion that in the presence of sufficient 
moisture, even less will be found adequate ; namely, 150. Provided the 
gas is prevented from escaping, there can be no doubt that the smaller 
amounts are effective within much less time than that usually given in 
practical work. In a series of experiments in a practically air-tight 
glass cabinet, using as test-objects smears of anthrax spores, Staphylo- 
coccus pyogenes aureus, a highly resistant non-pathogenic spore-bearer, 
and the bacilli of diphtheria and typhoid fever, the author found every- 
thing sterile after two and a-half hours' exposure to an atmosphere 
containing the equivalent of 110 cc. formalin in 1,000 cubic feet. 
Using it in the ratio of about a pint to the 1,000 cubic feet, the same 
result was attained in less than a half hour. 
Disadvantages.-The principal disadvantage observed in disinfection 
by formaldehyde, aside from its cost, which is considerable, is the strong 
odor, which is sometimes very persistent, especially when much moisture 
is present, and which, except under very unusual conditions, is plainly 
perceptible outside the room in which the gas is disengaged. Usually, 
however, this is a transient trouble and is met by thorough aeration. 
If deemed advisable on the score of saving time, and when the gas has 
been absorbed by the condensed moisture on the walls and furniture, it 
can be neutralized by means of ammonia water, which may be exposed 
in the room in shallow dishes or vaporized from a flask or other appa- 
ratus and conducted into the room by means of an outlet tube through 
1 Annales de 1'Institut Pasteur, Nov. 25, 1894. 
2Zeitschrift fur Hygiene und Infectionskrankheiten, XXIX., 1898, p. 276. 
3 Medical News, 1898, p. 641. 532 
DISINFECTANTS AND DISINFECTION. 
the keyhole of the door. Fliigge recommends the latter method and 
advises the use of about 120 cc. of the 25-per-cent. solution to each 
100 cc. of formalin, and 320 cc. to each 100 pastilles of paraform used. 
Articles of clothing, stuffed furniture, and the like must otherwise re- 
quire sometimes several days of airing. 
Technic of Room Disinfection.-See under Practical Disinfection, page 
536. 
Other Applications of Formalin.-Besides its use in the gaseous state 
for house disinfection, formaldehyde in the form of its aqueous solution 
is well adapted to the sterilization of urine, faeces, sputum, and other 
waste products, furniture, woodwork, toilet articles, and other objects, 
and it is also valuable as a deodorant. In the disinfection of urine, 
the addition of a few drops of formalin to a quart will be found to pro- 
duce sterility within an hour. Tuberculous sputum and diphtheritic 
membranes, covered by a sufficient volume of a mixture of about one 
and a-half tablespoonfuls of formalin in a quart of water, are sterilized 
within two hours. Liquid stools plus an equal volume of the same 
mixture are completely disinfected within the same period. Walter 1 
states that, with this strength, faeces are deodorized in 1 minute, and that 
treated with 10-per-cent. solution, they are sterilized in 10 minutes. 
He states also that a 3-per-cent. solution applied to the hands destroys 
all adherent organisms very quickly, especially if mixed with alcohol. 
The mixture above mentioned is very efficient as a wash for furni- 
ture, woodwork, and other objects, for spraying carpets and woolen 
clothing, etc., and for soaking bed linen and other washable fabrics. 
A tablespoonful to a quart of water will remove all odor from the 
hands after autopsies and will deodorize other parts of the body to 
which it may be applied. 
Prevention of Dissemination of Infectious Material; Practical 
Disinfection. 
Even with the best disinfectants available and with the exercise of 
the greatest care in their application, practical disinfection is by no 
means always effective in preventing the transmission of infective ma- 
terial to new fertile ground. Hence it is advisable and necessary to 
keep the infected area as small as possible and to prevent the accumu- 
lation of infective material by destroying it continuously and as quickly 
as possible after it is thrown off by the body. With the exercise of 
due care, the waste products which act as vehicles for the infective 
agents of our common and occasional scourges may be so effectively 
dealt with from hour to hour and from day to day as to make the after- 
treatment of the room and its contents somewhat of a mere form, carried 
out as a matter of routine practice, or in order to make assurance 
doubly sure. 
According to the nature of the disease, these agents reside in dis- 
charges from the mouth, nose, and throat (diphtheria and pertussis), 
1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXI., 1896, p. 421. DISINFECTION OF FAECES. 
533 
in sputum (pulmonary tuberculosis, influenza, and pneumonia), in dis- 
charges from the bowels (typhoid fever, cholera, dysentery, and tuber- 
culosis), in the urine (typhoid fever), and in matters thrown off by the 
skin (acute exanthemata). Therefore, the course to be pursued during 
the continuance of a sickness or convalescence varies according to the 
nature of the disease. 
The limitation of the infected area and of the amount of material 
which may require disinfection on the termination of the disease should 
be a matter for immediate action on the discovery of the existence of 
the disease. The patient, especially in the case of the acute exanthe- 
mata, should be placed in a room which, if possible, may be isolated 
from the rest of the house, and from which all unnecessary furniture, 
especially of the upholstered kind, hangings, carpets, and rugs have 
been removed. Disinfectants for the prompt treatment of. infective 
matter should be kept immediately at hand together with a sufficient 
number of appropriate vessels and utensils. 
In order to prevent or restrict the carriage of living organisms from 
the room, ingress should be denied to all whose presence is unnecessary ; 
the wearing of other than cotton" and linen dresses, that is, smooth- 
surfaced and washable, by the attendants should be interdicted ; no food 
remainders should be taken away to be consumed by others; no used 
bed linen or body linen removed until after immersion in disinfectant 
solutions, and no discharges finally disposed of until after appropriate 
treatment. Should it be necessary to use the broom, the dust should 
be kept down by the use of wet sawdust or tea leaves, which, with the 
gathered dirt and dust, should be treated with disinfectant and burned. 
Under no circumstances can the process known as " dusting," which 
is merely the scattering of dust through the air from surfaces where it 
was at rest and upon which and elsewhere it will again be deposited, 
be allowed, but such surfaces may be wiped with clothes moistened 
with or wrung out in disinfectant solution and afterwards soaked and 
boiled. According to season, the windows should be provided with 
wire screens to keep out flies, which not only are an annoyance, but 
through their habit of visiting all manner of excreta and other filth, act 
as carriers of infection. 
Disinfection of Faeces.-The discharges from the bowels in the dis- 
eases typhoid fever, dysentery, cholera, and intestinal tuberculosis 
should be received in vessels containing an amount of disinfectant so- 
lution equal to, or, better, larger than the probable volume of the dis- 
charges. Whatever the agent used, it must be brought into immediate 
contact with the entire mass of the discharge by thorough mixing, and 
the whole should stand under cover for about an hour before final dis- 
position. Milk of lime, though efficient, leaves a bulky residue which 
cannot be conveniently disposed of through the usual channels. Chlo- 
rinated lime is also efficient, but is disagreeable in odor. Corrosive 
sublimate is unsuitable for reasons elsewhere stated. Phenol, in 5-per- 
cent. solution with or without the addition of mineral acids or common 
salt, and the various cresol disinfectants may be employed, but their 534 
DISINFECTANTS AND DISINFECTION. 
strong odor is not always tolerable to the patient. Dilute formalin 
presents no objections and is very efficient and rapid in action. 
Urine.-In typhoid fever and tuberculosis of the urinary tract, the 
urine should be sterilized by the addition of an equal volume of a 5- 
per-cent. solution of chlorinated lime, carbolic acid, or one of the cresol 
compounds, but better by the addition of about a fortieth of its volume 
of formalin. 
Sputum.-In pneumonia and pulmonary tuberculosis, the sputum 
should be received in spit-cups partly filled with disinfectant solution 
and kept covered when not in actual use. It may be treated with 5- 
per-cent. carbolic acid, or about 5 per cent, of any of the cresol com- 
pounds, or 1 per cent, of formaldehyde. Milk of lime and chlorinated 
lime are also efficient. Corrosive sublimate is very uncertain. 
By reason of its consistency and adhesive properties, sputum is one 
of the most difficult materials to sterilize. It is especially dangerous 
as it may contain large numbers of entangled bacteria, which, on dry- 
ing, may be disseminated by air currents. 
Discharges from Mouth, etc.-In diphtheria and pertussis, all dis- 
charges from the mouth and throat should be received on pieces of rag 
which should be burned. The diphtheria organism retains its vitality 
a long time in the dry state and so may exist in the air of the room, if 
particles of false membrane which happen to be thrown out in cough- 
ing or sneezing are allowed to dry on walls, furniture, and elsewhere. 
Eating Utensils, etc.-All eating utensils used by patients with 
pneumonia, diphtheria, pertussis, the exanthemata, and tuberculosis 
should be well scalded. All napkins should be treated in the same 
manner as infected bed linen. All remains of meals should be de- 
stroyed. 
Bed Linen and Clothing.-In any case of sickness in which isola- 
tion is advisable or in which the morbific agent is known to exist in 
the bowel discharges, all used body linen, bed linen, towels, napkins, 
wash cloths, handkerchiefs, etc., even if not obviously soiled, should be 
immersed for an hour in disinfectant solutions and then conveyed 
under cover to the laundry or other suitable place and boiled for an 
hour. Should the organism survive the first treatment, which event 
with proper care is unlikely, it will perish in the second. Should 
there be no faecal or other stains, the boiling may be carried out with- 
out the preliminary soaking, but in no case should the articles in a dry 
state be removed from the room except under cover or wrapped in a 
sheet wetted with an efficient disinfectant. 
In scarlet fever, for example, the morbific agent, whatever it may 
be, is exceedingly tenacious of life and resides in the fine particles of 
epidermis which are continually cast off by the skin, and it is easily con- 
ceivable that an armful of linen from a case of this disease might shed, 
in its journey to the laundry, a number of dust particles capable of 
much mischief. Neither lime nor chlorinated lime may be used on 
clothing, on account of probable injury. Corrosive sublimate 1 : 1,000, 
phenols and cresols in 5-per-cent. solution, and formaldehyde in 1-per- AIR. 
535 
cent, solution may be advised. Colored goods are sometimes affected 
by some of the cresol compounds, but to no greater extent than may 
be caused by ordinary laundry soap. 
Hands.-In the nursing of cases of infectious disease, the soiling 
and infection of the hands is frequently unavoidable. After every 
use of the bed pan, every wiping away of discharges, every handling 
of the patient's body, and, in short, after every act by which the hands 
may become infected, they should be washed immediately and thor- 
oughly, though not necessarily with that thoroughness which is so 
essential in surgical practice. Ordinary soap and water treatment 
should be supplemented by the application of some more powerful 
disinfectant. Carbolic acid and the cresols may serve, but they leave 
an unpleasant smell and have sometimes an unpleasant effect on the 
skin. Formaldehyde in 3-per-cent. solution is efficient, but when ap- 
plied frequently causes a hardening of the epidermis which is far from 
agreeable. Corrosive sublimate 1 : 1,000 is efficient and its use has 
no drawbacks. Schenk and Zaufal1 recommend the use of sand soap 
followed by immersion in corrosive sublimate 1 : 1,000, as hot as the 
hands can bear. 
Air.-All attempts to disinfect the air of the sick-room in the pres- 
ence of the patient are wholly futile, for the presence of enough of any 
chemical disinfectant to have any effect on the bacteria present would 
cause the air to be irrespirable. It is a common practice to place 
about the room dishes containing carbolic acid, permanganate solution, 
chlorinated lime, iodine and other agents, and to suspend sheets wrung 
out in all kinds of active and inert solutions in the vain hope that 
thereby the air is made better for the patient and incapable of trans- 
ferring infection to others. Whether the agent used is a true disin- 
fectant in any strength whatever, and whether the sheet is continuously 
or only intermittently wet, do not appear to enter in any way into the 
question of efficiency. Ordinarily, anything sold in the shops at a 
high price and under a label alleging not infrequently the impossible 
will be accepted without question. But it may be safely asserted that 
no disinfectant known can be of the slightest service when used in this 
way, and if this is true of the disinfectant, it must be of the sheet. 
Much can be done to remove the well-known disagreeable sick-room 
smell, due to the excreta and to matters eliminated by the lungs and 
skin, but all hope of producing sterility of the air should be aban- 
doned. If pathogenic organisms are present in the air, a much easier 
and more reasonable method of dealing with them is that of thorough 
aeration, and this is one of the most important parts of treatment in 
general. The germicidal properties of sunlight must also not be over- 
looked when it is possible to make use of this important aid. If good 
ventilation is not enough to keep the air sweet, the old-fashioned pas- 
tilles, containing benzoin, may be employed as occasion demands, or 
one or two paraform pastilles may be slowly volatilized in a small 
lamp for the purpose. In very small amounts in the air, the gas is in 
1 Miinchener medicinische Wochenschrift, April 10, 1900. 536 
DISINFECTANTS AND DISINFECTION. 
no way disagreeable or irritating, and acts very powerfully as a deo- 
dorant, not by supplanting the smell, but by destroying it by chemical 
union. 
Room Disinfection.-Not until the termination of the disease or the 
removal of the patient should the disinfection of the sick-room and its 
contents be attempted. This is not such an easy matter as is com- 
monly supposed, and much supposed disinfection is, by reason of a 
lack of thoroughness, no better than none at all, or, indeed, worse, be- 
cause of undeserved confidence and unfounded sense of safety. Even 
with the utmost care, one can hardly expect absolute perfection of re- 
sults, though in ideal disinfection, every micro-organism present should 
be destroyed. Fliigge,1 who has devoted much time and study to the 
question of house disinfection, avers that with any process by which 
90 per cent, of the pathogens present are destroyed, one should be 
content, and that no process practicable will kill all of them. 
The processes employed up to within very recent years are notori- 
ously inadequate, and the far superior processes in use to-day may yet 
be made more perfect. House disinfection is often most insufficient, 
even when what has been done has been carried out with every care 
and under most favorable conditions, since it is the usual practice to 
disinfect only the particular room which the patient has occupied dur- 
ing his sickness, without regard to the fact that all the connecting 
rooms, hallways, and distant parts of the house may have become 
infected. 
The open doorway opposes no unseen obstacle to the passage of 
minute dried particles of false membrane or epidermal scales floating 
in the air, nor are these attracted to and retained by the interposed 
sheet like particles of iron by a magnet. Even when the door is closed, 
there are air currents, now' one way, now the other, under it and above 
the threshold. Infective material may be carried in one way and 
another by members of the family, visitors, attendants and even by 
the patient himself to various parts of the house, and the room in 
which he has lain ill may, by reason of proper attention, be the least in- 
fected one in the house, but yet in ordinary practice it is the only one 
treated. Probably oftener than not, much more than one room, and in 
not a small proportion of cases, the whole house, should receive atten- 
tion. 
The existing methods of room disinfection comprise mechanical 
treatment, direct application of disinfectant solutions as spray or 
washes, liberation of gaseous agents, and combinations of all three. 
The bread process, devised by Esmarch,2 consists in rubbing the walls 
with pieces of bread, to which bacteria adhere with great tenacity. 
This is not applicable to rough walls, and when thoroughly and prop- 
erly done, involves such an amount of labor and material as to be ex- 
ceedingly expensive. The bread pieces, together with all crumbs 
which break off and fall to the floor, are carefully removed and de- 
1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIX., 1898, p. 276. 
2 Zeitschrift fiir Hygiene, II., 1887, p. 491. ROOM DISINFECTION. 
537 
stroyed by fire. For the rest of the room and its contents, other proc- 
esses are necessary, including scrubbing with soft soap and water, 
wiping with disinfectants, and transportation of certain articles of 
clothing, furniture, bedding, etc., to the public disinfecting station to 
be treated by steam. 
The method of treating walls, floors, furniture, and clothing by 
spraying with solutions of mercuric chloride and other agents com- 
mends itself in some quarters and not in others. According to Rideal, 
35,000 houses in Paris were disinfected by means of sublimate spray, 
1 : 1,000, in 1893, and a still larger number in 1894 with satisfactory 
results and with no bad effects from the poison. It appears, however, 
according to later evidence,1 that a number of the employes of the dis- 
infecting squad have shown symptoms of mercurial poisoning, and 
Rideal mentions cases of salivation in India attributed to corrosive 
sublimate wash for floors. The spraying process, whether satisfactory 
or not and whether dangerous to health or not, is not quick and involves 
other treatment which consumes time and adds to the expense. 
The ideal disinfectant would be a gas with no destructive or dis- 
agreeable action on anything but micro-organisms, capable of penetrat- 
ing materials by which they are hidden, and acting with great quick- 
ness. Such an agent, it is safe to say, will never be discovered, for, 
even though the other requirements may be met, it is improbable that the 
physical law governing diffusion will ever be modified by any gas as 
yet undiscovered. Gaseous disinfection must ever be superficial or 
nearly so, and must be assisted by other methods to bring about the 
best results. Gaseous disinfectants which exert any injurious influence 
on the objects treated cannot be tolerated, and it happens that this 
class, which includes chlorine and sulphur dioxide, has been found 
wanting in efficiency. 
Formaldehyde gas approaches more nearly the requirements of the 
ideal disinfectant than any thus far tried and is rapidly supplanting all 
others. In its application, no matter how it is generated, whether from 
formalin or paraform, it is essential that every obstacle possible shall 
be interposed against its escape from the space under treatment and 
that all objects within that space shall be so disposed as to present as 
much of their surface as possible to its action ; and even then, absolute 
perfection of results cannot be attained. Flugge2 relates that twice he 
prepared a small room, containing but little furniture, by placing patho- 
genic organisms on marked locations and had the local disinfecting 
squad perform their office under careful supervision, and in both in- 
stances found that a fair percentage of the bacteria escaped destruction. 
He suggests, with good reason, that in routine practice, the results must 
ordinarily be far less favorable. 
For the attainment of the best results, the various articles of furni- 
ture must be moved away from the walls, all articles of clothing, 
blankets and other textiles must be suspended freely on lines or 
'Journal of State Medicine, IV., 1896, p. 146. 
2 Loco citato. 538 
DISINFECTANTS AND DISINFECTION. 
clothes-horses, the pockets of clothing turned inside out, and all cracks 
and other outlets carefully stopped with wet cotton, putty, adhesive 
paper, or other suitable material. 
Particular attention must be paid to the complete closure of all inlet 
and outlet registers; those in the walls should be pasted over with 
stout paper, and those in the floor may be so treated or covered with 
thick cloth wrung out in sublimate solution or diluted formalin. 
Loosely fitting window-sashes may be made tight by means of wooden 
wedges, and the cracks around them properly stuffed. If there is a 
stove in the room, its doors and openings for drafts must be securely 
sealed. Open fireplaces and Franklin stoves require complete closure 
of their flue-outlets. The doors of all closets and cupboards and the 
drawers of all bureaus and cabinets must be left open. All soiled 
places on the walls, floor, and furniture, possibly due to infective ma- 
terial, should be wetted with formalin or sublimate solution. 
When the room has been properly prepared, the generation of the 
gas may be begun. If paraform lamps or the Breslau apparatuses 
are employed, the operator leaves the room and stops the crack under 
the door with wet cotton and closes the keyhole with a gummed label 
or with putty. If an autoclave or other similar apparatus is employed, 
the stopping of the keyhole of the door is necessarily deferred until 
the generation of the gas is completed. The room is then left un- 
opened over night or, if the process is begun in the morning, through 
the day. 
On the expiration of the required time, ammonia in the necessary 
amount is vaporized through the keyhole, or the room is entered at 
once, the windows thrown open, and free aeration established. In the 
latter case, the operator's eyes should be protected by closely fitting 
goggles and he should hold his breath, if possible, until his object is ac- 
complished. If ammonia is employed to neutralize the gas, the room 
will be sooner inhabitable than otherwise, especially if steam has been 
generated simultaneously with the gas, as advocated by Fliigge, for 
aeration may require many hours, and, in some cases, days, to rid the 
room of the odor. This is a matter of extreme importance with people 
of small means living in limited spaces, who cannot afford even the 
temporary inconvenience and expense of finding outside accommoda- 
tions. 
Mattresses which have been polluted by soakage of urine, and ex- 
creta, thick clothing and other articles which do not lend themselves 
to superficial gaseous disinfection, require treatment by steam in the 
special apparatuses described on a preceding page. Straw, corn-husk 
and " excelsior " mattresses should be differently treated. Their con- 
tents should be removed and burned, and the ticking soaked in disin- 
fectants and boiled. Stuffed furniture covered with woven fabrics 
should be taken out of doors and be well beaten and left exposed to 
the air and direct sunlight. If upholstered in leather, it should be well 
wiped in all the crevices with cloths wrung out in sublimate solution 
or diluted formalin. DISINFECTION OF WATER-CLOSETS. 
539 
Heavy clothing and other fabrics are sometimes sent to be treated by 
the benzene process, in the belief that, by this means, not only are grease 
spots removed, but that sterilization is affected. Rupp,1 however, has 
pointed out that in the ordinary benzene process, pus cocci and the ba- 
cilli of typhoid fever, anthrax, diphtheria, and tuberculosis are not de- 
stroyed. 
Disinfection of Books.-Books are extremely difficult to sterilize 
with certainty, on account of the protection that is given to bacteria by 
the juxtaposed pages. Unbound books may be subjected to treatment 
by steam, but this process is not suited to bound volumes, because of 
its effect on the glue. For bound books, the only available disinfectant 
is formaldehyde, but even this agent is not efficient, unless the leaves are 
so disposed that the gas can have access to every page. Books of value 
will require very thorough and repeated treatment, but those of small 
value, known to have been probably or possibly infected, are best de- 
stroyed by fire. If formaldehyde treatment is deemed advisable, they 
should be placed on edge, with the leaves opened as much and as freely 
as possible, and subjected repeatedly to the action of the gas in a tight 
closet or box. 
Disinfection of Water-closets.-Water-closet bowls may be treated 
with dilute formalin or 5-per-cent. solution of the cresol preparations. 
The woodwork around and near them may be washed with the same 
agents. Sublimate solution should not be used in plumbing fixtures, 
on account of its action on lead. 
1 Correspondenzblatt fiir Schweizerische Aerzte, 1897, No. 19. CHAPTER IX. 
QUARANTINE. 
Quarantine is a term of wide signification. Derived from the 
French quarante, forty, its original meaning had reference to the num- 
ber of days' detention to which vessels and their personnel, arriving 
from places infected or suspected of being infected with the plague, 
were subjected in places set apart for the purpose to insure against the 
introduction of the disease into the country or port of arrival. 
The usual definitions of the term which, in a composite form, may be 
given as, " The enforced detention of vessels, their personnel, and car- 
goes, arriving from infected ports, or having, or being supposed to 
have, cases of certain infectious diseases on board, and interdiction for 
a fixed period of time of all communication therewith," are wholly in- 
adequate under present conditions. Far more accurate and compre- 
hensive is that given by Dr. Walter Wyman, U. S. M. H. S., "The 
adoption of restrictive measures to prevent the introduction of diseases 
from one country or locality into another," for the original meaning is 
now quite lost. To-day, we speak of port quarantine, land, interstate, 
railroad, municipal, house, and room quarantine. Restrictive meas- 
ures are not adopted solely against human diseases, but against those 
of the lower animals (cattle quarantine) and even of certain fruits and 
other important crops. 
The necessity of restrictive measures in certain cases has long been 
recognized ; in fact, in the case of leprosy, from earliest times. The first 
enactment providing for the detention and isolation of travellers from 
infected places dates back to the fifteenth year of the Emperor 
Justinian (A. D. 542), but quarantine in the modern sense had its 
origin in the fourteenth century in Italy where, on account of the 
ravages of the plague, local authorities at different times adopted pre- 
ventive measures. Thus, Florence and Venice in 1348 ; Lombardy, 
1374; Milan, 1399. 
The first maritime quarantine was instituted, in 1403, at Venice. 
A lazaret, the house of St. Lazarus, was founded on a small island, and 
all persons from the Levant were there detained for 40 days before 
admission to the city. The restrictive measures, enforced at Mediter- 
ranean ports and elsewhere, were for many years, and at some places 
now are, unreasonable, harsh, useless, and a great injury to trade. 
Most of the leading countries have, for a long time, been strongly op- 
posed to the oppressive, arbitrary, and irrational quarantine measures, 
and have now adopted rules and regulations, which, while effective as QUARANTINE LAW OF 1893. 
541 
far as can be hoped for or expected, impose the least possible burdens 
upon personal liberty and trade. The danger is estimated according 
to the condition of health of the port of departure, and this, with the 
sanitary history of the vessel, up to the time of arrival, determines 
what measures, if any, are to be taken. 
The periods of detention are fixed with reference to the probable 
incubative period of the disease in question, and questions of necessity 
of disinfection, and of methods to be followed in carrying out the same, 
are determined by the circumstances of each individual case. Quar- 
antines administered with reason do invaluable work by sifting out 
infection and protecting the public health from exotic diseases, which, 
in the absence of precautionary measures, might easily gain access. 
At the same time, they act in restraint of trade to the slightest possible 
extent, since healthy vessels are not unnecessarily detained. 
Unfortunately, not all quarantines are administered with reason, 
and it often happens that great injustice and unnecessary expense are 
caused by absurdly tenacious adherence to exploded theories and routine 
practice. As an example may be cited the case of the Helene, a Ger- 
man vessel, which, arriving in an English port in August, 1893, with 
two cases of cholera, was disinfected and given free pratique; nine 
months later, she was refused pratique at a South American port, be- 
cause in England she had not been held for a definite period at quar- 
antine. As an example of quarantine absurdity of a minor character, 
but indicative of what might be imposed in case opportunity presented 
itself, may be cited an experience with the municipal authorities at a 
Southern port, who required thorough disinfection of a barrel of car- 
bolic acid before it was allowed to be landed. 
The first action taken by any official organization in this country 
looking to the establishment of a uniform system of quarantine regu- 
lations was at a conference of boards of health at Philadelphia in 1857, 
called on account of the excitement caused by the breaking out of 
yellow fever at Bay Ridge in the previous year, but in spite of this 
and other attempts, the various quarantines of the country were admin- 
istered with no uniformity until after the passage of the Act of Feb- 
ruary 15, 1893, entitled "An Act granting additional quarantine 
powers and imposing additional duties upon the Marine Hospital Ser- 
vice." This act established a national system of quarantine, but in no 
way limited State and municipal authorities in their right to prescribe 
and enforce additional measures, and, indeed, it is beyond the power of 
Congress to interfere with local authorities so long as the minimum re- 
quirements of the national law are complied with. Divested of legal 
verbiage this act is in substance as follows. 
Quarantine Law of 1893. 
Section 1 makes it unlawful for a vessel from a foreign port to enter 
any port of the United States, except in accordance with the provisions 
of the act and with such rules and regulations of State or municipal 542 
QUARANTINE. 
health authorities made in the pursuance of or consistent therewith, 
under penalty of not exceeding $5,000. 
Section 2 provides that a vessel at a foreign port, clearing for any 
port in the United States, shall obtain from the consular or medical 
officer of the United States at that place a bill of health in duplicate, 
in the form prescribed by the Secretary of the Treasury, setting forth 
its sanitary history and condition and that it has complied with the 
rules and regulations prescribed for securing the best sanitary condi- 
tion of the vessel and its cargo, passengers and crew. Penalty for 
clearing and sailing without such bill of health and entering any port 
of the United States, not exceeding $5,000. By an amendment ap- 
proved August 18, 1894, it is provided that the provisions of this sec- 
tion shall not apply to vessels plying between foreign ports on or near 
the frontiers of the United States and ports of the United States ad- 
jacent thereto. But the Secretary of the Treasury is authorized, when, 
in his discretion, it is expedient for the preservation of the public 
health, to establish regulations governing such vessels. 
Section 3 directs the Supervising Surgeon-General of the Marine 
Hospital Service to cooperate with and aid State and municipal 
boards of health in the execution and enforcement of the rules and 
regulations of such boards and of those made by the Secretary of the 
Treasury to prevent the introduction of contagious or infectious dis- 
eases into the United States and into one State, Territory, or the Dis- 
trict of Columbia from another. 
It provides that all rules and regulations made by the Secretary of 
the Treasury shall operate uniformly and in no manner discriminate 
against port or place. Where no State or municipal quarantine regu- 
lations exist, and in the opinion of the Secretary of the Treasury are 
necessary to prevent the introduction of such diseases, and where ex- 
isting regulations are in his opinion insufficient, he shall make such 
additional rules and regulations as he may deem necessary, and they 
shall be enforced by the respective sanitary authorities; failing wffiich, 
the President shall execute and enforce the same and adopt such meas- 
ures as in his judgment are necessary, and may detail or appoint of- 
ficers for that purpose. The Secretary of the Treasury shall make 
such rules and regulations as are necessary to be observed by vessels 
at the port of departure and on the voyage to secure the best sanitary 
condition of themselves, their cargoes, passengers and crews. 
Section 4 makes it incumbent on the Supervising Surgeon-General 
of the Marine Hospital Service to perform all the duties in respect to 
quarantine and quarantine regulations and to obtain information 
through Consular officers of the sanitary condition of foreign ports 
and places from which contagious and infectious diseases are or may 
be imported into the United States. The Secretary of the Treasury is 
required to obtain through all available sources, including State and 
municipal sanitary authorities throughout the United States, weekly 
reports of the sanitary condition of ports and places within the 
United States, to transmit to collectors of customs and to State and QUARANTINE LAW OF 1893. 
543 
municipal health officers and other sanitarians weekly abstracts of the 
consular sanitary reports and other pertinent information received by 
him, to procure through all available sources, public or private, infor- 
mation relating to climatic and other conditions affecting the public 
health, and to make an annual report to Congress with such recom- 
mendations as he may deem important to the public interests. 
Section 5 provides for the issuance from time to time to the United 
States Consular and medical officers at the various foreign ports of the 
rules and regulations made by the Secretary of the Treasury to be 
used and complied with by vessels in foreign ports for securing the 
best sanitary conditions before departure for the United States, and in 
course of the voyage, and of all other rules and regulations as shall be 
observed in inspection on arrival at any quarantine station and for dis- 
infection and isolation, and treatment of cargo and persons on board so 
as to prevent the introduction of cholera, yellow fever, and other con- 
tagious or infectious diseases. No vessel shall enter a port or dis- 
charge its cargo or land its passengers except upon a certificate of the 
health officer at such quarantine station that the rules and regulations 
have in all respects been observed and complied with both by him and 
by the master in respect to the vessel and its cargo, passengers and 
crew. The master is required to deliver to the collector with the 
other papers of the vessel, the bills of health obtained at the port of 
departure and the certificate above-mentioned. 
Section 6 provides that on the arrival of an infected vessel at any 
port not provided with proper facilities for treatment, the vessel shall 
be remanded at its own expense to the nearest national or other quar- 
antine station where accommodations and appliances are provided for 
the necessary disinfection and treatment of vessel, passengers, and 
cargo. After treatment of such vessel and after certification by the 
United States quarantine officer that vessel, cargo, and passengers are 
free from infectious disease or danger of carrying the same, the vessel 
shall be admitted to entry at any port of the United States named in 
the certificate. But at ports where sufficient quarantine provision has 
been made by State or local authorities the Secretary of the Treasury 
may direct the undergoing of quarantine at said station. 
Section 7 provides that whenever the President is satisfied that by 
reason of the existence of cholera or other infectious diseases in a 
foreign country there is serious danger of the introduction of the same 
into the United States, and that notwithstanding the quarantine de- 
fense this danger is so increased by the introduction of persons or 
property from such country that a suspension of the right to introduce 
the same is demanded in the interest of the public health, he shall 
have power to prohibit, in whole or in part, the introduction of per- 
sons and property from such countries or places as he may designate, 
and for such period of time as he may deem necessary. 
Sections 8 and 9 are of no sanitary interest. 
In accordance with the provisions of this act, certain rules and regu- 
lations to be observed at foreign ports and at sea and at ports and on 544 
QUARANTINE. 
the frontiers of the United States have been adopted and amended 
and added to as occasion has made it necessary or advisable. 
For a proper understanding of what is required and of methods fol- 
lowed, the regulations themselves in abridged form, where possible, 
are herewith presented. 
Quarantine Regulations to be Observed at Foreign Ports 
and at Sea. 
Article I. Bills of Health. 
The following form of bill of health is prescribed in accordance with 
Section 2 of the Law of February 15, 1893 : 
United States Bill of Health. 
Name of vessel, . Nationality, . Rig, . Master, 
. Tonnage, gross, ; net, . Iron or wood. Number of 
compartments for cargo, ; for steerage passengers, ; for crew, 
Name of medical officer, . 
Number of officers, . 
Number of members of officers' families, . 
Number of crew, including petty officers, . 
Number of passengers, cabin, . 
Number of passengers, steerage, . 
Number of persons on board, all told, . 
Port of departure, . 
Where last from, . 
Number of cases of sickness and character, during last voyage, . 
Vessel engaged in trade, and plies between and . 
Sanitary condition of vessel, . 
Nature, sanitary history, and condition of cargo, . 
Source and wholesomeness of water supply, . 
Source and wholesomeness of food supply, . 
Sanitary history and health of officers and crew, . 
Sanitary history and health of passengers, cabin, . 
Sanitary history and health of passengers, steerage, . 
Sanitary history and condition of their effects, . 
Prevailing diseases at port and vicinity, . 
Location of vessel while discharging and loading-open bay or wharf, 
Number of cases and deaths from the following-named diseases during the 
past two weeks : 
Diseases. No. of cases. No. of deaths. 
Yellow fever 
Asiatic cholera 
Cholera nostras or cholerine 
Smallpox 
Typhus fever 
Plague 
Leprosy 
Number of cases of sickness and character of same while vessel was in 
this port, . 
Any conditions affecting the public health existing in the port of de- 
parture or vicinity to be here stated, . 
I certify that the vessel has complied with the rules and regulations made QUARANTINE LAW OF 1893. 
545 
under the act of February 15, 1893, and that the vessel leaves this port 
bound for , U. S. of America, via . 
Given under my hand and seal this day of , 190 . 
(Signature of consular officer :) , 
In case the vessel enters or calls at intermediate ports, supplemental 
bills of health must there be procured, but if any quarantinable dis- 
ease has appeared since leaving the original port of departure or if the 
vessel from any cause may be presumed to be infected, the supple- 
mental bill is withheld until necessary sanitary measures have been 
taken. 
Supplemental Bill of Health. 
Port of . 
Vessel , bound from to , U. S. A. 
Sanitary condition of port, . 
State diseases prevailing at port and in surrounding country, . 
Number of cases and the deaths from the following-named diseases dur- 
ing the past two weeks : 
Diseases. 
No. of 
cases. 
No. of 
deaths. 
Remarks. 
(Any condition affecting the public health existing in 
the port to be stated here.) 
Yellow fever 
Asiatic cholera or 
cholerine 
Smallpox 
Tvnhns fover 
Plague 
Leprosy 
Number and sanitary condition of passengers and crew landed at this port. 
Cabin, No. . Sanitary condition and history, . 
Steerage, No. . Sanitary condition and history, . 
Crew, No. . Sanitary condition and history, . 
Sanitary condition of effects, . 
Note.-If disembarked on account of sickness state disease, . 
Number and sanitary condition of passengers and crew taken on at this port, and 
sanitary condition of effects. 
Cabin, No. . Sanitary condition and history, . 
Steerage, No. . Sanitary condition and history, . 
Crew, No. . Sanitary condition and history, . 
Sanitary condition of effects, . 
Sanitary history of vessel since leaving last port. 
Form. 
A.-To the best of my knowledge and belief- 
(Form A will be used at intermediate ports where the 
vessel does not enter and clear.) 
B.-I have satisfied myself that- 
(Form B will be used at intermediate ports where the 
vessel enters and clears.) 
(Cancel form A, B, or C, as the case requires.) 
no quarantinable disease 
has appeared aboard 
since leaving . 546 
QUARANTINE. 
C.-Since leaving the following quarantinable disease has appeared 
on board , and I certify that the necessary sanitary measures have 
been taken. 
I certify also that with reference to the passengers, effects, and cargo 
taken on at this port, the vessel has complied with the rules and regulations 
made under the act of February 15, 1893. 
Given under my hand and seal this day of , 190 . 
(Signature of consular officer :) , 
Except when quarantinable diseases prevail at the foreign port of 
departure, bills of health are, under Act of Congress approved August 
18, 1894, not required for vessels plying between Canadian ports and 
adjacent ports of the United States on the Great Lakes and other lakes, 
and on the St. Croix, St. Lawrence, St. Clair, St Mary's, Detroit, and 
Niagara Rivers, or for vessels plying between Mexican ports on the 
Rio Grande and adjacent ports of the United States. 
Article II. Inspection. 
All vessels carrying steerage passengers and all vessels from ports 
where cholera prevails or yellow fever, typhus, or smallpox are epi- 
demic must be inspected by the officers issuing the bill of health 
in order that he may satisfy himself of the truth of the conditions 
certified therein. The inspection in the case of the class first men- 
tioned, if from a healthy port, is limited to the passengers themselves 
and their living apartments. Inspection of a vessel is such an ex- 
amination of the vessel itself, cargo, passengers, crew and personal ef- 
fects, and of manifests and other papers, food and water supply as 
will show whether the regulations have been complied with. It must 
be made by daylight and as late as practicable before sailing; the 
vessel should be inspected before the passengers go aboard; the pas- 
sengers just before embarkation, and the crew on deck; no cargo or 
person should be allowed to go aboard after inspection except by per- 
mission of the officer who issues the bill of health. 
Article III. Requirements with Regard to Vessels. 
Before stowing cargo or receiving passengers, vessels must be 
mechanically clean in all parts, especially the hold, forecastle and 
steerage. The bilges and limbers must be free from odor and deposit, 
and the air strokes sufficient in number and open for ventilation. 
The U. S. medical officer may require disinfection, and in case any 
infectious disease has occurred during the last preceding voyage this 
is imperative. 
Air space and ventilation must conform to the provisions of the law 
of August 2, 1882 ; food and water supply must be sufficient, the 
latter easily accessible. 
If cholera prevails at the port of departure and more than 250 
steerage passengers are carried, two medical officers must be carried. QUARANTINE LAW OF 1893. 
547 
All bedding provided for steerage passengers must be destroyed or 
disinfected before being used again or landed ; mattresses and pillows 
used by steerage passengers shall not be landed. 
The hospitals of vessels carrying steerage passengers must be located 
on the upper or second deck and not in direct communication with 
any steerage compartment. Solid partitions obstructing light and air 
should not be placed in any steerage compartment excepting when ab- 
solutely required. 
Article IV. Cargo. 
At ports infected with cholera, earth, sand, loam, and soft or porous 
rock should not be taken as ballast, and certain food products, viz., un- 
salted meats, sausages, dressed poultry, dried and smoked meats, ren- 
nets, fresh butter, unsterilized fresh milk, fresh cheese, fresh bread, 
and fresh vegetables coming from cholera-infected localities or through 
them, if exposed to infection should not be shipped. Fresh fruits 
from cholera districts shall not be shipped unless the inspector can 
certify that they have not been exposed to infection. 
At ports infected with yellow fever, ballast of the kinds above men- 
tioned should not be allowed on board vessels clearing for ports south 
of Maryland, when hard rock can be obtained or when water ballast 
may be used. 
Merchandise, personal effects, and bedding from infected districts, 
or of doubtful or unknown origin, should be disinfected prior to ship- 
ment. New merchandise in general may be accepted without question, 
and when packed for shipment in an infected port or place with a 
special view to protection from moisture incident to the voyage, may 
be accepted without disinfection. 
All rags and textile fabrics used in making paper, etc., collected, 
packed, or handled in any foreign port or place, with the exception be- 
low mentioned, shall be disinfected prior to shipment. Old bags of 
jute or cotton, old rope, and new cuttings of cotton or linen from fac- 
tories are not included. Rags, etc., from Canadian ports or places, 
free from quarantinable diseases for 30 days prior to shipment, accom- 
panied by proper affidavits that they have not been shipped to Canada 
from a foreign port, are exempted. Rags, old jute, old gunny, old 
rope, and similar articles gathered or packed and handled where chol- 
era or yellow fever prevails, or smallpox or typhus is epidemic, may 
not be shipped until 30 days after infection has disappeared and after 
disinfection of the articles. 
New feathers, unmanufactured hair, bristles, wool, and hides chem- 
ically cured, coming from a cholera district, cannot be shipped until 
after 30 days of freedom from infection, unless unpacked and disin- 
fected. Used feathers must be disinfected and invariably by steam. 
All these articles coming from yellow fever districts and destined for 
places south of Maryland during the quarantine season, or where small- 
pox or typhus is epidemic, may not be shipped without disinfection 
according to prescribed methods. 548 
QUARANTINE. 
Articles such as gelatin, glue, glue stocks, fish bladders and skins, sau- 
sage casings, bladders, dried blood, having been in any way liable to 
infection in the process of preparation, gathering, or shipment, should 
be disinfected. All coverings shipped from or through an infected 
place and believed to be infected should be disinfected. Any presum- 
ably infected article which cannot be disinfected (upholstered furniture, 
sheepskins used as wearing apparel, bedding, bones, horns, and hoofs) 
should not be shipped. 
Article V. Passengers and Crew. 
Persons suffering from a quarantinable disease, or scarlet fever, mea- 
sles or diphtheria, may not be shipped. Steerage passengers and crew, 
if from districts where smallpox is epidemic, or exposed to smallpox, 
must be vaccinated before embarkation, or show evidence of immunity 
or recent successful vaccination. If they have been exposed to typhus, 
they shall be detained at least fourteen days after such exposure and 
the disinfection of their baggage. Coming from cholera districts, they 
must be detained in suitable barracks five days after they have been 
bathed, their baggage and clothing disinfected, and all food brought by 
them removed. Those from uninfected districts, but shipping at a port 
infected with cholera, may, if it seems necessary, be treated in the same 
way. Should cholera break out among those undergoing the five days' 
detention and observation, no passenger may embark until five days' 
isolation from the last case and repetition of the same sanitary meas- 
ures as before. 
A cabin passenger, prior to sailing from ports infected with cholera, 
must produce satisfactory evidence as to his exact place of abode dur- 
ing the five days immediately preceding, and, if it appears necessary, 
he may be detained and his baggage disinfected. 
Passengers, crews, baggage, and merchandise prior to shipment at a 
non-infected port, but coming from an infected locality, shall be subject 
to the same restrictions as are imposed in an infected port. In ports 
infected with cholera or where yellow fever is epidemic, crews should 
remain on board during their stay, and any additional men shipped are 
subject to the same precautions as are observed in the case of steerage 
passengers. American vessels bound for the United States, Cuba, or 
Porto Rico shall not ship men in the ports of these two islands where 
smallpox or yellow fever exists, except when inspected and passed by 
the quarantine officer. 
The rules concerning disinfection of baggage and personal effects of 
passengers from cholera-infected ports apply as well with regard to 
plague, yellow fever, typhus, and smallpox. 
All steerage baggage inspected and passed shall bear a red label 
filled out and stamped in proper form ; if it has been disinfected, the fact 
is set forth on a yellow label filled out and stamped in the same manner. 
Each steerage passenger must have an inspection card stamped by 
the consular or medical officer. The form is as below. QUARANTINE LAW OF 1893. 
549 
INSPECTION CARD. 
[Immigrants and steerage passengers.] 
Port of departure Date of departure, 
Name of ship........................................................................................ 
Name of immigrant Last permanent residence 
Inspected and passed at 
[Seal or stamp of consular 
medical officer.] 
[The following to be filled 
Ship's list or manifest 
Passed at quarantine port of 
, United States. 
Passed by Immigration Bu- 
reau, port of 
[Date.] 
in by ship's surgeon or agent prior 
No. on ship' 
[Date.] 
to or after embarkation.] 
s list or manifest 
Berth No. 
3 ® a 
■2® 2^ 
to .S 
1st day. 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
To be 
punched 
by ship's 
surgeon 
at daily 
inspec- 
tion. 
On the back of the card shall be stated whatever are the facts bear- 
ing upon vaccination. 
Special inspection cards are provided for cabin passengers from 
cholera-infected ports and places. The baggage of such passengers 
must be labeled in the same manner as described above. 
Passengers should not be vaccinated at ports or places infected with 
plague, nor after leaving the same, since the liability to plague infection 
is thereby increased. Moreover, the induced fever and swollen glands 
tend to confuse diagnosis at the port of arrival. Just prior to release 
from quarantine at the port of arrival is the proper time for the 
operation. 
Article VI. Requirements at Sea. 
During the voyage, rigorous cleanliness and free ventilation must be 
maintained ; the water-closets must be washed and disinfected twice 
daily; and the vessel, including the steerage, must be inspected by the 
ship's surgeon every day. 
Patients with infectious disease should be isolated, their soiled body 
linen should be at once immersed in boiling water or in a disinfectant 
solution, and the places which they have occupied should be disinfected 
if possible by steam and then as far as possible be freely exposed to 
the air. During disinfection, all articles likely to convey infection 
should remain ; afterwards, the bedding and clothing may be removed 
and dried. In case of outbreak of cholera, cholerine, yellow fever, 
typhus, or smallpox, those who first show symptoms shall be immedi- 
ately sent to the hospital, and all of the effects liable to convey infec- 
tion which have been in use will be destroyed or disinfected. The 
dead must be wrapped without previous washing in a sheet saturated 550 
QUARANTINE. 
with one of the strong disinfecting solutions, and at once placed in a 
hermetically sealed coffin or buried at sea. 
A clinical record of each 'case of disease must be kept on a prescribed 
form and delivered to the quarantine officer at the port of arrival. 
Under this article, germicidal solutions for purposes of disinfection 
are limited to the following : Strong; acid solution of corrosive subli- 
mate (1 to 500); pure carbolic acid, 1 to 20. Weak ; acid solution 
of corrosive sublimate (1 to 1,000); pure carbolic acid, 1 to 40. 
Sailing vessels from ports infected with yellow fever and destined 
for any port south of Maryland not provided with proper facilities for 
treatment shall, during the quarantine period, be directed to proceed 
to some quarantine station in the United States for disinfection and 
treatment. 
Article VII. Disinfection. 
This article is given in its entirety, as follows : 
" Par. 1. The disinfection of iron vessels shall be as follows : 
" (a) Holds.-After mechanical cleansing, the hold to be thoroughly 
washed with an acid solution of bichloride of mercury, 1 to 800 (mer- 
cury 1 part, hydrochloric acid 2 parts, water 800 parts), applied under 
pressure to all surfaces by means of a hose. 
"IN CASE THE DISINFECTION IS REQUIRED FOR YELLOW FEVER. 
" If the cargo is so stowed as to admit of disinfection, the hold and 
cargo may be disinfected without breaking bulk, by sulphur dioxide, 
10-per-cent. per volume strength, forty-eight hours' exposure for iron, 
and seventy-two hours for wooden vessels. 
" (6) Steerage and forecastle.-The same treatment should be given 
the steerage and forecastle as the hold, but when practicable steam 
disinfection of these compartments should be practiced. The temper- 
ature in all parts of the compartments is to be not less than 100° C. 
" (c) Cabins, officers' quarters, staterooms, etc.-The bedding, fabrics, 
and carpets should be removed and disinfected by steam. After 
thorough mechanical cleansing, the exposed surfaces of fabrics, which 
can not be removed, should be washed with a solution of bichloride 
of mercury, 1 to 1,000, or 3-per-cent. solution of carbolic acid, both 
of which should be removed, but not under two hours. Afterwards 
the apartments should be thoroughly dried and aired. 
"Par. 2. The disinfection of wooden vessels is to be accomplished 
as follows : After mechanical cleansing, washing out the bilges until 
clean, etc. (first), by fumigation by sulphur dioxide, 10-per-cent. 
strength, twenty-four hours in the cabin and forecastle and forty-eight 
hours in the hold; and (second) flushing or washing with acid solution 
of bichloride of mercury in large quantity (1 to 800). The bilges to 
be first flushed with sea water, pumped out, and then treated with the 
acid solution of bichloride of mercury in large quantity, allowed to 
remain in long contact. In addition to the sulphur fumigation of such QUARANTINE LAW OF 1893. 
551 
apartments, the cabins, forecastle, and other apartments, and their con- 
tents, to be treated as those on iron vessels. 
" CARGO. 
" Par. 3. Disinfection of rags and old jute, etc., shall be by one of 
the following methods : 
" (a) By boiling in water for not less than thirty minutes. 
" (6) By steam at the temperature of 100° C. for not less than thirty 
minutes after such temperature is reached. 
" (c) By exposure for not less than six hours in a closed compart- 
ment to a 4-per-cent. strength (per volume) of sulphur dioxide gas- 
made by burning roll sulphur or by the liberation of liquefied sulphur 
dioxide-allowance to be made for leakage by increasing the amount 
of sulphur. 
" Par. 4. In all of the above methods, the rags, old jute, etc., must 
be unbaled, and in the disinfection by steam or sulphur the rags must 
be loosely spread on racks (preferably wire netting) in layers of not 
more than 6 inches in depth, and in such a manner as to insure the 
diffusion of the gas to all parts alike. 
" The articles must not at any time occupy more than 50 per cent, of 
the total cubic space, and the exposure to date from the complete com- 
bustion of the sulphur. 
" Par. 5. New feathers for bedding shall be disinfected by one of the 
following methods : 
" (a) By steam at a temperature of 100° C. for a period of thirty 
minutes after such temperature has been reached. 
" (6) By exposure to sulphur dioxide, 4-per-cent. strength per 
volume, for not less than six hours. 
" Par. 6. Human hair, or other hair, unmanufactured, and bristles, 
to be disinfected by sulphur dioxide, 4-per-cent. strength per volume, 
six hours, or, if not clean, by a solution of pure carbolic acid, 4-per- 
cent. strength, the articles to be thoroughly saturated. 
" Par. 7. Wool to be disinfected by sulphur dioxide, 4-per-cent. 
strength per volume, for not less than twenty hours, the wool to be 
unbaled and loosely spread on racks, as in the manner provided for the 
disinfection of rags. 
" Par. 8. Hides to be disinfected by sulphur dioxide, 4-per-cent. 
strength per volume, for not less than twenty hours, or by thorough 
saturation with a solution of pure carbolic acid, 4-per-cent. strength; 
hides to be invariably unbaled for the purpose." 
Par. 9. Articles mentioned in paragraph 10, Article IV. (gelatin, 
glue, glue stock, fish glue, fish bladders, fish skins, sausage casings, 
bladders, dried blood) should be disinfected by being spread on racks 
and exposed to sulphur dioxide, 4 per cent, per volume, 20 hours. 
"Par. 10. Coverings should be disinfected : 
" (a) In the hold, by exposure to sulphur dioxide, 10-per-cent. 
strength per volume, for twelve hours; the cargo being so stowed as 
to allow access to all parts of such surfaces. 552 
QUARANTINE. 
" (6) By breaking bulk and exposure to sulphur dioxide, 4-per-cent. 
strength per volume for twenty-four hours. 
" (c) By wetting thoroughly with solution of bichloride of mercury, 1 
to 800. 
"Par. 11. The disinfection of personal effects, prescribed by these 
regulations, should be as follows: 
" (A) Clothing and bedding should be disinfected by-(1) Exposure 
to steam from 100° to 102° C. for thirty minutes after such tempera- 
ture is reached, or by boiling for thirty minutes. (2) Immersion in 
bichloride solution, 1 to 800, or solution of pure carbolic acid, 3 per 
cent., until thoroughly wetted, and allowed to dry before washing. 
" This last process (2) to be used only for articles that will be injured 
by steam or boiling. 
" (B) Cooking and eating utensils should be immersed in boiling 
water. 
"Note.-A 4-per-cent. per volume strength of sulphur dioxide can 
be obtained by burning not less than 4 pounds 2 ounces of sulphur to 
each 1,000 cubic feet of space; the compartment to be air-tight. 
" A 10-per-cent. per volume strength can only be obtained by one of 
the following methods : By the use of a special furnace, or by liquefied 
sulphur dioxide gas." 
Article VIII. Records, Reports, etc. 
(This article provides for the recording of inspections and furnishing 
of reports.) 
Article IX. Regulations at Ports Infected or Suspected of being 
Infected with Plague. 
The regulations concerning cholera shall be observed at foreign places 
infected or suspected of being infected with plague, with regard to 
vessels and cargoes bound for the United States. The period of deten- 
tion is fixed at 15 days from the last possible exposure to infection, 
failing which, the vessel and all on board will be considered at the port 
of arrival as coming from an infected port. Baggage labeled and 
sealed by the proper official at a non-infected city may be admitted 
without disinfection, even though shipped through an infected port or 
locality, provided the seal is unbroken. Baggage from infected or 
suspected localities for shipment through a non-infected port must first 
be disinfected. 
Where plague prevails, the vessel should not tie up to the dock, nor 
should lines upon which rats can cross be passed to the shore. The 
passengers and cargo should be lightered, the crew kept aboard, and 
personal communication from shore to vessel be under medical super- 
vision. 
Pet niammals, such as cats, dogs, monkeys, mice, etc., should not be 
shipped from infected or suspected ports or places. QUARANTINE LAW OF 1893. 
553 
Article X. Baggage and Effects From Cuba and Porto Rico. 
Between April 1st and November 1st, all baggage and personal ef- 
fects, including hand baggage, leaving Cuba shall be labeled by the 
quarantine officer, either " Disinfected," or " Inspected and passed," or 
"Inspected and passed to northern territory," according to destination. 
All destined for places south of Maryland must be disinfected and so 
labeled ; that shipped through a southern port but checked through 
to a point north of the southern boundary of Maryland and not to be 
opened en route may be labeled accordingly and need be disinfected 
only if presumably infected or, concerning this point, if doubt exists. 
All bound for ports north of the southern boundary of Maryland and 
not intended to be shipped afterwards to a point south of Maryland 
may be labeled " Inspected and passed." If infected or doubtful it 
should be disinfected. Baggage not labeled shall be disinfected at the 
quarantine station at the port of arrival. These rules apply also to 
ports in Porto Rico when yellow fever is there present. 
Quarantine Regulations to be Observed at Ports and on the Fron- 
tiers of the United States. 
The preamble provides for the establishment of quarantine stations 
at or convenient to the principal ports of the United States, and for 
the maintenance of inspection stations at all other ports. A fully 
equipped quarantine station should have adequate facilities for board- 
ing and inspection, apparatus for the mechanical cleaning of vessels, 
for steam disinfection, for sulphur fumigation, for disinfecting solu- 
tions ; hospitals for contagious and doubtful cases, detention barracks 
for suspects, bathing facilities, crematory, and adequate water supply. 
The personnel of quarantine stations in the yellow fever zone and on 
the fruiters bound for southern ports should be immune to yellow 
fever. At quarantine stations, all articles liable to convey infection 
should be handled only by the employees thereof, unless the services 
of the crew are indispensable. 
The quarantine regulations are the required minimum standard, and 
do not prevent the addition of such other rules as State and local 
authorities may legally make. 
Article I. Inspection. 
This article provides that all vessels from foreign ports, vessels from 
domestic ports where cholera or yellow fever prevails, or where small- 
pox or typhus is epidemic, and all vessels with sickness on board must 
be inspected by a quarantine officer prior to entry. But vessels on 
inland waters of the United States not carrying passengers, and from 
ports of British America, provided they have not carried persons or 
effects of persons non-resident in America during the 60 days pre- 
ceding arrival, and provided the port of departure be free from 554 
QUARANTINE. 
quarantinable disease, are exempt. Passenger vessels from foreign 
ports, after entering a port without complete discharge of passengers 
and cargo, are subject to a second inspection before entering any other 
port. Vessels from ports suspected of infection with yellow fever 
having entered a port north of the southern boundary of Maryland 
without disinfection are subject to quarantine before entering any port 
south of Maryland during its quarantine season. 
Except in case of vessels in distress, inspection shall be made by 
daylight. The bill of health and clinical record of all cases treated 
during the voyage, crew and passenger lists, and manifests, and, if 
necessary, the log shall be examined. The crew and passengers shall 
be mustered and compared with the lists and manifests. If rags and 
similar articles are carried, a certificate of disinfection shall be shown 
and compared with the freight manifest, otherwise they shall be set 
apart in a proper place and in the event of non-arrival of the required 
certificate they shall be either disinfected or returned. 
Until a vessel has been inspected and discharged, no person other 
than the usual officials and the agents of the vessel shall be permitted 
to board. 
Tugboats and other vessels having had communication with vessels 
subject to inspection shall be themselves subject to inspection. 
After a vessel upon which cholera, smallpox, typhus, or plague has 
occurred has been given free pratique, the quarantine officer must 
notify the local Commissioner of Immigration, whose duty it then is to 
send by mail or telegraph to the health authorities of the various 
States to which immigrants from the vessel are destined, the date of 
departure, route, number of persons, and point of destination, together 
with the statement that they are from a vessel which has been subject 
to quarantine by reason of infectious disease, naming the disease. 
This information is for the purpose of enabling State authorities to 
maintain such surveillance over the arriving immigrants as they may 
deem necessary. 
Baggage and effects from Cuba and Porto Rico shall be treated in 
accordance with the provisions of Article X. of the regulations to be 
observed at foreign ports at sea. 
Paragraphs. Inspection for plague. [Unabridged.] 
" (a) In the case of vessels infected or suspected of being infected 
with plague, place vessel in quarantine in anchorage sufficiently remote 
from the nearest land or other vessel to prevent the escape of rats by 
swimming. 
" (6) Pilots, customs officials, agents of vessels, or others who go 
aboard vessel may be deemed and be treated as a part of the personnel 
of the vessel. Such persons shall be detained in quarantine a sufficient 
time to cover the period of incubation of the disease, if in the opinion 
of the quarantine officer said persons have been exposed to infection ; 
and their dunnage, if any, shall be disinfected. 
"(c) In inspecting infected or suspected vessels, the personnel of the QUARANTINE LAW OF 1893. 
555 
vessel shall be inspected after the removal of all clothing which will 
interfere with a thorough examination of all glandular regions, includ- 
ing axillary, inguinal, and cervical. 
" (d) Female inspectors should be provided for inspection of female 
personnel. They shall be instructed by the quarantine officer in the 
general symptomatology and recognition of the disease, but final de- 
cision is to be made by the quarantine officer. 
" (e) Special attention shall be given to the detection of ambulant, or 
walking, cases, which are a source of great danger and apt to be over- 
looked, because they present few objective signs to attract attention. 
" (/) Special attention should be directed to the pneumonic type of 
the disease. Any person presenting pulmonic symptoms of rapid 
course, with or without glandular enlargement, should be the subject 
of special inquiry, and if possible, of bacteriological examination. 
" (g} In suspected cases, specimens of pus, sputum, or the contents 
of lymphatic glands may be sent to the hygienic laboratory of the 
Marine Hospital Service at Washington, for examination, under the 
precaution prescribed by the postal regulations of the United States. 
" (K) The quarantine officer at the port of entry will carefully exam- 
ine the ship's manifest of cargo for household goods, bedding, second- 
hand articles, personal baggage, corpses, rags, and articles apt to carry 
infection. Any articles believed by the quarantine officer to be infected, 
must be disinfected in accordance with the quarantine regulations of 
the United States." 
Article II. Quarantine. 
First are enumerated the quarantinable diseases, as follows : cholera 
and cholerine, yellow fever, smallpox, typhus, leprosy, and plague. 
Any vessel arriving with any of these diseases aboard, or having had 
any within 30 days preceding arrival, or having had yellow fever 
aboard, after March 1 st of the current year, and having not been there- 
after satisfactorily disinfected, or coming from ports infected with 
cholera, or where typhus is epidemic and not having complied with 
the United States quarantine regulations for foreign ports, or bringing 
persons or cargo from places infected with cholera or yellow fever or 
where typhus is epidemic, or coming from ports where yellow fever 
prevails, unless disinfected according to regulations at least 5 days be- 
fore arrival, shall be placed in quarantine. But in case of vessels from 
ports quarantined against on account of yellow fever, those arriving 
between November 1st and April 1st, and those bound for ports north 
of the southern boundary of Maryland, with good sanitary condition 
and history, having had no sickness on board, and provided that 5 
days have elapsed since departure from the last infected or suspected 
port, may be admitted to entry. 
In inspecting a vessel between April 1st and November 1st from a 
port where yellow fever prevails, the destination of each passenger 
must be ascertained and the baggage of such as intend going south of 
Maryland shall be disinfected, according to the special rules, and labeled. 556 
QUARANTINE. 
Fruiters from ports declared safe for this purpose by the Supervising 
Surgeon-General may be admitted to entry without detention, if they 
carry no passengers and have no household effects or personal baggage 
in cargo and have complied with the special rules and regulations 
made for vessels engaged in the fruit trade. 
All persons arriving on a vessel which has had smallpox on board 
must submit to vaccination or show satisfactory evidence of recent 
vaccination or of having had smallpox or be detained in quarantine 
for not less than 14 days. All effects and compartments likely to con- 
vey infection must be disinfected. 
All passengers, except those of the first or second cabin on any ves- 
sel, must be vaccinated or show evidence of recent successful vaccina- 
tion or of having had smallpox or be detained in quarantine 14 days. 
No case of leprosy will be landed, except to the quarantine station, 
and no vessel arriving with leprosy on board will be given free pra- 
tique until the leper with his baggage has been so removed. The 
leper will be deported, if an alien, on the same vessel and will be de- 
tained at the vessel's expense at quarantine until departure. 
Article III. General Requirements at Quarantines. 
" Par. 1. Pilots bringing infected vessels will be detained in quaran- 
tine a sufficient time to cover the period of incubation of the disease 
for which the vessel is quarantined, if, in the opinion of the quaran- 
tine officer, such pilots have been exposed to infection. The dunnage 
of pilots shall be disinfected when necessary. 
" Par. 2. No direct communication shall be allowed between quar- 
antine or any vessel in quarantine and any person or place outside, 
and no communication except under the supervision of the quarantine 
officer. 
" Par. 3. No ballast shall be allowed to leave the quarantine station 
unless disinfected. 
" Par. 4. Where it is impossible to disinfect cargo in situ, it shall be 
removed and disinfected in the manner provided for articles of their 
class in these regulations; such articles to be unpacked and so ar- 
ranged as to allow the disinfectant used to reach every part of all sur- 
faces of said articles. 
" Par. 5. Vessels arriving at any port of the United States having 
cholera or yellow fever aboard during the quarantine season shall be 
remanded to an anchorage set apart for infected vessels, and there to 
remain until after the discharge of the passengers and purification of 
the vessel. 
" Par. 6. All passenger baggage disinfected under the requirements 
of these regulations shall be labeled. 
" Par. 7. All bedding provided for steerage passengers must be de- 
stroyed or be disinfected before being landed. Bed ticking or other 
covering of mattresses and pillows used by passengers or crew shall 
not be landed unless disinfected at the quarantine station in accordance 557 
QUARANTINE LAW OF 1893. 
with these regulations and tagged with labels certifying to said disin- 
fection." 
Article IV. Treatment in Quarantine of Cholera-Infected. Vessels. 
" Par. 1. Remove all passengers from the vessel and all of the crew 
(if cholera has occurred on board) save those necessary to care for her. 
Place the sick in hospital and carefully isolate those specially suspected. 
Segregate the remainder in small groups. No communication shall be 
held between these groups. Those believed to be especially capable of 
conveying infection must not enter the barracks until they are bathed 
and furnished with sterile clothing; nor shall any material capable of 
conveying infection be taken into the barracks, especially food. 
" Par. 2. If cholera has occurred in the steerage, all occupants 
thereof must be bathed and their clothing disinfected. 
" Par. 3. At once proceed with the disinfection of the hand baggage. 
" Par. 4. All baggage and effects accompanying steerage passengers, 
any other baggage or effects that may have been exposed to infection, 
must be disinfected. 
"Par. 5. Such articles of cargo as are liable to convey infection 
must be disinfected. 
" Par. 6. All living apartments and furniture and such other por- 
tions of a vessel as are liable to convey infection shall be disinfected. 
" Par. 7. On cholera-infected vessels the water supply must be 
changed without delay, the casks or tanks disinfected by steam or 10- 
per-cent. solution of potassium permanganate, and after thorough rins- 
ing refilled from a source of undoubted purity, or the water supplied 
must have been recently boiled. 
" Par. 8. Nothing shall be thrown overboard from a cholera-infected 
vessel, not even deck sweepings. Such things shall be burned in the 
furnace or in a place specially designated, but not in the galley." 
Article V. Disinfection, etc. 
"Par. 1. Holds.-The disinfection of iron vessels shall be as fol- 
lows : 
" (a) With cargo : If cargo is so stowed as to admit of disinfection, 
it and the hold may be disinfected without breaking bulk, except to 
such a degree as to make disinfection practicable, by sulphur dioxide, 
10-per-cent. per volume strength, for not less than twenty-four hours' 
exposure. 
" (6) Without cargo : After mechanical cleansing the hold (1) to be 
thoroughly washed with an acid solution of bichloride of mercury, 1 
to 800 (mercury 1 part, hydrochloric acid 2 parts, water 800 parts), 
applied under pressure to all surfaces by means of a hose ; (2) by 
sulphur dioxide, 10-per-cent. per volume strength, for twenty-four 
hours. 
"Par. 2. Steerage and forecastle.-When possible to obtain it. 
" (a) The steerage and forecastle shall be disinfected by steam; the 558 
QUARANTINE. 
temperature in all parts of these compartments to be not less than 
100° C. for not less than thirty minutes after such temperature has 
been reached. 
"(6) When steam cannot be obtained these compartments shall be 
treated in the same manner as required in the disinfection of the 
empty hold. 
" Par. 3. All beddings and furnishings of the steerage and fore- 
castle to be left in place during the disinfection by steam. 
"If steam disinfection of.steerage is not used, such articles must be 
removed under the strictest sanitary precautions for disinfection by 
steam or burning. 
" Par. 4. The bedding, fabrics, and carpets should be removed and 
disinfected by steam or by boiling. After thorough mechanical 
cleansing the woodwork and all other exposed surfaces shall be washed 
with an acid solution of bichloride of mercury, 1 to 1,000, or a 3-per- 
cent. solution of pure carbolic acid. Fabrics which can not be re- 
moved shall be thoroughly saturated with a solution of bichloride of 
mercury, 1 to 1,000, or a 3-per-cent. solution of pure carbolic acid. 
" Par. 5. The water ballast of a vessel coming from a cholera-in- 
fected port should be discharged at sea, or, if discharged in fresh or 
brackish water, must be previously disinfected. The tanks to be 
flushed and refilled with sea water or disinfected. 
" Par. 6. For a wooden vessel the treatment is as above, except that 
exposure of the hold and living apartments to sulphur dioxide, 10-per- 
cent. volume, must precede the other treatment. This exposure must 
be, for the hold, forty-eight hours, and for living apartments twelve 
hours. 
" Par. 7. All solid ballast, on vessels infected with, or suspected of 
being infected with, cholera, to be discharged or disinfected previous 
to disinfection of hold ; all such ballast discharged in fresh water to be 
disinfected by saturation with, or immersion in, an acid solution of 
bichloride of mercury, 1 to 800. 
"Clear,hard,close-grained rock may be permitted to remain on board, 
but only after disinfection by immersion in an acid solution, 1 to 800 
of bichloride of mercury. Ballast removed from vessels infected with, 
or suspected of being infected with, cholera, must not be taken from 
the quarantine station. 
" Par. 8. Disinfection of steerage, forecastle, and cabin of vessels by 
formaldehyd gas.-After the removal of the bedding, carpets, and fur- 
nishings, all apertures being tightly closed, the steerage, forecastle, 
and cabin of a vessel may be disinfected by formaldehyd gas in a per- 
centage of not less than 2-per-cent. per volume strength, the time of 
exposure to be not less than twelve hours. The gas may be generated 
by one of the following methods : 
" (a) From a mixture containing formalin 100 parts, calcium chloride 
or sodium nitrate 20 parts, and glycerin 10 parts. 
" The gas is evolved from this solution by heating it in a special 
boiler, autoclave, or formaldehyd generator. QUARANTINE LAW OF 1893. 
559 
" One liter of a 40-per-cent. solution of formaldehyd gas will evolve 
about 1,425 liters (50.1 cubic feet) of the gas at 20° C. (68° F.), and 
will be sufficient for 71 cubic meters (2,505.5 cubic feet) of space. 
" (b) From the substance known as trioxy methylene by means of a 
special lamp, not less than 2 grams (30 grains) to be used for each 
cubic meter (35.29 cubic feet) of space. 
" After the disinfection of apartments (steerage, cabin, and fore- 
castle) by formaldehyd gas, the latter may be neutralized by ammonia 
gas, evolved from water of ammonia by heat, or by evaporation from 
water of ammonia1 sprinkled upon the floor. 
" Par. 9. Disinfection of clothing, bedding, upholstered furniture, arti- 
cles of leather, etc., by formaldehyd gas.-These may be disinfected by 
formaldehyd gas in the ordinary jacketed steam-disinfecting chamber, 
the latter to be provided with a vacuum apparatus and special appa- 
ratus for generating and applying the gas. 
"Raise and maintain the temperature of the chamber at 90° C. by 
the use of steam in the jacket. 
" The number of cubic centimeters of the formalin mixture to be used 
may be found by dividing the capacity of the chamber in liters by 4 ; 
e. g., a chamber of 2,500 liters capacity would require 625 cc. of the 
mixture. The time of exposure should not be less than thirty minutes. 
Clothing, bedding, etc., thus disinfected, should be exposed in situ to 
equal amount of ammonia gas generated by the special apparatus2 at- 
tached to the chamber, using one-half as much water of ammonia as 
formalin. 
a Article VI. Detention of Passengers on Account of Cholera. 
"Par. 1. The people detained shall be inspected by the physician 
twice daily, and be under his constant surveillance, and no intercourse 
will be allowed between different groups while in quarantine. 
" Par. 2. No direct communication shall be allowed between any per- 
son detained in quarantine and anyone not in quarantine, except through 
the quarantine officer or, by his order, through his agents. 
" Par. 3. The water and food supply will be strictly guarded to pre- 
vent contamination, and issued to each group separately. 
"Par. 4. Food of a simple character, sufficient in quantity, thor- 
oughly cooked, shall be issued to those detained in quarantine. No 
fruit shall be permitted. 
" Par. 5. Cleanliness of quarters and of person shall be enjoined and 
enforced daily. Disinfectants shall be used where there is any possi- 
bility of infection. 
' '1 The quantity of water of ammonia required for neutralization after each of the 
above-named methods is as follows : After method (a), one-half liter (0.52 quart) of 
water of ammonia for each liter (1.04 quarts) of formalin ; after method (6), one-half 
liter of water of ammonia for each 150 grams (5 ounces) of trioxymethylene. 
" 2 The special apparatus must consist of a generator, constructed of copper for evolv- 
ing formaldehyd gas from its solutions, and a similar one of iron for evolving ammonia 
gas for neutralization. The principle upon which this apparatus is constructed is de- 
scribed and illustrated in Public Health Reports, Marine-Hospital Service, January 
29, 1897, Vol. XIL, No. 5, and September 22, 1899, Vol. XIV., No. 38." 560 
QUARANTINE. 
"Par. 6. Water-closets, urinals, privies, or troughs shall be pro- 
vided, and their contents disinfected before they are discharged. 
" Par. 7. In any group in which cholera appears, the sick will be 
immediately isolated in hospital, and the remaining persons in the 
group shall be bathed and their effects be disinfected, then removed to 
other quarters, if possible, and the compartment disinfected. 
" Par. 8. No direct communication shall be allowed between the 
physician and attendants of the hospital and those detained in quaran- 
tine. 
" No person shall be discharged from quarantine until five days have 
elapsed since the last exposure to infection and a final disinfection of 
such effects as were taken to barracks. 
" No convalescent from cholera shall be discharged from quarantine 
until after a sufficient time has elapsed to insure his freedom from in- 
fection.1 
" Par. 9. The body of no person dead of cholera shall be allowed to 
pass through quarantine. The body should be cremated if practicable. 
If not, it should be wrapped, without preliminary washing, in a sheet 
saturated with a solution of bichloride of mercury, 1 to 500, and buried, 
surrounded by caustic lime. 
" Article VII. Disinfection of Personal Effects of Passengers and 
Crew and Cargo. 
a Par. 1. Clothing, bedding, and articles not injured by steam shall 
be disinfected- 
" (a) By exposure to steam at a temperature of 100° to 102° C. for 
thirty minutes after such temperature has been reached. 
"(6) By boiling for fifteen minutes; all articles to be submerged. 
" (c) By a thorough saturation in a solution of bichloride of mercury, 
1 to 1,000, and allowed to dry before washing. 
"Par. 2. Articles injured by steam (rubber, leather, etc.), and con- 
tainers to the disinfection of which steam is inapplicable, shall be dis- 
infected by thoroughly wetting all surfaces with a solution of bichloride 
of mercury, 1 to 800, or a 5-per-cent. solution of carbolic acid, and 
allowed to dry in open air. 
" Par. 3. Cooking and eating utensils, by immersing in boiling 
water or steam. 
" Par. 4. All rags and old textile fabrics used in the manufacture of 
paper, and all old gunny, old jute, etc., fit only for remanufacture, 
gathered, collected, packed, or handled in any port or place where 
cholera (cholerine) or yellew fever exists, or where smallpox or typhus 
fever prevails in epidemic form, and for thirty days after the port or 
place shall be officially declared free from such diseases or epidemic, 
shall be denied entry into any port of the United States. 
" Par. 5. No rags or old textile fabrics used in the manufacture of 
paper, or articles enumerated in the preceding paragraph, which have 
"1 To be determined by bacteriological examination." QUARANTINE LAW OF 1893. 
561 
not been disinfected in accordance with Article VII., paragraph 3, of 
the United States Quarantine Regulations for foreign ports, shall be 
admitted into the United States. 
" (Old jute bags, old cotton bags, old rope, new cotton and linen cut- 
tings from factories not included.) 
" Par. 6. All unlabeled baggage of steerage passengers, including 
hand baggage, and all labeled baggage of said passengers, which in 
the opinion of the quarantine officer should be disinfected or redisin- 
fected, arriving from oriental ports, including ports of Hawaii, at any 
port in the States of Oregon, Washington, or California, shall be dis- 
infected as provided in Article VII. of the Quarantine Regulations for 
domestic ports before being landed. 
" This regulation will also apply to any other baggage which the 
quarantine officer may suspect of being infected. 
" Article VIII. Treatment of Vessels Infected or Suspected of being 
Infected with Yellow Fever. 
"Par. 1. Where practicable, at once remove the sick to hospital; 
remove and isolate all persons not required for the care of the vessel. 
11 Par. 2. If the hold is deemed infected, there shall be a preliminary 
disinfection as hereinafter provided. 
" Par. 3. The bilge should be cleansed with sea water, if possible, 
before disinfection, and the hold rendered mechanically clean. 
" Par. 4. All ballast, except close-grained, hard rock, must be dis- 
charged. This may be retained aboard if disinfected by immersion in 
an acid solution of bichloride of mercury, 1 to 800. 
" Par. 5. After discharge or disinfection of ballast the vessel should 
be disinfected. 
" Par. 6. If it is so stowed as to admit of disinfection, the cargo and 
the hold may be disinfected without breaking bulk, except to such a 
degree as to render disinfection practicable. 
" It shall be as follows : 
" Holds to be treated with sulphur dioxide, 10-per-cent. strength per 
volume, forty-eight hours' exposure for iron vessels, seventy-two hours' 
exposure for wooden vessels. 
" Par. 7. Empty holds to be disinfected as follows : 
" (a) If of iron, by sulphur dioxide gas, 10-per-cent. strength per 
volume, for twelve hours' exposure, or by washing with a solution of 
bichloride of mercury, 1 to 800, applied under pressure to all surfaces 
by means of a hose. 
" (6) If of wood, by both of the preceding methods, save that the 
exposure to sulphur dioxide gas shall be for twenty-four hours, air 
streaks to be open; the use of the gas to precede the use of the mer- 
curic solution. 
" Par. 8. Cabin, forecastle, etc., after mechanical cleansing, to be 
first treated with sulphur dioxide, not less than 6-per-cent. strength 
per volume, twenty-four hours' exposure. Then (after cleansing with 562 
QUARANTINE. 
water, if desired) wash all exposed surfaces with a solution of bichlo- 
ride of mercury, 1 to 800, or pure carbolic acid, 3 per cent. 
" Par. 9. Clothing, bedding, and all fabrics which can be removed, 
not injured by steam, shall be disinfected. 
" (a) By exposure to steam at a temperature of 100° to 102° C. for 
thirty minutes after such temperature has been reached. 
"(6) By boiling for fifteen minutes; all articles to be submerged. 
" (c) By a thorough saturation in a solution of bichloride of mer- 
cury, 1 to 1,000, and allowed to dry before washing. 
" Par. 10. Articles injured by steam (rubber, leather, etc.), and con- 
tainers, to the disinfection of which steam is inapplicable, shall be 
disinfected by (a) thoroughly wetting all surfaces with a solution of 
bichloride of mercury, 1 to 800, or a 5-per-cent. solution of pure car- 
bolic acid, and allowed to dry in open air; or (6) by exposure to the 
sulphur fumigation, in cabin, forecastle, or hold, or by method pre- 
scribed in Article V., paragraphs 8 and 9. 
"Par. 11. The personnel of the vessel shall be detained five days 
from the completion of the disinfection, or three days if all baggage, 
effects of passengers and crew, and the vessel are handled exclusively 
by quarantine employees. 
" Par. 12. If the vessel has been disinfected under the supervision of 
an accredited medical officer of the United States at the port of depar- 
ture, the period of quarantine may date from completion of such disin- 
fection, and shall not be less than five days. 
" Article IX. 
" Passenger traffic may be allowed during the quarantine season from 
any port infected with yellow fever to any port of the United States 
south of the southern boundary of Maryland under the following con- 
ditions : 
" (a) Vessels to be of iron and clean immediately prior to taking on 
passengers. 
" (6) The vessel must lie at moorings in the open harbor and not ap- 
proach the wharves, nor must the crew be allowed ashore at the port 
of departure. 
" (c) All passengers and crew must be immune to yellow fever, and 
so certified by the United States medical officer.1 
" (<Z) All baggage which has not been disinfected at the port of de- 
parture by the United States medical officer, or which is not in bond 
for points north of the southern boundary of Maryland, shall be dis- 
infected at the quarantine at the port of arrival; no bedding or house- 
hold effects to be allowed to enter. 
" Article X.-Miscellaneous. 
" Par. 1. The treatment of vessels infected with typhus fever shall 
be the same as that prescribed for yellow fever. 
" ' The evidence of immunity which may be accepted by the sanitary inspector is : 
First, proof of continued residence in an endemic focus of yellow fever for ten years ; 
second, proof of previous attack of yellow fever." QUARANTINE LAW OF 1893. 
563 
" Par. 2. The detention of passengers and crew for smallpox and 
typhus fever shall cover the period of incubation of the disease, the 
time of detention to commence from the date of last exposure ; typhus 
fever, not less than twenty days; smallpox not less than fourteen days. 
" Par. 3. Vessels detained at any national quarantine will be sub- 
ject to such additional rules and regulations as may be promulgated 
from time to time by the Supervising Surgeon-General. 
" Par. 4. The following is the form of certificate which shall be 
issued to the vessel by the health officer when she is released from 
quarantine : 
, , 190-. 
' ' I certify that , of , from , has in all respects complied 
with the quarantine regulations prescribed by the Secretary of the Treasury, 
and that in my opinion she will not convey quarantinable disease. Said 
vessel is this day granted free pratique. 
Health (Quarantine) Officer, 
Port of . 
" In the performance of the duties imposed upon him by the act of 
February 15, 1893, the Supervising Surgeon-General of the Marine- 
Hospital Service shall, from time to time, personally or through a 
duly detailed officer of the Marine-Hospital Service, inspect the mari- 
time quarantines of the United States, state and local as well as 
national, for the purpose of ascertaining whether the quarantine regu- 
lations prescribed by the Secretary of the Treasury have been or are 
being complied with. The Supervising Surgeon-General, or the officer 
detailed by him as inspector, shall at his discretion visit any incoming 
vessel, or any vessel detained in quarantine, and all portions of the 
quarantine establishment for the above named purpose and with a 
view to certifying, if need be, that the regulations have been or are 
being enforced. 
" Article XI. Inspection of State and Local Quarantines. 
" Article XII. Canadian and Mexican Frontiers. 
"Par. 1. When practicable, alien immigrants arriving at Canadian 
and Mexican ports, destined for the United States, shall be inspected 
at the port of arrival by the United States consular or medical officer, 
and be subjected to the same sanitary restrictions as are called for by 
the rules and regulations governing United States ports. 
" Par. 2. Inspection cards will be issued by the consular or United 
States medical officer at the port of arrival to all such alien immigrants, 
and labels affixed to their baggage, as is required in the case of those 
coming direct from foreign ports to any port of the United States. 
" Par. 3. Whenever alien immigrants are not inspected at the port 
of arrival by the United States consular or medical officer they shall 
enter the United States through certain designated places on the fron- 
tier, where they shall be inspected for the purpose of preventing the 564 
QUARANTINE. 
introduction of quarantinable disease. This inspection shall be held 
by daylight. 
" Par. 4. If any person be found suffering from a quarantinable 
disease, or presumably infected, he shall be denied entry so long as 
danger of conveying the infection exists. 
" Par. 5. Any baggage or other effects believed to be infected shall 
be refused entry until made safe by a proper disinfection. 
" Par. 6. Persons coming from localities where smallpox is prevail- 
ing in epidemic form shall not be allowed entry without vaccination, 
unless they are protected by a previous attack of the disease or a re- 
cent successful vaccination. 
" Par. 7. Persons coming from localities where typhus fever pre- 
vails in epidemic form shall not be allowed entry until they have been 
away from such locality fourteen days and their baggage disinfected. 
" Par. 8. During the quarantine season, persons coming from places 
where yellow fever prevails will not be permitted to enter until they 
have been away from such locality ten days and their baggage has 
been disinfected. But persons immune to yellow fever will not be 
detained. 
" Par. 9. No common carrier which is infected, or suspected of 
being infected, shall be allowed to enter the United States until after 
such measures have been taken as will render it safe. 
" Par. 10. Articles of merchandise, personal effects, etc., which are 
capable of conveying infection, and which are presumably infected, 
shall not be allowed entry into the United States until after disinfec- 
tion. 
"Par. 11. The methods of disinfection shall be those prescribed in 
the Rules and Regulations made for the maritime quarantines of the 
United States. 
" Immigrants who, with their baggage, have been inspected at a 
port of the United States by a quarantine officer upon landing, will 
be exempt from further quarantine inspection when reentering the 
United States from Canada, unless there is reason to believe that 
disease has developed among such immigrants since such landing and 
inspection. 
" Par. 12. Rags gathered and baled in Canada, accompanied by 
affidavits that the ports or places where collected or handled were free 
from quarantinable disease for thirty days prior to shipment, may be 
admitted to entry ; but rags from foreign ports shipped through Canada 
shall not be admitted to entry, unless they are accompanied by a cer- 
tificate of a United States consul or medical officer of the United 
States that they have been disinfected in accordance with the United 
States quarantine regulations. 
" Foreign rags, not originating in Canada, but shipped through Can- 
ada to ports in the United States, will not be permitted to entry by col- 
lectors of customs unless accompanied by the above-named certificate, 
or until after they have been unbaled and disinfected as required by 
the United States quarantine regulations. QUARANTINE LAW OF 1893. 
565 
" Article XIII. Special Regulations Relating to Naval Vessels. 
" Par. 1. Such communication may be allowed with vessels of the 
United States Navy as the certificate of the medical officer of said 
vessel shows will not be liable to convey infection. 
" Par. 2. The certificates of the medical officers of the United States 
Navy that the United States Quarantine Regulations have been com- 
plied with may be accepted for naval vessels. 
"Par. 3. Vessels of the United States Navy, having entered the 
harbors of ports infected with yellow fever, and having held no com- 
munication which is liable to convey infection to the vessel or her 
crew, may be exempted from the quarantine restrictions imposed on 
merchant vessels from such ports. 
" Article XIV. Treatment of Vessels Suspected of Plague. 
"Par. 1. The regulations heretofore promulgated with regard to 
cholera shall be observed with regard to vessels, cargo, passengers, and 
crews infected, or suspected of being infected, with plague, but persons 
who have been exposed to the infection, or are liable to convey the 
disease, shall be detained for a period of not less than fifteen days from 
the last possible exposure to infection. 
" Par. 2. If a vessel has been disinfected at the port of departure 
and the personnel bathed and their body clothing and baggage disin- 
fected by a commissioned medical officer of the Marine-Hospital Ser- 
vice, where proper facilities for such work exist, and in all other re- 
spects has complied with the United States Treasury regulations, and 
if no suspicious sickness has occurred en route, such vessels may, in 
the discretion of the quarantine officer, have the time of the voyage de- 
ducted from the period of detention. 
" Par. 3. No person from an infected or suspected port or place 
shall be admitted into the United States until a total period of fifteen 
days shall have elapsed under observation either at the port of de- 
parture, at sea, or at port of arrival, excepting as hereinafter provided. 
" Par. 4. A first-cabin passenger, bearing the certificate of an offi- 
cer of the Marine-Hospital Service, certifying to non-exposure to the 
infection of plague for the fifteen days immediately preceding embarka- 
tion, may be admitted to entry without detention, provided, in the 
opinion of the quarantine officer at the port of arrival, he has not been 
exposed en route to persons or things presumably infected. 
" Par. 5. All passengers excepting the first-cabin passengers, shall 
be bathed, and body clothing disinfected before landing. Similar meas- 
ures shall be taken with the crew and their effects if the quarantine 
officer believes the crew has been exposed to infection. 
" Par. 6. A11 baggage from infected places should be disinfected, 
either at the port of departure or entrance, in full accordance with 
United States Quarantine Regulations. When disinfected at the port 
of departure, the containers shall be sealed and ticketed with a yellow 
"disinfected" label, signed by a medical officer of the Marine-Hos- 566 
QUARANTINE. 
pital Service at the port of departure, and if seals and labels are intact 
at port of arrival, such packages may, in his discretion, be passed by 
the quarantine officer at the port of arrival, without further disinfec- 
tion. Hand baggage and baggage opened or used on the voyage must 
be disinfected on arrival. In no case shall soiled body linen be ad- 
mitted without disinfection. 
" Par. 7. A vessel from a plague-infected or suspected port, carry- 
ing passengers but no ship's surgeon, may, in the discretion of the 
quarantine officer, be quarantined with all on board, for the full fifteen 
days from the completion of disinfection. (See note.) 
" Par. 8. A vessel from a plague-infected or suspected port, arriv- 
ing with fewer persons on board than are accounted for on the bill of 
health, may, in the discretion of the quarantine officer, be considered 
as an infected vessel. 
"Par. 9. Vessels suspected of plague shall be disinfected in whole 
or in part, in the discretion of the quarantine officer, and said disinfec- 
tion shall be in accordance with the provisions of Article XVI. 
"Article XV. Treatment of Plague-infected Vessels. 
"Par. 1. Remove all passengers from the vessel, and all of the 
crew save those necessary to care for her. Place the sick, if any, in 
hospital, and isolate those specially suspected. Segregate the re- 
mainder in small groups, wherever facilities for such segregation exist. 
" Par. 2. Persons with abrasions or open sores should have them 
protected with proper dressings before being permitted to handle per- 
sons or articles believed to be infected with plague. 
" Par. 3. Preliminary disinfection.-After removal of the personnel 
a preliminary disinfection of all accessible parts of the vessel must be 
performed with sulphur dioxide. This preliminary disinfection should 
be started in the morning in order that guards may be placed on deck 
and in small boats around the vessel to detect and destroy any escap- 
ing rats. 
" Par. 4. The water supply must be changed without delay, the 
casks or tanks disinfected by steam or 10-per-cent. solution of potas- 
sium permanganate, and, after thorough rinsing, refilled from a source 
of undoubted purity, or the water supply must have been recently 
boiled. Some water tanks are not readily inspected and cleansed on 
account of their inaccessibility ; these may be rendered safe by leading 
a steam pipe into them and boiling the water in situ. 
"Par. 5. Nothing shall be thrown overboard from the vessel, not 
even deck sweepings. Such material shall be burned in the furnace or 
in a place specially designated, but not in the galley. 
" Par. 6. Plague-infected vessels shall be disinfected in accordance 
with Article XVI. 
" Par. 7. Detention of personnel. 
" (a) If practicable, antipeste serum should be used as a preventive 
measure on all the personnel of any vessel arriving with a history of 
sickness of a suspicious character on board during the voyage. QUARANTINE LAW OF 1893. 
567 
" (b) The personnel of vessel shall be detained under observation 
fifteen days from the last possible exposure to infection. 
" (c) The people detained shall be inspected by the physician twice 
daily and be under his constant surveillance, and no intercourse will 
be allowed between the different groups while in quarantine. 
" (d) No direct communication shall be allowed between any person 
detained in quarantine and any one not in quarantine, except through 
the quarantine officer. 
" (e) The water and food supply shall be strictly guarded to prevent 
contamination, and issued to each group separately. 
" (/) Cleanliness of quarters and of persons shall be enjoined and 
enforced daily. Disinfection shall be used where there is any possi- 
bility of infection. 
"(g) Water-closets, urinals, privies, or troughs shall be provided, 
and their contents disinfected before they are discharged. 
" (A) In any group in which plague appears the sick shall be im- 
mediately isolated in hospital, and the remaining persons in the group 
shall be bathed and their effects disinfected, then removed to other 
quarters, if possible, and the compartment disinfected. 
" (i) No convalescent from plague shall be discharged from quaran- 
tine until after a sufficient time has elapsed to insure his freedom from 
infection, to be determined by bacteriological examination. 
" (k) The body of no person dead of plague shall be allowed to pass 
through quarantine. The body should be cremated, if practicable. If 
not, it should be wrapped,. without preliminary washing, in a sheet 
saturated with a solution of bichloride of mercury, 1 to 500, surrounded 
in the coffin by twice the body weight of caustic lime and buried. 
" (1) Mammalian animals, such as dogs, cats, monkeys, mice, etc., 
which not infrequently accompany passengers as pets, should not be 
shipped from a plague-infected or suspected port or place. Should, 
however, such arrive, they shall be held in quarantine at least fifteen 
days. 
" Article XVI. Disinfection of Vessels Infected or Suspected of 
Being Infected with Plague. 
" Par. 1. Holds of iron vessels. 
" (a) With cargo.-By twenty-four hours' exposure to sulphur di- 
oxide, 10-per-cent. per volume strength, generated by an approved 
furnace, or forty-eight hours' exposure to 5-per-cent. per volume 
strength, generated by pots. 
" (6) Where cases of plague, or deaths from the same, have occurred 
on board, or where there have been deaths presumably from plague 
among the rats on a vessel, the cargo shall be lightered, in order to 
complete the disinfection of the vessel and facilitate the removal of all 
rats and other vermin. 
"This same procedure may be required by the quarantine officer 
whenever in his judgment the vessel or cargo is disinfected. 
" (c) Where it can be procured in sufficient quantity, liquefied sul- 568 
QUARANTINE. 
phur dioxide may be used in the disinfection of cargoes, holds, and 
living apartments, it being borne in mind that it will be necessary to 
employ 2 pounds of this material in lieu of 1 pound of sulphur where 
indicated in the above regulations. 
" (d) No person should be allowed on the vessel or around the cargo 
with bare feet, and the use of proper precaution in handling dead 
vermin is advised. 
" (e) Without cargo.-After the preliminary disinfection, provided 
for in Article XV., paragraph 3, followed by mechanical cleansing the 
hold must be thoroughly washed with a solution of bichloride of mer- 
cury, 1 to 800, applied under pressure to all surfaces by means of a 
hose, or disinfected by sulphur dioxide, 10-per-cent. per volume 
strength, for twenty-four hours, or 5-per-cent. per volume strength for 
forty-eight hours. 
" (/) The water ballast of a vessel coming from infected or suspected 
ports should be discharged at sea, or, if discharged in fresh or brackish 
water, must be previously disinfected, the tanks to be flushed and re- 
filled with sea water, or disinfected. 
" Par. 2.-Holds of wooden vessels. 
" For a wooden vessel the treatment is the same as for iron vessels, 
except that the exposure of the hold to sulphur dioxide, 10-per-cent. 
per volume strength, must precede the washing with bichloride, and 
this exposure must be forty-eight hours in wooden vessels without 
cargo, or, if only 5-per-cent. per volume strength sulphur dioxide is 
obtainable, the exposure must be seventy-two hours. 
" Par. 3. All solid ballast on vessels infected, or suspected of being 
infected, with plague, to be discharged or disinfected previous to dis- 
infection of hold; all such ballast discharged in fresh water to be dis- 
infected by saturation with, or immersion in, a solution of bichloride 
of mercury 1 to 800. 
"Pae. 4. Clear, hard, close-grained rock may be permitted to re- 
main on board, but only after disinfection by immersion in a solution 
1 to 800 of bichloride of mercury. Ballast removed from vessels in- 
fected, or suspected of being infected, with plague must not be taken 
from the quarantine station. 
"Par. 5. Bilges shall be cleansed and disinfected in the matter 
provided for water tanks. (Article XV., paragraph 4.) 
" Par. 6.-Living compartments of all classes of vessels. 
" (a) The preliminary disinfection shall be done with sulphur diox- 
ide and not with formaldehyd on account of the greater potency of the 
former against animal life. 
"(6) After this preliminary disinfection, remove bedding, hangings, 
carpets, clothing and textiles, for disinfection by steam or boiling, or 
other methods prescribed by United States Quarantine Regulations. 
Subsequently the compartments themselves, with the nonremovable 
fabrics therein, shall be disinfected in accordance with the United 
States Quarantine Regulations. 
"Par. 7. Personal effects.-Clothing, bedding, and other such arti- QUARANTINE LAW OF 1893. 
569 
cles shall be disinfected in accordance with the provisions of Articles 
V. and VIII., United States Quarantine Regulations. 
" Par. 8. After the cargo has been discharged, the vessel must be 
subjected to a disinfection of all parts simultaneously by sulphur diox- 
ide gas of 5-per-cent. per volume strength for not less than twenty- 
four hours, in order to insure destruction of all animal life aboard. 
The remains of all rats and vermin should be gathered and burned, 
and the places where gathered subsequently disinfected. Rats must 
not be handled with bare hands. 
"Par. 9. After final disinfection as provided in paragraph 8, the 
vessel must be kept under observation a sufficient length of time to satisfy 
the quarantine officer that the ship is freed from all rats and vermin." 
From the foregoing sets of regulations, it is seen that the prevention 
of the introduction of infectious diseases begins at the port of departure 
and that the strictness of supervision is not relaxed in any way until 
the vessel is admitted to entry. It will also be seen that the details 
of the quarantine stations must vary according to the circumstances of 
each port since, for example, barracks for detention cannot be needed 
at stations where immigrant vessels do not enter, and the same facili- 
ties for discharging and disinfecting ballast are not everywhere required. 
It is essential that the station be at a goodly distance from resident 
populations and sufficiently removed from the main channels of com- 
merce, and yet, at the same time, easy of access. Separate anchorages 
should be provided for infected and non-infected vessels, sufficiently far 
apart to ensure safety to the latter from infection from the former. 
Detention barracks must be well ventilated and scrupulously clean 
and kept under constant surveillance in every part. 
The details of management of a station and of inspection of arriving 
vessels are sufficiently set forth in the foregoing rules and regulations. 
Additional provision for ensuring a healthy condition of a ship is 
made by Section 4263 of the Revised Statutes, which authorizes the 
master of any vessel engaged in transporting passengers between the 
United States and Europe to adopt and post regulations for the main- 
tenance of good discipline and habits of cleanliness among the passen- 
gers, and requires him to cause the passengers' apartments to be kept 
at all times in a clean healthy state. The owners of every such vessel 
are required to construct the decks and all parts of the apartments so 
that they can be thoroughly cleansed, and to provide a safe convenient 
water-closet for the exclusive use of every 100 passengers. The 
master is required also, when the weather is such that the passengers 
cannot be mustered on deck with their bedding, and at such other times 
as he may deem necessary, to cause the deck occupied by said passen- 
gers to be cleansed with chloride of lime or some other equally efficient 
disinfecting agent. 
Following the passage of the quarantine law of 1893 and the 
promulgation of the regulations made in accordance therewith, at 
many ports the quarantine service was voluntarily surrendered to the 
national government, and at others it was taken over by the same au- 570 
QUARANTINE. 
thority, because of non-compliance with the regulations. At others, 
the regulations have been adopted and efficiently enforced by the local 
authorities, but these and all others are regularly inspected by the Ma- 
rine Hospital Service, to ensure efficiency of administration and cor- 
rection of faults in methods and defects in appliances. 
In 1900, there were in the United States no less than 120 quaran- 
tine and inspection stations, of which number, 81 were on the Atlantic 
coast, 17 on the Pacific coast, and 22 on the Gulf of Mexico. They 
vary, naturally, very widely in importance and equipment, the most 
important one being that of New York, the chief gate of entrance of 
immigrants and of foreign commerce, and the least important being 
several with practically no arrivals of vessels from foreign ports. 
Only a small proportion are equipped with extensive disinfecting ap- 
pliances, and but 8 are provided with quarters for the detention of 
persons held for observation. 
To prevent the introduction of contagious diseases from one State to 
another, Congress, on March 27, 1890, passed an Act providing that 
whenever the President is satisfied that cholera, yellow fever, small- 
pox, or plague exists in any part of the United States and that there 
is danger of the spread thereof into other States, Territories, or the 
District of Columbia, he is authorized to cause the Secretary of the 
Treasury to promulgate such preventive rules and regulations as he 
may deem necessary, and to employ such inspectors and other persons 
as may be necessary to enforce them. 
These rules and regulations shall be prepared by the Supervising 
Surgeon-General of the Marine Hospital Service, under the direction 
of the Secretary of the Treasury, and any violation thereof entails a 
fine of not exceeding $500, or imprisonment for not more than two 
years, or both, in the discretion of the Court. In the case of any 
officer or other person employed to prevent the spread of said diseases, 
willful violation of any of the quarantine laws of the United States or 
of any of the rules and regulations made and promulgated as above 
or of any lawful order of his superior officer or officers, the penalty is 
a fine not exceeding $300 or imprisonment for not exceeding one year, 
or both, in the discretion of the Court. Any common carrier or 
servant thereof who shall willfully violate any of the same shall be 
liable to a fine of not exceeding $500, or imprisonment for not ex- 
ceeding two years, or both, in the discretion of the Court. 
Interstate Quarantine. 
State Quarantine. 
The national quarantine law and the rules and regulations made 
thereunder are, as has been said already, intended only as minimum 
requirements, to which State or municipal authority may make such 
additions as may be deemed necessary for the preservation of the health 
of the people within its jurisdiction. Such additional requirements STATE QUARANTINE. 
571 
may be established for specified periods or without limit of time, and 
to meet general conditions or a special class of cases. As an example 
of special regulations made for a limited period, the following, adopted 
by the State Board of Health of Louisiana with reference to vessels en- 
gaged in the tropical fruit trade during the season of 1899, may be cited. 
" All vessels engaged in the tropical fruit trade between Central 
American, South American, and West Indian ports and New Orleans 
will be allowed to pass the Mississippi River Quarantine Station with- 
out detention longer than is necessary for a thorough inspection by day 
by the quarantine officers, so long as a properly accredited medical 
agent of this board certifies that such ports and places are free from 
contagious or infectious disease, and provided said vessels shall strictly 
conform to the following conditions : 
" 1. They shall not be allowed to bring to this port bedding or house- 
hold effects of any kind. 
" 2. After leaving New Orleans, said vessels may take on board 
passengers during any part of their trip, and bring passengers to this 
port as herein provided. 
" Cabin passengers only will be allowed at the discretion of the med- 
ical officer. This officer must satisfy himself that the applicant has 
not been in any infected locality in the past thirty days, and that none 
of his effects have been exposed to infection, and further such effects 
shall have been fumigated or disinfected before going on board. 
" Passengers may be taken on board from one healthy port to another, 
each of said ports having a medical officer representing this board; 
under the same restrictions said passengers may be brought to New 
Orleans. Personal effects of passengers are restricted to personal 
wearing apparel, and should as much as possible consist only of clean, 
recently laundried clothing, and such effects, together with passengers' 
trunks, bags, valises or baskets, must be fumigated before being brought 
on board. 
" The medical officer will refuse to permit the bringing of any un- 
usual or unnecessary amount of baggage, it being the purpose of the 
board of health to facilitate the affairs of commerce by permitting 
passenger communication whereby business may be transacted in a safe 
manner, holding highest the health of the community; and it is in- 
sisted that material capable of carrying any possible infection should 
be limited to the least possible amount. Woolen bags or carpet sacks 
will be prohibited. Trunks should be of metal, wood, or paper; 
valises of leather or paper. 
" The medical officer will make a personal inspection of all passengers 
and of every member of the crew just prior to the departure of the 
vessel, and give a certificate to the master of the vessel of the con- 
dition of such persons examined, marking opposite the name of each 
person on the list furnished him by the officers of the vessel of every 
person on board such observations as may seem to him to be advisable 
concerning the condition of said person's present or previous state of 
health. 572 
QUARANTINE. 
Medical officers will invariably assist masters of vessels in treatment 
of members of crew or passengers taken sick on board vessels and 
should make notes of such treatment in writing to be sent to the quar- 
antine officer at home ports. 
11 3. Vessels shall not touch at any infected port or have any com- 
munication with any vessel during their voyage except in case of dis- 
tress. 
" 4. They shall not touch at such ports or stations as are not men- 
tioned in their schedule, which latter shall be communicated to the 
board of health. 
" 5. They shall be required to make a full disclosure when arriving at 
quarantine station of all ports and places they have visited on their 
voyage. 
u 6. They may take on board a crew of laborers after inspection by 
the medical officer and disinfection of clothing of such crew for such 
healthy point where they permanently reside and remain, the crew 
being as nearly as possible composed of the same men. The captain or 
other officer may go ashore only for the purpose of entering or clearing 
vessels. Any further communication with shore or natives will be 
considered a violation of regulations, and vessels in default will be 
treated accordingly. 
" 7. These vessels shall be cleansed, and, when necessary, disinfected 
in the city of New Orleans after discharge of cargo." 
Sanitary Cordon. 
What is known as a sanitary cordon (" cordon sanitaire ") consists 
of an extended line of guards thrown about a district to pre- 
vent access thereto or egress therefrom of any person or thing 
which may act as the carrier of infection. The object is, in other 
words, to protect the district from infection from the surrounding 
country or to protect the latter from infection from the district. 
Sometimes a double line is established, the territory intervening being, 
perhaps, only suspected of being infected. Cordons are not uncom- 
monly established in the South against yellow fever, but are practically 
unknown in the North. In California, in 1900, a cordon was main- 
tained, for a short time only, against a district in which cases of bu- 
bonic plague were believed to be concealed. 
Municipal quarantine comprehends measures for isolating those sick 
with certain of the infectious diseases, such as scarlet fever, diphtheria, 
and smallpox, keeping others under observation, and disinfecting rooms 
and houses and objects contained therein which may be capable of har- 
boring infection. It is beyond dispute that public safety requires that 
certain sick should be shut off from free communication with the out- 
side world. This isolation is most complete and entails less hardship 
when it can be carried out at a special hospital for contagious diseases, 
Municipal Quarantine CAMPS OF DETENTION. 
573 
but generally it is enforced, if at all, at the patient's home. Room and 
house quarantines are commonly difficult or impossible of enforcement, 
especially in tenement districts among the very poor, for it is among 
this class that danger of infection is least understood and mutual help 
and neighborly visiting most extensively practiced, and thus the foci 
of infection may become increased indefinitely. In hospitals, on the 
other hand, where indiscriminate egress and ingress are under control 
and facilities for the disinfection of discharges are at hand, the danger 
of spread is reduced to a minimum. 
Especially difficult and productive of hardship is the isolation not 
only of the patient, but of the other members of his family. This is 
commonly practiced in the case of smallpox, but is unnecessary if the 
other members have undergone recent successful vaccination and their 
clothing and other effects are disinfected and they are then separated 
from all possible contact and communication with the patient. But 
even then, they should be kept under surveillance for a time equal to 
the period of incubation. In times of epidemics of yellow fever in the 
South, house quarantine of entire families has proved to be the cause 
of much hardship and anything but an unqualified success. It causes 
great popular dissatisfaction, leads to concealment of cases, and tends, 
therefore, to spread rather than restrict the disease. Treatment of the 
sick in isolation hospitals and removal of those who have been ex- 
posed to infection to camps of detention for five full days have been 
found to give far better results. 
In some outbreaks of infectious diseases, it is necessary or advisable 
to conduct a house-to-house inspection for the discovery and isolation 
of unreported cases. When such a course is undertaken, the visits 
must be repeated at intervals equal to the period of incubation. 
The making of regulations for municipal quarantine and inspection 
is subject to no general rule, each local authority being a law unto 
itself. In some cities, the rules governing notification, isolation, and 
disinfection are exceedingly thorough and strictly enforced ; in others, 
they are inadequate in varying degrees and enforced with laxity. 
Camps of Detention.-Camps of detention are places set apart for 
the reception and observation of persons who have been exposed or 
who are under suspicion of having been exposed to the contagion of 
yellow fever, smallpox, or other quarantinable disease. They should 
be under strict surveillance and governed by inflexible rules. Every 
person should be examined before admission, and such effects as he may 
be permitted to bring in should be thoroughly disinfected, for above 
all things, it is necessary to guard against the introduction of infection. 
The entire personnel must be mustered in quarters and examined at 
least twice daily, and such as are beginning to show symptoms must 
be promptly isolated. Indiscriminate ingress and egress must be 
strictly prevented. At the expiration of the proper period, in each 
case the clothing and other personal effects should be thoroughly dis- 
infected before discharge. CHAPTER X. 
MILITARY HYGIENE. 
Since the most important factor in the efficiency of an army is its 
health, it follows that everything which can influence this in any way for 
the better or worse should be looked after with the utmost care. The 
men who compose an army are drawn from civil life, in which each indi- 
vidual has, to a greater or less extent, independent control of his time, 
choice of occupation, selection of food and dwelling-place, and general 
sanitary care. After enlistment, they lose most of this independence ; 
they are housed, clothed, fed, and exercised under regulations which it 
is beyond their power to amend ; they are moved about from one point 
to another, differing perhaps very widely in climatic and other condi- 
tions, under orders which they may not presume to question ; their 
hours for sleep, meals, work, and recreation are fixed for them with- 
out consultation with them, and without regard to individual or com- 
munal preference. 
Since the government necessarily deprives the soldier of his inde- 
pendence of action, it is bound by every principle of fairness to him to 
look after his health and comfort, to promote contentment, and to ward 
off ennui by all reasonable and proper means. Thus, the care of troops 
is a double obligation ; the men have every right to expect it, and the 
efficiency of the army is dependent upon it. But no matter how care- 
ful the sanitary administration, it is a matter of common knowledge 
that in all wars, excepting the Franco-Prussian, and here only with 
regard to the Germans, the mortality from disease has been far in ex- 
cess of that from casualties, and in all armies, more discharges are due 
to sickness than to injuries. 
The responsibility for the care of troops and health of camps is 
placed upon the medical officers, who have no power to command and 
are hampered by being subordinate to laymen having often no adequate 
appreciation of matters purely medical. They have only advisory 
functions and must be most careful in recommending changes to the 
very conservative military mind, which finds in long continuance of a 
condition the strongest argument for its longer retention and is prone 
to look upon recommendations for sweeping changes as evidence of 
whimsical disposition and deficient training in sanitary science. 
Nevertheless, the medical officer has a very heavy responsibility placed 
upon him and must advise his lay superiors and explain the impor- 
tance of the principles underlying sanitary practice. He must make 
proper recommendations for the protection of health of the troops in 
war and in peace, in camps and in garrison. MILITARY HYGIENE. 
575 
Since the efficiency of a military body is so largely dependent upon 
the health of the units of which it is composed, the result of a cam- 
paign may be largely influenced by the adoption or rejection by the 
commanding officer of the recommendations of his medical adviser. 
Unfortunately, if, by reason of physical unfitness of the troops, a move- 
ment fails or an epidemic of disease occurs, the public at once places 
the blame upon the medical department and especially upon the head 
thereof, the Surgeon-General, and demands a reorganization, a sifting 
out of incompetent material, and especially, a change in the head, quite 
regardless of the possible fact that the choice of an unsanitary camp- 
ing place may have been made against the judgment and advice of the 
medical branch, that the commissary department may have been 
largely to blame, or that other influences quite beyond the control of 
the medical corps may have been at fault. 
The medical officer, both at home and in most countries abroad, has 
much with which to contend. The corps is, as a rule, not sufficiently 
large for the body for which it is to care, but is expected to perform 
an amount of work and assume a responsibility which would fairly tax 
the capacity of one of double size. In an emergency requiring large 
additional levies and consequent employment of civilian physicians un- 
trained in military life, the responsibility becomes proportionately greater. 
The recent experiences of this country and of England, when the 
outbreak of war necessitated the assembling and transportation of 
large armies, serve very well as illustrations. With us, on the break- 
ing out of war with Spain, a standing army of 25,000 was suddenly 
increased by enlargement of the regular service and enrollment of vol- 
unteers to ten times that size, but the small body of trained military 
surgeons, too small before, could hardly have been expected to be equal 
to the demands of the new army, even with the assistance of the 
physicians from civil life, who, though doubtless highly efficient in 
civil practice, were for the most part inexperienced in camp hygiene. 
The difficulties of sanitary administration were very largely in- 
creased by the recklessness and ignorance of the volunteers in personal 
hygiene and general sanitation. The results were what might be ex- 
pected and are too well known to need further mention. The blame 
for all the disastrous experience was placed at once upon the medical 
department, which had but little to say in the choice of camps and 
nothing whatever to do with the inadequate means of transportation 
and other factors in the production of a large mortality from disease. 
The experience of the English in the war in South Africa was essen- 
tially the same and due to the same causes. 
In the large standing armies on the Continent, a different order of 
things obtains. The officers of the line are more inclined to defer to 
the opinions and advice of the medical staff in matters requiring ex- 
pert sanitary knowledge, and the authorities demonstrate a much 
higher appreciation of the value of an adequate medical service. As 
an illustration of the difference in the ordering of such matters in 
Germany and England, the following is cited: 576 
MILITARY HYGIENE. 
The British first infantry division and first cavalry brigade, with 
two batteries of field artillery, a company of engineers, telegraph 
corps, railway company, ammunition corps, and hospital corps, ordered 
to South Africa in the autumn of 1899, and the German expeditionary 
corps, consisting of two brigades of infantry, three squadrons of cav- 
alry, four batteries of light artillery, a battalion of pioneers, with a 
telegraph corps, railway company, sanitary company, ammunition 
corps, and hospital corps, organized in the summer of 1900 for service 
in China, were about equal in number of men. For the care of these 
troops, the English authorities detailed 49 regular medical officers and 
13 civilian surgeons, a total of 62 ; the Germans detailed 91 regular 
army surgeons, or nearly 50 per cent. more. The English hospital 
ship had 3 surgeons; the German had 10. The English sent 4 field 
hospitals with 16 surgeons ; the Germans sent an equal number with 
24. The English general hospital had 18 surgeons, of whom 11 were 
civilians ; the German had 19, all of whom were regulars. 
The superior medical equipment of the Germans is not dictated by 
extravagance, but by a greater appreciation of the necessity of furnish- 
ing adequate medical service. 
In a standing army such as is maintained in this country, it would 
be far better to err on the side of extravagance than of undue economy 
in the size of the medical corps. There should be systematic in- 
struction in general hygiene, which should not be limited to the med- 
ical officers alone, for the line officers also should be required to ac- 
quaint themselves with the principles of the science, and especially with 
the sanitation of camps. Then, when the medical officers point out 
methods of conserving the health of troops, those in actual command 
would be in a better position to apply their authority with a larger 
appreciation of the advice given. 
Military hygiene has to deal with the selection and examination of 
men offering themselves as recruits, their habitations, clothing, ex- 
ercise, food, diseases, and medical care; with camp sanitation, includ- 
ing water supply and sewerage, disposal of waste, and general police; 
and, in general, with all matters having any bearing on the health and, 
impliedly, the efficiency of troops. 
THE RECRUIT. 
Not every adult man accustomed to hard work can be transformed 
into a good soldier, for there are many points of disqualification for 
military service, and an unsound man can never be depended upon 
when his services are needed. The ideal recruit is one who, in the 
first place, is well built and of superior muscular force, capable of re- 
sisting influences tending to depress the nervous and physical powers. 
According to the great Napoleon, " The first quality of a soldier is the 
power to endure fatigue and privation ; courage is only second." This 
primary qualification is very commonly thought to be an attribute 
more of the country-bred than of the city-bred lad. THE RECRUIT. 
577 
Dr. Woodhull,1 Lt.-Colonel, Med. Dep't U. S. A., however, says 
on this point, " In raising new troops, when it is possible to select, for 
sharp and immediate active service take town-bred men. If a year or 
two can be added in which to train them, take country-bred men. 
Open-air military life is physical promotion to city men accustomed to 
irregular hours, unwholesome meals, and poorly ventilated rooms. To 
country lads the irregular and sometimes scanty meals, broken rest, 
necessity for prompt and exact action, and above all the certainty of 
acquiring such diseases as measles, whooping-cough, and mumps, which 
town boys always have in childhood, are very exhausting. After a 
year's training, country youths are more valuable." 
Under the regulation of the United States Army,2 any male citizen 
or person who has legally declared his intention to become a citizen, if 
above the age of 21 and under the age of 30 years, able-bodied, free 
from disease, of good character and temperate habits, may be enlisted; 
but in regard to age or citizenship, the rule does not apply to soldiers 
who have already served honestly and faithfully a previous enlistment. 
Boys between the ages of 16 and 18 may be enlisted as musicians or 
to learn music, with the written consent of father or guardian and ap- 
proval of the Adjutant-General. 
Enlisted men of good character and faithful service, who, at the ex- 
piration of their terms, are undergoing treatment for injuries incurred 
or disease contracted in the line of duty, may reenlist, and if the dis- 
ability prove to be permanent, they will be subsequently discharged. 
An enlisted man, not under treatment, but with infirmities contracted 
in the line of duty not such as to prevent his performing the duties of 
a soldier, may be reenlisted by authority of the War Department, on 
application made through the surgeon and proper military channel, 
since it is recognized that what he may lack in some minor particulars 
in soundness may be counterbalanced by experience and habits of dis- 
cipline. 
Those whose enlistment is prohibited include former soldiers having 
bad records, deserters, drunkards, insane persons, minors below 16 
years of age (musicians), persons who have been convicted of felony 
or who have been imprisoned under sentence of a court; and for first 
enlistments in time of peace, non-citizens, except those who have 
legally declared their intentions to become citizens, those who cannot 
speak, read, and write English, and those over 30 years of age. 
Age.-Recruiting officers are directed by the regulations to be very 
particular to ascertain the true age of the recruit, boys below 18 not 
being accepted in time of peace, excepting as musicians or to learn 
music, and then only with the consent of guardians and approval of 
the Adjutant-General. The minimum age for all arms of the service 
is 18 years; the maximum for the cavalry is 30, and for other arms 
35; but for reenlistments, there is no limit of age. Men of all ages 
between 18 and 45 are accepted in the volunteer service. In the 
1 Notes on Military Hygiene for Officers of the Line, New York, 1898, p. 18. 
2 Regulations for the Army of the United States, Washington, 1899, p. 113. 578 
MILITARY HYGIENE. 
British service, the limits of age are 18 and 25 years, except for the 
medical staff corps and engineers, for which the maximum is respec- 
tively 28 and 30. 
It is almost the universal opinion that recruits ought not to be ac- 
cepted below 20, or better, 22. At 18 years, the recruit is immature ; 
the bones are not fully formed, nor have they reached their final hard- 
ness ; the epiphyses have not yet become incorporated with the shafts 
of the long bones ; the joints are not yet fully developed ; the muscles 
are soft and not wholly developed ; the chest has by no means attained 
its full capacity ; and the organs of the body, in general, are imma- 
ture. So it happens that, at this age, it is useless to expect them to be 
in good condition after long-continued exertion or to undergo priva- 
tions which are as nothing to the man of mature years and strength. 
At this period of life, he is still in the growing stage and needs all the 
energy of his body to bring the organism to completion, and the in- 
fluences which mature soldiers contend against with varying degrees 
of success, namely, vicissitudes of weather, long marches, hard work 
in trenches, possible overcrowding in barracks and camps, poor venti- 
lation, and poor and insufficient food, send him very quickly to the 
hospital. 
It is beyond reason to expect the same work and endurance of a 
youth of 18 to 20 as of a fully mature man. During the Civil War, 
most of the boys who enlisted under 18 and many of those above that 
age and under 20 had to be discharged within the first few months. 
It has been demonstrated repeatedly that the least efficient armies 
are those containing the greatest proportion or men below the age of 
22. The first Napoleon objected to boys, saying on one occasion, " I 
demand a levy of 300,000 men. But I must have grown men ; boys 
serve only to fill the hospitals and encumber the roadsides." A re- 
markable example of the importance of maturity in soldiers is related 
by Tardien.1 In the campaign of 1805, in which the army marched 
400 leagues to reach Austerlitz, hardly any sick or stragglers were left 
on the way. In this army, the youngest were 22 years of age and 
had had two years' training. In the campaign of 1809, on the other 
hand, the army, which had but a short distance to march on its way 
to Vienna, filled all the hospitals on the way with its sick. More 
than half of the soldiers of this army were under 20 years of age and 
inexperienced. In the celebrated march of Lord Roberts from Kabul 
to Kandahar, the young soldiers gave out from day to day and fell be- 
hind, while the old campaigners appeared to gain in vigor with each 
day's march. 
Not only are young recruits less able to undergo the usual work and 
the hardships than seasoned men, but they are much more susceptible 
to disease. Aitken 2 relates that during the Crimean War, when the 
Commander-in-Chief, Lord Raglan, was informed that 2,000 recruits 
were ready to be sent to him, he replied : " Those last sent were so 
1 Dictionnaire d'Hygiene, III., p. 2. 
2 On the Growth of the Recruit and Young Soldier, 2d Edition, London, 1887, p. 
58. THE RECRUIT. 
579 
young and unformed that they fell victims to disease and were swept 
away like flies." He preferred to wait rather than have such young 
lads sent to him as soldiers. Other commanders in the Crimea testi- 
fied that young recruits were of very inferior value. 
The greater susceptibility of young soldiers to typhoid fever was 
demonstrated by Dr. Farr, the British Registrar-General, and Dr. Bal- 
four, who showed that in 1883, the army in India contained 41 per cent, 
of soldiers under 25 years of age, and that among this contingent the 
death-rate from this disease was 4.34 per thousand, while that of the 
men of 25 to 29 years was but 1.50 per thousand. In newly arrived 
regiments, nearly half of the total death-rate was from this disease. 
Aitken gives a number of instances of the influence of youth and short 
residence on the pre valance of this fever. At one station, for example, 
out of 44 cases, 35 occurred in one regiment composed principally of 
young soldiers, and 33 among men of less than one year's residence 
in India. 
In 1883, in India, 36.55 per cent, of those invalided home were under 
25 years of age, and in 1884, 38.70, the principal diseases necessitat- 
ing invaliding being anaemia, debility, phthisis, hepatitis, and diseases 
of the heart and arteries. Throughout the Peninsular War, from 1805 
to 1814, it was observed that the "corps which arrived for service 
were always ineffective and sickly in proportion as they were made 
up of men who had recently joined the ranks," and it was calculated 
that 300 men having five years' experience were worth more than 1,000 
newly arrived, including the usual proportion of young recruits. 
Surgeon-General Sternberg, of the U. S. Army, in his annual report 
for 1885, shows that the greater proportion of sickness occurred among 
soldiers under 31 years of age, and that up to the age of 25, the rate 
was so much above the average for the whole army, that he questions 
whether their services had been a fair return for the cost of their main- 
tenance. In 1899, the British Medical Association passed a resolution 
requesting the Council to communicate to the War Office the opinion 
of the section of medicine, that no soldier ought to serve in the tropics 
earlier than 22 years of age. 
In favor of the young recruit, Woodhull1 says that young men are 
more easily trained and moulded than older men, especially for the 
cavalry, and when well led, fight as well, as far as mere courage goes. 
But as we cannot keep young soldiers several years in training, and as 
large bodies of troops can only be raised for sudden war, men not 
absolutely mature must be rejected. Lord Wolseley prefers young men 
and says :2 "Give me young men ; they do what they are bid and they 
go where they are told ; they become more amenable to discipline and 
though when you catch them first they may have some difficulty in 
carrying their knapsacks, once they get beyond that they are in a fit 
condition to take the field." 
If young men are enlisted, the work should be sffited to their 
1 On the Growth of the Recruit and Young Soldier, 2d Edition, London, 1887, p. 58. 
2 Quoted by Aitken. Loco citato. 580 
MILITARY HYGIENE. 
strength, and it must be kept in mind that they are still in the grow- 
ing and developing stage and should have no greater amount of 
physical exercise than is suited to their condition. In other words, 
their work should be proportioned to their growth, and in two years, 
they will, perhaps, have developed into valuable soldiers. Taken be- 
tween the ages of 18 and 20 and drilled and trained with due regard 
to his immaturity and limit of endurance, the recruit often shows great 
progress in general development within the first half-year, particularly 
if, before enlistment, he was poorly fed, clothed, and housed, and en- 
gaged in an indoor occupation. 
His work should be moderate in the beginning and only gradually 
increased, since changes for the better in the human body cannot be 
brought about suddenly like those for the worse, induced by attempt- 
ing to do too much at the outset. Since his lungs, heart, and blood 
vessels are not yet fully developed, he can neither go through the 
manual nor cover ground like the seasoned soldier. The heart is 
called upon by the new and unaccustomed exercise to contract at a 
greater rate than had been its habit, and he soon becomes "winded." 
When this stage is reached and he begins to feel or show distress, he 
should be allowed and encouraged to rest until the throbbing of the 
heart and the swelling of the blood vessels subside and permit his 
lungs to resume easy breathing; otherwise, he is more than likely to 
break down sooner or later. 
With properly regulated exercise and good food, he ought soon to 
show gain and not loss in weight. Should progressive loss be ob- 
served, it is a question whether he is likely to become an efficient sol- 
dier, and he should forthwith be referred for medical examination. 
Under the regulations of the British army, all recruits are kept under 
medical observation during the first three months of service, during 
which time, in addition to the ordinary drill, they have an hour of 
gymnastic exercise daily, under the supervision of a medical man ; and 
if, during this period, a man shows unfavorable indications, he is exam- 
ined by a medical board. Should this body conclude that he will not 
ultimately develop into an efficient soldier, he is at once discharged on 
that ground. 
Height.-In this country, the minimum height for all branches of the 
service is 5 feet 4 inches, " although recruiting officers are allowed to ex- 
ercise their discretion as to the enlistment of desirable recruits (such as 
band musicians, school teachers, tailors, etc.), who may fall not more than 
one-fourth of an inch below the minimum standard of height." The 
maximum for the cavalry alone is 5 feet 10 inches, and for all other 
branches, according to weight. The minimum height is subject to 
change, if necessary, but it has been demonstrated that 5 feet 2 inches 
is about the lowest limit for efficiency, men below that height having 
proved, as a class, to have comparatively little staying power, and to 
break down for want of strength. In the British army, the minimum 
for the infantry is the same as with us ; the limits for the cavalry are 
5 feet 6 inches to 5 feet 11 inches; for the household cavalry, 5 feet 11 EXAMINATION OF THE RECRUIT. 
581 
inches to 6 feet 1 inch. In the French army, the minimum for Cui- 
rassiers is 5 feet 7 inches; for the infantry, 5 feet 1 inch. 
Military organizations composed exclusively of very tall men of 
imposing appearance are intended for display and not for the usual 
work of the soldier, and, indeed, have often proved to be lacking in 
the essentials of good soldiers, unless they are unusually well-propor- 
tioned. The superiority of additional height is commonly found to 
lie in the leg and neck, and when 6 feet 3 inches is exceeded, the in- 
dividual, as a rule, is not proportionately developed in the chest and 
muscular system. Such men are said to be prone to diseases in gen- 
eral, and more especially to pulmonary complaints, than men of me- 
dium height, and they become fatigued more early on the march and 
under all circumstances where endurance is of the first necessity. 
Their muscles are longer, possess less fasciculi, and work longer levers 
than those of the short men. They also offer a better target for the 
enemy. 
On the other hand, very short men are quite as objectionable as 
their over-tall comrades. During the Civil War, the smallest men en- 
listed broke down, as a rule, after but a few weeks' service in the 
field. There are, of course, exceptionally short men who are unus- 
ually muscular, but, as a class, they are wanting in strength. 
Weight.-In this country, there is no minimum weight for the cav- 
alry " in which enlistments may be made without regard to a mini- 
mum, provided the chest measurement and chest mobility are satisfac- 
tory." The maximum for this branch is 165. In all other branches, 
the minimum and maximum are respectively 128 and 190, but a re- 
cruit, exceptionally good in all other respects, may be accepted in any 
branch at 120. 
Examination of the Recruit.-The first step in the examination of 
a recruit is thorough washing with soap and water. " It is not be- 
lieved to be good policy to enlist men who, though able-bodied and 
intelligent, appear at recruiting stations in ragged or filthy dress, as 
the chances are such men are tramps and vagabonds and will not make 
good soldiers. Men who, though attired in clean and respectable cloth- 
ing, are found to be filthy in their persons, should be promptly rejected 
for like reason."1 He is then presented to the examining officer with- 
out clothing, in a well-lighted room large enough for exercise in walk- 
ing, running, and jumping. Here, he is subjected to a searching phys- 
ical examination, and each deviation from the normal standard is noted. 
In addition, his family and personal history are obtained of the appli- 
cant, whose replies to the prescribed questions are recorded with such 
other information as bears on his fitness for the duties of a soldier. 
This inquiry is made before the physical examination is begun. 
The examination is very thorough and includes the mental condition, 
the senses, the principal organs of the body, the general formation, the 
chest capacity, the condition of the teeth, skin, joints, and feet, and 
the presence or absence of hernia, varicocele, and other disqualifications. 
1 Manual for the Medical Department, Washington, 1898, p. 65. 582 
MILITARY HYGIENE. 
The leading characteristics of a good constitution, as enumerated by 
Dr. C. S. Tripier, U. S. A., are as follows : " A tolerably just propor- 
tion between the different parts of the trunk and members, a well- 
shaped head, thick hair, a countenance expressive of health, with a 
lively eye, skin not too white, lips red, teeth white and in good condi- 
tion, voice strong, skin firm, chest well formed, belly lank, parts of 
generation well developed, limbs muscular, feet arched and of mod- 
erate length, hands large. The gait should be sprightly and springy, 
speech prompt and clear, and manner cheerful. All lank, slight, puny 
men, with contracted figures, whose development is, as it were, ar- 
rested, should be set aside. The reverse of the characteristics of a 
good constitution will indicate infirm health or a weakly habit of body ; 
loose, flabby, "white skin ; long, cylindrical neck ; long, flat feet; very 
fair complexion ; fine hair; wan, sallow countenance." 
On being accepted, the recruit must be vaccinated immediately, unless 
there is unmistakable evidence of successful vaccination within a 
reasonable period. 
Chest Capacity.-The determination of chest capacity is of great 
value and importance, since it furnishes an index of the vigor of the 
candidate. The factors employed are the chest measurements and ex- 
tent of mobility. The chest girth is measured by means of a tape- 
measure passed round on a line including the lower portions of the 
scapulae and on a level with or just below the nipples. It is taken at 
forced inspiration and forced expiration, and the difference in the two 
measurements represents the chest mobility, -which is one of the best 
indications of capacity for endurance and of much greater value than 
the actual maximum and minimum circumferences, since a very large 
chest may have less mobility than one considerably smaller. For men 
under 5 feet 7 inches, the mobility should be not less than 2 inches ; 
between that height and 6 feet, not less than 2.5 inches; 6 feet and 
above, not less than 3 inches. 
Chest girth, weight, and height are very closely correlated in the 
growth and development of a healthy man, and these proportions should 
be carefully observed. The following table of physical proportions is 
taken from the Manual for the Medical Department. 
Height. 
Weight. 
Chest measurement. 
At expiration. 
Inches. 
Mobility. 
Inches. 
Feet. 
Inches. 
Pounds. 
5 A 
64 
128 
32 
2 
5?* 
65 
130 
32 
2 
5A 
66 
132 
321 
2 
5/^ 
67 
134 
33 
2 
5 8 
I 
68 
141 
331 
21 
5 A 
69 
148 
331 
21 
70 
155 
34 
21 
71 
162 
341 
21 
6 
72 
169 
341 
3 
73 
176 
351 
3 EXAMINATION OF THE RECRUIT. 
583 
" It is not necessary that the applicant should conform exactly to 
the figures indicated above, a variation of a few pounds from either 
side of the standard in the minimum and maximum weights and of a 
fraction of an inch in chest measurement being permissible if the ap- 
plicant is otherwise in good health and desirable as a recruit. The 
table is given to show what is regarded as a fair proportion, but the 
weight must be at least 125 pounds, except for cavalry, or when less 
is especially authorized by the Adjutant-General." 
It will be observed that up to 5 feet 7 inches, the normal weight is 
taken to be two pounds to the inch, and for each inch above that height, 
7 pounds are added, and that the chest girth at expiration is, for all 
heights above the minimum, just below half the height. 
Grounds for Rejection.-The most frequent single cause of rejection 
is defective development. During 1898, over a fourth of the re- 
jections of candidates for the regular army were made on this ground. 
Second in order was defective vision; third, diseases of the circula- 
tion. Such is the order which commonly obtains also in the British 
army. Other causes, in order, were diseases of the genito-urinary 
organs, diseases of the digestive apparatus, bad character, general un- 
fitness, deafness, and illiteracy. Men of defective development, if ad- 
mitted, are noted for the time which they spend in the hospital and in 
the guard-house. During the early part of the Civil War, thousands 
of physically inefficient men were allowed to enter the army, only to 
be discharged after a few weeks' service, most of which was passed in 
the hospitals. Another element which it is most important to exclude 
is the habitually intemperate. As Dr. Tripier has said, " First in a 
mutiny and last in a battle, the intemperate soldier is at once an ex- 
ample of insubordination and a nuisance to his comrades." 
Inasmuch as the ability to march is one of the prime qualifications 
of a soldier, particular attention is paid to the condition of the legs, 
ankles, and feet. The existence of enlarged veins of the ankle or 
thigh or back of the knee is sufficient cause for rejection. Large or 
recent bunions, and corns on the sole, flatfoot, and 11 hammer-toe " are 
disqualifications. Foetid perspiration of the feet is an intolerable nuis- 
ance to others in close association, and is sufficient ground for exclusion. 
The loss of many teeth or a condition of general decay indicates, as a 
rule, a lack of stamina. Moreover, the soldier in the field needs good 
teeth to chew his hard biscuit and not always tender meat. An insuf- 
ficient number of opposed molars to ensure proper mastication is suf- 
ficient ground for rejection. In 1898, in England, of 66,501 recruits 
for regular service, 1,767, or nearly 1 in 38, were rejected on account 
of bad teeth alone ; but this figure gives no indication of the proportion 
of candidates who might have been rejected on that ground, since many 
were summarily rejected on other grounds without examination of the 
teeth. 
Defective hearing, that is, inability to distinguish ordinary conversa- 
tion with either ear at 50 feet, is a disqualification, since orders may be 
either not heard at all or misunderstood. 584 
MILITARY HYGIENE. 
THE HYGIENE OF THE SOLDIER. 
Personal cleanliness is of very great importance in the mainte- 
nance of health and efficiency and should be the subject of much atten- 
tion on the part of the inspecting officers. General bathing can hardly 
be expected in a large camp in the winter months, or at any time when 
water is scarce, but whatever the season a small amount of water, a 
quart or so, applied with a wash-rag or sponge, and with soap, should 
be sufficient for a decent degree of cleanliness. In the warmer months, 
where water is plenty, full baths and swimming should be encouraged. 
During prolonged campaigns with limited opportunities for keeping the 
person and clothing clean, many men are disabled by chafing and ul- 
cerations, following irritation of the skin by perspiration, dust and dirt, 
and contact with unwashed hardened underclothes. Body lice always 
make their appearance and add much to the discomfort, which is only 
temporarily relieved, but eventually augmented, by scratching with the 
nails. Infested dirty men convey the evil by contiguity to their cleaner 
associates, who then suffer not only in body but in mind, filled with 
disgust and loathing, and longing to return to civil life. 
Contentment and cheerfulness are very essential to the well-being 
of an army ; discontent and ennui undermine health and discipline and, 
consequently, efficiency. In the continental armies, ennui, leading to 
homesickness, is believed to be a prime cause of the large number of 
suicides and cases of insanity. This is more marked with the in- 
fantry, which branch requires less time devoted to work. In all armies, 
it is recognized as leading to excessive use of tobacco and liquor and 
to all manner of bad habits. On the march and in time of general 
activity, the mind is stimulated and needs no special diversion, but 
after a camp has been permanently established and the men have settled 
down to the routine of camp life, they begin to fret and soon seek solace 
in tobacco, alcohol, and gambling, and not infrequently in perversions 
of the generative function. Gambling is not only an unhealthy excite- 
ment, but engenders serious quarrels, bitterness, and disappointment, 
and is commonly carried on in crowded quarters and foul air. 
The ability to keep troops in camps contented is regarded as one of the 
strongest evidences of capacity for command and administration. To 
keep men occupied is not enough ; the occupation must not be wholly 
routine drilling and marching, but interesting and pleasant work of 
other kinds, and entertainments largely of an amusing nature. Extra 
drills, known to the men to be unnecessary and carried out only to keep 
them busy, do not relieve the situation, but add to the difficulty. The 
establishment of reading rooms and opportunities for following mechan- 
ical trades are of much service. All men of experience testify to the 
great value of athletic sports, competitive target shooting, gardening 
for pleasure and profit, vocal and instrumental concerts, vaudeville and 
minstrel shows, theatricals, and, in fact, anything which will offer a 
change from the hum-drum of life. Very little things suffice to break 
the monotony of life in camps, just as in the country and at summer CLOTHING OF THE SOLDIER. 
585 
hotels, where the arrival of the train or stage or the passing of a 
strange carriage is an event calling forth the deepest interest, and a 
new arrival a genuine excitement. 
Clothing of the Soldier. 
Since the primary object of clothing is the conserving of body heat 
in cold weather and protection from the direct heat of the sun, it is 
essential that that worn in any one kind of climate should be adapted 
to the necessities of that particular climate. It is obvious that the 
same uniform cannot be used in the northwest and in the West Indies 
and the Philippine Islands, where the blue uniform, ordinarily used in 
our army, has been universally condemned on account of its weight. 
Therefore, the material should vary according to the nature and place 
of service. 
In choosing material for uniforms, the chief points to be borne in 
mind are the properties of heat conduction and heat absorption, per- 
meability and durability. Wool is a poor conductor and is not easily 
penetrated by cold winds; therefore, it is very suitable for cold cli- 
mates, but likely to be oppressive in the tropics. It absorbs water 
freely, being very hygroscopic, and thus it absorbs the perspiration and 
prevents it from evaporating directly from the surface of the skin and 
causing thereby loss of heat. The chief disadvantage of wool is the 
difficulty with which it is properly washed. When improperly washed, 
the fiber shrinks rapidly and the fabric becomes smaller and much less 
soft and absorbent. During washing, woolen materials should never be 
rubbed or wrung. They should be placed in water containing a proper 
amount of soap in solution, and moved about freely, well rinsed in 
water containing no soap, and hung up to dry without wringing. The 
soap used should be of good quality, as free as possible from excess of 
alkali, which injures the woolen by acting upon the natural fat of the 
wool, which is largely cholesterin. 
Cotton and Linen.-Both these articles are good heat conductors, 
but are non-absorbent of moisture. Both soak up moisture from the 
skin, and evaporation of this requires so much heat as sometimes to 
cause chill of the body. Both are durable, and neither, particularly 
cotton, need be very expensive. For underclothing, both are much in- 
ferior to wool, which, being a bad heat conductor and a good absorb- 
ent of moisture, prevents rapid cooling of the body when it is in a con- 
dition of active perspiration after physical exercise. It is far more 
permeable, also, to air, which it holds in the spaces between the fibers, 
which adds to its property of non-conduction. 
Light woolen underclothing should, therefore, be preferable to 
either cotton or linen. A very good material is what is commonly 
known as merino, a mixture of woolen and cotton, in which the cotton 
constitutes about a third. This combines, in a way, the advantages of 
both materials and is a very much more washable fabric than pure 
woolen. 586 
MILITARY HYGIENE. 
Shoddy is a very inferior material, made of the fiber of old, used, 
woolen goods, mixed with fresh wool, with which it is woven. The 
manufacturers do not introduce any more fresh wool than is absolutely 
necessary. 
Color.-The color of clothing has an important bearing, both phys- 
iologically and from a military point of view. Color influences the 
absorption of heat more than the nature of the material itself. White 
materials absorb least and black the most heat. The difference in ab- 
sorptive power of different colors is shown in a marked degree by the 
fact that white cotton over a black surface will reduce the temperature 
in the sun over 10°. Gray stands next to white and blue next to 
black. 
From a military point of view, color is important, since different 
colors vary in their conspicuousness, and, therefore, strategically, the 
one which stands forth the least in the landscape is the best. The 
most conspicuous color is red, next white, then black and other dark 
shades, light blue and light brown and gray ; but, naturally, much de- 
pends on the background : thus, green would be inconspicuous against 
grass and other green vegetation, but would show very distinctly 
against bare soil, whereas the light brown of the ordinary khaki 
is the least conspicuous in the latter position. Color also influences 
the absorption of odors by materials in practically the same order in 
which it influences the absorption of heat; that is, black and the dark 
shades are most absorbent, and white the least. 
Military dress coats are usually closely fitting, warm and oppressive, 
and interfere with proper expansion of the chest, through tightness. In 
active service in the field, they are not worn. Undress coats are usually 
loose and far more comfortable and adapted to muscular effort. The 
khaki suits, worn by our troops in the tropics, are stiff and heavy at 
first, but become softer and more pliable with repeated washing. They 
are sufficiently loose for all purposes of comfort. Trousers are made 
sufficiently roomy in the seat, and reasonably tight about the waist, 
with an inner belt, as no suspenders are worn. The bottoms are cut 
narrow rather than with a 11 spring." 
Gaiters and leggings are used for protecting the ankles and legs 
from dust and mud. They are*made of brown cotton duck with straps, 
and commonly are not well fitting. When lined, as they sometimes 
are, with thin leather, they are likely to be uncomfortably hot. The 
puttee is made of a soft kind of cloth, in a strip four inches wide and 
some six or seven feet long. To one end, about 2 feet of strong tape 
are fastened. In applying the puttee, it is rolled up with the tape 
in the center of the roll. Two turns are wound over the top part of 
the ankle-boot and it is then wound spirally up the leg to a point be- 
low the knee, and the tape at the end is then continued spirally over 
the whole and fastened at the end. It is found to be more comfort- 
able and more pliable than leggings, and does not blister the heels, 
which leggings sometimes do. 
Head Covering.-The head covering is a very important article in CLOTHING OF THE SOLDIER. 
587 
the dress of a soldier. It should protect against cold, heat, rain and 
the burning sun. It should be light, durable and comfortable, not too 
closely fitting nor pressing unduly anywhere. The leather helmets, 
worn in some armies abroad, and the felt helmet, used in ours, are hot, 
heavy and oppressive. The ordinary white helmet is conspicuous, but 
comfortable in the sun. The ordinary forage cap is flexible and 
serviceable, but not sufficiently ventilated for hot weather use. The 
campaign hat of drab felt with broad brim and high crown has been 
found to fill most of the requirements in the field. In Cuba and in 
our new possessions, it was found at first to be too heavy, but ex- 
perience, especially during the rainy season, has shown that it has ad- 
vantages not possessed by any other form of head covering. 
In foreign armies, unnecessarily heavy helmets and other head cover- 
ings are used largely for purposes of display, but to a certain extent 
also as a protection against mechanical injury. In the matter of dis- 
play, there can be no question that many of them fulfill their object 
admirably, but as a means of defence, helmets of heavy leather and 
metal, weighing from three to four pounds and over, would hardly seem 
to secure such an amount of protection as to compensate for the great 
discomfort and the waste of energy which their use entails. In hot 
climates, helmets of bamboo, provided with puggeries, are very largely 
used, being light and affording good protection from the sun. 
Stockings.-Concerning stockings, a great divergence of opinion 
exists. Woolen stockings frequently cause the feet, to perspire, even 
in cold weather, but they are much warmer, and hence more conducive 
to comfort than cotton at that time. Cotton is naturally more com- 
fortable in summer, and to many people, also in winter. In our army, 
both kinds are issued. Many regard thick woolen stockings as the 
best for walking, in all climates, and as a protection against foot-sore- 
ness ; yet it is probable that many cases of sore feet are brought about 
by excessive perspiration induced by them. Perhaps a happy mean 
is a thin woolen stocking or one of fine merino. It is important that 
the stocking should fit the foot properly, for an ill-fitting stocking, 
particularly one too long in the foot or too broad, gives rise to folds 
which cause excoriations and blisters. 
Boots.-The value of well-fitting comfortable boots, permitting un- 
obstructed action of the muscles and joints and free circulation of 
blood when walking for pleasure and exercise, is too well known to 
need any extensive discussion. To the soldier, the importance of good 
boots is still greater, since, as has been said, an efficient army is one 
that can march well; and soldiers cannot march with crippled feet. 
Moreover, it frequently happens in time of war, that in an emergency 
which makes a man dependent upon his walking power for his own life 
and liberty or for the proper carrying out of his order, a good boot is 
his best friend. 
The sole should be thick and generously broad, so as to project all 
round beyond the upper, but should not be too heavy. The heel should 
be broad, low and flat. The boot should be square at the toe or 588 
MILITARY HYGIENE. 
slightly rounded on the outer side in accordance with the natural out- 
line of the foot, so as to allow the toes full play in walking. When 
placed side by side, the inner margins of each should nearly touch 
throughout the whole length from the end of the toe to the ball of the 
foot. The inside should nowhere have rough inner seams or projec- 
tions which may cause chafing and blistering. If treated to a liberal 
amount of oil or grease at frequent intervals, the leather will be made 
more supple and at the same time more impervious to water. A prep- 
aration, recommended by the late Professor Parkes, consists of a mixture 
of a half pound of shoemaker's dubbing in a half pint each of linseed 
oil and of a solution of India-rubber. Solution is effected by gentle 
heat, which should not be applied by naked flame, since the India-rub- 
ber solution, containing naphtha or ether, is exceedingly inflammable. 
This preparation is well rubbed into the leather and renewed at inter- 
vals of three months. This is said to be the best water-proofing 
material for leather. 
Cavalry boots with long legs are not suited to walking, as they are 
likely to produce chafing. Woodhull recommends as a substitute a 
shoe with a heavy detachable leg and stiff brace, which substitute, he 
thinks, will probably add to comfort and efficiency. 
Underclothing.-Undershirts should be of woolen or, better, of 
merino, since pure woolen is unbearable by many and because of 
the rapid deterioration which follows improper washing. The woolen 
undershirts issued at first to the troops in Cuba and the Philippines 
were complained of as causing much irritation of the skin from prickly 
heat. In the tropics, a light weight woolen undershirt is of the highest 
importance in the prevention of body chilling from evaporation of 
perspiration. Half cotton and half woolen or two-thirds cotton and 
one-third woolen are highly recommended as advantageous combina- 
tions. 
The ordinary shirt of the soldier is made of flannel, with a collar 
and breast pockets. It is made fairly full and is very comfortable. 
Woodhull recommends the carrying of an extra shirt for wearing next 
the body, the two being worn alternately. " At the close of the day's 
work the worn shirt should be taken off, dried, stretched, well-beaten, 
and hung in the wind and sun. This should be done even when there 
is no change." Drawers, stockings and trousers should be treated in 
the same manner. Drawers are necessary for cleanliness and warmth. 
They are made of the same material as undershirts. In many of the 
foreign armies, drawers are not issued, and men who desire them are 
obliged to furnish them at their own expense. 
Abdominal Bands.-Abdominal protectors, either in the form of the 
well-known abdominal band or of small flannel aprons to be worn next 
the skin over the bowels, are regarded as very essential in the keeping 
down of bowel troubles, which so commonly appear after abrupt 
changes in temperature ; and especially valuable in the tropics, where 
diarrhoeal diseases should be prevented as much as possible, on account 
of their leading to serious and fatal results. The abdominal band, THE SOLDIER'S EXERCISE AND WORK. 
589 
commonly called also " cholera belt," encircles the whole of the lower 
part of the body. The flannel apron protects only the anterior part 
and is fastened with a tape around the waist. 
The " kummerbund " is much preferred by many. This is a very 
common article of dress among the natives of hot Eastern countries. It 
is a broad fold of cloth, wound tightly five or six times about the waist, 
for the protection of the lower part of the spine from the sun's rays, 
and to act as a support to the back and loins. It is made of silk or 
cotton, or a mixture of the two, in lengths of ten to fifteen feet and 
about twelve to eighteen inches in width. To put it on, one needs 
the assistance of a companion. It is folded once lengthwise, so that 
its breadth is reduced a half and its thickness doubled, and then, while 
stretched taut, one end is placed in position and held there, and the person 
turns the body round rapidly until the full length is wound off, when 
the end is neatly and carefully fastened, so that it may not work loose. 
These protectives of the abdomen prevent the evaporation of per- 
spiration and chilling of the abdomen; without them, diarrhoea is 
likely to be called forth by slight causes. 
Water-proof blankets of rubber or other material are very important 
as a protection against rain or soil moisture. When obliged to lie on 
damp ground, they are a great protection. In the tropics, at certain 
seasons, the rainfall is exceedingly heavy and makes the use of some 
form of water-proof overcoat necessary, but since these are very hot, it 
is important to obtain them of as light a material as possible without 
sacrificing lightness to durability. India-rubber itself cannot be worn 
habitually or for a long time, because of its causing great discomfort 
through retention of heat and perspiration. It is of much more value 
in the form of a blanket to spread on the ground than as an article of 
clothing. Cloth may be made water-proof by alternate dipping into 
solutions of aluminum sulphate and soap or by thorough soaking in 
raw linseed oil and exposing to the sun until thoroughly dry. 
Other articles issued during very cold weather for extra warmth in- 
clude hoods, gloves, overshoes and overcoats. The overcoats are un- 
lined. 
Marching1.-Since the most efficient army is that which has the 
greatest capacity to endure hardship, it follows that such an army can 
do the longest and best marching. While the civilian may regard 
daily walks of 10, 15, 20 and more miles as no great strain on the 
system, the first-mentioned figure is accounted good average travelling 
for soldiers on a long march, and the second for short movements, but 
either of these figures may represent exceedingly good work by the 
best of men in some climates and seasons and over some roads, or by 
raw recruits in their first marches over the best of roads. This is not 
for a moment to be looked upon as evidence of the civilian's superiority 
over the soldier as a walker, for the two perform the exercise under 
very different conditions. 
The Soldier's Exercise and Work. 590 
MILITARY HYGIENE. 
The civilian, in the first place, walks by himself or with a companion 
or two, at his own gait and according to his own will. He may vary 
his step and may rest at his pleasure ; he carries no greater burden than 
a walking stick, and can suit himself in the matter of dress and in the 
manner of wearing it. The soldier, on the contrary, is one of a large 
body proceeding somewhat stiffly at a pace set by one in command 
and not alterable at will. He carries his arms, accoutrements, and all 
his belongings, and, perhaps, his rations for a number of days, and is 
hampered by straps and clothing which interfere with free circulation. 
He rests when ordered, may be halted, without resting, with an- 
noying frequency, and may "march at ease" only when, in the judg- 
ment of the commanding officers, this is practicable. At one time, he 
is moving with exasperating slowness on account of obstacles ahead, 
and again, is hurrying to catch up with those gone before. Moreover, 
his marching ground is chosen for him, and his miles are either through 
dust or mud, for a soil so damp as to give off no dust is speedily con- 
verted to mud by the impress of many feet. 
Therefore it is, that the soldier's 10 miles represents much more 
physical exertion than the civilian's 20, and his 15 miles much more, 
all things considered, than 50 per cent, increase over his 10. Forced 
marches of 25 miles and more are very exhausting and cannot be kept 
up more than a very short time. One of the most notable instances 
of long distance marching in a few hours in recent times is that of the 
City of London Imperial Volunteers who, in South Africa, in August, 
1900, covered 30 miles in 10 hours hoping, according to a despatch of 
Lord Roberts, to prevent Gen. DeWet from crossing the Krugersdorp- 
Potchefstroom railway. 
Among the best known long marches are several by United States 
troops, who hold the record for long distance continuous marching. 
In 1859, for example, a regiment of infantry marched from Fort 
Leavenworth, Kansas, to a point in California, a distance of 1,800 
miles in 190 days, 28 of which were given up to resting, so that in 
162 days of actual marching, an average distance of a little over 11 
miles was traversed. In 1860, a portion of another regiment went 
from Camp Floyd, Utah, to Fort Buchanan, New Mexico, a distance 
of 1,000 miles in 140 days. The celebrated march of Lord Roberts 
from Kabul to Kandahar, in 1880, over very rough country, was per- 
formed in 23 days. The longest day's marches were 20 and 21 miles, 
and the average distance covered was nearly 17 miles. 
In the Franco-Prussian War of 1870, a company of French chas- 
seurs marched, in very bad weather, over an exceedingly difficult road, 
for 41 hours, with one rest of an hour, another of two and a-half hours, 
and halts of 8 minutes in each of the marching hours. The exact dis- 
tance marched is not known, but the instance is cited as one of excep- 
tional endurance and hardship. 
In our army, ordinary and quick marching call respectively for 90 
and 120 steps of 30 inches each per minute, or slightly over 2.5 and 
3.4 miles per hour. Double time, which is quickly exhausting, calls THE SOLDIER'S EXERCISE AND WORK. 
591 
for 180 steps of 35 inches each per minute, the equivalent of nearly 6 
miles per hour ; it can be sustained for not longer than 2 miles by 
more than average good troops. With the weight carried, 30 inches 
per step is quite enough. In the French army, 2.5 miles per hour is 
considered good average marching, beginning with 120 steps per 
minute, increasing gradually to 125 and 135, and returning during 
the second half hour to the original rate. The English quick-step is 
the same as ours; the " double quick " is less than ours in length and 
frequency-33 inches, 175 to the minute. The German step is be- 
tween 31 and 32 inches, and 114 to the minute; the Austrian and 
Italian, 29 inches, 120 to the minute; the Russian, 28 inches, 120 to 
the minute. From the above, it will be observed that in none of the 
great armies of the world is the marching rate equal to that of the 
active civilian when out for an exercise walk. 
Every soldier is obliged to carry, besides his arms and accoutre- 
ments, certain necessary articles, the aggregate weight of which is 
variable, but always considerable. In the carrying of this weight, 
great care is necessary so to dispose it that it shall not be over-burden- 
some or detract from his efficiency. In all services, the reduction to a 
minimum of the weight to be carried is a matter of great importance, 
but the disposition of the weight is, perhaps, of greater importance, for 
considerable harm may be induced by interference with respiration and 
circulation by pressure from the necessary straps across the chest and 
nnder the arm-pits. Under favorable circumstances, his impedimenta, 
with the exception of arms and canteen, may be transported for him, 
the result being not only greater covering of ground with less strain, 
but great conservation of efficiency. In adjusting weight, care should 
be taken to avoid compression of the chest as much as possible and to 
equalize the distribution so as to avoid fatiguing any one set of mus- 
cles unduly. 
The German infantry soldier is more heavily equipped than the Brit- 
ish or American, the total load exceeding 70 pounds, of which his cloth- 
ing, exclusive of the heavy polished leather helmet, accounts for nearly 
24 pounds, and his arms and equipments, filled water-bottle, and en- 
trenching tools nearly 43 pounds, the balance being rations and sundries. 
His kit is carried in a leather knapsack, around which his rolled over- 
coat is fastened, and to the back of which his camp kettle is strapped. 
The Russian soldier also carries over 70 pounds ; the Italian, about 
the same; the French, between 65 and 70, and the Austrian, about 60 
pounds. 
The blanket bag, that is to say, clothing and other articles en- 
closed in a blanket rolled lengthwise, used in our army is more op- 
pressive than the blanket roll, but the blanket roll is also oppressive, 
since, being carried across the body from one shoulder with the ends 
tied together, it impedes the movements of the chest. Moreover, its 
use implies a certain degree of inconvenience, since when the blanket 
itself is in use, the articles contained must be cared for in some other 
way. Other devices to take the place of blanket rolls and knapsacks 592 
MILITARY HYGIENE. 
are in use and meet with different degrees of approval. The one 
most highly commended neither impedes respiration or circulation nor 
involves contact with the back and consequent shutting out access of 
air. The weight is supported chiefly by the hips. 
With new levies, the first marches should not exceed a very few miles, 
the distance being gradually increased day by day, until they become 
well seasoned, with occasional days, not including Sundays, set apart 
for rest and recreation. When thoroughly seasoned, there is less fric- 
tion, and with greater experience, comes increased efficiency. It takes 
but a short time for new soldiers to learn not to attempt to carry 
unnecessary articles which, at first, they are invariably prone to look 
upon as essential to comfort and pleasure. 
Cavalry and infantry should march separately if possible and in as 
open order as practicable in order to avoid crowd-poisoning, which is 
a consequence not alone of indoor overcrowding, but also of close ag- 
gregation of men in the open air. 
If possible, marching by night and in the hottest part of the day 
should be avoided, for in hot weather the men are easily exhausted by 
exercise in the blazing sun, and since they can get no sleep during the 
day, they need the night hours for their proper rest. The early morn- 
ing hours are the best for marching, as for other forms of work, the 
men being then at their best; but unless absolutely necessary, their 
sleep should not be broken before the usual time, since what is thereby 
gained in distance is more than lost through the interruption of neces- 
sary sleep. Before starting, a light breakfast, including hot coffee, 
should be taken. 
During the first hour, the pace should be fairly slow, and when two 
miles have been covered, there should be a halt of at least a quarter of 
an hour, during which the men should attend to calls of nature and 
throw off their loads and rest at full length. When the march is re- 
sumed, the distance to be covered may be lengthened by a half mile, 
and when this distance has been traversed, there should be another halt 
of about the same length as the first. After this, the rate may be in- 
creased to three miles per hour with a halt of ten minutes in each hour, 
and this rate is quite fast enough, except for forced marches. The halt 
in the middle of the day for dinner should be of several hours' dura- 
tion, so that the men may have a good rest, avoid heavy work directly 
after a hearty meal, and look after the condition of their feet. As it 
is unsafe to eat heartily or drink copiously while greatly fatigued or 
overheated, a reasonable interval should be allowed before dinner. 
Halts due to accidental circumstances are very trying to patience 
and strength, and when their probable duration can be determined, 
this should be communicated down the column, in order that, if the in- 
interval is to be of long enough duration, the men may have the ad- 
vantage of resting, rather than stand with their arms, losing patience 
and temper. Since, also, irregular rate of movement is fatiguing and 
annoying, minor obstacles, such as mud and water, should not be al- 
lowed to interfere with regular progress. Music of all kinds is very THE SOLDIER'S EXERCISE AND WORK. 
593 
invigorating to marching men ; band music, fife and drum, the drum 
alone, and singing. In the continental armies, singing is much en- 
couraged, as it keeps up the spirits and gives a rhythm and swing to 
the march. 
If the weather is hot, men should be allowed to promote evaporation 
of their perspiration by opening their coats or blouses ; otherwise, water 
is lost from the body without performing its function of reducing the 
body-heat. To avoid excessive thirst, a full drink of water should be 
taken before starting. The canteens should be filled with water or 
cold tea for use during the day, but free drinking on the march is not 
to be advised, since it tends to beget a constant thirst. The mouth 
should be kept closed as much as possible during the march, and the 
sensation of thirst can be controlled by holding a smooth pebble in the 
mouth or chewing a green leaf. The simple occasional moistening of 
the mouth is better than free and frequent drinking. 
In case of exhaustion by excessive loss of fluid by perspiration, 
drinking on the march is necessary, but undei' the usual conditions, the 
canteens should be used only at meals and near or at the end of the 
day's march. Another reason for abstaining as much as possible from 
drinking is the uncertainty of supply, for no dependence can be placed 
on the probability of refilling the canteens during the day's march. 
Hence, each man should conserve his supply as though he were certain 
that no more is to be had before the day's destination is reached. The 
amount carried can be kept fairly cool by wrapping the canteen in a 
wet cloth, the evaporation from which causes perceptible lowering of 
temperature. A little vinegar or lime juice, if obtainable, added to the 
water, gives it a relish and helps to allay thirst. 
"In many parts of the West, water is so scarce that judicious 
management is required to forward troops over the route. Some camp- 
ing-stations having only enough for one or two companies, the com- 
mand, if larger, must pass in detachments. Or it may happen that 
the distance between the nearest water-supplied sites is too great to be 
marched without rest, in which case a dry camp must be formed at 
some intervening point. The passage of the Gila Bend Desert, 35 or 
40 miles from water to water, is usually effected by making a night 
march of 25 miles, when the troops go into camp to rest for a few 
hours before resuming their journey, and to have coffee issued from a 
water-supply carried in the wagons." (Smart.1) On arriving at a 
camping place, the water supply must be immediately guarded to pre- 
vent pollution and trampling of the margin. If the supply is small, 
the guard must be doubly efficient. If the supply presented is a small 
and shallow stream, it may be well to make small reservoirs by means 
of temporary dams, one for drinking water for the men, another below 
for the horses, and another for bathing and laundry purposes. 
Straggling must be prevented as much as possible, since it is a very 
serious evil to the morale and efficiency of the body as a whole. If 
straggling becomes considerable, the column should be halted until the 
'Buck's Hygiene and Public Health, New York, 1879, Vol. IL, p. 119. 594 
MILITARY HYGIENE. 
stragglers can overtake it, else these will get no rest, since the hourly 
intervals for rest must be utilized by them in coming up, and the 
column is, perhaps, already in motion again. Those claiming to be sick 
or unable to march should be examined by the medical officers, who 
will separate the really unfit from the malingerers ; the former are given 
careful transportation ; the latter, disposed of according to their deserts. 
At the end of a day's marching, the men should be dismissed as soon 
as possible and they should be careful to guard against getting chilled 
through reckless removal of clothing and should again look after the 
condition of their feet and persons. 
On long marches, an occasional day should be taken for complete 
rest and recuperation, otherwise an inevitable diminution in efficiency 
will be occasioned. Woodhull cites an interesting instance of over- 
marching in the Franco-Prussian War. The German Garde-Corps, 
consisting of 30,000 infantry, left the Rhine on August 3d, lost less 
than 9,000 in action, and on September 2d, the day after Sedan, num- 
bered 13,000 for duty. On September 19th, they reached Paris with 
but 9,000 men, more than 11,000 having been broken down by exer- 
tion, little actual sickness having occurred. 
Care of the Feet on the March.-If good marchers make the best 
soldiers, it follows that the possession of the best soldiers is largely de- 
pendent upon the condition of the feet, and, therefore, it is incumbent 
on the line officers and medical corps to see that the individual men 
are properly instructed in their care and that they are faithful in per- 
formance. The footsore man, so far as efficiency is concerned, is a sick 
man and becomes the equivalent of baggage. He cannot march and 
suffers pain when at rest. Nearly all new men not accustomed to 
marching are likely to suffer from excoriations across the toes, on the 
insteps and malleoli, and on the back and sides of the heels. This is 
due to friction and, if attended to at once, may be prevented from be- 
coming serious. 
The application of strips of adhesive plaster of generous size to the 
affected parts will afford the same protection as is given by a leather 
glove to the hand engaged in any frictional work. Blisters should not 
be opened, except by a minute puncture at the edge ; after the fluid has 
oozed away, the spot should be protected with adhesive plaster. The 
extensive opening of a blister permits access of air to the sore area 
beneath, and the stimulation therefrom is very active and painful. 
Men should be instructed to trim their toenails square across and not 
too close. 
Before marching is begun, all men with any soreness of the feet 
should report themselves and be examined, and at the end of the day, 
if not before, they should be regularly inspected. Men unused to 
marching will often find greasing or soaping the feet and stockings an 
excellent prophylactic against soreness. A neutral grease like mutton- 
tallow is preferable to soap, since sometimes it happens that the latter as- 
sists the perspiration in macerating the cuticle. If the boots are made 
supple with grease, they tend less to cause soreness and, in addition, are THE SOLDIER'S EXERCISE AND WORK. 
595 
rendered waterproof. An excellent plan for officers and others who 
can afford them is to wear silk stockings under the ordinary socks, es- 
pecially when the feet are naturally tender. The feet may be tough- 
ened by being soaked in warm strong solutions of alum or common 
salt. Zinc ointment, containing 5 per cent, of tannin, is also very use- 
ful. Salicylated talc (talc 87, starch 10, salicylic acid 3 parts by 
weight) is used in the German army both on the march and in garri- 
son. It is sifted from a dredging box into the shoes and over the feet. 
If the soreness is due to the stockings and not to the shoe, it is 
often advantageous to change them from one foot to the other or to 
put them on inside out. Some of the continental armies use bandages 
in place of stockings, and some use neither, substituting therefor a 
liberal coating of grease. Soreness is often due to neglected bunions, 
corns, both hard and soft, and infleshed nails. These troubles need 
special treatment. In the British army, the authorities have caused a 
number of the non-commissioned officers to be instructed in chiropody, 
and the success of the experiment has made it probable that a perma- 
nent corps of trained chiropodists will be established for the infantry. 
During the long halt at midday, each man should remove his shoes 
and stockings and, if water is to be had in abundance, he should re- 
move the acrid perspiration and dirt from his feet by thorough wash- 
ing, paying particular attention to the surfaces between the toes, where 
excoriations and soft corns are prone to appear. Dusting powder or 
zinc ointment on absorbent cotton may be applied, if advisable, between 
the toes. The feet should be made quite dry before the stockings are 
again drawn on. If water cannot be obtained in sufficient amount, 
wiping with a dry or moist cloth will be found to add materially to 
comfort, and is much to be preferred to long soaking, which, by soft- 
ening the cuticle, assists the formation of blisters. At the end of the 
day, the feet should be washed and the stockings changed; those re- 
moved should be washed as soon as practicable and dried during the 
night. 
Care of Other Parts.-Not uncommonly, soldiers, especially raw re- 
cruits, are much inconvenienced and annoyed by chafing at various 
points, particularly on the inside of the thighs and between the nates. 
This is promoted by perspiration and restrained by dusting powder, 
zinc ointment, vaseline, and cleanliness. Woodhull advises against 
washing the face and neck in the morning while on the march, because 
the removal of the natural secretion makes the skin more susceptible 
to the influence of heat and dust. He recommends washing the eyes 
and mouth and merely wiping the face and neck with a damp cloth. 
At night, the face, neck and whole body should be washed, if possible, 
but foremost of all, the head, armpits, feet, and genitals and adjacent 
parts. 
Care should be taken that the bowels are not neglected while on the 
march, any more than while in garrison. If purgatives are required, 
those given should be mild in character and not such as may require 
repeated operations at short intervals. 596 
MILITARY HYGIENE. 
The Soldier's Food ; "Rations." 
The word "ration" is commonly understood to mean the amount of 
food issued to each soldier for a single meal. This, however, is far 
from being the truth. Under the regulations, "a ration is the allow- 
ance for sustinence of one person for one day, and consists of the 
meat, the bread, the vegetables, the coffee and sugar, the seasoning, 
and the soap and candle components." Enlisted men and hospital 
matrons and, when the circumstances of their service make it neces- 
sary, civilians employed by the army each draw one ration per day. 
The ration is not necessarily the diet, since parts of it may be ex- 
changed for other things or for the cash equivalent with which to buy 
them. It is fixed by law and can be changed only by legislative 
enactment. 
The different articles composing the ration for troops, where cooking 
is practicable, and their amounts are as follows: 
Articles. 
Quantities. 
Meat Components. Ounces. 
Fresh beef 20 
or Fresh mutton when the cost does not exceed that of beef 20 
or Pork 12 
or Bacon 12 
or Salt beef 22 
or, when meat cannot be furnished, Dried fish 14 
or Pickled fish 18 
or Fresh fish 18 
Bread Components. 
Flour 18 
or Soft bread 18 
or Hard bread 16 
or Corn meal 20 
Baking powder for troops in the field when necessary to enable 
them to bake their own bread 
Vegetable Components. 
Beans 
or Peas 
or Rice 
or Hominy 
Potatoes 
or Potatoes 12| and Onions 31 
or Potatoes Ilf and Canned Tomatoes 4| 
or other fresh vegetables not canned when they 
in the vicinity of the post or transported in a 
dition from a distance 
2f 
2f 
If 
If 
16 
; 16 
can be obtained 
wholesome con- 
16 
Coffee and Sugar Components. 
Coffee, green 
or roasted 
or Tea, green or black 
Sugar 
or Molasses (gills) 
or Cane Syrup (gills) . 
If 
Wx 
A 
92 
1 6 
2X 
1 6 
ux 
Seasoning Components. 
Vinegar (gills) 
Salt 
Pepper, black 
A 
If 
A THE SOLDIER'S FOOD; "RATIONS." 
597 
What is known as the " travel ration " is issued in place of the 
ordinary ration " when troops travel otherwise than by marching or 
when for short periods they are separated from cooking facilities and 
do not carry cooked rations." It consists of the following articles and 
is issued in the amounts stated, per hundred rations. 
Articles. 
Per 100 rations. 
Soft bread, pounds 
112.5 
or Hard bread, pounds 
100 
Beef, canned, pounds 
75 
Baked beans, 1-pound cans, number 
33 
or 3-pound cans, number 
15 
Coffee, roasted, pounds 
8 
Sugar 
15 
After four days' subsistence upon this ration, troops may be allowed 
in addition a pound of tomatoes daily per man. On arrival at their 
destination, they return to the ordinary ration. When travelling un- 
accompanied by an officer, each man may be allowed a cash sum per 
day for the purchase of liquid coffee in place of the coffee and sugar 
portion of the travel ration. 
The " emergency ration " consists of : 
Bacon 10 ounces Saccharin 4 grains 
Hard bread 16 " Salt 0.64 ounce 
Pea meal 4 " Pepper 0.04 " 
Coffee (roasted) 2 " Tobacco 0.50 " 
or Tea 0.5 " 
Of this, as many days' rations are issued at once as may seem necessary. 
Abroad, the well-known pea sausage, consisting of pea flour and fat 
pork, is much used in the emergency ration. This, mixed with hot 
water, makes a very good soup, but soon proves to be cloying. Meat 
biscuits and dried meats are also much used. 
It will be observed that the ordinary ration is fairly flexible as it 
stands, but it may be made more so by exchanging articles not wanted. 
It is established by law, but is not necessarily the daily dietary. Thus, 
the various articles (excepting the fresh vegetables, bread and baking- 
powder) not needed for consumption may be purchased by the com- 
missary as savings at the invoice prices. " Savings and sales of fresh 
beef (except of that issued for the sick in hospital, the detachment of 
the hospital corps and the hospital matron serving therein) are pro- 
hibited," 1 but the fresh meat allowance can be reduced in amount and 
its money value drawn in other things. For each ration of flour 
turned in, the company is entitled to one ration of bread or the price 
of one flour ration. 
In many permanent camps, gardens can be cultivated and a supply 
of fresh vegetables thus obtained both for immediate and future 
use. Commutation for these is allowed at the prices of potatoes and 
onions in the vicinity or in the market from which supplies are de- 
rived, in the proportion of 80 per cent, of potatoes and 20 per cent, of 
1 Army Regulations, p. 180. 598 
MILITARY HYGIENE. 
onions. The amounts of money from all sources form the company 
fund, which is disbursed by the company commander solely for the 
benefit of his own men. 
Fruits and vegetables are very essential in the dietary, on account of 
their anti-scorbutic properties. The most valuable of the antiscor- 
butics is commonly held to be lime-juice; the juice from the fresh 
limes is superior to the bottled article. Lemons are of about the same 
value as limes. Among the vegetables, potatoes, onions, and cabbage 
take high rank. The legumes are devoid of antiscorbutic properties. 
According to Woodhull, the best antiscorbutic is the agave. "To 
prepare it cut off the leaves close to the root, cook them well in hot 
ashes, express the juice, and drink, raw or sweetened, 1-4 wineglass- 
fuls three times a day. The white interior of the leaves may be 
eaten." The dried vegetables and fruits are less valuable than the 
fresh and should be allowed to supersede the latter only when these 
cannot be obtained, but they are far superior to compressed vegetables, 
which, in the process of compression, lose much of their salts and a por- 
tion of their proteids. Dried vegetables must be well soaked in water 
before use, else they may cause digestive disturbance and diarrhoea. 
Alcohol in Ration.-The question of the advisability of including 
a spirit allowance in the ration has been the subject of much careful 
consideration in all countries, and has been answered with practical 
unanimity in the negative. But there are times when a single issue of 
spirits, or repeated issues according to circumstances, may be useful 
and even necessary. Thus, on a forced march, when exhaustion is great, 
the stimulant may be of very great necessity, though it is said that 
hot tea, if time admits of its preparation, may be equally or still more 
serviceable. When given at all, it should be taken well diluted and 
never in concentration. 
During the Civil War, a daily issue of a gill of whiskey to each offi- 
cer and man of the Army of the Potomac was ordered, half to be given 
out in the morning and half in the evening. This was brought about 
by the fact that for several weeks the men had been subjected to un- 
usual hardships and extra duty and were breaking down under the 
strain. The issue, which was to continue " until further orders," was 
greeted with enthusiastic appreciation of the farsightedness of the au- 
thorities responsible for it. " Until further orders " proved to be ex- 
actly one month, and hot coffee was substituted for the whiskey, the 
issue of which was ordered to be "immediately discontinued." During 
the month, the general condition of health of the troops was not only 
in no way improved, but became markedly worse, while drunkenness, 
with its attendant evils, became much more common. 
Concerning the use of beer and light wines, a very different opinion is 
held by many of those best qualified to judge by results observed. In 
several of the great armies of Europe, an allowance of light wine is cus- 
tomary, and it seems reasonable to suppose that where the importance 
of a large standing army is so great, alcohol in this form would not be 
issued, were it not upon the belief, based on long experience, that, di- PREPARATION OF FOOD. 
599 
rectly or indirectly, it is a benefit and not an evil. A little light wine 
at the close of a day of hard work, but not before or during its per- 
formance, appears to be recuperative and restful, either in the usual 
strength or diluted with water. In this country, the so-called canteen 
system is believed to be productive of a distinct gain for temperance 
among the soldiers ; and by temperance is not meant total abstinence. 
The canteen is a place at a military post where small wares, little lux- 
uries, tobacco and the lighter alcoholic drinks can be purchased under 
close supervision, so that abuses cannot occur. There is no inducement 
held out for the men to buy drink, and what is sold must be consumed 
on the premises. What small profit is derived goes to the post ex- 
change, which, besides the canteen, comprises a general store, a lunch 
counter, recreation rooms supplied with reading matter, and a gym- 
nasium. 
It is believed that the system has worked out the solution of much 
of the problem concerning drunkenness in the army. The soldier ac- 
customed in civil life to the use of beer is enabled to obtain it in a 
decent way and only to a decent extent, and hence has no temptation 
to seek alcohol in, perhaps, stronger forms elsewhere and not under 
supervision. He is more likely to remain habitually sober, instead of 
being occasionally helplessly drunk and commonly in difficulties. It 
is said that the order of things that obtained on pay day under the old 
system has been very largely abolished. Then, pay day was a source 
of satisfaction to nobody but the saloon-keepers, who sold bad liquor 
at high rates ; men were absent days at a time without leave; courts- 
martial were busy and there was much guard-house service. Those 
who have studied the matter regard the canteen as the friend of de- 
cency and discipline and the enemy of every saloon near a garrison. 
Naturally, the saloon-keepers and that class of reformers who believe 
in the possibility of bringing about radical changes in human nature 
by legislation are violently opposed to the continuance of the system ; 
and, indeed, the latter have been so successful in their agitation against 
it that, in spite of the practical unanimity of the officers of the army 
of all grades in its favor, it was abolished by Act of Congress in Jan- 
uary, 1901. 
Preparation of Food.-The art of cooking is a very valuable ac- 
complishment of a soldier, especially when on active service. In camps, 
the cooking is done by persons enlisted for that purpose, one cook be- 
ing allowed by law for each company, troop, or battery. On applica- 
tion, he must first pass the regular examination of a recruit and then 
one in which he must demonstrate his knowledge of methods and skill 
in caring for, preparing, and serving food. Kitchens are placed under 
the immediate charge of non-commissioned officers, who are held re- 
sponsible for their condition and for the proper use of rations. Only 
those employed or those on duty are allowed to visit or remain in the 
kitchens. The general supervision of the cooking and messing devolves 
upon the company commanders, who are charged to exercise personal 
care and judgment to prevent waste and nuisance and to see " that 600 
MILITARY HYGIENE. 
suitable men in sufficient numbers are fully instructed in managing 
and cooking the ration of the field," since when the conveniences for 
cooking on a large scale are not at hand, it becomes necessary for men 
to divide into small squads and prepare their own meals. 
The baking of Inroad is carried on in post bakeries under the charge 
of enlisted men detailed as chief and assistant bakers. Baking by 
companies at posts is expressly prohibited, but is the rule in temporary 
camps and with marching columns, portable ovens of various kinds 
and barrel ovens being employed. The barrel oven is best made with 
a barrel with iron hoops, which is placed on its side, covered completely 
with clay or stiff mud, except at its open end, and then with a thick 
layer of dry earth, leaving, however, a small (3-inch) opening at the 
top of the inner end to serve as a flue. A fire is made in the barrel 
and kept up until all the wood is burned, leaving an oven of clay, for 
which the hoops act as a support. 
In the field, on account of transportation, it is necessary that cooking 
appliances should be as simple and economical of space as possible. 
The greater the amount of baggage, the greater the number of wagons 
necessary ; the greater the number of wagons, the greater the number 
of animals and the greater the amount of necessary forage. 
Is the U. S. Ration Adequate in Amount and Composition?- 
This question has agitated the minds of many during recent times and, 
more particularly, since the outbreak of the war with Spain, and the 
ration has been denounced, whether justly or un justly, in respect to both 
quantity and quality. For a better understanding of the subject, a 
comparison of the official ration with those of other countries in which 
warfare is a larger industry than with us may not be amiss. 
The British soldier receives, on home service, 12 ounces of meat 
and one pound of bread, and obtains what he can of vegetables and 
groceries from a per diem allowance of seven cents, which is deducted 
from his pay. What he needs in addition, he buys at the canteen 
(at cost) or elsewhere. 
In the field, he receives one pound of fresh, salted, or preserved 
meat, or when the supply of cattle is abundant, 1.25 pounds of fresh 
meat; 1.25 pounds of fresh bread, or one pound of biscuit, or one 
pound of flour or meal; one-third ounce of coffee and one-sixth ounce 
of tea, or a double allowance of either, or one-third ounce of chocolate 
or cocoa ; two ounces of sugar, one-half ounce of salt, one-thirty-sixth 
ounce of pepper ; one ounce of compressed vegetables, or one-half pound 
of potatoes or other fresh vegetables, or two ounces of split peas, or 
one-fourth pound of onions, or two ounces of rice ; one-tenth gill lime 
juice with one-fourth ounce of sugar when fresh vegetables are not 
issued or when the medical officer thinks necessary; one-half gill of 
spirits, when considered necessary, besides tobacco, light and fuel. 
This ration is subject to change for better or worse, according to cir- 
cumstances. 
The French soldier receives 10.6 ounces of meat, 26.4 ounces of 
munition bread and 8.8 ounces of white bread for soup, or 19.4 ounces 601 
IS U. S. RATION ADEQUATE IN AMOUNT AND COMPOSITION? 
of hard bread; 3.5 ounces each of dried vegetables, chiefly beans, and 
fresh vegetables, with salt and pepper. Much of this comes out of his 
pay. The German soldier receives in time of peace, according as he is 
in garrison or in camp and field manoeuvres, 5.30-17.65 ounces of 
meat, or 4.40-6.00 ounces of bacon ; 26.50-35.30 ounces of bread, 
3.18-6.00 ounces of rice, or 4.25-6.00 of groats, or 8.10-12 of peas 
or beans, or 53.00-71.00 of potatoes ; and in camp or field manoeuvres, 
a liter of beer, or a half liter of wine, or a tenth liter of spirits, and 
1.75 ounces of butter. In time of war, he receives 13.25 ounces of 
fresh or salted meat, or 8.80 ounces of smoked meat or sausage, 26.50 
ounces of bread, 4.40 ounces of rice or groats, or 8.80 of peas, beans, 
or flour, or 53.00 ounces of potatoes, 0.90 ounce of roasted or 1 ounce 
of raw coffee, and 0.90 ounce of salt. 
The Russian soldier, in time of peace, receives 7.25 ounces of meat, 
43.35 of rye bread or 28.9 of biscuit, 32.65 of flour, and 4.80 of 
groats. In time of war, he receives, according to whether he is on the 
smaller or larger war ration, 14.45-21.65 ounces of meat, 36.15 of 
rye bread, 4.80 of groats, and 1.35-2.70 of suet or butter. He is also 
allowed money for 1.50 ounces extra of meat, and an additional cent 
and a-half for vegetables and other articles. The Austrian soldier re- 
ceives in peace 6.70 ounces of meat, 30.90 of bread or 17.65 of hard 
bread ; 6.60 of flour, or 2.50 of peas or beans, or 4.95 of groats, or 
5.30 of millet, or 4.00 of barley, or 3.70 of rice, or 19.75 of potatoes ; 
5.55 of saner kraut, and 0.60 of suet. In time of war, 9.90 ounces of 
meat, or 6.00 of salt meat or bacon ; 25.20 of flour, 3.50 of hard bread, 
5.30 of peas, or 4.94 of groats, or 5.55 of saner kraut, or 8.80 of 
potatoes ; and 1.05 of suet, with coffee, and beer, wine or spirits, and 4 
cents for extra vegetables. 
The Spanish soldier receives 24 ounces of bread and is required to 
spend 7 cents out of his daily pay of 9 cents for the rest of his sub- 
sistence. In time of war, his pay is increased from 2.5 to 5 cents per 
day. The Italian soldier receives 7.05-10.60 ounces of meat, 0.50 of 
bacon, 32.40 of bread, 5.30 of rice, 0.70 of sugar, 0.50 of coffee, 0.50 
of salt, and a quarter liter of wine. 
Comparison of these figures with those of our own ration demon- 
strates at once that ours is in all respects the most liberal ration in the 
world. In only one instance is there a conspicuous superiority in the 
amount of an important constituent; namely, the very generous allow- 
ance of potatoes in the German ration. Not only is it the most abun- 
dant, but it admits of greater variety than any other. But even at that, 
it is held by many to be insufficient in amount for the proper perfor- 
mance of the work a soldier may be called upon to perform. Experts 
in the making of dietaries have proposed increasing the flour and soft 
bread allowance by about a fourth and adding about 5 ounces of flour 
to the alternative allowance of hard bread and 20 per cent, to the al- 
ternative allowance of corn meal, with a reduction of 40 per cent, in 
the allowance of potatoes, and the alternative of money value in milk 
or cheese in place of the allowance of peas or beans. 602 
MILITARY HYGIENE. 
In the consideration of the question of quality and variety, it must 
be borne in mind that while it is necessary to have a standard of food 
value fixed by law, it is not necessary to consume precisely the articles 
named. Nor is it possible to fix a money value to the ration and give 
out the cash equivalent in place of actual food, for the soldier is not 
always near a market, and, moreover, if he were, it is most evident 
that the same amount of money in different places would yield very 
different amounts of nutriment, since in one, the food supply is abund- 
ant and cheap, and in another, scanty and expensive. What the soldier 
eats, depends upon circumstances and largely upon the discretion of 
company commanders guided by the advice of the medical officers, but 
as said before, the actual food value is fixed by Congress and is based 
on the experience and study of many years. 
In the public mind, the ration is niggardly in amount and exceed- 
ingly limited in variety, and there has been a loud outcry and demand 
for a change. This is due to a series of unfortunate happenings during 
the war with Spain, when, from one cause and another, supplies were 
slow in coming, or were very scanty, or, when received and dis- 
tributed, were unfit for food. This is not creditable, for the importance 
of good food in abundance at critical times cannot be overstated. But 
the blame for neglect or incompetence on the part of those whose 
business it is to transport troops and feed an array ought not in justice 
to be placed upon the ration itself. 
Nevertheless, no sooner were the facts known, than "Senex," "Ve- 
ritas," " Pro Bono Publico," " Fiat Lux," " Outraged," and other ama- 
teur dietists and arm-chair strategists, each imagining himself to have 
inherited the mantle of Junius, attacked the ration in all its particu- 
lars in the public press, demanded instant changes for the better, and 
succeeded in creating a widespread prejudice against it. And yet, had 
Congress stipulated that it should include bisque of lobster, tenderloin 
steak, fresh green peas and asparagus, and similar articles, it seems un- 
likely that, under all the circumstances, the men would have been any 
further removed from starvation. Had the supplies been properly for- 
warded in good condition, it is unlikely that any very great complaint 
as to the fitness of the ration for fighting men would have been heard, 
although its general suitability as a tropical diet for any length of time 
can hardly be maintained, as is shown below. As to its suitability for 
feeding those broken down by typhoid fever and malarial diseases, on 
their way home on crowded transports, there can be but one opinion. 
Is the United States Ration Suited to the Tropics ?-The ques- 
tion of the suitability of our ration to the tropics is one which has as- 
sumed great importance since the necessity arose for maintaining large 
armies in our new possessions, and its discussion has been marked by 
a much more temperate tone and has, therefore, yielded better results. 
The beginning of the discussion may be said to have arisen from the 
fact that it became generally understood that bacon was a necessary 
constituent of the daily food, both in camp and in active operations, in- 
stead of an alternative as may be gathered from the wording of the IS THE U. S. RATION SUITED TO THE TROPICS? 
603 
statute-fresh beef, or fresh mutton, etc., or pork, or bacon, or salt 
beef, or dried fish, or pickled fish, or fresh fish. Bacon has its advan- 
tages at certain times, but is not eagerly sought after by those not in 
good health, nor is it acceptable in very hot climates as a regular diet 
any more than any other fatty food. Fats are much needed in cold 
climates for the production of heat; in hot climates, the necessity for 
their use is but slight in comparison. But when fresh meat cannot be 
obtained either on the hoof or from cold storage, and when the appe- 
tite is cloyed by canned meats (and this is soon brought about), bacon 
is acceptable as an occasional substitute. 
To those at a distance and unacquainted with local conditions, the 
ideal supply of fresh meat is cattle on the hoof. But the cattle of the 
tropics are not the same as those which we know, nor are they always 
to be had in even small numbers. Sending live cattle from home, to 
be driven along on the march to be killed as needed, is not always 
practicable, for even if landed in good condition, they cannot be kept 
on the march, and unless the country traversed is good grazing land, 
they lose weight and die off rapidly. Canned meats are much inferior 
to fresh meats and cannot long be eaten with relish. The canned so- 
called roast beef is commonly the residue of meat after the extractives 
have been boiled out of it for the manufacture of meat extract, and it 
is, therefore, lacking in flavor, although not materially diminished in 
nutritive properties. It is often as tasteless and almost as difficult 
to chew as towelling, and is very far from inviting in appearance, 
especially when the cans are opened at ordinary hot summer tem- 
perature. 
According to many experienced minds, the consumption of meat in 
any form should be much limited in the tropics. Roquemaure 1 ad- 
vises the European in the tropics to take nothing into his stomach, ex- 
cept articles easily digested; mutton, beef, and pork only in modera- 
tion and not too thoroughly cooked and not regularly or too often ; 
birds, eggs, and fish are more to be commended; especially to be re- 
lied upon are rice, dried vegetables, fresh vegetables, starchy foods, 
and ripe fruits in good condition. Kohlbtigge2 places above all other 
influences in the deterioration of Europeans in the tropics the too ex- 
tensive use of animal fats, which, he claims, are responsible for much of 
the diarrhoeal troubles of the tropics. He recommends the vegetable 
oils for supplying what fats are needed by the body. 
The observations of Dr. L. L. Seaman,3 in Porto Rico, lead, in part, 
to the same conclusion. He relates that within a week after landing 
in the summer of 1898, in spite of the strictest sanitary precautions 
and personal hygiene, the entire force with which he was connected 
suffered from some form of intestinal catarrh from one cause and an- 
other, and that medication was of no avail, since the diet of bacon, salt 
1 Hygiene alimentaire aux pays chands, Bordeaux, 1895. 
2 Die Acclimatisation der Europaer in den Tropen : Deutsche medicinische Wochen- 
schrift, 1898, Nos. 27 and 28. 
3 New York Medical Journal, March 18 and 25, 1899. 604 
MILITARY HYGIENE. 
beef, canned beans and pork, and hardtack proved to be a continual 
irritant, by which the troubles were aggravated and the power of re- 
sistance much reduced. Under such conditions, malaria and typhoid 
fever could gain a foothold in the system with much greater ease ; first 
came the malarial fevers of the various types, and, in the early part of 
September, on the introduction of the germs from Tampa and Chicka- 
mauga, typhoid fever broke out and, spread by flies, continued with 
varying severity until embarkation for home in November. The value 
of a milk diet was emphatically demonstrated. 
Koerfer's1 recommendation to Europeans, to leave their pork fat, 
meats, and alcohol at home with their heating stoves and furs when 
they go to reside in the tropics, is quoted in confirmation. 
While the use of green vegetables is universally recommended in 
the tropics, it is not always easy, and, in fact, it is often extremely diffi- 
cult or impossible, to obtain them, since the natives of the tropics are 
commonly content to live on rice, dried beans, and fruit, with an occa- 
sional taste of fish or meat. Canned vegetables, while grateful to the 
system, are not wholly to be recommended, on account of transporta- 
tion. A can of string beans, for example, contains a maximum of 
water and a minimum of nutriment, and for its real service in the 
dietary may be said to be hardly worth its cost of carriage. Dried 
vegetables and fruits are more economical, but must be well soaked 
before use. 
The Court of Inquiry, appointed to investigate the food supply of 
the army during the war with Spain, reported among other conclusions 
the following : " As to the effects of the food supply, having regard 
to sufficiency and quality, it seems to be clearly established that the 
army ration as supplied, without modification, to the troops serving 
in the West Indies was by no means well adapted for use in a tropical 
climate. If this be true, the unfitness of the ration should have mani- 
fested itself by its failure to keep the troops, who subsisted upon it, in 
the best possible condition for service in hot climates. This, in the 
opinion of the court, is fully established in evidence." Seaman advo- 
cates a reduction in the meat components, the use of salted meats not 
oftener than twice per week, and an increase in the allowance of vege- 
table and farinaceous foods and dried fruits. 
Dr. Edward L. Munson, U. S. A.,2 has studied the subject of trop- 
ical diet from the standpoints of physiological science, availability, and 
practicability, and concludes that the articles of the ration are correct 
as they stand, being admirably selected and of good variety, but need 
some rearrangement in their respective amounts. He proposes certain 
modifications and offers four dietaries, the average of which is not 
widely variant from a proposed nutritive standard for soldiers in the 
tropics, as follows : Protein 100 grammes, carbohydrates 650, fats 
65. (Nitrogen 16, total carbon, 392, fuel value 3,491 calorics.) 
1 Deutsche medicinische Wochenschrift, July, 1898. 
2 The Ideal Ration for an Army in the Tropics. (Prize essay.) Boston Medical and 
Surgical Journal, May 3, 10, 17, and 24, 1900. IS THE U. S. RATION SUITED TO THE TROPICS? 
605 
Dietary I. contains the greatest amount of food material which can be 
drawn by the soldier. 
TROPICAL DIETARY I. 
Articles. 
Quantity, 
ounces. 
Fats, 
grammes. 
Carbohy- 
drates, 
grammes. 
Protein, 
grammes. 
Nitrogen, 
grammes. 
Fuel 
value, 
Calories 
Fresh beef 
10 
44.75 
41.68 
6.67 
590 
Flour 
18 
5.60 
380.46 
55.08 
7.90 
1,850 
Beans 
2.4 
1.22 
40.18 
15.16 
2.42 
240 
Potatoes 
16 
.45 
81.70 
9.50 
1.52 
380 
Dried fruit 
3 
1.53 
33.80 
1.77 
.27 
220 
Sugar 
3.5 
94.25 
397 
Total 
52.9 
53.55 
630.39 
123.19 
18.78 
3,677 
Total carbon, 395.14 grammes ; nitrogen to carbon 1 :19.6. 
Dietary II. is especially applicable to field service; in this, the fatty 
constituents attain their maximum and the potential energy is high. 
TROPICAL DIETARY II. 
Articles. 
Quantity, 
ounces. 
Fats, 
grammes. 
Carbohy- 
drates, 
grammes. 
Protein, 
grammes. 
Nitrogen, 
grammes. 
Fuel 
value, 
Calories 
Bacop 
6 
105.06 
15.64 
2.49 
1,042 
Hard bread 
18 
6.63 
371.81 
73.12 
11.74 
1 926 
Beans 
2.4 
1.22 
40.18 
15.16 
2.42 
240 
Dried fruit 
3 
1.53 
50.70 
1.77 
.27 
220 
Sugar 
3.5 
94.25 
397 
Total 
32.9 
114.44 
556.94 
105.69 
16.92 
3,825 
Total carbon, 328.76 grammes ; nitrogen to carbon, 1 : 23. 
Dietary III. is proposed for garrison duty. 
Articles. 
Quantity, 
ounces. 
Fats, 
grammes. 
Carbohy- 
drates, 
grammes. 
Protein, 
grammes. 
Nitrogen, 
grammes. 
Fuel 
value, 
Calories 
"Fresh beef 
10 
44.75 
41.68 
6.67 
590 
Soft bread 
20 
6.80 
299.20 
53.83 
8.61 
1,506 
340 
Potatoes and onions 
16 
.72 
73.09 
8.60 
1.40 
Dried fruit 
3 
1.53 
50.70 
1.77 
.27 
220 
Sugar 
3.5 
94.25 
397 
Total 
52.5 
53.80 
517.24 
105.88 
16.95 
3,053 
TROPICAL DIETARY III. 
Total carbon, 328.76 grammes ; nitrogen to carbon, 1 :18. 
Dietary IV. is a combination of the several articles of the ration most 
closely approaching in character the food materials used by the natives 
of the tropics, proportioned according to the proposed standard. 606 
MILITARY HYGIENE. 
Articles. 
Quantity, 
ounces. 
Fats, 
grammes. 
Carbohy- 
drates, 
grammes. 
Protein, 
grammes. 
Nitrogen, 
grammes. 
Fuel 
value, 
Calories 
Fresh fish (cod), whole... 
14 
.79 
31.73 
5.07 
120 
Soft bread 
20 
6.80 
299.20 
53.83 
8.61 
1,506 
Rice 
4 
.45 
88.87 
8.75 
1.40 
407 
Potatoes and tomatoes.... 
16 
.54 
65.80 
8.17 
1.36 
297 
Dried fruit 
3 
1.53 
50.70 
1.77 
.27 
220 
Sugar 
3.5 
94.25 
341 
Total1 
64.5 
10.11 
598.82 
104.25 
16.71 
2,947 
TROPICAL DIETARY IV. 
Total carbon, 327.50 grammes; nitrogen to carbon, 1 : 19.6. 
The following table shows the mean nutrient composition of the four 
dietaries and admits of ready comparison of one with another. 
Dietary. 
Quantity, 
ounces. 
Fats, 
grammes. 
Carbohy- 
drates, 
grammes. 
Protein, 
grammes. 
Nitrogen, 
grammes. 
Fuel 
value, 
Calories 
No. I 
52.9 
53.55 
630.39 
123.19 
18.78 
3,677 
No. II 
32.9 
114.44 
556.94 
105.69 
16.92 
3^825 
No. Ill 
52.5 
53.80 
517.24 
105.88 
16.95 
3'053 
No. IV 
64.5 
10.11 
598.82 
104.25 
16.71 
2^947 
Average 
50.7 
57.97 
575.85 
109.75 
17.34 
3^375 
Total carbon, 350 grammes ; nitrogen to carbon, 1 :20. 
Posts and Camps. 
Posts are permanent camps or those of position, and camps, in the 
usual sense, are temporary or incidental. At posts, the troops are 
housed in barracks, while at temporary camps, they occupy tents and 
huts. The same sanitary considerations apply equally well to both, but 
choice of location of temporary camps in time of war is commonly de- 
termined by immediate and strategical considerations. Both must be 
laid out in such a manner as to insure proper air supply, cleanliness, 
and general salubrity and should be as compact as is consistent with 
the principles of hygiene, for a compact camp is more easily cared for 
and defended, while one unnecessarily extended involves increased labor, 
slower delivery of orders and supplies, and greater difficulties in sani- 
tary policing. With the tactical and strategical requirements and 
general plan, which is a matter of regulation, the hygienist has noth- 
ing to do, and his interest lies only in the distances between different 
bodies of men, the size of company areas, the cubic space per man, the 
proper location of sinks, latrines, and urinals, the measures adopted for 
surface drainage, disposal of sewage, garbage and stable manure, the 
water supply, and other matters having a bearing on the health of the 
troops. 
' It will be noticed that the first and sixth columns do not add up according to the 
totals expressed. The latter, however, being used in the table below, are retained un- 
changed. 607 
POSTS AND CAMPS. 
The general plan of a camp is shown in Fig. 98, taken from the In- 
fantry Drill Regulation and amended in the matter of distances and 
intervals by Dr. P. C. Harris, U. S. A.,1 since no distances and inter- 
vals are given in the regulation, for they must vary according to the 
nature of the ground and the strength of the command. The plan is 
Fig. 98. 
Explanation. 
Bunning Water 
Concrete Foundation. 
Plan of camp (reduced so that scale of 64 feet to the inch no longer applies). 
made "on a basis of 3 men to a common tent or 10 to a conical wall 
tent; the maximum allowance of tentage is 6 men to a common tent 
and 20 to a conical wall." 
Sites.-One of the most important matters connected with military 
hygiene is the selection of a proper site for camps. Everything bear- 
1 Camps of Instruction, Reprint, Buffalo, Dec. 14, 1898. 608 
MILITARY HYGIENE. 
ing on the health of those -who are to occupy the camp must be con- 
sidered important, and every effort should be made to ensure, so far as 
it is possible, that there is no point of least resistance in the barriers 
against disease. If an unhealthy site is chosen, no amount of care can 
ward off, though it may check the extent of, evil consequences. In 
active warfare, choice of sites is not always a wide one, and convenience 
and necessity play a greater part than sanitary consideration. When 
practicable, they should be placed on high well-drained ground. 
Proximity to water is always necessary and this may involve ex- 
posure to malarial infection, but other things being equal, the driest 
site should be selected. Where the choice is restricted, advantage 
should be taken, in cold weather, of any available protection from winds, 
and in hot climates, from the burning sun. The general slope of the 
ground should be considered, so that the surface drainage may be best 
provided for. 
The soil should be dry and porous ; clay and other soils of low per- 
meability to air and moisture, but with the high retentive power for the 
latter, should, if possible, be avoided. If the ground-water level is high, 
it should be lowered by tile draining or ditching, in case the camp is to 
be one of permanence. A clay soil or a soil underlaid at a short dis- 
tance by a clay soil is commonly regarded as the worst possible site for 
a camp, since it is retentive of water and is cold and causes the atmo- 
sphere immediately above to be damp. Old river bottoms, deep allu- 
vium, and marshy ground should be avoided. Grass land may be 
commonly accepted as good camping ground, but ground covered with 
rank vegetation, as in the tropics, is not acceptable, because such is 
generally rich in decaying organic matter, and the presence of rank 
vegetation is in itself evidence either of a very humid atmosphere or 
of an undesirable degree of soil moisture. Lands subject to periodical 
flooding, especially by salt water, should be avoided as unhealthy. 
Above all, it should be a rule to avoid old camp grounds, for these 
are usually left in a filthy condition by the previous occupants and the 
soil is always extensively contaminated and, perhaps, infected. If an 
old camp site is particularly desirable on account of the accessibility 
of wood, water and grass (the three essentials demanded by the line 
officer), a position to windward and as near as is consistent with hy- 
gienic considerations may be selected. 
Dryness of the site and vicinity is of prime importance in its bear- 
ing on the health of troops, but too great dryness with much dust is 
hurtful to the eyes. A position on the side of a hill is warmer than 
one at the top and drier than one at the bottom, and is favorably situ- 
ated as regards that most essential provision in camp sanitation, 
drainage. 
Barracks.-Barracks are permanent structures for the lodgment of 
soldiers and are commonly built of one or two stories, but not more. 
Each building of a group should be completely independent of the 
others and placed with reference to prevailing winds and exposure to 
the sun. It is essential that the site be dry, the foundation walls 609 
POSTS AND CAMPS. 
solidly laid, the walls, of whatever material constructed, dry and pro- 
tected against capillary moisture, the floors, of hard wood, tightly laid, 
and the ventilation efficient. Barrack rooms, which are the soldiers' 
living rooms as well as sleeping quarters, are generally made long and 
narrow and each occupant has floor space and air space according to 
the regulations obtaining in the country which he serves. In this 
country, 600 cubic feet of air space per man is reckoned adequate, and 
this, in a room 12 feet from floor to ceiling, gives a floor space of 50 
square feet. 
Cavalry and artillerymen are given somewhat more, on account of the 
odors which cling to them from contact with horses. A less amount is 
allowed when troops are quartered in ordinary dwellings. At Southern 
posts, 800 cubic feet of air-space and 70 square feet of floor-space are 
allowed. In England, the allowances are the same as with us for in- 
fantrymen in the North ; in India, they are from 1,500 cubic feet and 75 
square feet to double those limits. In France, the cubic space allowed 
is 420 cubic feet for infantry and 500 for cavalry. In Germany, it is 
500 cubic feet. 
The wash rooms, urinals, and latrines should be placed with due 
regard to convenience and to general hygienic considerations. 
Ventilation should be carefully planned with a view to the greatest 
possible reduction of the natural impurities due to occupancy, but with 
the present cubic space allowance, whatever the system employed, ideal 
results cannot be attained. Barrack life is necessarily one of over- 
crowding, but the conditions which now obtain are far and away superior 
to those which formerly prevailed. The evils of overcrowding of sol- 
diers were first brought to light by an investigation of the health of 
British soldiers in 1858. It was shown that, whereas the mortality 
rate of the population of England and Wales of the same age as the 
army was 9.2 for town and country and 7.7 for country alone, and 
12.4 for the most unhealthy town (Manchester), that of the different 
arms of the service ranged from 11 for the household cavalry to 20.4 
for the footguards. According to age periods, the mortality was dis- 
tributed as follows : 
Ages 20 to 25. Civilians 8.4 
Soldiers 17.0 
Ages 25 to 30. Civilians 9.2 
Soldiers 18.3 
Ages 30 to 35. Civilians 10.2 
Soldiers 18.4 
Ages 35 to 40. Civilians 11.6 
Soldiers 19.3 
Since the soldiers were picked men, all applicants with any evidence 
of weakness or tendency to disease being rejected, these data indicated 
a serious condition of affairs. Comparison was made with the rates ob- 
taining among the class of agricultural laborers, their work, like that of 
the soldiers, being mainly out of doors. It would be expected that the 
latter, being well clothed, housed, and fed, and given free medical care, 610 
MILITARY HYGIENE. 
would present the better showing, but such proved not to be the case, 
for the mortality of the laborer being expressed as 1, that of the house- 
hold cavalry was 1.8, dragoons 2.2, infantry of the line 2.9, and foot- 
guards 3.3. Comparison with men in other occupations showed that 
the soldiers presented the most unfavorable statistics. 
Inquiry as to the cause revealed that, whereas among civilians at the 
soldiers' ages the deaths from diseases of the lungs were 6.3 per 1,000, 
they were 7.3, 10.2, and 13.8 respectively for the cavalry, infantry of 
the line, and guards, and, furthermore, that of the entire number of 
deaths from all causes in the army, the proportion due to lung diseases 
amounted to 53.9, 57.3, and 67.7 per cent, respectively in the arms 
above mentioned. Finally, by exclusion, the cause of this great mortality 
was attributed to overcrowding and lack of ventilation. Comparison 
of the mortality of the army at home with that of the troops quartered 
before Sebastopol in 1856 was much in favor of the latter. The rates, 
reckoned per annum, were as follows : Before Sebastopol, including 
deaths by violence and accident, 12.5; at home, 17.9 (infantry), and 
20.4 (guards). 
Increase in space allowance was soon followed by a marked decrease 
in phthisis mortality. 
Tents.-In the United States Army, four kinds of tents are used. 1. 
The conical, or modified Sibley, tent. This is 16 feet 5 inches in di- 
ameter at the base; wall, 3 feet high; apex, 10 feet from the floor; 
the area of the floor equals 212 square feet; the air space, 1,450 cubic 
feet; allowance, 20 infantry or 17 cavalry. The original Sibley tent 
had a diameter of 18 feet at the base and was 13 feet high. The apex 
was cut off, thus giving place to a circular aperture which, being left 
open in fair weather, promoted ventilation. In foul weather, it was 
covered. The allowance was the same. 2. Common tent, " I " or 
modified "A." Wall, 2 feet high; base, 8 feet 4 inches by 6 feet 10 
inches; ridge, 6 feet 10 inches from the ground; floor space, 57 square 
feet; air space, 250 cubic feet; allowance, 4 mounted or 6 infantry. 
3. Wall tent. Wall, 3 feet 9 inches; floor, 9 square feet; ridge, 
8 feet 6 inches above the ground; floor space, 81 square feet; air 
space, 500 cubic feet; covered by fly or false roof. 4. Shelter tent. 
These are issued to troops in the field and are not regarded as tent 
allowance, but are provided in order that men and officers in bivouac 
while on active campaign or on the march with deficient means of 
transportation may be sheltered. One forms a shelter for two men, 
each of whom carries his half, which weighs about two and a-half pounds. 
The pieces are joined together by buttons and put over a ridge pole, 
which is supported by uprights about 4 feet high. The corners are 
fastened to pegs driven into the ground, and the uprights are steadied 
by guy lines. 
Hospital tents are wall tents of a larger size and capable of being 
open at each end ; several may be thrown together so as to make a 
continuous whole. They are 14x15 with a 4|-foot wall; ridge, 12 
feet from the ground. POSTS AND CAMPS. 
611 
The English army uses the circular, or bell, tent. Diameter at base, 
12 feet 6 inches ; walls, 1 foot; apex, 10 feet; floor space, 123 square 
feet; air space, 492 cubic feet; allowance, 12 to 16 men and in Avar 
18 and 20. Formerly, the ventilation was practically nil, but now it 
has been somewhat improved. The French army uses a similar tent, 
ventilated at the top. The air space is 1,059 cubic feet; allowance, 
16 men. The Germans use a conical tent like the English bell tent. 
Diameter, under 15 feet; apex, 12 feet from the ground; floor space, 
180 square feet; air space, 1,050 cubic feet; allowance, 15 men. 
They use also small bivouac tents designed to shelter two or more men. 
The different parts are distributed among and carried by the men who 
are to use them. 
It will be observed that, of the four armies mentioned, ours is the 
most liberal in point of air space, the minimum allowance in the larger 
tents being 72| cubic feet, against a maximum of 41 in the English 
service, 66 in the French, and 70 in the German service. 
The material of which tents are made is cotton duck, which has 
proved to be much better for shedding water than linen. Compara- 
tively little ventilation can occur through this material under the best 
of circumstances, and none at all when it is wet by rain, for then it is 
impervious to air. Ventilation of tents is always defective, and com- 
monly the atmosphere becomes exceedingly foul. Since there is so 
little ventilation, it is necessary that the sides should be kept raised 
during the day, in order that thorough airing, and, if possible, sunning, 
may occur; and at night, when practicable, the sides should be open to 
leeward, and more, if advisable. 
Dr. Edward L. Munson, U. S. A.,1 has suggested improvements in 
the regular tentage, and especially in the hospital tents, for service in 
our new tropical possessions, since the several forms in use, though 
well adapted to our climatic conditions, are intensely hot and close in 
the high temperatures and humid atmosphere that there obtain. He 
proposes enlarging the tent fly of the hospital tent two feet in length 
and four in width, and that it be raised upon a light false ridge, 
four feet longer than the true ridge and projecting two feet to the 
front and rear. Further, he proposes that the canvas forming the top 
of the tent be cut out for a space two feet wide on each side of the 
ridge and running the entire length of the tent, except one foot, front 
and rear, the canvas thus removed being replaced by heavy rope net- 
ting with a two-inch mesh. 
In order better to reflect the heat rays, the fly should be made of 
white canvas, the tent itself being of dark canvas, with a view to sub- 
duing the light in the interior. An experimental tent, made under 
orders of the Surgeon-General, was pitched within a few feet of a reg- 
ular hospital tent and a regular conical wall tent for purposes of com- 
parison. Thermometric observations showed an average difference of 
7° in favor of the improved tent, which was never less than 4.5° cooler, 
1 Tentage for Tropical Service, Boston Medical and Surgical Journal, Nov. 16, 1899, 
p. 487. 612 
MILITARY HYGIENE. 
twice was 8.5°, and once 10.5° cooler than the regular hospital tent. 
Compared with the conical wall tent, the temperature ranged 9.5 to 18.5° 
lower in the improved tent, which difference " means in the tropics 
all the difference between comfort and distress for the well and such 
relief from great and depressing heat as would do much to bring about 
recovery in the sick." The experimental tent demonstrates that no tent 
should be issued for use in the tropics without the protection afforded 
by a fly. The U. S. A. Board of Equipment promptly adopted the use 
of the improved hospital tent. 
Dr. Myles Standish, M. V. M.,1 first called attention to the intense 
white glare to which the occupant of the hospital tent is subjected from 
the covering above his head and which must be a source of actual 
injury to eyes already in a pathological condition. Reasoning from 
general laws, he recommends a pale blue or an olive green as the safest 
color. 
In India, the British use a tent with a double fly, having an air 
space of 2,373 cubic feet and accommodating 16 healthy or 8 sick men, 
which gives a far greater allowance of space than in the usual service. 
For field service, tents of 686 cubic feet capacity, accommodating 16 
British or 20 native soldiers, and smaller ones of 392 cubic feet capac- 
ity, accommodating 8 British or 10 native soldiers, are in use. 
Tents are best arranged in short single lines, the individual tents 
being distant from each other at least once and a-half the tent's diam- 
eter ; the intervals are not fixed by regulation. If possible, they 
should face the east, so that when the day is advanced, the southern 
wall may be lifted so as to admit the sun's rays to the whole of the in- 
terior. Each tent should be ditched as soon as it is placed in position. 
The tent ditch should be 6 inches wide and 4 deep and must con- 
nect with the company ditches and these in turn with each other, 
forming a complete system of surface drainage. All surface drainage 
from higher ground must be prevented by being intercepted and 
turned aside. 
The floor of the tent should never be lowered by excavating, for 
men should sleep above the level of the ground and never below it. 
If the soil is not quite clean and firm, it should be dug out to the 
depth of about a foot and replaced by clean gravel or sand, if such is 
obtainable, and then covered with boards. Elevated platforms are 
eminently desirable, and tents not so provided should be moved every 
week to the open spaces between, so that the sun may exert its purify- 
ing influence and, together with fresh air, may put the vacated sites 
again in a condition for occupancy. The floors of the tents should, 
when possible, be covered with loose boards, if these are obtainable, 
and occasionally the surface of the soil should be scraped and replaced 
with clean gravel or sand. In malarial and yellow fever districts, 
nettings to exclude mosquitoes, especially at night, and individual 
netting on light frame-work for the protection of the head, the other 
1 Color the Canvas of Hospital Tents. Reprint, Transactions of the Association of 
Military Surgeons of the United States, 1896. POSTS AND CAMPS. 
613 
parts of the body being protected by clothing, will be found to have 
great influence in checking infection. 
Huts.-During cold weather, wooden huts are much better adapted 
for occupation than tents, and have come into extensive use in the 
German, French, and English armies, both in war and in time of 
peace. The use of log cabins is advocated by Col. Charles Smart, 
M.D., U. S. A., to house 4 men apiece. The inside dimensions given 
are 13x7 feet; walls, 6 feet; ridge, 10 feet from the floor ; the door to 
open in the middle of one side; the chimney opposite the door out- 
side the wall; the roof consists of canvas 14 x 12 feet, with a larger 
fly. This is regarded as the best size and allowance, but the present 
tactics require squads of 8 for whom, according to Woodhull, " there 
should be two huts 8x11 feet end to end, 6 feet apart, with one con- 
tinuous roof and door in the adjacent ends, but not midway. The 
chimney should be in the middle of one long end. Two platforms 
each 6Jx4|, one lengthwise and one across the end, would accommo- 
date two men, each sleeping with their heads adjacent. The covered 
porch between the huts would be 6 x 9 feet in the clear, the sleeping 
platform be open beneath, and under no pretence should two-storied 
bunks be allowed." On damp sites, the walls should be raised a foot 
from the surface, but on dry soil, they may be built directly on the 
ground level, the soil well pounded down, covered with sand and 
gravel and concreted. 
The floor of the huts raised from the ground is best made of split or 
dressed logs. The canvas roof and fly are attached in such a way that 
they can be readily removed when it is desired to admit the sun to 
the interior. Portable huts may be furnished, having frames of wood 
or iron. The German huts are made with wooden or iron frames 
covered with felt and lined with canvas. They are easily ventilated 
and warmed. The French huts are made circular in shape; the walls 
are of boards with glass windows. They are easily ventilated and heated. 
The huts should be at least 10 feet apart at the ends and the inter- 
spaces should be carefully protected from pollution. 
Water Supply.-It goes without saying, that one of the first consid- 
erations in the establishment of a permanent camp is an adequate sup- 
ply of potable water, which subject is elsewhere presented. It is cus- 
tomary to allow at least five gallons per capita per diem for all purposes, 
and as much more as is practicable. Water-closets and baths require, 
naturally, a very generous allowance. Hospitals require much more 
per capita than barracks. For horses, from 5 to 10 gallons per diem 
are required. In general, it may be said that the more generous the 
supply, the greater the general cleanliness and efficiency. 
In temporary camps, the supply, both as to quality and quantity, is 
determined by natural conditions and must be taken as it is found. 
If purification of that intended for drinking appears to be necessary, 
the methods mentioned in the consideration of the subject of water 
supplies may be adopted according to availability. The simplest are 
boiling and the application of alum, with subsequent filtration, if possi- 614 
MILITARY HYGIENE. 
ble, through sand held in suitable receptacles such as half barrels with 
perforations through their bottoms. The so-called " mechanical fil- 
ters/' so much used in the purification of public water supplies, are 
more efficient and convenient. Experience has shown that no mat- 
ter how urgent the necessity for care in the avoidance of pollution of 
water, it is always difficult to prevent some of the men from reckless- 
ness in drinking. The operation of purification should be in the im- 
mediate charge of a non-commissioned officer, properly instructed and 
with a suitable detail. 
Sewerage.-The introduction of an abundant water supply in a 
camp is, of course, followed by more or less lavish use of water for all 
general purposes, and this necessitates a system of sewerage for carry- 
ing off liquid waste and human excreta. Camp sewers should be con- 
structed in a proper manner of bricks or drain pipe and never of wood. 
The method of final disposal of the sewage at the outfall will depend 
upon individual circumstances. All permanent camps should be prop- 
erly sewered. 
In case of outbreaks of typhoid fever, yellow fever, or cholera or 
other diseases of the same general class, the excreta should be disin- 
fected before being otherwise disposed of. In army practice, chloride 
of lime 4 per cent, and carbolic acid 5 per cent, are commonly used 
with weaker solution of carbolic acid and corrosive sublimate 1-1,000 
for washing floors and articles of furniture or for soaking soiled clothes. 
Milk of lime is highly to be recommended for excreta, as is also for- 
maldehyde solution, if it can be obtained. The Manual for the Medical 
Department says on this point: " Sulphate of iron and other cheap 
antiseptics and deodorants may be used when necessary. But the 
necessity for their use is a reproach upon the sanitary police of a 
post and should only be required under exceptional circumstances. 
The alvine discharges of healthy persons do not require disinfec- 
tion, and when properly disposed of, do not require treatment with any 
chemical agent whatever. If water-closets or earth-closets are offen- 
sive, this is due to faulty construction, to insufficient supply of water 
or dry earth, or to neglect of ordinary cleanliness. The attempt to 
remedy such defects by the systematic use of antiseptics is expensive 
and unsatisfactory in its results. The same is true of foul drains, bad 
smelling urinals, accumulations of garbage, etc. The proper remedy 
for such conditions is cleanliness and strict sanitary police." 
When there is reason to believe that any infectious diseases are pres- 
ent in camps, the latrines and cesspools should be disinfected with milk 
of lime to the extent of one twentieth of their contents, to which should 
be added every day an amount equal to at least a tenth of the daily 
addition of excrement. Hospital sewage is dangerous enough to 
warrant treatment on the spot with disinfectants. 
In the absence of a regular system of sewerage, Surgeon-General 
Sternberg recommends cylindrical galvanized iron vessels 18 inches in 
depth and diameter, with a trough around the upper end three inches 
deep filled with disinfectant. Into this, the cover fits and thus serves POSTS AND CAMPS. 
615 
as a valve and prevents the escape of foul odors and the entrance of 
flies. A second cover with a hole serves as a seat. The receptacle is 
to be partly filled with carbolic solution or the contents are to be treated 
with caustic litne or ashes or dry earth. These vessels should be re- 
moved at regular times and clean ones should be substituted while 
they are removed, emptied, and cleaned. 
Sinks and Latrines.-A sink, in military parlance, is a cesspool or 
privy vault in a temporary camp ; usually, a trench from twelve to 
fifteen feet in length, about two feet in width and eight in depth, with 
the earth, which has been thrown up, piled along one side. The requi- 
site number should be dug before a camp is occupied or as quickly 
thereafter as possible. They should be placed to leeward, or in such 
position that the prevailing winds shall not convey the odor therefrom 
over the company areas, and should never be placed near existing 
wells. They should not be placed any farther away from the men's 
quarters than absolutely necessary. For convenience of use, a strong 
pole is laid horizontally on upright forks at the proper height and on 
the side opposite the excavated earth. The latter, kept as dry as 
possible, is thrown back each day over the deposited excreta, often 
with caustic lime, chlorinated lime, or ashes. 
Behring1 recommends, in case of necessity, from 5 to 7.5 liters of 
milk of lime for each 250 men; Pfuhl2 advises 400 cc. per man. 
The addition of chlorinated lime possesses a double advantage, since 
it not only acts as a disinfectant, but serves to drive away flies, which 
otherwise collect and may become active agents in the spread of infec- 
tious disease. 
Small sinks for each company are regarded as much better on sev- 
eral accounts than one or more large ones for each regiment. They 
afford greater privacy when enclosed with brushwood and are gener- 
ally better looked after, since the responsibility for their care is more 
definitely fixed. 
When filled to within two feet of the surface, the remaining earth 
should be thrown in and rounded over, the site marked, and, at the 
same time, new trenches prepared. On breaking camp, all sinks, how- 
ever little used, should be filled up and marked. 
When the probable stay is to be more than of a few days' duration, the 
horizontal poles are commonly replaced by box seats, open at the back. 
In winter, the trenches should be completely covered by box seats 
with covers; hinging of the top or rear side will be necessary for the 
proper throwing in of the excavated earth. 
The word latrine is commonly used as synonymous with sink. It is 
properly defined as " a privy or water-closet, especially in trough form 
accommodating several at the same time."3 A further description of 
a latrine is elsewhere given (se$ page 621). Latrines are more com- 
monly installed in barracks or permanent camps. They require fre- 
1 Zeitschrift fur Hygiene, IX., p. 395. 
2 Ibidem, VI., p. 97. 
3 Standard Dictionary. 616 
MILITARY HYGIENE. 
quent flushing, if connected with a system of sewerage, and frequent 
emptying and cleansing, if not so connected. The seats and floors 
must be kept thoroughly clean by periodical washing ; twice daily is 
strongly recommended. 
Urinals apart from sinks and latrines are installed in both perma- 
nent and temporary camps, and in both it is essential that they be of 
easy access and their use compelled on account of the nuisance arising 
from indiscriminate voiding of urine on the ground and of the possi- 
bility of the dissemination of typhoid fever by the urine of ambula- 
tory cases of that disease and of convalescents therefrom. In bad 
weather and at night, all parts of a camp, and especially the company 
areas, are liable to urinary contamination, which should be prevented 
as far as possible by stringent rules and constant vigilance. 
Inspections.-Under the Army Regulations, an annual inspection of 
the buildings at every post is made by the commanding officer and 
quartermaster on the first day of March, and immediately afterward 
a report is submitted giving a description and showing the condition 
and capacity of each building and the character and extent of any 
additions, alterations, and repairs. Sanitary inspections are more fre- 
quent and more searching in character. The surgeon is required to 
examine, at least once a month, and note in the medical history of the 
post, the sanitary condition of all public buildings, the drainage, sew- 
erage, amount and quality of water supply, clothing and the habits of 
the men, and character and cooking of the food, and immediately after 
such examination to report thereon in writing to the commanding 
officer with such recommendations as he may deem proper. Super- 
ficial inspection is not enough, for everything may look clean exter- 
nally and yet the general condition may be bad. 
The condition of the air is of much more importance during the 
sleeping hours than during the day; therefore, ventilation should be 
investigated at night. Walls and floors should be carefully ex- 
amined, especially if they are made of porous material. Walls found 
to be contaminated with organic filth should be scraped and then 
thoroughly whitewashed. The floors, whether of barracks, tents or 
huts, should be scrupulously clean and dry ; the bedding should be 
free from dampness; the spare clothing and the men themselves and 
their clothing in use should be clean. The site and immediate sur- 
roundings of every permanent or temporary structure should be ex- 
amined with particular reference to the drainage and general condition 
of the soil. 
Sanitary Police.-Exceedingly strict sanitary policing is necessary to 
keep a camp in a healthy condition. The responsibility for condition 
rests with the commanding officer, but is shared in by the company 
officers, who must look after their quarters and men. Under the title 
of " officer of the day," company commanders serve in turn, each for a 
day, in charge of general sanitation, and each is responsible to his com- 
manding officer for the order and cleanliness of the camp on the day 
of his service. POSTS AND CAMPS. 
617 
It has been demonstrated repeatedly that untrained or inexperienced 
soldiers cannot be depended upon for thorough cleaning or keeping 
things clean, and unless sanitary police be very strict, a clean and 
everyway good natural site may quickly be contaminated and made 
unhealthy. Until discipline is well established, the enforcement of 
proper sanitary regulations is extremely difficult, for while they may 
be most carefully formulated, the necessary orders are difficult of en- 
forcement. Even with the utmost care and vigilance, contamination 
of the site is only a question of time, but the more efficient the system, 
the longer is that time deferred. A camp in which no attention is paid 
to cleanliness of the company streets and to habits of personal cleanli- 
ness is sure to be an unhealthy one, and men who will permit such 
conditions to obtain are commonly bad soldiers in every sense of the 
word, with no esprit de corps, slovenly in all their habits, conspicu- 
ously attentive to sick call, and with no respect for themselves or their 
superiors. 
In such a camp, the development of epidemics of infectious diseases, 
particularly typhoid fever, is only a question of time, since it needs 
only the introduction of the specific germ and favorable opportunities 
for its dissemination. Since this disease is endemic in all parts of the 
country, it is not strange that among large numbers of men brought in 
from different quarters there should be one or more carriers of the in- 
fection. In any camp of whatever degree of efficiency in sanitary po- 
lice, unless such cases are recognized at once and their excreta com- 
pletely disinfected or otherwise disposed of so that no danger shall be 
possible therefrom, the site is likely to become polluted and the bacilli 
distributed through the usual agencies. 
One of the first essentials of maintaining cleanliness in camp is good 
surface drainage. If the soil is damp, the site soon becomes an 
expanse of mud, owing to the constant impress of hundreds of feet. 
Mud assists in the conservation of refuse and filth which it envelopes 
and masks, and hence arises the necessity for efficient and thorough 
ditching and for filling up depressions likely to retain surface water. 
The usual pathways and sidewalks should be made as dry as possible 
by the application of gravel and by such other methods as are appli- 
cable to each individual case. 
All refuse of whatsoever kind must be prevented from accumulating 
within the lines ; everything must be promptly removed and disposed 
of, if possible, by burning. Kitchen refuse should be deposited in 
covered receptacles, which should be carried away twice daily. On no 
account should it be left exposed on the ground or elsewhere, since not 
only does it speedily develop the well-known nauseous odor of swill 
and thus become a nuisance, but it is an attraction for flies, which, by 
their investigation of all sorts of filth including the faecal discharges in 
the sinks, and then of the soldiers' food both in the kitchen and at 
mess, have again and again proved themselves to be largely responsi- 
ble for the spread of epidemic diseases, as will be explained more in 
detail on a later page. 618 
MILITARY HYGIENE. 
The final disposition of kitchen refuse is often a problem fraught 
with serious difficulties. When possible it should be burned in one of 
the numerous forms of incinerators devised for the purpose, but on no 
account should it be spread out in the vicinity of the apparatus to dry. 
If it be advisable to bury any part of it, at whatever distance below 
the surface it is deposited, it should be well covered with clean earth. 
The deeper it is buried, the longer will it resist complete decomposition. 
Stable manure should be removed every day and deposited at a 
sufficient distance and in such a location as to ensure that it shall not 
be a nuisance or a source of danger to the water supply. Incombusti- 
ble harmless refuse should be removed out of sight and not allowed to 
accumulate, for anything promoting untidiness of appearance invites 
additional untidiness by its example. 
Considering the many details of camp police and the necessity for 
cooperation on the part of every man, it is not strange that, in our re- 
cent war with Spain, the hasty gathering together of large bodies of 
undisciplined troops from all parts of the country into large impro- 
vised camps, largely under the control of inexperienced officers both of 
the line and medical service, was followed very quickly by the out- 
break of epidemic diseases, which carried off large numbers of men who, 
to a certain degree, were victims of their own carelessness. 
It is related, for example, that a certain regiment of volunteers, en- 
camping nearly side by side with one of regulars, was invaded to an 
extraordinary degree by typhoid fever, while the regulars were prac- 
tically free from disease. One of the medical officers informed the 
author that most of these men were so dirty, lazy, ignorant, intempe- 
rate, and immoral, that nothing short of an extensive epidemic among 
them could have been expected and was expected from the start. 
They saw some active service and were conspicuous for general ineffi- 
ciency and lack of discipline. Their ranks were very largely reduced 
by disease, and the casualties were practically nothing. The survivors 
returned to civil life and were welcomed as heroes ; those who perished 
in consequence of their own and their comrades' revolting habits of 
life are enrolled with those who sacrificed their lives in defence of 
their country's honor. 
A striking and interesting object lesson in camp sanitation is given 
by Col. Chas. R. Greenleaf, M.D., Medical Inspector, U. S. A.1 Two 
camps located very near together, nearly equal in the number of men 
contained (about 12,000), and with the same conditions of climate, 
soil, water supply, and food, showed very different records of morbid- 
ity and mortality. In one, " the men were scourged with sickness and 
death, and large numbers of them were permanently invalided; local 
epidemics became general, and soon the entire camp was so thoroughly 
infected that it was of necessity abandoned." In the other, " but little 
sickness (the percentage never exceeding five and a-half of the aggre- 
gate strength), few deaths and a few cases permanently invalided; 
' An Object Lesson in Military Sanitation, Boston Medical and Surgical Journal, 
Nov. 16, 1899, p. 485. POSTS AND CAMPS. 
619 
local epidemics of contagious disease, due to importation," were quickly- 
controlled, and in no case extended beyond the respective commands 
which brought them, nor did a single case of infectious disease originate 
in the camp. 
The difference in the health conditions of the two camps was due to 
the fact that in one, " the advice of sanitarians was seldom asked, and 
when asked was not followed, and nearly every law of health was 
either ignored or violated," while in the other, " the advice of sani- 
tarians was freely sought, accepted and carried out, no pains being 
spared to secure as far as possible, compliance with the laws of health." 
The benefits of sanitation were recognized by both officers and men, 
and the advice of its teachers was carried out by all to the fullest ex- 
tent. 
The following sanitary regulations, published for the governing of 
certain model camps established in the Presidio Reservation, one for 
five regiments of volunteers returning from the Philippine Islands, 
one for four regiments of out-going volunteers, or about 5,200 men, 
and one for about 2,000 recruits for the regular regiments already in 
the Philippines, are communicated by Dr. Greenleaf. (" In planning 
these camps the primary objects were to remove the kitchens as far as 
possible from the latrines, to provide a safe method for the disposal 
of excreta, garbage, etc., to secure means for the personal cleanliness 
of the men, to heat their quarters, and to supply them with an abun- 
dance of good food and water.") 
" The commanding officer of the troops occupying the camps will de- 
tail from his command two sanitary inspectors; one from the line, 
preferably a major of the regiment, and the other a regimental med- 
ical officer, whose daily duty it shall be to jointly inspect the regiment, 
inquiring into the general police of the company quarters and streets, 
the kitchens, the food, its preparation, quality and method of serving, 
the latrines, urinals and sewers, and making to the regimental com- 
mander a brief report of any unsanitary conditions they may discover, 
this report to be forwarded the same day to the medical inspector of 
the army at department headquarters. 
" One medical officer and one hospital steward from each regiment 
will be required to be present for duty with the regiment at all times 
of the day and night. 
" A daily sick call will be held and slight cases of illness treated in 
quarters or in the regimental hospitals provided for that purpose, but 
all men who are likely to remain sick more than three days will be 
promptly sent to the General Hospital at the Presidio of San Francisco. 
11 If any case of infectious disease occurs, the fact will be promptly 
reported to the camp surgeon, who is authorized to make proper dis- 
position for its isolation and care. 
" An ambulance fully equipped with a team will be assigned to the 
camp by the commanding officer of the Presidio. This ambulance will 
report daily to the camp surgeon at sick call, remaining in the camp 
during the day, subject to his orders. Under no circumstances will 620 
MILITARY HYGIENE. 
this ambulance be used for any other purpose than the transportation 
of the sick, or medical supplies. The commanding officer of the 
Presidio will also cause another ambulance to be sent to the camp for 
service at night time. This ambulance will remain on duty from re- 
treat to reveille for night emergency service. When the night ambu- 
lance reports for duty, the day ambulance will be relieved and returned 
to the post. 
"Company commanders will caution their men against exposure to 
the fogs and high winds that prevail here, especially in the early 
morning and evening, at which time overcoats will be worn. Riding 
on the ' dummy ' of the street cars, especially at night, is particularly 
hazardous to men recently returned from service in the tropics. Guard 
duty and other military functions required at these hours will be held 
in overcoats, and at breakfast and supper the stoves in the dining- 
rooms will be provided with fires. The sale, by civilians, of food or 
drink within the limits of the camp will be forbidden. 
" At retreat, urine tubs, two to each company, will be placed in each 
company street, and men desiring to urinate at any time during the 
night will be required to use them. The tubs will be removed from 
the company street at reveille to a place convenient for the scavengers, 
who will remove, clean and place lime in them for use the next night. 
" The quartermaster's department will be required to provide an 
ample force of scavengers to clean the latrines and urinal troughs at 
least once daily, and to refill the troughs with milk of lime ; they will 
also remove all kitchen garbage, and either cremate it or dispose of it 
in such place as the quartermaster shall direct. Particular care will 
be enjoined on company cooks to keep grease traps clean, and to de- 
posit all solid garbage in cans prepared for that purpose in time for its 
removal by the scavengers. 
"The quartermaster's department will furnish to each regiment an 
ample supply of necessary policing implements, to enable the men to 
thoroughly and effectively police the camp daily." 
These regulations, Dr. Greenleaf reports, were promptly carried out 
by officers and men, and, in spite of the fact that nearly every body 
of men brought some form of infectious disease, including typhoid 
fever, tropical dysentery, diphtheria, smallpox, measles and mumps, 
not a single case of any infectious disease originated in the camps, all 
of the imported cases being promptly segregated from the command, 
all infected material disinfected or destroyed, and all men who had 
been exposed isolated and quarantined. 
In all these camps, the latrines and bath-houses were placed on the 
flanks and rear ; the kitchens and mess halls, in the central lines. In 
the rear of each mess hall, a zinc-lined wash trough, supplied with a 
dozen bib cocks, was placed to be used as a lavatory ; near the door of 
each kitchen was a grease trap connected with the sewer, and galva- 
nized cans for garbage and ashes were placed on the porch. Large 
caldrons for heating water for laundry and other purposes were set up in 
convenient places. Two galvanized wash-tubs were furnished to each POSTS AND CAMPS. 
621 
company, and " night soil tubs were placed in every company street at 
* tattoo ' for the use of the men during the night, a sentinel being 
posted in the street to see that the orders regarding their use were car- 
ried out." The construction of latrines and disposal of excreta were 
carried out according to the recommendations of a board of medical 
officers, consisting of Major Reed, U. S. A., and Majors Vaughn and 
Shakspeare, U. S. V., as follow's : 
" A trough made of No. 22 galvanized iron, fourteen feet long, 
twenty-two inches wide at the top, parabolic in cross section, and with 
a maximum depth of eighteen inches, if set in a light wooden frame- 
work, which serves as a protective crate in transportation, gives sup- 
port to the trough while in position, and serves for the attachment of 
a lid in two sections, furnished with seven seat holes. These holes are 
shaped so as to render soiling of the seat difficult, and a slanting board 
one foot wide, permanently fixed at a proper angle above the seat, pre- 
vents the men from getting up on it with their feet. When in position, 
one end of the trough is raised four inches higher than the other. 
The trough is placed in an ordinary frame privy house. At the upper 
end of the trough there is placed a galvanized iron gutter of proper 
height and inclination leading into the trough to serve as a urinal. 
" The rear side of the gutter or that attached to the wall of the build- 
ing is higher than the front side, to prevent soiling the building. The 
trough is prepared for the reception of fiecal matter by filling it with 
water until a certain level, indicated by a line on the inside of the 
trough, is reached. A measure for the purpose, and holding one-sixth 
of a barrel, is now filled with quicklime and emptied into the water; 
some dry lime should also be placed in the urinal. The lime in the 
trough is thoroughly stirred with a wooden paddle. This stirring is 
repeated three times every day. The wrooden paddle wrhen not in use 
stands in a pail filled with milk of lime. Toilet paper is provided for 
the men's use in the latrines, because large pieces of newspaper will 
float on the water holding masses of fecal matter above the surface, 
thus exposing it to the flies and other insects. 
" Once a day the contents of these troughs are pumped out into an 
odorless excavator, carted away and properly disposed of. The milk 
of lime destroys the typhoid bacillus, and the contents of the trough, 
if properly cared for, will be quite innocuous. Not only is the milk 
of lime and fecal matter innocuous, but its value as a fertilizer is con- 
siderable." 
It may be stated, however, that these excellent results in sanitary 
police were not brought about without outside assistance, for it was 
found advisable to employ a corps of civilian scavengers consisting of 2 
overseers, 22 pight scavengers, 54 day scavengers, and 17 teamsters, 
with 5 odorless excavating carts, 6 sanitary cars, and 12 dust carts. 
By means of this outside force, the camp was kept thoroughly clean, 
and the excreta were promptly removed and disposed of. The latrine 
troughs were emptied twice in 24 hours, and garbage and all manner 
of waste material was removed twice daily. The tent floors, kitchens, 622 
MILITARY HYGIENE. 
mess halls, and company streets were swept daily by the soldiers them- 
selves, and one man from each company did duty each day in the com- 
pany latrine to keep it clean and stir the lime solution frequently. 
The Diseases of the Soldier. 
While there are no diseases peculiar to the soldier, there are many to 
which the circumstances and conditions incident to camp life render 
him conspicuously susceptible. These are mainly of the preventable 
class and can be largely checked by proper regard to the principles of 
camp sanitation, by avoidance of polluted water, bad cooking, over- 
crowding, and overwork, and, in some degree, by the inculcation of 
the principles of moral living. 
It is difficult or impossible to determine how soldiers compare with 
civilians in the amount of sickness which they suffer, since we have no 
statistics of general morbidity, especially of corresponding age periods, 
of the civil population ; and even were such available, it would be neces- 
sary to bear in mind that the soldier is often on the sick list with ail- 
ments which, in civil life, would neither deter him from attending to his 
daily work nor cause him to go to the added expense of medical ad- 
vice. The soldier has absolutely free medical attendance and care, and 
of this he freely avails himself, excepting, with many, in case of vene- 
real troubles. 
Concerning the constitution of the medical corps, the hospital ac- 
commodations and general administration, all of which are fixed by law 
and regulation, no description or discussion is necessary; and a brief 
consideration of the prevalence and predisposing causes of the chief 
diseases of armies is all that lies within the scope of this work. 
It is a well-known fact that in both war and peace the greatest mor- 
tality among soldiers is from disease and not from violence, the single 
exception which history records being afforded by the German army in 
the war of 1870 with France. In our war with Mexico, according to 
Woodhull, 935 of the regular force were killed or died of wounds and 
4,714 died of disease in the field. In the Civil War, 99,183 whites and 
3,417 negroes were killed or died of wounds, and 171,806 whites and 
29,963 negroes died of disease. In our recent war with Spain and 
troubles in the Philippines, during the year from May 1, 1898, to April 
30, 1899, according to the report of the Surgeon-General, 968 men 
were killed or died of wounds, injuries, and accidents, and 5,438 died 
of disease. Typhoid fever was responsible for more than half the deaths 
from disease, next in order came malaria, followed by pneumonia, yel- 
low fever, and smallpox. 
Tuberculosis.-In the large standing armies of the world, tubercu- 
losis has long played a leading part, due largely, as has been pointed 
out, to overcrowding and deficient ventilation, and to the enlistment of 
men in whom the disease is latent before entrance and developed by 
changes in habits of life, climate, etc. 
Yet, according to Colin,1 Inspector-General of Hygiene in the 
1 Journal d' Hygiene, March 1, 1900. THE DISEASES OF THE SOLDIER. 
623 
French Army, many persons with latent tuberculosis not only stand 
the hardships of military service well, but even become stronger and 
generally healthier. According to a statement by Surgeon-General 
Schjerning at the Tuberculosis Congress in Berlin (1899), a decided 
decrease in tuberculosis has been observed in the German army, while 
in other armies an increase from year to year in loss of men from this 
cause may be looked for as a certainty, especially when large increases 
in enlistment necessitate the inclusion of many not fit for service. 
Colin's statistics of losses to the French army are corroborative of 
Schjerning's statement, especially those for the year 1895, when a large 
increase of the army, necessitating a reduction in the quality demanded, 
was followed by a more marked increase in yearly loss. The figures 
follow: 
Year. 
Discharges per 1,000 
army strength. 
Deaths per 1,000 army 
strength. 
Total loss per 1,000 army 
strength. 
1888 
4.30 
1.18 
5.48 
1889 
4.94 
1.05 
5.99 
1890 
5.70 
1.08 
6.78 
1891 
6.10 
1.33 
7.43 
1892 
6.55 
1.04 
7.59 
1893 
6.33 
.94 
7.27 
1894 
6.55 
1.01 
7.56 
1895 
8.34 
1.14 
9.48 
1896 
7.34 
.94 
8.28 
Id the English service, phthisis is the chief cause of mortality and 
invaliding, the annual loss averaging somewhat below 5 per 1,000 
army strength. In the French service, the disease stands second to 
typhoid fever. 
In armies, as in general life, tuberculosis finds the greater number 
of its victims among those who are most confined and is more frequent 
in the garrisons of large towns than among troops in the less thickly 
settled parts. The most careful prophylaxis is demanded to prevent 
its spread, and the ideal measures would include the discharge of all 
persons capable of acting as foci of the disease. 
Typhoid Fever.-Typhoid fever is very prominent as a scourge, 
especially in time of war, when large bodies of raw and undisciplined 
troops are brought together in camps of instruction. Among large 
bodies of men drawn from different parts of a country in which the 
disease is very generally distributed, it is almost inevitable that there 
will be some who will introduce the specific germ. The individual 
soldiers, owing to their age and the abrupt changes in the nature of 
their surroundings and general habits of life, are very susceptible to 
infections in general. Statistics demonstrate that the seasoned regular 
suffers much less from disease, in proportion to numbers, than the un- 
disciplined volunteer and raw recruit. This is due to the fact that he 
has become accustomed to the mode of life, and, through training, has 
better learned how to take care of himself in all departments of 
personal hygiene. Great care is necessary to isolate cases as soon as 624 
MILITARY HYGIENE. 
recognized and to treat excreta so that their final disposal shall not be 
a menace to the safety of others. 
Of the highest importance is the prevention of access of flies to the 
discharges, for, as has been stated elsewhere, these pests have been re- 
sponsible for the spread of this and other diseases by contaminating the 
food supply after visiting the sinks. Also of the highest importance 
is the avoidance of a polluted water supply; boiling of water concern- 
ing which nothing is known should always be done as a matter of 
routine precaution, and the attention of the men should be drawn to 
the danger which they incur in the indiscriminate drinking of water 
which has not been thus treated or shown by competent authority not 
to require it. In general, it may be stated that without efficient san- 
itary police, typhoid fever among troops is always to be expected. 
Preventive inoculation against this disease, though in its infancy, has 
given sufficiently encouraging results to warrant trial on a large scale. 
The great majority of English troops sent to war in South Africa were 
so treated, and it is expected that valuable statistics concerning the 
efficacy of the treatment will be forthcoming. 
Dysentery.-In the South and in our new tropical possessions, dys- 
entery is one of the most important camp diseases; in fact, it is said 
that, within the tropics, dysentery annually claims far more victims 
than Asiatic cholera. Once introduced, like typhoid fever, it is likely 
to become epidemic. Prophylactic measures adopted are the same. 
Yellow Fever.-This disease of hot climates is confined practically 
to the Western Hemisphere. It is essentially a filth disease, or, at 
least, it finds in high temperatures, humidity, and filthy surroundings, 
the conditions most favorable to its spread. Concerning modes of in- 
fection but little is known, but the exciting cause is believed by some 
to reside in the excreta and vomitus, and by others in the blood and to 
be spread by mosquitoes and other insects. Strict sanitary police and 
general hygiene are demanded more than ever when yellow fever is 
prevalent, and when a camp becomes infected, it is advised to move at 
once to new and higher ground, taking due precautions not to carry 
along any infection on clothing or other articles. 
It is to be said, however, that the experiments of Dr. Reed, U. S. 
A.,1 and others at Quemados, Cuba, rather indicate that infected cloth- 
ing is without danger, and that mosquitoes are alone responsible for 
the spread of the disease. A room was divided by a wire screen, and 
into one side were introduced disinfected bedding and clothing and 
several infected mosquitoes; into the other, only infected clothing 
and bedding from the yellow fever hospital. A non-immune occupied 
the former until bitten, and developed the disease four days afterwards. 
Another slept in the latter in infected clothing and bedding for many 
nights and was unable to contract the disease. 
Malaria.-The various forms of malarial diseases are always a 
curse to armies, especially those operating in hot climates. Though 
the death roll from malaria may not be great, sickness and consequent 
1 Philadelphia Medical Journal, Jan. 19, 1901, p. 98. THE DISEASES OF THE SOLDIER. 
625 
invaliding are commonly enormous in amount, and an army stricken 
with malaria is an army unfit for field operations. The infection weak- 
ens the natural power of resistance to other infections and is said to 
predispose the victim especially to infection by typhoid fever and to 
exert a particularly pernicious influence on those who have already ac- 
quired or subsequently acquire venereal diseases. 
For many years, a variety of influences have been regarded as active 
agents in the spread of malaria ; these have already been discussed in 
the chapter on Soils. Since the confirmation of the discovery of the im- 
portant part played by certain genera of mosquitoes in the dissemination 
of the malarial poison, the necessity of the use of netting against these 
pests has been very clearly demonstrated. The preventive measures 
against malaria consist in the avoidance, if possible, of sites near which 
the conditions are favorable to the puddle-breeding mosquitoes, the 
avoidance of unnecessary going about during the hours when mosqui- 
toes are most active, prevention of access of mosquitoes to the sleeping 
quarters, and the systematic use of prophylactic doses of quinine morn- 
ing and night. Whiskey is not needed as an adjuvant, and is more 
likely to be an injury than an aid. Hot tea and coffee are more highly 
regarded. 
Measles.-In all new levies of troops, measles is a serious impedi- 
ment to efficiency, for once introduced, the disease spreads rapidly 
through the camp, especially if the troops are largely from the country, 
where they have escaped the diseases of childhood which ravage the 
population of cities and large towns. The importance of the disease 
appears, according to recent evidence, to be likely to be underrated by 
commanding officers. 
Diarrhoeal Diseases in General.-Because of the lesser resistance 
to specific infections, which appears to accompany even mild conditions 
of diarrhoea, it is essential to take such measures and precautions as are 
possible to prevent them. Among the prominent causes may be men- 
tioned the use of badly cooked, indigestible food, and chilling of the 
body, particularly at night while sleeping on the ground, even though 
separated from immediate contact therewith by rubber blankets. The 
prevention of the first cause needs hardly to be pointed out; for the 
prevention of the second, the habitual use of light flannel garments or 
abdominal bands is recommended. 
Sunstroke.-This consequence of extreme heat or over-exertion in 
high temperatures is very likely to be induced by imprudence in the 
matter of water supply and by continuous work without periods for 
rest and recuperation. According to Dr. Smart, U. S. A.,1 "If the 
allowance of water is scanty it must, nevertheless, be used at regular 
intervals, but economically lest it give out. There is manifestly less 
danger of a fulminant stroke with a stinted but steady supply than with 
full allowance for a given time followed by a period of enforced ab- 
stinence. On the other hand, if the supply is liberal it may be indulged 
in freely and with advantage when the skin is acting well." 
1 Philadelphia Medical Journal, Jan. 19, 1901, p. 158. 626 
MILITARY HYGIENE. 
He relates that, during a service of four years in the hot climate of 
Arizona, with commands of varying size, making long marches, often on 
scant allowance of water, he saw sunstroke on but one occasion, and in 
this instance, the rule to use the canteen in the early part of the march 
with caution, as if no more could be had until arrival in camp, was not 
followed. It was the rule, when a supply presented itself on the line 
of march, to use it freely, and then on proceeding to use the refilled 
canteens with the same caution as before. A canteen of tea, not neces- 
sarily strong, containing a little lemon juice, lime juice, or vinegar, is 
more desirable when obtainable than plain water. 
Venereal Diseases.-These are responsible for a very large amount 
of sickness in all armies, and their prevention has been the subject of 
much consideration by military authorities everywhere. But the reme- 
dies against the prevailing high figures of morbidity, namely, scientific 
and practical control of prostitution, find always and everywhere active 
opposition on the part of the public. 
Transmission of Epidemic Diseases by Flies.-Although the pos- 
sibility of the spread of such diseases as cholera, dysentery, and ty- 
phoid fever was suggested and demonstrated as early as 1892, the mat- 
ter did not receive any particular attention until the unusual prevalence 
of typhoid fever in the great military camps in the South in 1898 was 
made the subject of a careful inquiry, which led to the conclusion that 
the great swarms of flies which infested the camps were largely respon- 
sible. The first series of experiments on the subject of infection 
through the agency of flies was conducted by Sawtschenko 1 with pure 
cultures of cholera bacilli. The bacilli, fed to two kinds of flies, were 
found in the excreta and bowels as late as four days after ingestion; 
removed on the third day and inoculated into guinea-pigs, they were 
found to be quite as active as the pure cultures themselves. 
Similar results were obtained when, instead of pure cultures, the dis- 
charges of cholera patients were employed as feeding material. Some 
of the experiments indicated that the bacilli probably multiply within 
the fly, which thus acts as a breeder and distributing agent at the same 
time. A fly, caught in the autopsy room at Hamburg during the 
great epidemic of 1892, was examined by Simmonds,2 and yielded 
numerous bacilli. This suggested an inquiry into the length of time 
the cholera poison would retain its activity when adherent to flying 
insects, and experiment showed that it remained virulent for at least 
an hour and a-half after drying. Surgeon-General Sir William Moore3 
drew attention, in 1893, to the fact that, in India, flies abound most ex- 
tensively during the time and season of greatest prevalence of cholera ; 
he suggested that they might act as carriers of typhoid fever, phthisis, 
and ophthalmia. He instanced an epidemic of anthrax spread by flies 
which had covered the carcass of a dog thrown into a ditch. 
An instance of strong presumptive evidence of an outbreak of 
1 Centralblatt fur Bakteriologie und Parasitenkunde, XII., p. 983. 
2 Deutsche medicinische Wochenschrift, 1892, No. 41. 
3 Medical Magazine, July, 1893. THE DISEASES OF THE SOLDIER. 
627 
cholera through the agency of flies is furnished by Buchanan,1 who re- 
lates that in June, 1896, nine cases of the disease occurred in the Burd- 
wan jail, where, prior to and after the attack, there was exceptional 
freedom from bowel complaints. The water supply was above suspicion 
and was the same for all the inmates, who numbered 190 and were 
divided into two groups, the ordinary prisoners and the " infirm gang." 
The latter worked, slept, and associated generally with the former, 
but their food was specially cooked and they were fed in a separate 
place in the hospital compound. 
The ordinary prisoners-and it was among these that all the cases 
occurred-had their food prepared and were fed at the extreme oppo- 
site corner, diagonally from the hospital. Over the wall at their 
corner were a deserted compound and a row of dirty huts where cholera 
had existed during the preceding year. At the time, the city was 
more than usually infested with swarms of flies, and just before the 
outbreak, a storm had occurred, during which a strong E.N.E. wind 
blew across the jail yard from the locality above mentioned. All who 
were seized were among those who were known to have had their 
evening meal in the corner 
during the storm, and it 
was believed that swarms 
of flies were blown from 
the huts, and on reaching 
the trees and corner of the 
high jail wall, obtained 
shelter from the storm and 
settled upon the food ex- 
posed in the plates before 
the gang. 
The accompanying fig- 
ure shows the relative po- 
sitions of the two gangs at 
their meals, and of the 
deserted compound and 
dirty huts from which the 
flies were supposed to have 
come. The evidence here 
is purely circumstantial, 
U 5a ko nntorl fhok Plan of grounds of Burdwan jail, where cholera is supposed 
DUl IL IS LO Oe uoiea LliaL to have been carried by flies, 
all of the sick belonged 
to the same gang; that all had been over a month in jail, excepting 
two, who had been there seven and twelve days respectively; that 
there had been no prevalence of diarrhoea before, during, or after the 
outbreak ; that the water and milk supply were the same for all, and 
that the outbreak was very limited in extent. 
The prevalence of typhoid fever among Europeans in India has 
been attributed by Surgeon-Major Battersby 2 to the agency of flies, 
Fig. 99. 
FEEDING 
PLACES 
COOK 
HOUSE 
HOSPITAL 
GANG AT A WERE ATTACKED. 
GANG AT B ESCAPED. 
1 Indian Medical Gazette, March, 1897. 
2 British Medical Journal, Aug. 10, 1895. 628 
MILITARY HYGIENE. 
since,year by year, outbreaks occur which are most difficult or impossible 
to trace to a water-borne cause, the water supply being in many in- 
stances above suspicion and even of exceptional purity. The connec- 
tion in our own experience in 1898, though not absolutely proven, 
seems most reasonable and probable. 
The presence of plague bacilli in the intestines of flies has been 
demonstrated repeatedly within recent years, first by Yersin in 1894, 
who, noting the large number of dead flies where the victims were be- 
ing autopsied, crushed one fly and inoculated it into a guinea-pig, 
which died of the disease in 48 hours. Further investigation showed 
the bacilli present in the intestines of the living fly and led to the con- 
clusion that they actually multiply therein. 
It is conceivable that flies may spread infection through their own 
dejecta and by material adherent to their feet and other parts. The 
latter seems the more probable and common method when one con- 
siders the frequency with which these pests alight, now here, now 
there, on all manner of filth and food, for example, tracking that which 
adheres from the one over the surface of the other. Visiting the sinks 
at one time and the mess-tables at another, they have, in the absence of 
thorough camp sanitation, the widest opportunity for spreading disease. CHAPTER XL 
NAVAL AND MARINE HYGIENE. 
The conditions of life at sea in relation to health are very different 
in many respects from those which obtain ashore. The sea-faring 
man, wherever he goes, travels in his habitation, in which, necessarily, 
his share of cubic space is far less in amount than that which the prin- 
ciples of general hygiene stipulate as a permissible minimum for those 
ashore. His air supply while at work on and above the deck is of the 
greatest known purity, and while below in his sleeping quarters it is 
likely to be at times unutterably foul, and under usual conditions, even 
with the best of care and appliances, is usually not in conformity with 
the generally accepted standard. His work exposes him to the hard- 
ships of the most inclement weather, to extremes of heat in the stoke- 
holds of vessels propelled by steam, to long sustained muscular effort 
at critical periods; and involves short hours for sleep, and these not in 
one consecutive whole, but divided by intervening periods of duty. His 
food supply for the entire period from port to port must be transported 
with him, must necessarily possess keeping qualities, and hence con- 
sists largely of preserved instead of fresh meats, and dried and canned 
vegetables instead of those fresh from the fields. 
In the matter of kitchens, cooking appliances, and fuel, he is more 
fortunately circumstanced than the soldier, since wherever he goes they 
accompany him and he is quite independent of the frequently trouble- 
some question of transportation of supplies and appliances in time of 
need. Thus it was that, during the battle of Manila Bay, all hands 
could be piped to breakfast, whereas at the fierce onslaught by the land 
forces at San Juan, no such comfortable relief could be afforded. 
His water supply must be carried in proper storage or be obtained 
by distillatipn from the salt water in his path. But he has not to cope 
with the difficulties which beset the soldier in the matter of camp sani- 
tation, for his sewer is the boundless ocean and the question of disposal 
of garbage requires no thought. 
NAVAL RECRUITS. 
The United States Regulation forbids the enlistment as a landsman 
of any man over 25 years of age unless he has learned some mechan- 
ical trade, and in this instance he may not be enlisted without special 
authority, if over 34 years of age. A landsman is one who never be- 
fore has gone to sea, or, having been already at sea, does not possess 630 
NAVAL AND MARINE HYGIENE. 
the skill required of an ordinary seaman. An ordinary seaman must 
already have had two years' experience. An able seaman is one who 
has had at least four years' experience and understands the navigation 
of ships. Apprentices are enlisted not under 16 years of age and 
serve as such until 21, when their term expires. 
A candidate for the service is required to undergo a thorough ex- 
amination. If afflicted with stricture, internal piles, or any serious 
disease, or suffering from the results of any former disease or injury, 
or subject to fits, he is debarred from the service. Applicants for 
positions as skilled mechanics must demonstrate their knowledge of 
their craft and show that they possess the necessary qualifications for 
following it. 
THE NAVAL RATION. 
The naval ration is always different from that of the soldier for rea- 
sons already given. The ration of the United States Navy as pre- 
scribed by Congress consists of the following daily allowance of pro- 
visions to each person : (1) One pound of salt pork and half a pint 
of beans or peas, or (2) one pound of salt beef, half a pound of flour 
and two ounces of dried apples or other dried fruit, or (3) three-fourths 
of a pound of preserved meat, half a pound of rice, two ounces of 
butter, and one ounce of dry mixed vegetables, or (4) three-fourths of 
a pound of preserved meat, two ounces of butter and two ounces of 
dried potato ; and in addition to either of the above allowances, four- 
teen ounces of hard bread, a quarter of an ounce of tea or one ounce 
of coffee or cocoa, and two ounces of sugar. In addition, each person 
is allowed a weekly allowance of one-half pound of pickles, and one- 
half pint each of molasses and vinegar. 
It is further provided " that fresh or preserved meat may be sub- 
stituted for salt beef or pork, and vegetables for the other articles 
usually issued with the salted meats, allowing one and a quarter 
pounds of fresh or three-quarters of a pound of preserved meat for 
one pound of salted beef or pork, and regulating the quantity of vege- 
tables so as to equal the value of the articles for which they may be 
substituted." Furthermore, the substitution of one pound of soft bread 
or one pound of flour, or half a pound of rice for the daily allowance 
of fourteen ounces of hard bread, and of half a pound of rice for half 
a pint of beans or peas, and vice versa, is permitted in case of necessity 
of varying the daily allowances. 
It is further provided that "in case of necessity, the daily allowance 
of provisions may be diminished or varied in the discretion of the 
senior officer in command ; provided, that an additional ration of tea 
or coffee and sugar be hereafter allowed to each seaman, to be provided 
at his first ' turning out.' That in addition to the navy ration, as now 
established by law, the apprentice boys in the naval service who are 
attached to training vessels shall be allowed four ounces of oatmeal 
and four ounces of hominy, coarse or fine, on alternate days, together 
with one-half of a gill of molasses." Further substitutions are al- THE NAVAL RATION. 
631 
lowed as follows : Six ounces of canned vegetables in place of one 
ounce of dried mixed vegetables or two ounces of dried potatoes, and 
extract of coffee with milk and sugar in place of the daily allowance of 
coffee and sugar. 
Preserved meats, in the meaning of the law, comprise canned beef, 
mutton, corned beef, bacon, ham, sausages, salt fish, and any other 
smoked or salted meats. Flour comprises wheat, rye, oatmeal, corn- 
meal, and hominy. Dried fruits include apples, peaches, prunes, raisins, 
dates, figs, and others susceptible of preservation by drying. 
From the above, it will be noted that our naval ration is very elastic 
and generous, and, indeed, it is said to be superior in amount and va- 
riety to that of any foreign navy, just as our army ration surpasses in 
these respects those of other armies. According to the late Dr. C. A. 
Siegfried, U. S. N.,1 the average ration yields 157.34 grams of protein, 
75.59 of fats and 549.77 of carbohydrates, equivalent to 3,615 calories 
of potential energy. It thus yields nearly 40 grams of protein, nearly 
20 of fat, and nearly 50 of carbohydrates in excess of Voit's estimate 
of the daily requirement of a laboring man working from nine to ten 
hours a day and weighing from 154 to 165 pounds. 
In spite of the elasticity and abundance of the ration, considerable 
improvement and much greater satisfaction appear to be attained by 
the system of the consolidated mess, instituted originally, in 1889, by 
Lieutenant Delehanty of the U. S. S. Independence. Not the least of 
its advantages is the improvement in the preparation and serving of 
the food. In the ordinary method of messing, the ship's company is 
divided into a number of messes of about twenty men and each has its 
own cook and mess attendants. The preparation of the food for all 
is in charge of the chief cook and a number of assistants, and the serv- 
ing out and the care of the mess gear are attended to by the mess at- 
tendants or berth-deck cooks. According to Lieutenant B. C. Decker,2 
of the U. S. S. Indiana, "the present system of messes with incom- 
petent and often broken-down landsmen as cooks, * * * and with 
general waste and mismanagement is a failure." 
In the consolidated mess of the Indiana, as described by Decker, 
the crew of 380 men have a common interest and are attended to by 
seven cooks, one of the first class, two of the second, and four of the 
third class, a commissary yeoman and a storeroom keeper. Funds 
for provisioning the mess are derived from the commuted rations and 
the canteen. (Here may be stated that, in the discussion of the paper 
noted, the canteen system, as it existed in the Navy, was the subject of 
severe criticism by officers of the line. It is now abolished.) 
The system saves much trouble, requires fewer cooks, and by mak- 
ing possible the purchase of a still wider variety of food materials, en- 
sures greater satisfaction throughout at a diminished cost. Half the 
rations are commuted to this end, but according to Surgeon H. G. 
1 Journal of the American Medical Association, Dec. 31, 1892. 
2 The Consolidated Mess of the Crew of the U. S. S. Indiana, Proceedings of the U. 
S. Naval Institute, XXIII., 1897, p. 463. 632 
NAVAL AND MARINE HYGIENE. 
Beyer,1 the food value of the ration can be still further increased in 
direct proportion to the number of rations commuted, and in view of 
the figures of food values offered, "the most impartial judge would 
declare in favor of the commutation of all ship's rations; he would 
have the regular ship's ration, in its pure and unmodified form, rele- 
gated to the function of an emergency or iron ration, to be used only 
whenever ships are kept at sea and have, from necessity, no communi- 
cation with any of the markets on shore." 
Under the usual system, it is claimed, the waste from bad manage- 
ment, poor cooking, and worse service is very great. Under the con- 
solidated system, the conversion of rations into money, contributions to 
the general mess fund, and utilization of the profits of the canteen 
admit of the purchase in open market of such articles as the men desire. 
As shown by Dr. Beyer, the legalized naval ration is theoretically 
generous both in quantity and quality, but, nevertheless, good and 
sufficient reasons exist for the desire on the part of the men to com- 
mute part of their allowances and obtain a decided change. He urges, 
therefore, the consolidation of messes, the training of cooks, the com- 
mutation of rations whenever communication with markets ashore can 
be established, and the relegation of the ship's ration to the function 
of an emergency ration to be used only in case of necessity. 
The principal defects of all dietaries for sea-faring men comprise 
monotony, deficiency in vegetable components, and excess of preserved 
meats. In order to guard against the results of an insufficient supply 
of antiscorbutic vegetables, the Revised Statues require that all vessels 
of over 75 tons bound across the Atlantic or Pacific or around Cape 
Horn or Cape of Good Hope, or engaged in whaling or sealing shall 
carry a sufficient supply of lemon juice or lime juice, and vinegar, 
which shall be served out within ten days after salt provisions have 
been served out, the lemon juice or lime juice at the rate of one-half 
ounce daily, and the vinegar at the rate of one-half pint weekly, per 
man. 
Water Supply. 
The satisfactory storage of water aboard ships is a matter of some 
difficulty. Small vessels, as ordinary merchant ships and similar 
craft, not provided with distilling apparatus must necessarily carry 
a sufficiency of water for the passage between ports, reckoned at 
three quarts daily per man plus an amount sufficient for cooking. 
Water is stored in wooden casks and metallic tanks. Storage in casks 
is far from satisfactory, on account of the deterioration which occurs 
in the quality of the water. This is due to the action of the water 
in extracting matters from the wood and to decomposition of these 
matters induced and carried on by the usual agencies. Casks should 
not be made of any soft wood, and the interior should be very thor- 
oughly charred, in order to diminish as much as possible the extrac- 
'The Hygiene of the Navy Ration, Proceedings of the U. S. Naval Institute, 
XXV., 1899, p. 607. THE SAILOR'S SLEEPING QUARTERS. 
633 
tion of soluble constituents and to guard against decay. Tanks are 
commonly made of galvanized iron, lined sometimes with cement. 
They should be placed in easily accessible locations which admit of 
ready inspection and cleansing. 
No water should be taken on board unless its source is known and 
its quality is such as to preclude the danger of introducing water- 
borne diseases. Large vessels and steamships provided with distilling 
apparatus do not, of course, need to provide for the storage of large 
volumes of water. The water yielded by a distilling apparatus is, on 
the whole, far superior in quality to that which, however good origi- 
nally, has been stored for any considerable length of time. For full 
consideration of the subject of water and its storage, the reader is re- 
ferred to the chapter devoted to that subject. 
The Sailor's Sleeping Quarters. 
The sailor is commonly berthed either in deck houses, forecastles, 
or between decks. Deck houses are by far to be preferred, since they 
are well lighted and can be well aired. They are placed about mid- 
ships and are most accessible and convenient. There are two kinds 
of forecastles ; one, known as the top-gallant forecastle, has side lights 
and is entered through a doorway; the other, commonly found on 
merchant vessels and small craft in general, is entered from above 
through a hatchway and is not lighted. This is the least desirable 
lodging place and exceedingly difficult to keep in a cleanly condition. 
In fact, on merchant vessels, it is commonly infested with bedbugs and 
other vermin and is the storehouse for wet dirty clothes and all 
manner of rubbish. Forecastles are likely to be damper than other 
parts, on account of the greater amount of water shipped over the 
fore part of the vessel when under way. 
Cubic space per capita depends upon the facilities for the convenient 
hanging of hammocks; it can never be generous : it is always far less 
in amount than is regarded ashore as essential to the maintenance of 
a fair degree of health. In fact, sailors are almost always over- 
crowded : they have nothing like the allowance which obtains in bar- 
racks, but rather that of the tent in the field. The fact that the 
sailor's rest is broken in upon, so that at no time does he get more 
than four hours of consecutive sleep, may perhaps be a benefit to him 
in that, in the intervals, he breathes the pure outside air, and can thus, 
in some measure, counteract the evil results of breathing the neces- 
sarily impure air below. The English statute requires that a seaman 
in the merchant marine shall have not less than 72 cubic feet of air 
space and 12 square feet of floor space exclusive of that occupied by 
the necessary articles of furniture and dunnage. 
In the matter of cubic space, the crews of merchant vessels are, as a 
rule, better off than those of men-of-war, since on vessels of the latter 
class, the complement of men required for all the various duties is so 
large that overcrowding is to be looked upon as a matter of course. 634 
NAVAL AND MARINE HYGIENE. 
The sleeping quarters of most of the crew are located below the water 
line on the berth deck. Some are quartered on the gun deck, which 
is above the water line and consequently is better circumstanced as to 
light and air. 
The sailor sleeps in either a hammock or a bunk. The hammock is a 
hanging bed, made of heavy canvas about six feet long and half as wide. 
At each end, brass or copper eyelets are worked in, through which the 
nettles of the clews pass and are fastened. The clews end in an iron ring, 
to which the lashing for each end is attached. In the hammock are placed 
a mattress and the necessary coverings, and on this he gets his modicum 
of rest in a constrained unnatural position, bent into a curve, no matter 
how he may dispose himself. Bunks are far more rational and com- 
fortable, since they permit of a horizontal attitude. They are made of 
iron framework, wound with canvas or other non-conducting material, 
or of wood. They possess the additional advantage of occupying less 
space and being more easily kept in clean condition. Commonly, they 
are placed in two tiers and sufficiently far apart to permit of easy 
passage on either side. The lower tier should be not less than nine 
inches from the deck. 
Quarters for officers and passengers are, as may naturally be sup- 
posed, more favorably located and more commodious than those as- 
signed to the crew. 
The Diseases of Sailors. 
The chief diseases to which persons on shipboard are subject include 
diseases of the respiratory organs (particularly tuberculosis), rheumatism, 
diseases of the digestive apparatus, venereal diseases, and sea-sickness. 
Of nervous troubles, nostalgia, melancholia, and hypochondriasis are 
common. Skin diseases of various kinds are also common. Cholera and 
yellow fevei' and other important infectious diseases appear to be closely 
connected with ships, by which, as elsewhere noted, the contagion is fre- 
quently carried from one country to another. Formerly, scurvy was 
especially associated with life on shipboard, but since the discovery and 
introduction of the proper prophylactic remedy, the disease has been 
practically eliminated from the list. In addition, troubles of minor 
importance, arising from special duties, are of common occurrence, but 
not lasting in character ; such, for instance, as eye strain and other dis- 
turbances of vision, disturbances of hearing, and trauma. 
In spite of improved hygiene, diseases of the lungs, particularly 
tuberculosis, appear generally to be on the increase among sea-faring 
men, instead of on the decline. It is said that in the British Navy, be- 
tween 1883 and 1890, diseases of the lungs increased 60 per cent. It 
had been supposed that the doing away with masts, sails, and rigging, 
with the consequent lessened exposure of the men to cold and wet, 
would have a contrary effect, but its influence, if any it had, has been 
more than counterbalanced by the change in conditions below, the men 
living now in a very crowded condition in hot steel ships. 
Firemen and stokers are very prone to phthisis and not infrequently VENTILATION OF VESSELS. 
635 
the exhausting nature of their work causes them to become debilitated, 
morbid, and inclined to suicide. Among this class, vertigo, stupor, and 
convulsions are somewhat common. 
Hospitals for the treatment of the sick at sea should not be located, 
as they usually are, on the berth deck forward, but should be about 
amidships where they may receive a sufficient amount of light and air. 
The furniture should be of iron, thus permitting easy cleansing. 
Ventilation of Vessels. 
The air of a ship below the deck is commonly far from meeting the 
requirements generally accepted and is often extremely foul and hence 
wholly unfit for respiration. The contributing causes of this condi- 
tion are an excess of aqueous vapor from respiration and from water 
used in swabbing decks or shipped over the sides while under way; 
an excess of carbon dioxide from respiration, combustion of illu- 
minants, and decomposition of organic matters ; effluvia from the bilge- 
water, from oil, tar, paint and other necessary supplies, from the com- 
ponents of the cargo, and from other sources. The crew's sleeping 
quarters, even though protected by all practicable means from contami- 
nated air from the hold, bilges, and fore-peak, are commonly reached 
through some channel by the effluvia, which, mingling with those 
natural to the place, serve to make a very bad condition much worse. 
The problem of efficient ventilation of vessels is exceedingly com- 
plex and quite different from that of ventilating dwellings and other 
buildings, since the fundamental conditions are so little in agreement; 
and it becomes more complicated with increase in the size of the ship. 
The principles are the same as in house ventilation, but the applica- 
tion of methods is surrounded by greater difficulties, due to peculiari- 
ties of construction and to external conditions. Natural ventilation 
may be effected under favoring conditions through the medium of 
hatchways, port holes, and other openings; canvas tubes or funnels 
with a side opening at the top, stayed to face the wind or the ship's 
course, known as windsails ; fixed ventilating tubes acting in the same 
manner, hollow masts, and other appliances. 
Hatchways are commonly the only openings for ventilating the 
lower forecastles and in foul weather are kept closed. Sometimes an 
outlet, capped by a cowl, is provided, but it is usually kept closed, on 
account of the discomfort of drafts. Deckhouses and top-gallant fore- 
castles are much more efficiently ventilated through the side openings 
and because of their greater exposure to the external air. Holds and 
spaces between decks are ventilated through hatchways, fixed tubes, 
and windsails, hollow masts which act as ventilating flues, funnel cas- 
ings which act like jacketed stoves, and other means. 
Vessels of large size cannot depend upon any system of natural ven- 
tilation, but must have recourse to mechanical methods of propulsion 
and extraction, and even then only an imperfect result can be hoped 
for. As in the mechanical ventilation of buildings, propulsion is 636 
NAVAL AND MARINE HYGIENE. 
likely to prove far more effective than extraction, and its efficiency is 
very greatly dependent upon the intelligent planning of the system of 
the channelways and valves. Valves are required not only for the 
purpose of shutting off the air current where it is not at the moment 
required, but also, on men-of-war and other large vessels, for the pro- 
tection of water-tight bulkheads in case of accident, and of different 
compartments in case of fire. 
The ventilation of vessels engaged in carrying passengers is pro- 
vided for in part by legislation. The U. S. Revised Statutes require 
that vessels carrying a hundred or more passengers shall have for each 
apartment two ventilators, one forward and one aft, of a capacity pro- 
portionate to the size of the apartments, a tube 12 inches in diameter 
being regarded as the proper size for an apartment for 200 persons. 
If other means of attaining the same measure of ventilation are pro- 
vided, they may be used in place of those stipulated. Under the Eng- 
lish law, the provisions for lighting and ventilating must receive the 
approval of the Emigration officer at the port of clearance, and if 
there are as many as a hundred passengers on board, the vessel must 
be provided with " an adequate and proper ventilating apparatus to 
be approved by such officer and fitted to his satisfaction." 
When artificial heating is required, use is made of stoves and steam 
heating. In the forecastle of sailing vessels, small square stoves of 
cast iron with a movable cover are employed. They are dirty, incon- 
venient, and generally unsatisfactory. 
General Hygiene of Ships. 
Of the very first importance in the hygiene of ships is general 
cleanliness of ship and personnel. Cleanliness of the ship requires 
constant watchfulness and unremitting attention, and daily inspection 
is necessary to ensure that cleanliness is not wholly superficial, since it 
often happens that, whereas the decks and all visible portions are clean, 
parts which are out of sight are not in a wholesome condition. Naval 
vessels of all countries are, as a class, much more carefully looked after 
in this respect than those of the merchant marine. 
In securing cleanliness, it is a mistake to use water too frequently and 
in too great abundance, and great care should be taken that all super- 
fluous water is removed as quickly as possible from all parts below 
decks, since one of the cardinal directions is to keep dry, for damp 
ships are notoriously unhealthy. The dampness that condenses from 
the moist air upon the surface of metal plates and overhead beams is 
a source of great annoyance from its constant dripping, and keeps up 
a continual dampness. This can be remedied only by sheathing or 
coverings of non-conducting material such as granulated cork or as- 
bestos fiber. 
The most difficult parts to keep in even fairly sweet condition are 
the bilges, in which collects that most disagreeable and offensive liquid 
known as bilge water, the internal drainage of the ship, much of which, GENERAL HYGIENE OF SHIPS. 
637 
in wooden ships, leaks from without inward, through the seams. The 
disgusting odor of bilge water is due to the decomposition of the or- 
ganic matters present and to the reduction of sulphates of the salt water 
to sulphides. The bilges require periodical pumping and are connected 
for this reason with pumps known as bilge pumps. The bilge water 
removed is discharged into the sea, and after removal, the bilges are 
flushed out with clean sea-water and again pumped out; sometimes 
they are regularly deodorized and disinfected. 
Next in importance, on account of their commonly unwholesome 
condition and the difficulty with which they are made clean and kept 
so, are the peaks. In small vessels, the fore-peak very commonly 
causes fouling of the air of the crew's quarters in the forecastle. 
From a hygienic standpoint, the stoke holds of steamers are of great 
importance, for here, in a very restricted space, exposed to excessive heat 
from the furnaces, the stokers perform their exhausting office. The 
air of the stoke holds is commonly not only excessively hot, but exceed- 
ingly foul, and these conditions can be abated only by proper ventila- 
tion, which may be secured either by means of mechanical appliances or 
windsails. 
Water-closets and latrines should be of as simple a type as possible 
and capable of effective flushing. The soil pipes may discharge above 
or below the water line. Where closets must be located below the 
water line, special pumping arrangements are provided for their empty- 
ing and flushing. Their placing differs according to the size and char- 
acter of the ships. Latrines for the crew are placed forward and com- 
pletely disconnected from the forecastle. They are supplied at the 
rate of not less than three for every hundred men. Urinals are com- 
monly a source of great nuisance and hence require extra care. 
On passenger ships, three closets should be provided for every hun- 
dred persons carried, and they should be so located with reference to 
sleeping quarters that they may not give rise to nuisance. 
Whenever weather and other circumstances permit, all bedding 
should be thoroughly aired, each article being brought up from below 
and exposed separately, fastened to the rigging or upon the girt lines. 
Hammocks should be thoroughly cleaned and dried about once in every 
fortnight. Blankets should be washed with soap at least every six 
months ; hammocks and all articles of bedding should be, when prac- 
ticable, exposed for part of each day to the direct action of the sun- 
light. 
For methods of disinfection and general cleansing, the reader is re- 
ferred to the chapter on Quarantine. 
Personal cleanliness of the men is of even greater importance than 
cleanliness of their surroundings, and, indeed, the two go hand in 
hand, for men of cleanly habits will not permit their surroundings to 
be otherwise than wholesome, and those who are not naturally so in- 
clined must be required to keep themselves clean. Each man must be 
allowed a sufficient supply of fresh water daily, and the necessary ap- 
pliances for washing must be provided. In navies, the washing of the 638 
NAVAL AND MARINE HYGIENE. 
person is commonly made a part of the routine. Special provision 
for the care of the person is required for those who have the dirtiest 
work to perform, namely, the firemen and stokers, since their occupa- 
tion precludes the use of much wearing apparel and the air of the place 
where they work is laden with coal dust and so hot that their bodies 
are constantly bathed in perspiration. Short bathtubs of galvanized 
iron, a sufficient number of wash-basins, and a reasonable allowance of 
water and soap should be provided. Given the conveniences and en- 
couragement to make use of them, the chances are that they will be 
appreciated and freely used. 
As is the case with soldiers, it is of very great importance that 
sailors should be kept busy and, at the same time, should have suf- 
ficient time for relaxation, which they should be encouraged to spend 
in such pursuits as will best conduce to the promotion of cheerfulness 
and the prevention of ennui. CHAPTER XII. 
TROPICAL HYGIENE. 
THE SOLDIER AND THE CIVILIAN IN THE TROPICS. 
The following pages, dealing with hygiene in the tropics, have greater 
general applicability to the life of civilians, who have a wide choice in 
their mode of life and distribution of their time, but the main princi- 
ples are equally applicable to the life of the soldier, even though his 
liberty of action in the following of his own inclinations is very 
greatly restricted. 
It is a very common mistake among persons in temperate climates 
to suppose that the change to a tropical climate means chiefly a sudden 
access of heat and that it is simply this increased heat which one has 
to consider; but it is not, as a rule, the actual temperature which 
affects the individual, for in the North we may have for days at a time 
a higher temperature than obtains customarily in some parts of the 
tropics, without suffering in the same way. The principal difference 
lies in the excessive tropical humidity, but tropical climates are not 
equally humid, some being exceedingly moist, and some exceptionally 
dry. 
In some parts of Australia, for example, the climate is exceedingly 
dry and the temperature is very high, and yet there is much less 
liability to sunstroke and heat apoplexy than in some parts of India 
where the temperature is less high, but the atmosphere exceedingly 
humid. Since all hot climates are not alike, the mode of life also 
varies, and in any case it is necessary to take into consideration the 
special local characteristics of climate and the methods of life followed 
by the natives, and if one takes care to adapt his clothing, his diet, 
and personal habits to the conditions which surround him, life in the 
tropics may be bearable, even if not thoroughly enjoyable. On this 
point, Dr. S. O. L. Potter, U. S. V.,1 writing on the spot, says: " If 
people can take reasonable care of themselves and do not give way to 
excesses in any form, drink, eating, or working, they will live as 
healthily in Manila as in New Orleans or St. Louis or New York." 
But they cannot withstand the effects of any tropical climate for long 
without an occasional visit to the Temperate Zone, for prolonged resi- 
dence brings about an undoubted deterioration of the system in spite 
of all possible care. 
According to Freeman,2 Europeans, after some years' continuous 
residence in a hot country, degenerate, losing energy, initiative and 
1 Notes on the Philippines, Philadelphia Medical Journal, April 7, 1900, p. 803. 
2 The Sanitation of British Troops in India, London, 1899. 640 
TROPICAL HYGIENE. 
memory, which, from a military point of view, is not compensated for 
by diminished liability to disease. Hence the necessity of furloughs 
at stated intervals. Potter says, " Many of our older officers have 
undergone a process of rapid aging here without any definite ailment 
to account for their condition. They simply grow thinner and thinner 
day by day, running down gradually in physical strength as emaciation 
goes on until finally the General takes pity and sends them home." 
According to a number of observers, the body temperature of new 
arrivals in hot climates is appreciably elevated (0.4-0.9 degree F.) 
above the normal, and under some conditions of high temperature, 
since the body cannot radiate heat to hotter surrounding air, the body 
temperature may run as high as 102° in health. The body is then 
dependent chiefly upon evaporation from the surface for the keeping 
down of the temperature as nearly as possible to normal. But when 
high temperature is conjoined with high humidity, the difficulty and 
discomfort are much increased. Continued moist heat, through its in- 
fluence on metabolism and the various functions of the body, causes 
great nervous exhaustion and general deterioration. The respiration is 
depressed, the force and rate of the pulse lowered, the mind becomes 
idle and dulled ; the sweat is doubled in amount and thirst increased 
in proportion ; the digestive function is weakened, and appetite for 
even the lessened necessity for food is diminished and requires constant 
stimulation. The body loses in weight, and both body and mind in 
energy. 
Dr. Federico Montaldo, of the Spanish Navy, in a practical hand- 
book 1 written for the use of Europeans intending to visit the Spanish 
colonies, published just prior to the outbreak of our war with Spain, 
urges upon those who are not sure of the soundness of their health 
the necessity of submitting themselves for thorough physical examina- 
tion, since a trivial ailment, easily corrected at home, may develop in 
the tropics into a trouble not easily managed. Potter,2 also, on this 
latter point, remarks : " It is all very nice as long as one is well, but 
those who get sick don't easily recover here. Convalescence is very 
slow and very difficult." 
And again, " the general climate of these islands is not pernicious for 
those who are able to avoid exposure, but when broken down by hard- 
ship or incidental disease, complete recovery is doubtful and convales- 
cence is very slowly established." Burot and Legrand,3 also, lay stress 
on the necessity of selection of healthy individuals for service in the 
tropics, saying that if the soldier is too young or if his constitution is 
not strong, he will be an easy prey to disease, while if, on the contrary, 
he has been carefully selected in the light of the peculiar conditions 
and the demands upon his strength, he will be better able to resist 
morbid influences. 
1Guia Practica Higi^nica y M^dica del Europeo en los Paises Torridos (Filipinas, 
Cuba, Puerto Rico, Fernando Poo, etc.), Madrid, 1898, p. 19. 
2 Loco citato. 
3 Hygiene du Soldat sous les Tropiques, Paris, 1898. THE SOLDIER AND THE CIVILIAN IN THE TROPICS. 
641 
Dr. Lucca,1 speaking from an experience of a number of years as a 
military surgeon in Borneo, urges the exercise of great care to ensure 
the health of troops on transports, so that they may not be landed 
already sick and weak and ready for shipment home. Rasch 2 advises 
all who are prone to nervous disorder, those already suffering, and, 
above all, epileptics to keep away from the tropics, and Macleod3 offers 
the same advice to anyone whose heart and blood vessels are not wholly 
normal. 
It is also well to chose, if possible, the best time of year for landing. 
There are, it is true, only two seasons in the tropics, the dry and the 
rainy, but there are, nevertheless, transition periods of greater or less 
duration. 
Residence.-If one has a choice in the matter of residence, it is 
well to be cautious in its exercise and to begin on high land and away 
from the coast. The English have long recognized the necessity of 
sending their soldiers inland and to the hills, when military require- 
ments are not opposed. After getting somewhat accustomed to new 
conditions, the lower parts and the coast may be gradually ventured 
upon. 
In some parts of the tropics, it is customary to leave sleeping apart- 
ments open during the day and closed at night, but in others, the con- 
trary is the rule, the doors and windows being closed by day. The 
best form of bed is that made of not too heavy iron, with a frame or 
other device to support a mosquito bar. The bed should be placed 
away from the walls and out of draughts. The legs should stand in 
small vessels filled with water, in order to keep away small crawling 
insects. If in the country and neither bed nor hammock is to be had 
and one is obliged to sleep on the floor or ground, a rubber or other 
waterproof sheet or a dressed hide should be spread, and the body 
should be well protected against condensing moisture and troublesome 
insects. 
Habits of Life.-All authorities agree in at least one particular, and 
that is in urging moderation in all things-diet, drink, work, exercise, 
dress. The diet must be chosen with care and iced drinks taken in 
great moderation, if at all. The clothing must be chosen with judg- 
ment, both as to protection from the heat of the sun and against chill- 
ing of the body. 
Work must not be excessive nor should it be performed in the sun 
during the hottest part of the day. Montaldo4 advises one to rise 
with the sun and take a quick cool bath, and then, after a very light 
breakfast of coffee, tea, or chocolate, with a little bread, to attend to 
whatever duties one has to perform, until about 10.30 A. M., when 
luncheon may be had. This should not be heavy as to food or drink. 
The latter may consist of a little water with claret or lemon juice, or 
1 Einige Bemerkungen uber Acclimatisation und Leben in den Tropen, Munich, 1898. 
2 Allgemeine Zeitschrift fur Psychiatric, 1897, p. 745. 
3 Journal of Tropical Medicine, Vol. I., No. 1. 
4 Loco citato. 642 
TROPICAL HYGIENE. 
tea or coffee. If one's work is out of doors, it should not be resumed 
before 3 in the afternoon, and in the meantime one should rest indoors. 
After 6.30, a substantial, but not too hearty, dinner should be taken, 
observing the same moderation in the matter of drinking. One should 
never go out with an enfpty stomach nor do work immediately after a 
meal. After dinner, a walk or some form of recreation until 10.30 or 
thereabouts, which is the proper time for retiring. 
One is strongly advised not to expose one's self to the cool external 
night air; to avoid cold bathing and cold drinks while perspiring ; and 
especially to avoid standing for a long time in the shade in garments 
wet with perspiration. If one is compelled to be exposed to the sun 
for long, the protection afforded by umbrellas and colored spectacles 
against heat and glare should be sought. The consequences of expo- 
•sure may be exceedingly severe or even fatal. There are various forms 
of what are commonly known as sunstroke and heat apoplexy. A very 
common form is one of syncope, brought on by overexertion in the di- 
rect sunlight or even within doors by one already in a depressed con- 
dition. The skin is moist and clammy, the pulse very feeble and almost 
imperceptible, the muscular power almost completely lost. Death may 
occur by cardiac failure, but recovery under appropriate treatment is 
the general rule. Another form, due to direct action of the sun's rays 
on the brain and cord, is in the nature of a very sudden severe shock 
affecting the respiratory and cardiac centers and very commonly quickly 
fatal. Complete recovery is rare. 
A third form, commonly known as heat apoplexy, is due to exposure 
to constantly high temperature not necessarily involving direct ex- 
posure to the sun, and, in fact, may occur in cloudy weather and at 
night. The whole body becomes overheated and the temperature may 
exceed 110° F. The skin is generally dry, though sometimes moist; 
the pulse full and regular or small and irregular; respiration labored. 
There is intense restlessness, and epileptiform convulsions may super- 
vene. These cases are frequently fatal, and if recovery occurs, it is not 
complete. In India, according to Freeman,1 heat apoplexy and sun- 
stroke occur usually toward the end of hot weather, although the mid- 
day sun is strong enough in most places to cause severe headache, if 
not sunstroke, the year round. 
For the avoidance of sunstroke, in addition to having proper head 
covering and umbrella, the neck and spine must be properly protected 
from the sun's rays. The double pleat in the back of the Norfolk 
jacket is intended as a protection to the spine. A few green leaves in 
the hat are sometimes conducive to comfort. 
The commonly given advice to follow the customs and habits of the 
natives in respect to diet and physical exercise can be accepted only in 
part, for the native of the tropics is, as a rule, a lazy individual who 
merely exists ; the wear and tear of his system require but little in the 
way of repair and his food is of the simplest kind ; he has no ambi- 
tion and no desire to hoard up a fortune which he cannot use. But 
1 Journal of Tropical Medicine, Vol. I., No. 1. THE SOLDIER AND THE CIVILIAN IN THE TROPICS. 
643 
between his indolence and our high-pressure life, there is a happy 
mean, especially in the tropics. 
Diet.-The question of diet in the tropics is a very serious one, for 
errors may be followed by disastrous results. Since prolonged heat 
exerts an unfavorable influence on digestion, this function should not 
be made to bear too heavy a burden and it becomes necessary to re- 
strict the diet in several particulars. No more food should be taken 
than can be comfortably digested, for both dysentery and diarrhoea are 
favored by the irritation caused in the intestines by food partially di- 
gested or undergoing fermentative processes. But the change from 
the accustomed diet must not be made with too great abruptness. 
The natives depend chiefly upon a vegetable diet, in which rice and 
beans and fruits of all kinds play prominent parts. Meat, if eaten at 
all, is taken usually in very small quantities. As a rule, in hot climates, 
it is not tender, for it cannot be hung days and weeks, as with us, to 
ripen, but must be cooked and eaten within a very few hours after 
slaughtering. Fish must not be used unless very fresh, and shell-fish 
of all kinds should be avoided. Fresh milk is ordinarily not to be 
had or, at least, is difficult to obtain. It speedily sours and becomes 
unfit to drink. Condensed milk of good quality is more to be de- 
pended upon. Vegetables must be thoroughly cooked or they will 
seriously tax the digestive organs. Fruits must be perfectly ripe and 
sound ; over-ripeness is quite as objectionable as greenness. Overin- 
dulgence in fruit, even of the best quality, and especially in the sour 
fruits, is particularly to be avoided. 
Tea, coffee, and chocolate are advised in moderation. Lime juice 
with water or cold tea makes a most refreshing drink. Tamarinds in 
water are also most grateful. 
If alcohol in any form is desired, the light wines diluted with water 
are recommended more highly than beer. Spirits are generally con- 
demned, but there appears to be no good and valid reason why, when 
very largely diluted with water or soda water, they should exert a more 
pernicious influence than wine only moderately extended. In any event, 
alcohol should be taken only with food. 
The Use of Alcohol in the Tropics.-Writers on tropical hygiene 
are almost unanimous in the opinion that, whatever may be said for 
and against the use of alcoholic drinks in other climates, their use in 
the tropics constitutes a distinct danger, and that much of disease 
commonly attributed to climate is due actually to alcohol. Especially 
is this true of the various renal and hepatic troubles. According to 
Treille,1 the abuse of alcohol is the chief cause of the frequency of dis- 
eases of the liver, not alone among visiting Europeans, but among 
natives as well. 
Dr. Chr. Rasch,2 speaking of the futility of talk about Europeans 
getting accustomed to continued high temperature with high humidity, 
and describing the various steps in physical and mental deterioration, 
'Principes d'Hygiene Coloniale, Paris, 1899, p. 272. 
2 Allgemeine Zeitschrift fur Psychiatrie, 1897, p. 745. 644 
TROPICAL HYGIENE. 
to counteract which, one turns to alcohol and other stimulants, says 
that these together with insomnia and enforced lack of exercise bring 
about a general atonic condition or, in other words, a lowered physio- 
logical resistance to diseases in general. Dr. Breitenstern,1 who for 20 
years served as an army surgeon in the Malay Archipelago, gives it as 
his opinion, based on long observation, that total abstinence from alco- 
hol is far preferable to even the most moderate indulgence. 
A writer in Manila has pointedly remarked concerning the health 
of the American troops, " It is not so much the climate as the glass 
bottle which injures people out here," which statement is corroborated 
by another who had seen actual service as a member of a company, 
many of whose members were total abstainers and the rest made up of 
moderate drinkers and those prone to excesses, the latter constituting 20 
to 25 per cent, of the whole. Of the latter class, only two returned 
home in approximately the same condition of health which they enjoyed 
at the time of enlistment. Of the moderate drinkers who confined 
themselves to malt liquors, a large majority suffered greater or less im- 
pairment of general health. But the total abstainers returned almost 
to a man in excellent health, having endured the same hardships of an 
active campaign. The same correspondent, speaking of the far greater 
harm induced by the stronger alcoholic drinks, relates that he had re- 
peatedly seen American soldiers, after spending several hours under 
shelter, drinking round after round without perceptible harm, fall over 
with all the symptoms of sunstroke as soon as they stepped into the 
glaring rays of the hot sun. 
On the other hand, in opposition to the general opinion adverse to 
even the moderate use of alcohol in the tropics, Dr. C. E. Woodruff,2 
U. S. A., after a careful survey of the conditions obtaining in the Phil- 
ippines, declares that he would change the statement in the general 
order from headquarters of the army, July 2, 1898, "The history of 
other armies has demonstrated that in a hot climate abstinence from 
the use of intoxicating drink is essential to continued health and effi- 
ciency" to "Experience has demonstrated that in a hot climate the 
moderate use of intoxicating drink is essential to continued health and 
efficiency." He claims that the almost universal drinking must mean 
a natural defensive craving occasioned by the terrible nervous exhaus- 
tion, a true neurasthenia, due to long-continued exposure to great heat 
and atmospheric humidity, indicating that waste is greater than repair. 
He asserts that men who want no alcohol at home have this defen- 
sive craving for it in the Philippines, and cites Spanish authority that 
a daily ration of wine has been found necessary. 
Whisky, when sufficiently diluted, is the equivalent of wine, and the 
Scotch variety is regarded by him as superior for the purpose to Amer- 
ican, which soon occasions nausea. Beer, by reason of being conducive 
to colic, diarrhoea, headache, loss of appetite, and general distress, he 
regards as distinctly harmful. While advocating the moderate use of 
1 Hygiene in den Tropen, Monatsschrift fur Gesundheitspflege, 1898, Nos. 7 and 8. 
2 Philadelphia Medical Journal, April 7, 1900, p. 768. THE SOLDIER AND THE CIVILIAN IN THE TROPICS. 
645 
alcohol, he believes that the results of abuse are far more serious than 
at home. 
Concerning beer in the tropics, there is much divergence of opinion, 
some regarding it as a valuable safeguard against abuse of stronger 
alcoholics, others agreeing with Woodruff that it is harmful. It is 
said that the drinking of much beer followed by heavy sleeping pre- 
disposes to sunstroke and heat apoplexy. 
Clothing.-One is advised to take plenty of light cotton, linen, and 
merino underwear, a generous assortment of trousers and coats of 
white duck or flannel, and light merino stockings. High boots, well 
oiled and with hob nails, laced boots, leggings of cloth and leather, 
and light foot wear for indoor and city use should be included. Light 
waterproof outer garments with cape and hood are recommended, and 
for protection against the sun, white umbrellas lined with blue or 
green material, and spectacles with green or blue colored glasses. 
The head covering: should be selected with the double consideration 
of comfort and protection for the head and neck. The material of 
which it is made must be chosen with regard to local climatic con- 
ditions. In a particularly dry hot climate, for instance, pith is the 
most suitable material, being lighter than either cork or felt, but a 
hat made of this material is absolutely worthless in a wet climate, since 
on being exposed to rain it absorbs water, becomes exceedingly 
heavy therefrom, and becomes reduced to a worthless shapeless pulp. 
Hats should be properly ventilated in the crown and there should be 
a generous space for the free passage of air between the head band and 
the inner side of the hat; that is to say, the head band should be fas- 
tened to the crown of the hat only at a limited number of points and 
with intervening small pieces of wood or other material so that the 
band shall keep its proper shape. All head covering of whatever 
form should afford proper protection for the sides of the head and the 
ears, as well as for the front and back. A puggery affords additional 
protection. 
The brim of the head covering should be lined with some material of 
a bluish or green color as a relief to the eyes. The outside should be 
light in color. The head band is made of leather and is easily saturated 
with perspiration, and then hardens on drying; while it is wet, it is 
exceedingly uncomfortable. If covered with fine flannel, it will be 
found to be much more comfortable. 
Jackets and other outer garments should afford perfect freedom of 
action in both riding and walking. The Norfolk jacket is a favorite 
form and may be made of duck, khaki, or similar material. It is 
well to leave a few inches of the arm size unstitched for the sake of 
ventilation. For shirts, a mixture of silk and wool, known as kashmir, 
is regarded as the best material, being very light in texture and per- 
fectly absorbent. Gauze undershirts with short sleeves or with no 
sleeves at all should be worn beneath the shirt. Elastic cotton and 
jean are the best materials, so far as comfort and durability are con- 
cerned, for drawers. 646 
TROPICAL HYGIENE. 
If one is to do much riding, it is advised that as much care be ex- 
pended in the selection of a saddle as in selecting boots, since comfort 
in horseback riding in the tropics is very largely dependent upon the 
fit of the saddle. 
Care of the Person.-The irritating effect of hot winds, which fre- 
quently bring along fine particles of sand and dust, and the glare of 
the sun, which conduces to troubles with the eyes, should be guarded 
against. The ears, too, are not infrequently injuriously affected by 
hot winds, but they are easily protected by external coverings or by 
cotton-wool plugs. The nose and lips are subject to cracking and 
uncomfortable dryness, which may be helped by cold cream or some 
similar application. The nails should be kept closely pared, since they 
become very brittle and crack off. 
The skin, having a very important function to fulfill, should be kept 
thoroughly clean, if on no other account; but bathing in too cold water 
or for too long a time must be avoided. Parasites abound in tropical 
climates and must be looked for on the person and removed with all 
care. Among these may be mentioned the chigoe, or jigger, which is 
an exceedingly troublesome small flea (Sarcopsylla penetrans) which 
burrows beneath the skin, particularly of the feet, and beneath the 
nails. At first, it causes only itching, but if not then removed, sharp 
pain and inflammation ensue. A half teaspoonful of flowers of sulphur 
inside the shoe is said to be an efficient preventive. Another parasite 
of far greater importance, especially to the troops in the Philippines, is 
that which occasions the dhobie itch, which can be avoided only by 
very great attention to personal cleanliness and frequent changing of 
underclothes. It first attacks the perineum and axillae, and when the 
acute stage passes by and the inflammation somewhat subsides, the 
scales become rubbed off and reach the feet, where the trouble spreads 
rapidly, causing intense itching with consequent scratching and the evil 
consequences thereof. 
Diarrhoea and constipation are alike to be avoided. The former 
should be checked at once and on no account be allowed to continue 
without treatment. It is easily brought on by improper or ill-cooked 
foods, impure water, green and over-ripe fruit, sudden changes in the 
weather, and intemperance. Constipation should be avoided by the 
acquirement of a regular habit. Sometimes, a cup of tea or coffee on 
rising will act beneficially, and oatmeal and coarse bread, figs and 
prunes may be found to assist, but purgatives and enemata should be 
avoided, if possible to get along without them. 
Tropical Diseases.-It is beyond the scope of this work to enter 
upon the field of tropical medicine, but it may be said, in general, that 
the diseases of hot climates are exceedingly varied. Some of them are 
peculiar to certain districts ; some are exaggerated forms of what we in 
the Temperate Zone regard as simple maladies. In general, it may be 
said that in the tropics one meets nearly all the diseases of the Tem- 
perate Zone plus a great variety of others, but some of our most com- 
mon diseases may be very rare in certain places. Thus, scarlet fever THE SOLDIER AND THE CIVILIAN IN THE TROPICS. 
647 
and diphtheria are rare in the tropics as a whole, tuberculosis is rare 
in parts of India and common and quickly fatal in other parts of the 
tropics. Rabies is more common in India than in England and the 
victims are almost always Europeans. Leprosy, beri-beri, and elephan- 
tiasis are common among the natives, but very rare among Europeans. 
Throughout the tropics, dysentery kills many more people annually 
than cholera and works greater havoc in armies than the contending 
forces. Typhoid fever always appears sooner or latei' in camps of sol- 
diers from temperate climates, and the new arrivals are commonly ob- 
served to be the most susceptible. This disease and cholera, according 
to Freeman, rarely occur in India during the hottest months, when the 
burning rays of the sun act as a germicide; but when the rains come 
and sweep all the accumulated surface dirt into the water courses, they 
quickly appear. 
For a most interesting description of the diseases observed in the 
tropics, the reader is referred to Dr. Patrick Manson's " Tropical Dis- 
eases." (Second edition, 1900.) CHAPTER XIII. 
HYGIENE OF OCCUPATION 
The influence of occupation on health and length of life has been 
the subject of much investigation since attention was first called to its 
importance by Professor Bernardino Ramazzini, of Padua, in 1700, but 
more particularly during the last half century. Although his work 
was anonymously translated into English as early as 1705, the subject 
appears to have been one that did not appeal with any special force to 
English social scientists and medical men, for the first English work 
of any importance was that by Mr. C. Turner Thackrah, a practitioner 
of Leeds, on " The Effects of the Principal Arts, Trades and Profes- 
sions, and of Civic States and Habits of Living, on Health and Lon- 
gevity," published in 1831. 
A French translation of the work of Ramazzini appeared in 1777 
and formed the groundwork of P. Patissier's " Traits des Maladies des 
Artisans et de celles qui R6sultent des Diverses Professions, d'apr^s 
Ramazzini," which was published at Paris in 1822. It was translated 
early also into German, but the first work of any importance on the 
subject by a German writer was that of Halfort, " Entstehung, Ver- 
lauf, und Behandlung der Krankheiten der Kunstler und Gewerbe- 
treibenden," published at Berlin in 1845. 
Since the awakening of interest in the subject in England, France, 
Germany and other European countries, and the United States, it has 
been very extensively and minutely studied in all its aspects, and to- 
day its bibliography includes thousands of titles, mostly, however, as 
would naturally be supposed, of monographs and memoranda pertain- 
ing to individual callings. From this vast amount of material from 
all sources, numerous tables have been constructed, showing, it is gen- 
erally supposed, how the various occupations stand relatively in the 
amount of influence which they exert on the longevity of those engaged 
in them. From these tables it appears, for example, that those who 
follow some particular calling are more prone to contract certain dis- 
eases than those engaged in another; that in each hundred individuals 
of some one class, a greater number of deaths will occur in a year than 
in each hundred of another; that the average age at death of those en- 
gaged in one employment is lower or higher than that of those in an- 
other, and so on. 
As in all findings based upon groups of units with, perhaps, but one 
common bond, each unit being subject to a variety of outside influ- 
ences, the conclusions drawn from this vast mass of material are 
largely influenced by fallacy and include wheat and chaff, fact and HYGIENE OF OCCUPATION. 
649 
fancy. In many cases, general statements are based upon such a slight 
foundation as to indicate that their authors are possessed of that de- 
gree of genius which has been defined as the ability to generalize from 
a single instance. In many others, they are based upon facts and con- 
ditions which no longer exist, the methods followed in the manufac- 
ture of the particular article concerned having undergone a complete 
change. For example, a process, formerly carried on by men in small 
establishments run by water-power in the country, may have been con- 
centrated in large mills run by steam and situated in crowded cities ; 
the machinery is different and more perfect, and requires nothing 
more than feeding, and this can be done by a boy or girl, instead of 
an adult man. Here, the older facts may no longer apply in any way 
and for present purposes should be abandoned as belonging to an ex- 
tinct occupation. 
It is often difficult or impossible in the study of the effects of occu- 
pation to eliminate outside influences which may affect the health of 
the worker as much as or more than the circumstances of his trade. 
A hundred men, for example, from different strata of society-some 
married, others single; some living in comfortable houses, others in 
cheerless unsanitary tenements ; some spending their evenings in whole- 
some recreation amid wholesome surroundings, others doing evening 
work in places of public entertainment and elsewhere or spending 
their time and wages in the paths of vice; some naturally robust, and 
others inclined to disease-engage in the same occupation at the same 
time. 
During the year, there is considerable sickness among them, and 
some of them die; perhaps these include mainly young men. Shall 
it be said without a careful analysis of all the circumstances of their 
lives and of the immediate causes of their deaths, that their calling is 
necessarily inimical to health and longevity ? This one died of small- 
pox ; this one of consumption; this one of a blow on the head while 
drunk ; this one was drowned ; two were victims of typhoid fever and 
two of pneumonia ; eight in all-truly a large percentage, but shall the 
trade be blamed ? 
It must, of course, be self evident that certain occupations must be 
intrinsically dangerous to health, because of the nature of the sub- 
stances with which the workers are brought in contact; and these are 
properly classed as dangerous trades. Many others are so classed, not 
because of any intrinsic danger, but on account of the peculiar condi- 
tions under which they are ordinarily carried on, these tending to re- 
duce the physiological resistance to disease. Still others are classed 
as dangerous to health which are merely dangerous to life, the individ- 
ual being subject to mechanical violence while in the enjoyment of 
perfect health. These also are properly to be included among the 
dangerous trades. But the great majority of callings are neither intrin- 
sically dangerous nor carried on under peculiar conditions favoring a 
low state of health, yet many of these figure in statistical tables in such 
a way as to lead to the conclusion that those engaged in them may 650 
HYGIENE OF OCCUPATION. 
have little hope of green old age, while others in occupations of practi- 
cally the same character, but under different names, give promise of a 
full period of usefulness. 
Statistical tables of longevity of groups of individuals engaged in 
the various callings must be used with much circumspection and a 
due regard to the various circumstances which determine the choice of 
trade, the age of the individual at the time of engaging upon it, the 
length of time which one may serve before engaging in another, the 
peculiar conditions under which the calling is pursued, and the prob- 
able character of the influences which affect the well-being of the in- 
dividual while he is not immediately engaged; that is to say, his home 
surroundings, his personal habits, the nature of his relaxations, the 
quality of his food, and other factors. Tables based on foreign statis- 
tics must, furthermore, be not too freely accepted as applicable to home 
conditions, owing to differences in racial peculiarities and of conditions 
under which those engaged work and live, for one can hardly suppose 
that any one class works and lives under the same conditions in all 
countries. 
The conditions which govern the choice of an occupation are of very 
great importance. Many callings demand men of robust build and 
good health and are manifestly unsuited to the weakling, who natur- 
ally is attracted to other occupations of a lighter character. On this 
score alone, statistics may be grossly fallacious. For example, in cer- 
tain tables it will be observed that the class designated as clerks have 
a low average age at death, and from this it may be inferred that the 
calling is one which is intrinsically incompatible with long life. But 
is it fraught with danger? Is it conducted under peculiar conditions 
which tend to bring its unfortunate followers to an early grave? Or 
is it not rather the fact that it is the refuge of a great number of those 
whose physical powers are such that they are unsuited to employments 
which call for greater robustness, and who, inevitably marked for an 
early death, regardless of their calling, reduce the average age at death 
of the entire class? 
On the other hand, certain occupations involving much severe mus- 
cular effort appear to be conducive to long life, in spite of the condi- 
tions under which they are pursued. Here must be borne in mind 
that in these, the weaker individuals and those whose powers begin to 
fail are forced out into other occupations, and that those who remain 
until the end show an average age at death which is eloquent of the 
benign influence of the calling. It is undoubtedly true that muscular 
effort, carried to excess, will undermine the health ; but not forced be- 
yond reasonable limits, and particularly if carried on under good hy- 
gienic surroundings, instead of being in itself prejudicial to health is 
promotive of it. Those who are forced into lighter occupations may 
find the change advantageous, or, on the other hand, entering upon 
them already broken in health, may help to reduce the average age at 
death of all those engaged therein. 
Another influence having a bearing on the choice of occupation is 651 
HYGIENE OF OCCUPATION. 
the high wage offered to attract workmen to trades which are generally 
and properly conceded to be dangerous to health. These are natu- 
rally unattractive to men of sound body and mind, to whom health and 
life are sweet, and hence they find their recruits among the broken- 
down and vicious, to whom the rate of pay offers, in the one case, im- 
mediate much-needed and otherwise unattainable financial relief, and 
in the other, opportunity for a short period of unrestrained license. 
Statistics concerning occupations entered upon at an early age and 
followed for but a limited number of years as a preliminary training 
for other callings, and those which from their very nature demand 
men of wide experience, hence well matured, can be of little or no 
value unless the occupations are in some way of intrinsic danger. We 
find, for example, in certain statistical tables dealing only with individ- 
uals above the age of 20 years, that the average age at death of students 
is about 23 years, while that of professors exceeds 50. 
The manifest absurdity of attempting comparisons of the healthful- 
ness of these two occupations is still further brought out by reversing 
the case and supposing the professors to die off at 23 and students at 
50. Since even advanced students in the professional schools pass, as 
a rule, out of the student class and into their chosen fields of usefulness 
long before their thirtieth year, it cannot cause surprise that those who 
die before their training is completed do not show a high average age at 
death ; and on the other hand, since men of learning are not ordinarily 
called upon to assume the duties of professors until they have passed 
through the lower grades which lead to that rank, it is to be expected 
that their average age at death will be fairly high. To compare lieu- 
tenants and major generals, shipping-clerks and retired merchants, ap- 
prentices and master carpenters, would be no more absurd. The average 
age at death of any one calling must be largely influenced by the rela- 
tive number of individuals of the different age periods engaged therein, 
just as is the case with the population in general. 
Another fact that affects the age at which work is undertaken is a 
very low wage offered even in times of prosperity, so low as to be no 
inducement to heads of families, but sufficiently high to cause them to 
help out their financial condition by making use of their offspring. 
Before proceeding to a classification of occupations according to the 
circumstances which determine their healthfulness, it is desirable to 
consider the significance of the somewhat loosely applied term, occupa- 
tion diseases. Every form of occupation and every form of life of 
leisure has some attendant circumstances which may at some time, in 
one way or another, bring about a predisposition to some form of dis- 
ease ; and to regard every disease of an artisan, tradesman, or profes- 
sional man as attributable to his particular calling, is to fall into a 
common inexcusable error, for workers and drones have most diseases 
in common. It is beyond dispute that certain pathological conditions 
are caused and others promoted by certain occupations, and it is equally 
true that most diseases already acquired may be influenced for the 
better or worse by one or another calling. 652 
HYGIENE OF OCCUPATION. 
The true occupation disease is that which in all probability would 
not have been acquired had the individual not engaged in his particu- 
lar calling or some other in which the conditions are essentially simi- 
lar. As an instance may be cited the lead paralysis of the house 
painter, potter, compositor, and file cutter. Certain diseases of com- 
mon occurrence in the population at large are promoted by the condi- 
tions under which various callings are carried on, but these cannot 
properly be called occupation diseases, since the exciting cause is in no 
way a part of the business, and under better hygienic management, 
combined with better outside influences, might be avoided. As a con- 
spicuous instance of this class may be cited the tuberculosis of dress- 
makers, cutlery grinders, and operatives in the cotton and flax indus- 
tries, promoted by overcrowding and inhalation of dust while at work, 
and by all extraneous conditions tending to lower vitality. 
The plying of the needle is in itself in no way inimical to the in- 
tegrity of the lungs ; the grinding of the steel implement on the wheel 
and the running of the loom send forth none of the specific bacilli ; 
but the overcrowding in the one case, and the avoidable inhalation of 
irritating dust in the others, bring about the conditions which offer fer- 
tile soil to the germ of the disease. 
Certain conditions are influenced for the better or worse by differ- 
ent occupations, as has been stated. Among these may be mentioned 
anaemia, which is not uncommonly classed among the diseases of occu- 
pation. Under the conditions of many indoor callings, this state is 
easily brought about or, if already existing, increased ; but, on the 
other hand, under those of outdoor occupation, it is not likely to be in- 
duced, and if already existing, may be made to disappear. Many oc- 
cupations, for easily explainable reasons, draw their workers largely 
from that portion of the population which is, if not already diseased, 
predisposed by heredity, habit, and home surroundings to anfemia, tu- 
berculosis, and other disorders, the onset of which may be hastened or 
delayed, according to circumstances. In these, and in occupations in 
general, it is not an easy matter to determine correctly the amount of 
influence properly chargeable to the calling when disease appears, 
since the conditions under which a trade is carried on may be widely 
variable and their influence for good or evil exceedingly complex. 
Among these conditions may be mentioned indoor confinement, nature 
of materials, geographical location, and wages paid. 
Whether an occupation is carried on indoors or outdoors, is of much 
importance, for, other things being equal, outdoor employment is far 
more conducive to good health than confinement, even in well-venti- 
lated factories, in which, with the best of systems, the air cannot be 
maintained in the condition of purity which obtains outside. Even 
those callings which subject their followers to great vicissitudes of 
weather appear to be more conducive to robustness than those carried 
on indoors, particularly if the nature of the work is such as to call 
for freedom of movement and great bodily activity. 
The sailor, the letter carrier, or the farm hand, for example, work- CLASSIFICATION OF OCCUPATIONS. 
653 
ing in the open air, in heat and cold and in all kinds of weather, is 
better circumstanced in many ways than the loom tender, the entry 
clerk, and the salesman at the ribbon counter. He works, perhaps, 
in a broiling sun, rather than in an overheated room filled with impure 
air; the air he inhales contains some dust, perhaps much, but it is a 
less harmful dust, less abundant, and not continuous. The air of the 
factory and workshop may be almost as pure as that out of doors, or it 
may be laden with fumes, gases, foul odors, or dust of a special na- 
ture, according to the materials used. The outdoor worker is also 
much less oppressed by the monotony which is so conspicuously a con- 
comitant of indoor work. He can, at least, see some part of his world 
in ever-changing conditions, while the mill operative tends his machine, 
of which he is perhaps only a minor part, day in and day out, seeing 
it do the same thing with mechanical exactness so many times per 
minute or per hour, with no more sense of responsibility than might 
reside in an automaton. 
Geographical location of the place of employment has an important 
sanitary bearing on the condition of the workers, since it determines 
very largely the outside influences to which they are subjected. Loca- 
tion in the country districts is likely to insure better and cheaper homes 
than can be found in crowded cities, with, perhaps, a patch of garden 
which may be worked for pleasure, profit, and variety in the diet. It 
is, furthermore, further removed from the influence of the tippling- 
shop and other unhealthy influences of the city. 
The wages paid affect the health of the working classes in several 
ways. A small wage means necessarily a small expenditure for rent, 
clothing, and food ; it means overcrowded tenements, lack of ventilation, 
insufficient protection of the body by cheap clothing of inferior qual- 
ity, inadequate food-usually improperly prepared and hastily bolted, 
personal and general uncleanliness, and other conditions which lower 
the mental, moral and physical well-being of the workers and all who 
are dependent upon them. It means more beside : it means the utili- 
zation of child-labor and the breaking down of women, who perform 
the double duty of looking after the home and assisting in its main- 
tenance. All these circumstances promote the morbidity and mortality 
rates, and the particular occupations, perhaps intrinsically wholesome, 
are then said to be inimical to health, when it is not the nature of the 
callings, but the attendant circumstances, that are at fault. Thus, it 
often happens that the conditions leading to the most serious evils may 
be traced to some circumstance or combination of circumstances which 
are wholly external. 
Classification of Occupations.-In a general way, we may, from a 
sanitary standpoint, classify occupations as follows : 1. Those which 
are intrinsically dangerous to health by reason of the nature of the ma- 
terials involved. 2. Those which are carried on under conditions, 
avoidable or unavoidable, which promote susceptibility to disease. 3. 
Those which, involving exposure to mechanical violence, are danger- 
ous to life and limb rather than to health. 4. Those neither intrinsic- 654 
HYGIENE OF OCCUPATION. 
ally dangerous to health or life nor carried on necessarily under pecu- 
liar avoidable or unavoidable circumstances. 
The first and second of these classes are of especial interest to the 
sanitarian, whose efforts are directed toward the removal of all unsani- 
tary influences of whatsoever kind attending any and all occupations. 
The third class includes occupations which involve the possibility of 
injury due to circumstances bearing no relation to hygiene. Thus, no 
effort of the hygienist can prevent a brakeman from falling beneath 
the wheels of a train or the operatives in a dynamite industry from 
being blown into eternity by the force of an explosion due to careless- 
ness. The fourth class-and this includes a great variety of perfectly 
colorless callings-presents nothing of any especial hygienic interest, 
since the physical condition of the individual would be essentially the 
same whether he were engaged in one or another of the different fields, 
and only those which are carried on under peculiar conditions can be 
studied to advantage. Therefore, only the first two classes will be 
here considered, and since the dividing line between the two is often 
difficult to define, and since some occupations may be said to belong to 
both, the two may be merged into one for the sake of convenience and 
then subdivided as below. 
The occupations which are of particular hygienic interest embrace 
those which involve exposure to- 
1. Air vitiated by respiration. 
2. Irritating and poisonous gases and fumes. 
3. Irritating and poisonous dusts. 
4. Infective matter in dust. 
5. Offensive gases and vapors. 
6. Extremes of heat. 
7. Dampness. 
8. Abnormal atmospheric pressure. 
Of distinct, but minor, importance are those which involve- 
9. Constrained attitude. 
10. Over-exercise of parts of the body. 
11. Sedentary life. 
Some occupations are conducted under such conditions that they 
may very properly be regarded as belonging to a number of these 
groups. Mining, for example, may be considered under groups 2, 3, 
6, 7, 9, and 10, and cigar-making under groups 1, 2, 3, 9, and 11. 
To attempt to describe the conditions which surround each individual 
industry and to give the details of the countless processes involved, 
would be far beyond the scope of a work of this nature and quite un- 
necessary for a general understanding of the relation of occupation to 
health. Therefore, in the following pages, only the most conspicuously 
characteristic examples will be cited by way of illustration of the 
dangers to which the workers are exposed. EXPOSURE TO VITIATED AIR. 
655 
1. Occupations Involving Exposure to Air Vitiated by 
Respiration. 
This class may be made to include any indoor calling carried on in 
overcrowded, ill-ventilated rooms, in which the air is vitiated only by 
the processes of the body and not by adventitious gases or dust. These 
occupations, therefore, are not in themselves dangerous, but are made 
so by a preventable cause. 
As examples may be cited the callings of tailoring and dressmaking, 
which, only too commonly, are conducted in rooms in which fresh air 
and cubic space per capita are at a minimum. The workers are packed 
into quarters no larger than absolutely necessary for the performance 
of their daily task, impossible of proper ventilation without an expen- 
sive mechanical system, so great is the overcrowding, and, as is natu- 
rally to be supposed, overheated. Here, the unfortunates spend a fairly 
long day, leaving at night to go to homes, perhaps no less unsanitary. 
If not already so when they begin, they become, after a time, aneemic, 
dyspeptic, and depressed, these conditions, as in many other callings, 
being promoted by lack of exercise, by ill-chosen and badly-cooked 
food, and by absence of healthful recreations. They become greatly 
susceptible to cold and hence opposed to the admission of fresh air 
from without. Breathing excremental air by day and night, denying 
themselves proper food, their minds depressed, it is not to be wondered 
at that their condition invites disease, more particularly the one which 
stands forth conspicuously as a consequence of overcrowding ; namely, 
pulmonary consumption. 
The onset is insidious. Beginning with a cold that resists being 
" thrown off," the cough becomes chronic; they continue to lose weight 
and strength, and the end can be foreseen. It is not to be understood 
that these callings are always or even generally associated with these 
conditions; but when they are, the result is generally the same. 
2. Occupations Involving Exposure to Irritating and Poisonous 
Gases and Fumes. 
This class includes a great variety of callings which may or may 
not be intrinsically dangerous, according to individual circumstances. 
In many cases, the danger may be much lessened by a due regard to 
personal hygiene and by the use of respirators. These are simple 
pieces of apparatus designed to remove noxious matters from the air, 
on its way to the respiratory passages. It is the rule, however, that 
workmen will refuse to wear them after the first days, even though 
well aware of the possible consequences of laying them aside. One 
reason for this is that not one of the several forms invented can be 
worn with any degree of comfort. They demand faster respiration, 
soon get wet with expired moisture, and cause excessive perspiration. 
Furthermore, they cannot be made to fit tightly, and so, even when 
conscientiously worn, they only partially perform their office. Most 656 
HYGIENE OF OCCUPATION. 
of them are designed to filter out dust, but all are made on essentialle 
the same principle, those intended for noxious fumes containing spongy 
or other absorbent material, wet with agents which exert a neutralizing 
influence. 
One form consists of a muzzle of fine wire gauze, single or double, 
on a metallic frame. If made with a single layer, it is lined with cot- 
ton-wool kept in place by a very loosely woven fabric stitched to the 
wire meshes ; if made double, the intervening space is occupied by a 
piece of thin flannel. Another form is made of woven or knitted stuff, 
instead of wire. This is said to be even hotter than the first-mentioned, 
particularly in summer, and both are extremely uncomfortable. A 
third form, made of pieces of flat sponge large enough to cover the 
nose and mouth, interferes very much with free respiration. Another, 
consisting of a large bag of fine cambric, is said to be less objection- 
able, but difficult to fasten tightly. 
Aside from the discomfort caused by respirators of whatever form, 
the operatives have another, a senseless, objection to their use, women 
complaining that they are made to " look ridiculous," and men being 
moved to discard them by the gibes of their more reckless fellows. 
(a) Irritating Gases and Fumes.-As examples of irritating gases 
or fumes may be cited ammonia, chlorine, sulphur dioxide, hydro- 
chloric acid, and nitrous fumes. In small amounts, they cause, per- 
haps, no more disturbance than a slight tickling cough, but in large 
amounts, they bring about great discomfort and acute and chronic ca- 
tarrhal conditions. 
Chlorine, which is used or given off very extensively in a number 
of industries, is unimportant when it is present in the air in very small 
traces, but when in large amounts, it is said to cause minor catarrhal 
troubles and diminution or even loss of the sense of smell. It is said 
by Pettenkofer that from 1 to 5 parts of chlorine in 100,000 of air is 
sufficient to affect the lungs; that 40 to 60 parts in 100,000 will pro- 
duce alarming symptoms; and that over 60 parts will cause death. 
It is given off in the processes of making and using bleaching powder, 
in the Operation of glazing bricks, and in various other processes. 
Among the workmen who make or use bleaching powder, the oc- 
currence of bronchitis, asthma, and caries of the teeth, is noticeably 
frequent. 
Hydrochloric acid fumes are given off in various industries, and es- 
pecially from alkali works, the immediate neighborhood of which is 
likely to be barren of vegetation in consequence thereof. They are 
given off also in the process of galvanizing iron, the first part of the 
work consisting in " pickling " the iron in the acid to clean it and 
prevent the presence of oxide on the surface when it is dipped into the 
molten zinc. These fumes act much less energetically on the respira- 
tory passages than chlorine. Pettenkofer states that as much as one 
part in a thousand of air can be borne without difficulty by men who 
are accustomed to it, but that this amount cannot be exceeded. In 
the galvanizing process, the workmen are exposed also to the dense EXPOSURE TO POISONOUS FUMES. 
657 
fumes arising from the sal ammoniac which is, from time to time, 
thrown upon the surface of the molten zinc. These are more insup- 
portable than the acid fumes. 
Sulphur dioxide is evolved in the smelting of various ores, in pre- 
paring hops, in the manufacture of sulphuric acid and of ordinary 
matches, and is used extensively as a bleaching agent. In small 
amounts, it causes cough and, by those unaccustomed to it, cannot be 
tolerated. Those who are exposed to it in their daily work establish a 
gradual tolerance and take no notice whatever of an atmosphere in 
which it is present to such an extent that persons unaccustomed to it 
cannot breathe it. The weight of evidence concerning the relation of 
this gas to health indicates that its effects are neither serious nor last- 
ing and are exerted more on the digestive than on the respiratory 
function. In some individuals, a small amount in the atmosphere 
causes epigastric pain and heartburn very quickly. 
Bromine is exceedingly irritating to the respiratory passages and to 
other mucous membranes with which it may come in contact. In small 
amounts, it causes cough, dizziness, and a feeling of general malaise ; in 
large amounts, spasm of the glottis and asphyxia. Bronchial asthma 
is commonly observed among those constantly exposed. The fumes of 
iodine act practically in the same way, though to a much less marked 
extent. In occupations in which these two substances are used, men 
with a tendency to pulmonary troubles should not be permitted to 
work. 
There is no evidence that ammonia in small amounts produces any- 
thing more than temporary irritation of the air passages, but it is a 
general belief that it is conducive to emphysema. 
Nitrous fumes, given off in a number of processes involving contact 
of metals with nitric acid, are also of no very great importance in small 
amounts, but it is said that those who are exposed are especially sub- 
ject to phthisis, in the causation of which it is conceded that the con- 
strained attitude and lack of ventilation have a large influence. It is 
noted that the tendency is greatest in those exposed to the largest 
amounts. 
(6) Poisonous Gases and Fumes.-This class includes a very large 
number of occupations, since poisonous gases are an incident of proc- 
esses without number. 
Carbon monoxide is one of the most important of the poisonous 
gases, and this is given off in many manufacturing operations, usually 
in company with other gases, and it is, therefore, not always an easy 
matter to determine what proportion of the effects noticed are due to 
any one constituent of the mixture. The constant inhalation of even 
very small amounts of carbon monoxide causes disturbances of the 
digestive function, general weakening of the system, and diminished 
mental power. The one class in which one would naturally expect to 
find the greatest evidence of injury, namely, laborers in gas plants, 
yields very little. 
Carbonic disulphide is much used as a solvent for fats, but its chief 658 
HYGIENE OF OCCUPATION. 
use is as a solvent and vulcanizing agent for India-rubber. The very 
peculiar effects produced upon the operatives in rubber factories, espe- 
cially when the work is carried on in badly ventilated rooms, have been 
attributed generally to the use of this agent. There is at first a dull 
headache, which increases much in severity toward the close of day ; 
sight becomes somewhat confused ; vertigo and epileptiform convul- 
sions, pains in the extremities, and formication are common. 
In the early stages, an unrestrainable inclination to talk is almost 
invariably observed, and, coincidently, a stimulation of sexual desire. 
Soon, the victim becomes moody, irritable, and subject to violent out- 
breaks of anger; eyesight becomes further impaired; the sense of 
smell is much diminished. During this stage, obstinate insomnia is the 
rule. Next occurs a stage of depression, in which the loquacity and 
increased sexual sense give way to impaired memory, feebleness of 
mind, taciturnity, and diminution of sexual desire and power even to 
complete abolishment, with intense headache, either somnolence or 
wakefulness, and local areas of anaesthesia. Sometimes cough, dyspnoea, 
and paraplegia are observed. As a rule, however, no permanent injury 
is caused, since, from the very nature of the symptoms, the victims are 
unable to continue to work; and removal from the cause, with appro- 
priate medication, in which phosphorus is highly regarded, usually 
brings about a perfect cure. 
This train of symptoms seems to be peculiar to the workers in rub- 
ber factories; and since the evidence at hand shows that those who 
make the substance do not suffer in the same way, it seems reasonable 
to suppose that other agents than this one are to be considered in the 
etiology. It happens that, in this same industry, naphtha is very much 
used as a solvent. The vapors of this substance cause some embar- 
rassment of respiration, and also dizziness and mental confusion. In 
France, the employment of women under eighteen in rubber factories 
and in any work which exposes them to the combined fumes of naph- 
tha and carbon disulphide is prohibited. Santesson 1 has reported nine 
cases of naphtha poisoning, four of which were fatal. They occurred 
in a rubber factory where a solution of rubber in naphtha was used. 
The symptoms were headache, dizziness, vomiting, palpitation, and 
hemorrhages. In those cases which recovered, the symptoms lasted 
several weeks. All the victims were young women. In one fatal 
case, the autopsy showed fatty degeneration of the heart, liver, kidneys 
and other parts. 
Naphtha is used very extensively also in cleansing woolen and other 
unwashable clothing, and young women employed in establishments 
devoted to this kind of work suffer from dizziness, nausea and vomit- 
ing, headache, insomnia and hysteria. They find it necessary to go 
frequently into the open air in order to avoid hysterical outbreaks. 
Another much more poisonous substance is nitro-benzol, which is 
very insidious in its effects. It is used in making aniline, like which 
1 Gazette Hebdomadaire de Medicine et de Chirurgie, August 26, 1897. EXPOSURE TO POISONOUS FUMES. 
659 
it is a narcotic poison, and in the manufacture of ruburite and other of 
the newer explosives. Long exposure to small amounts produces a 
train of symptoms which include headache, dyspnoea, drowsiness, dizzi- 
ness, nausea and vomiting, and loss of muscular strength, and terminate 
in stupor and not infrequently in death. Death sometimes occurs 
within a few hours of the onset. 
The most prominent of all the poisonous vapors in manufacturing 
processes are those of mercury and phosphorus. It is hardly neces- 
sary here to enumerate the well-known effects of exposure to these 
two poisons, since they are so universally well known; but it is not 
so commonly recognized that operatives in industries in which metallic 
mercury is extensively used appear to be very subject to phthisis, and 
that, among the women, miscarriage is very common. It is said that 
the offspring show the effects of the poison, and that two-thirds or 
more of those born at term die without completing a year of life; but 
it is well to consider that among the classes from which the operatives 
for this and similar occupations are drawn, child life, at best, labors 
under great disadvantages. 
Mercury is commonly supposed to be used chiefly in the manufac- 
ture of mirrors and in gilding and silvering. This, however, is far 
from being the case. In fact, the processes of making mirrors and of 
gilding have been so revolutionized that, in these industries, mercurial 
affections have been practically done away with. At present, one of 
the most common sources of mercurial poisoning is the industry of 
felting, in which it has been discovered that the coney and other hairs 
used make better felt, if they have a preliminary treatment in a bath 
of mercuric nitrate. In a later process, the raw product is heated to a 
temperature sufficient to volatilize the mercury. Other occupations in 
which mercury is extensively used include the manufacture of ther- 
mometers, barometers, and certain forms of electric batteries, and the 
bronzing of plaster casts with an amalgam containing tin, bismuth, and 
mercury. 
Phosphorus is a substance of much more importance to the public 
health than mercury. The only industry of any magnitude in which 
phosphorus is extensively used is that of match-making, in which in- 
dustry the operatives suffer from the well-known lesions which phos- 
phorus produces. This is a danger which has received much legisla- 
tive attention in England and other European countries, and much 
has been done to avert it by more strict attention to hygiene and the 
introduction of machinery to take the place of human beings. In 
Switzerland, indeed, even the use of any matches other than those 
made with amorphous phosphorus is absolutely forbidden. 
Ordinary phosphorus gives off poisonous fumes at ordinary tempera- 
tures, provided the air contains moisture. Amorphous, or red, phos- 
phorus is not poisonous and gives off no fumes unde/' ordinary condi- 
tions. It cannot be used in the same way as common phosphorus 
and is employed only in the manufacture of matches that strike only 
on the box or on a specially prepared surface ; this is obviously a dis- 660 
HYGIENE OF OCCUPATION. 
advantage, since a match that will strike anywhere is much more con- 
venient. It is said that, in England alone, no less than 60 tons of 
white phosphorus are consumed annually, against 4 tons of the red 
variety. 
It is a very common notion that most of the workmen suffer ex- 
tensively from the effects of the poisonous fumes and that necrosis of 
the jaw is exceedingly common. It appears, however, that, while this 
class of workmen are in general anaemic and badly nourished, the ex- 
tensive lesions that were formerly noticed have been of late years 
much less common. In 1897-8, in the United Kingdom, over 1,500 
persons were engaged, but in the 4 years, 1894-8, only 36 cases of 
necrosis of the jaw were recorded, 21 of which occurred in 1898 ; but 
possibly more may have occurred. This reduction is due to precau- 
tions taken to carry off the fumes by thorough ventilation and to pre- 
vent their production as far as possible by the use of substances like 
turpentine, and by drying the matches as quickly as possible after they 
have been dipped, since the fumes are given off only in the presence 
of moisture. Again, much of the work of dipping is done in closed 
hoods. It is said that the most difficult part of prevention lies in the 
handling of the work-people themselves, since they are of a class that 
can rarely be made to understand the importance of cleanliness and of 
attention to the condition of the teeth. Persons with decayed teeth 
should be excluded from the business, since caries is known to in- 
crease the risk of poisoning enormously. They cannot, for reasons 
already explained, be persuaded to use respirators. 
In the industry of brass founding, fumes are given off which cause 
what is commonly known as " brass-founders' ague," which is a dis- 
order occurring sooner or later-usually, within a very short time-to 
all engaged. The trouble begins with a feeling of malaise, headache, 
stiffness, great muscular pain, and soreness of the chest. A chill 
comes on, which lasts generally about a quarter of an hour, after which 
the patient falls into a profuse perspiration. The symptoms then be- 
gin to abate and within a day or two disappear. 
Although this train of symptoms does not commonly recur, a more 
or less marked chronic poisoning is common, in which the most prom- 
inent symptoms are ansemia, cough, tachycardia, headache, neuralgia, 
disordered digestion, progressive emaciation, and annoying eruptions of 
the skin. 
The acute and chronic poisoning suffered by this class of workmen 
are supposed by some to be due to zinc, by some to copper, by some to 
both together, and by others to arsenic, which is an important constitu- 
ent of some kinds of brass and an impurity of others. Some incline 
to the belief that brass-founders' ague is a true infection, for which the 
poisoned air prepares the ground and paves the way. 
Fumes of arsenic are given off in various smelting operations, but 
the chief danger from this substance is met with in occupations to be 
considered later, in which it is given off in the form of dust. A pecu- 
liar source of poisoning by arseniuretted hydrogen has been brought EXPOSURE TO IRRITATING DUST. 
661 
to public notice by Maljean,1 who observed a number of cases of icterus 
among the balloonists of a regiment of engineers. The cause was traced 
by him to the hydrogen gas used in filling the balloons, which was 
made by the action of ordinary commercial sulphuric acid on commer- 
cial zinc, both of which contain arsenic in variable amounts, in conse- 
quence of which the product contained the poisonous arseniuretted 
hydrogen. The impure gas was liberated through the valve of the 
balloon, but the main source of the danger was the habit of smelling at 
the stopcock during filling, to ascertain when the air in the pipes had 
been expelled by the gas. In the cases observed, the onset was marked 
by great malaise, headache, nausea, stiffness of the joints, jaundice, and 
haemoglobinuria. The symptoms subsided in a few days, leaving the 
patients in a bad condition of anaemia and pronounced malnutrition. 
3. Occupations Involving Exposure to Irritating and 
Poisonous Dusts. 
Dust is of very great importance in its influence on health. Its 
production is a prominent feature of many occupations, in some of 
which so much is caused as to be of the highest possible importance. 
It may be divided into poisonous and irritating, and the latter may be 
subdivided into mineral, metallic, vegetable, and animal. 
(a) Poisonous Dusts.-The most important of the poisonous dusts 
are arsenic and lead. One of the most dangerous of arsenical trades 
is the grinding of the well-known green pigments, Scheele's green (ar- 
senite of copper) and Schweinfurt green (aceto-arsenite of copper). 
These and many other arsenical colors are used in printing wall papers, 
cretonnes, and other decorations, and in the manufacture of artificial 
flowers. The latter is an especially dangerous occupation, since after 
the leaves have been cut to the proper shape, they are smeared with 
gum, the green pigment is then dusted on from a dredging box and 
much of the substance becomes suspended in the air. Much of the 
green glazed paper used for covering boxes is made with these pig- 
ments, and other papers and articles of paper in green and other colors 
(playing cards, etc.), are made with arsenical pigments. 
Arsenite of soda is a very common mordant and white arsenic is 
much used in taxidermy. In fact, the list of processes in which ar- 
senic is used is almost endless. The symptoms produced may be acute, 
but ordinarily are chronic in character. Workmen of this class fre- 
quently suffer from eczematous sores and obstinate ulcers. The symp- 
toms of chronic poisoning are too well known to need description. 
Lead is infinitely more disastrous in its effects upon health and by 
far the most important of all industrial poisons, because of the great 
diversity of its uses. Among the many occupations in which it figures 
may be mentioned all the processes involved in obtaining lead in its 
commercially pure state from ores, the making of white and red lead, 
the glazing of many kinds of paper; type-founding and setting, glass 
'Archives de Medicine Militaire, February, 1900, p. 12. 662 
HYGIENE OF OCCUPATION. 
cutting and polishing, file cutting; enamelling, dyeing and printing, 
working in weighted silk; plumbing, painting, leather varnishing; 
making artificial flowers, leaves, and jewels; and several of the proc- 
esses used in the making of earthenware and china. In many of 
these, the lead gains access to the system through inhalation, and in 
some it is carried into the mouth by the soiled fingers. The latter 
method of introduction is very commonly the case with compositors, 
plumbers, workers in lace and silk weighted with lead acetate, and 
others. 
In Paris alone, it is said, there are over 30,000 of the working 
classes following callings which expose them to this very deleterious 
substance. In England, the great importance of the subject of indus- 
trial lead poisoning has led to extensive investigation, resulting in 
stringent legislation; and in the year 1895, it was required that all 
cases of lead poisoning should be reported to the authorities. During 
the year 1897, the number reported was 1,124, and in 1898, 1,278. 
The largest number of cases are reported from the china and earthen- 
ware trades. It appears to be the fact, wherever the matter is inves- 
tigated, that women suffer less than men. This is explainable in two 
ways : first, that the women are naturally more cleanly in their habits ; 
and second, that women are more likely to give up their work after 
the occurrence of the first symptoms and before the affection becomes 
chronic. Men appear to be able to work longer without showing any 
evidence of injury. 
Particular attention has been given of late years in England, France, 
and elsewhere to the pottery industry, in which lead is used in the 
glazes, the flux being made of litharge, clay and flint. Much at- 
tention has been given to the possibility of finding a glaze which shall 
be free from lead. In the manufacture of ordinary white porcelain, no 
lead glaze is required, and the danger of lead poisoning arises almost 
wholly in the work of decoration, the powder which is dusted on and 
off the transfer paper, containing lead compounds. According to a 
report of a committee of the master potters of Staffordshire, it is not 
possible to substitute a leadless glaze for ordinary china and earthen- 
ware, but this is said to be only partly true. 
In Limoges, where 16,000 people, of whom 2,500 are children, are 
employed in sixteen pottery establishments, the workers are much less 
subject to lead poisoning than those in Staffordshire, and in one of the 
establishments where the ware produced is of the same kind as made 
in Staffordshire, the glaze contains only 8 per cent, of lead carbonate 
against 13 to 24 in that used in Staffordshire. It has been pointed 
out that where lead glazes are necessary, the danger can be very much 
diminished, if the lead is used in the form of a double fritted silicate. 
In the Limoges factories, the lead is used in this condition, and to this 
fact, part of the difference in the amount of poisoning is probably due. 
In English potteries, the tendency is toward the abandonment of the 
old methods and the adoption of fritted lead. 
Lead is, however, not the only danger to health with which work- EXPOSURE TO IRRITATING DUST. 
663 
men in potteries have to contend. In certain of the operations, large 
amounts of mineral dust are given off, and in consequence they suffer 
from the effects of not only poisonous, but irritating, dust; in fact, the 
occupation is regarded from a sanitary standpoint as one of the least 
desirable. The flint grinders, who belong to this class, are, accord- 
ing to Hirt, quite low down in the scale of longevity. It is said that 
the dust which is given off in the operation of grinding kaolin is un- 
usually irritating to the lungs-worse, even, than steel dust. The most 
common diseases among potters are bronchitis, phthisis, rheumatism, 
and lead poisoning. 
As another example of an industry in which the workmen suffer 
largely from lead poisoning may be cited that of file-making, in 
which, as in pottery-making, the operative is subjected to the action 
of dust both poisonous and irritating. The best files are those cut 
by hand, no machinery having yet been invented to produce as satis- 
factory an article as the hand-made. While being cut, the file is held 
upon a leaden bed, called the " stiddy," which offers sufficient resis- 
tance to the blow, without at the same time being so unyielding as to 
cause a recoil. As fast as it is cut, it is brushed off, and the air be- 
comes charged with a combination of steel, lead, chalk, and charcoal, 
and granite from the block, or " stock," upon which the " stiddy " is 
secured. The danger of lead poisoning is thus always present, and its 
occurrence is hastened by the careless habits of the workman, who, 
in handling the leaden bed, constantly wets the thumb and forefinger 
of his left hand with his tongue. 
Doubtless, if more attention were paid to personal hygiene, a smaller 
proportion would suffer from colic and paralysis of the extensor muscles 
of the wrist and thumb. It is said that a robust file-cutter is rarely 
seen ; as a class, they are sallow, anaemic, and dull, and the majority 
show the blue line of chronic lead poisoning. 
A more modern industrial danger is that involved in making and 
charging storage batteries of a certain kind. Dr. Talamon 1 relates 
that, during a single year of hospital service, he saw 30 cases of lead 
poisoning among workmen so engaged. The work consists largely in 
spreading red lead and litharge over lead plates with the bare hands, 
and the results on the system are doubtless due in greatest part to ab- 
sorption through the alimentary tract, the lead being conveyed to the 
mouth by the hands. The symptoms come on much more rapidly and 
are much more acute than with painters, typesetters, and others. Many 
of the men fall victims within three or four weeks from the beginning 
of their service. 
(6) Irritating Dusts.-The irritating dusts act with variable in- 
tensity, according to their nature. It is generally thought that that of 
vegetable origin is the most irritating of all; then, in order, metallic, 
animal, and mineral. The disease which is conspicuously common 
among dust workers-more common than among any other large 
class-is phthisis, a predisposition to which is favored by constant irri- 
1 La Medicine Moderne, Feb. 7, 1900. 664 
HYGIENE OF OCCUPATION. 
tation of the dust, assisted by bad ventilation, constrained attitude, 
and other unsanitary circumstances. In general, the first effects of 
an abnormal amount of dust in the air are cough and increased secre- 
tion of mucus. Then the cough becomes chronic, and when the soil 
has been properly prepared, the specific bacillus finds a lodgment and 
soon produces its results. Many of the dust workers' disorders are 
traceable not to a single kind of dust, but to a mixture. Thus, the 
condition formerly known as "grinders' asthma" is superinduced by 
a mixture of metallic particles from the implement ground and min- 
eral matter from the stone, and to which, if either, of the two kinds 
the preponderating influence belongs, cannot be stated. 
The relative frequency with which diseases of the lungs occur in the 
different classes of dust workers and in those whose occupation creates 
no unusual amount of dust was determined by Hirt1 from a large mass 
of material, in which, of course, the value of the primary factors can 
hardly be determined ; nor that of collateral circumstances, such as 
habits, heredity, and locality. But his facts, which, to say the least, 
are coincidences of occupation and disease, show that the different 
classes of dust workers suffer from pneumonia and phthisis in varying 
degrees and much more frequently than those not exposed to dust, and 
that in the frequency of diseases of the digestive system, on the other 
hand, there is practically no difference. In the following table, com- 
piled from his figures, the relative frequency of these diseases per 100 
workmen is shown. 
Pneumonia. 
Phthisis. 
Digestive disorders. 
Workers in metallic dust 
17.4 
28.0 
17.8 
" tl mineral " 
5.9 
25.2 
16.6 
" " vegetable " 
9.4 
13.3 
15.7 
" " animal " 
7.7 
20.8 
20.2 
" " mixed " 
6.0 
22.6 
15.2 
" " non-dusty trades 
4.6 
11.1 
16.0 
With regard to the influence of the different kinds of dusty occupa- 
tions, one must not lose sight of the fact that quantity as well as qual- 
ity must be considered, and that local conditions of ventilation must 
have a very decided bearing. 
Among the occupations in which metallic dust is given off in notable 
amounts, that which stands forth most conspicuously as a dangerous 
occupation is that of steel grinding. In this work, the danger varies 
inversely with the size of the object ground ; that is to say, the smaller 
the object, the greater the danger. This is because large objects can 
be ground in the wet way, but very small ones, as needles, must be 
ground dry and require constrained attitude and close inspection, and 
thus the grinder constantly inhales the very fine sharp particles of 
steel that are thrown off in the process. These, by constant irritation 
of the mucous membranes of the air passages, prepare them for the re- 
ception of the specific organisms of pneumonia and phthisis. At first, 
'Die Krankheiten der Arbeiter, Breslau, 1871. EXPOSURE TO IRRITATING DUST. 
665 
the cough is dry, but in a short time is accompanied by expectoration. 
Among those individuals who have followed the work for a year or 
more under the usual conditions, a sound man is rare. Their average 
age at death is variously stated between 25 and 40 years. The danger 
can be much reduced by the use of respirators and by the employment 
of a blast of air to carry the dust away from the grinder into an appro- 
priate exit. 
Not all metallic dust is as irritating as that given off in cutlery 
grinding, and in some occupations in which it is given off even more 
abundantly, there is no noticeable tendency to phthisis, though, per- 
haps, the subject has not been investigated with sufficient thoroughness. 
In the operation of bronzing in the manufacture of show cards, Christ- 
mas cards and the like, the bronze powder, which, under the micro- 
scope shows sharp angles, is applied to the pattern, printed in sizing, by 
means of a soft pad worked largely by hand. The dust adheres tena- 
ciously to the skin and causes much local irritation, and is inhaled and 
causes catarrh of the upper air passages. In addition, the workers 
suffer headache, bad taste in the mouth, anorexia, nausea, vomiting, and 
diarrhoea, from absorption and local action in the alimentary canal. 
When the operations of dusting on and off are done by machinery, the 
evolution of dust is very much lessened. 
The dusts of many of the metallic salts produce more or less serious 
local effects, aside from the results due to absorption into the system. 
In the manufacture and use of potassium dichromate, for example, 
great irritation of the nasal mucous membrane is caused, followed by 
ulceration which in most instances ends in perforation of the septum. 
Ulcers are produced wherever the skin is abraded, and especially on 
the scalp, where action is promoted by the scratching which the irrita- 
tion calls forth. No local effects appear to be caused in the lungs. 
As an example of a calling in which mineral dust is given off in 
abundance, that of glass grinding may be mentioned. This is much 
like cutlery grinding, in a general way, and the dust produced is nearly, 
if not quite, as sharp and irritating. In addition, the workmen are 
often subject to lead poisoning, due to the use of putty powder contain- 
ing 70 per cent, of lead oxide. It is as rare to find sound men 
among this class as among needle grinders. Gem polishers and pot- 
ters belong in this same category. Stonecutters and quarrymen are 
exposed to coarser kinds of mineral dust, but their work being con- 
ducted in the open air or in open sheds, they are by no means so 
prone to diseases of the lungs. Some stone is much dustier than 
others and hence may cause more marked effects. Mica dust is ex- 
ceedingly irritating and, like the sharp particles of glass and steel, pre- 
pares indoor workers for the reception of the bacillus of tuberculosis. 
In the wall paper industry, it is applied to obtain the effect of " frost- 
ing," and assists or is assisted in its action on the operatives by another 
very fine dust made of finely chopped or ground lamb's wool, which is 
applied to the pattern printed in size in much the same manner as 
obtains in bronzing cards. The workers are very prone to phthisis. 666 
HYGIENE OF OCCUPATION. 
Vegetable dust is of very many varieties, which affect the system 
with varying degrees of intensity. Ordinary wood dust appears to be 
quite innocent of injurious action on the lungs of carpenters, whose 
employment is very largely out of doors, and of cabinet makers, who, 
on the other hand, work in confinement. Grain threshers, millers, and 
many others exposed to vegetable dust present no great evidence that 
their callings are markedly inimical to health. Certain others, how- 
ever, offer important and interesting facts, indicating that, either alone 
or as one of a group of influences, some of the vegetable dusts are as 
disastrous in their effects as some of the most irritant of those of me- 
tallic nature. Among the most unhealthy classes of work people are 
those engaged in cotton and linen factories. Cotton dust, or " flue," 
is very irritant to the upper air passages and causes dryness of the 
throat, followed by cough and expectoration. In some operations, a 
sized cotton thread containing kaolin is used, and then the air is laden 
also with this very irritating substance. Flax dust, or 11 ponce," is 
even more irritating than cotton. 
In the linen factories of Belfast, which, according to G. H. Perris,1 
employ 30,000 persons, five-sixths of whom are women, the deaths 
from phthisis and other respiratory diseases have been shown to out- 
number those from all other diseases by about two to one. Among 
the women below 30 years of age, the death rate from phthisis is three 
or four times as high as among women of the same ages engaged in 
other employments. In 1892, the phthisis death rate reached the enor- 
mous height of 41.1 per 10,000, against 14.6 for the whole of England 
and Wales and 21.6 for all Ireland. Apart from the intrinsic danger 
of the occupation, however, must be noted that the city itself, from 
the nature of its soil and climate, cannot be a healthy place, but, on the 
other hand, it must be said that overcrowding, which is so great a fac- 
tor in the causation of the disease, cannot, in this instance, be charged 
with an unusual amount of influence, since in no other city in Great 
Britain and Ireland are there so many houses in proportion to the pop- 
ulation. 
Workers in tobacco are exposed not alone to irritating and poison- 
ous dust, but to fumes as well. They are much subject to nasal and 
bronchial catarrhs and disorders of the digestive apparatus and nerv- 
ous system. The women engaged are said to abort very commonly, on 
account of death of the foetus. Many claim that the occupation in 
itself is not an unhealthy one and that it possesses certain advantages 
in that it renders the individual less susceptible to infective agents. 
As evidence of this, it is said that during the great cholera epidemic at 
Hamburg, in 1892, there were but 8 cases of the disease, with 4 deaths, 
among the 5,000 cigarmakers there resident. 
Animal dust is given off in the numerous industries in which wool, 
silk, feathers, fur, bristles, hair, horn, bone, shell, ivory, and other 
substances of animal origin are used. These substances are irritating 
to different extents, as would naturally be supposed from their very 
Journal of State Medicine, March, 1895. EXPOSURE TO INFECTIVE MATTER. 
667 
diverse character, some, as wool, feathers, and silk, resembling in action 
cotton and flax, and others, as shell, bone, and ivory, acting more like 
the mineral dusts. The operatives in woolen mills appear on the whole 
to be rather less subject to phthisis than those engaged in the cotton 
and flax industries. Among the others of this class, those making 
brushes and buttons, especially pearl buttons, are regarded as taking 
greater risks than the rest. Most statistics of these industries are 
faulty and inconclusive. 
4. Occupations Involving Exposure to Infective Matter in Dust. 
This class includes those having to do with rags, wool, horsehair, 
hides, and other materials likely to be infected. The importance of 
rags as a vehicle for infection has been much overrated, but the dan- 
ger is, nevertheless, a real one, as the experience of paper makers has 
often demonstrated. The only method of ensuring freedom from in- 
fection through the handling of rags is thorough disinfection, a proc- 
ess involving an expense, it is asserted, much disproportionate to the 
results achieved. 
The most common disease connected with infected raw material is 
anthrax, or " wool sorters' disease," the spread of which is often traced 
to horsehair, wool, and hides. Nichols1 reported 26 cases of this dis- 
ease as occurring in one curled hair factory in three years. Ravenel2 
collected 12 cases occurring in men and 60 in cattle in three localities 
in Pennsylvania, during the summer and autumn of 1897. All of the 
men worked in tanneries, and all of the cattle were pastured in mead- 
ows watered by streams which received waste products from tanyards. 
The skins at fault came from China. 
According to Dr. S. Leduc,3 imported horse hair is the most danger- 
ous material brought into France. The French market is supplied by 
South America, whence it is shipped in bales compressed by hydraulic 
pressure. Unpacking the bales and sorting the contents according to 
color are alike regarded as dangerous. After being sorted, the hair is 
beaten, and in this process much dust is caused. It is then carded and 
spun into ropes. The precautions to be taken include removal of dust 
by special blower apparatus, perfect cleanliness, and great watchful- 
ness. Disinfection of the hair without impairing its commercial value 
or unduly increasing its cost is said to be impracticable. 
Naturally, the danger of infection by the spores of anthrax on hides, 
hair, and the many kinds of wools coming from countries where the 
disease is common cannot in any individual case be foreseen. From 
ordinary sheep's wool, the danger is slight, and from native wools is 
practically non-existent. When, for any reason, danger is apprehended, 
workmen with sores, cuts or abrasions on their hands, arms, faces, or 
necks should not be employed, ventilation should be thorough, and all 
precautions should be taken to prevent dissemination of the dust. 
1 Second Annual Report of the State Board of Health of Massachusetts, p. 86. 
2 Report and Papers of the American Public Health Association, Vol. 24, p. 302. 
3 Public Health Reports, May 25, 1900, p. 1306. 668 
HYGIENE OF OCCUPATION. 
5. Occupations Involving the Inhalation of Offensive 
Gases and Vapors. 
This class of occupations includes a great variety of what are known 
as " offensive trades," having to do with organic matter largely of 
animal origin, such as tanning and currying, soap-making, glue-making, 
fertilizer-making, fat-rendering, bone-boiling, keeping animals, etc. 
While there can be no doubt that these offensive trades are a frequent 
source of nuisance to the community at large, evidence of injurious in- 
fluence on the health of those actively engaged and of the population in 
the immediate vicinity of the works is decidedly slender. There can be 
no doubt of the disadvantage of having such establishments located in 
the midst of thickly settled communities, and hence their supervision 
constitutes a most important part of the duty of public authorities. 
The workmen are likely at first to suffer from nausea, vomiting, loss of 
appetite, and headache, but these evidences of disturbance disappear 
within a short time and do not recur. 
Contrary to general opinion, these occupations not only do not ap- 
pear to shorten life, but from such facts as are presented by the mor- 
tality statistics of occupations, it may be inferred that they conduce to 
longevity, for, as a class, their average age at death is quite high. It is 
hardly necessary to go into the details of the processes involved in the 
different callings. 
6. Occupations Involving Exposure to Extremes of Heat. 
Exposure to extreme heat is a concomitant of a number of other 
unsanitary influences which affect the health of the worker in a variety 
of occupations, which include those of engineers, stokers, cooks, bakers, 
miners, foundrymen, weavers, employees in rolling mills, wire mills, 
sugar refineries, and glass factories, and others. The effects of great 
heat alone are exhaustion and thermic fever, and when to these are 
added those of vitiated air, dust, irritating fumes, and dampness, the 
consequences may be very grave. Sudden chilling of the body and 
prolonged exposure without intervals of rest are especially to be 
guarded against. The workmen of this class are commonly affected 
with catarrhal and rheumatic troubles, diseases of the kidneys, and 
skin eruptions. 
7. Occupations Involving Exposure to Dampness 
Exposure to indoor dampness is usually only one of a number of 
debilitating influences, the effects of any one of which are not suscep- 
tible of correct measurement. Outdoor dampness is probably far less 
influential for evil, but continued exposure, coexistent with exhausting 
labor, is conducive to rheumatism and bronchial troubles. With ordi- 
nary care, however, those exposed to vicissitudes of weather and to 
wetness from other causes-drivers, boatmen, fishermen, and trench 
diggers, for example-enjoy good health and are, as a class, long lived. EXPOSURE TO ABNORMAL ATMOSPHERIC PRESSURE. 
669 
8. Occupations Involving Exposure to Abnormal Atmospheric 
Pressure. 
The principal calling of this group is that of caisson workers, who 
suffer from what is known as the caisson disease, the pathology of which 
is by no means clear. A caisson may be defined as a large inverted 
water-tight box in which work is performed below the water-level, as 
in the laying of foundations for the piers of bridges. It is, in fact, a 
diving bell on a large scale. It is provided at the top with a shaft for 
ingress and egress, communicating with which and with the interior is 
a chamber with two sets of doors, known as an air-lock. Placed in 
position and heavily weighted with masonry, it sinks into the mud 
beneath. The air in its interior is compressed by the action of the 
surrounding water, and the thereby diminished air space is restored by 
downward displacement of water through the agency of powerful air 
pumps. The deeper the caisson sinks, the greater, of course, the 
atmospheric pressure within. 
As the work of excavation progresses, the apparatus sinks deeper and 
deeper, being assisted in its downward movement by the weight of the 
superimposed masonry; and when the proper geological formation is 
reached, the interior is filled with concrete, which thus forms the solid 
foundation, and the box is left there. In entering the caisson, the 
workman goes first into the air-lock and closes the door. The pressure 
in this compartment is then gradually equalized with that of the caisson 
chamber by means of an inlet pipe controlled by a valve, after which 
he opens the inner door and, entering the chamber, closes it again. In 
emerging, the process is reversed : the pressure in the air-lock being 
raised, he enters and closes the door; by means of another valve, the 
pressure is gradually lowered to normal, and then the outer door is 
opened. The operations of locking in and out must be conducted 
gradually. In locking out, the rule is to allow at least one minute for 
each six pounds of pressure within the chamber. Attention must be 
paid also to the lowering of temperature which accompanies the expan- 
sion of the air within the lock. 
The symptoms of the peculiar disturbance do not, as a rule, ap- 
pear until the pressure equals 20 pounds, and some time, measured 
in minutes or even hours, after emerging. In some cases in which 
cerebral and spinal symptoms are severe from the beginning, death 
occurs within a short time. The symptoms include headache, pain in 
the ears, rapid pulse, sweating, severe pains in the legs, back, and epi- 
gastrium, and, later, paralysis of the motor nerves, generally of the legs, 
sometimes of the arms, and not infrequently of the bladder and rectum. 
The motor nerves are in some instances involved before the sensory 
disturbances appear. The epigastric pain is sometimes accompanied 
by vomiting, more or less severe in character. Mild cases of the disease 
last from a few hours to a week or longer, but whether mild or severe, 
complete recovery is the rule. Where electric lighting is not employed, 
irritation of the bronchial mucous membrane, cough and expectoration, 
due to unconsumed soot, are not uncommon. 670 
HYGIENE OF OCCUPATION. 
The cause of the main symptoms has been the subject of consider- 
able speculation, and whether it is an excess of oxygen in the tissues, 
which seems improbable, or congestion of the central nervous system, 
or some other condition, appears to be incapable of elucidation. The 
use of intoxicants appears to be a predisposing influence; hence, 
drinking men should not be employed. Thin men are much less sus- 
ceptible than the stout and full-blooded. Work should never be per- 
formed on an empty stomach, and periods of absolute rest should be 
frequent when the pressure is unusually high. 
Submarine divers are subject in a lesser degree to the same train of 
symptoms. 
9. Occupations Involving Constrained Attitude. 
These include a wide variety of trades leading to various deformities, 
the most important of which is constriction of the chest. Bad air is a 
common coexistent condition, and phthisis is a frequent cause of death. 
10. Occupations Involving Overexercise of Parts of the Body. 
The occupations of this class bring about a variety of deformities 
and of fatigue neuroses characterized by disturbance of the functional 
activity of groups of muscles trained by practice in highly specialized 
coordinated movements. These include such conditions as the cramps 
of writers, telegraphers, pianists, violinists, engravers, seamstresses, 
and others, and localized paralyses and tremors. The pathology of 
these conditions is very obscure, but in certain of the cases, especially 
those in which the larynx is overexercised, the element of hysteria 
enters to a considerable extent. These abnormal conditions are of far 
less hygienic importance than any that have been considered, and are 
of interest chiefly to the specialist. 
11. Occupations Involving Sedentary Life. 
Certain callings are commonly set down as sedentary occupations, 
but, strictly speaking, this class is very closely interwoven with several 
of those already mentioned. For instance, a very large number of 
indoor occupations, carried on, perhaps, under conditions peculiar to 
themselves, are at the same time sedentary in their nature. 
The abnormal conditions brought about by sedentary life are those 
induced by a lack of general exercise of the body. This brings about 
a general sluggishness of the functions, which is ordinarily most 
marked in those of the abdominal organs and heart. The consequences 
of too close confinement and lack of exercise are too well known to 
need any detailed mention. Ordinarily, they can be expressed by the 
term " general debility." There is no particular reason why sedentary 
occupations should injure health, and it will be found in almost all in- 
stances of impaired function that the sedentary habit is not peculiar 
to the individual while at work, but during both work and leisure 
hours. The sedentary worker has the matter of prophylaxis in his 
own hands and should take a reasonable amount of exercise daily, EMPLOYMENT OF WOMEN AND CHILDREN. 
671 
preferably in the open air. It is common to include brain-workers in 
this class and to attribute to the sedentary side of their lives the con- 
sequences of overexertion of the mind. It must be remembered that 
activity of the mind has no shortening influence on life, but abuse of 
the mental powers, and especially mental worry, conduce to headache, 
insomnia, and general breaking down of the nervous system and of 
the general health. 
PROPHYLAXIS IN GENERAL. 
In what has gone before, it will be noticed that the disastrous effects 
attributed to occupations are in very large part due to non-observance 
of the principles of general hygiene, and chiefly to inattention to that 
most important sanitary measure, perfect ventilation. It will have been 
noted that in Groups 1, 2, 3, 4, 5, and 6, the conditions which bring 
about an impairment of health can be reduced very largely by a con- 
stant supply of fresh air. With proper attention to this matter and 
improvement in the home and home influences, greater attention to 
the character and preparation of food and a more general observance 
of the beneficial influence of active outdoor exercise, no very great 
differences would be noted in the health of the various classes of 
workpeople, and the expression " occupation diseases " would lose 
whatever significance it now has. 
Employment of Women and Children. 
In view of the dangers and conditions incident to a great variety of 
occupations directly or indirectly inimical to health, it is of the utmost 
importance to protect the health of women and children by restricting 
them in the daily number of hours which they may give and pro- 
hibiting their employment in distinctly dangerous surroundings, for 
women and children are more delicately organized and less resist- 
ant to weakening influences. Particularly must women be protected 
during the child-bearing age, so that they may be ensured, so far as is 
possible, a healthy progeny. It hardly needs to be said that children 
should be most carefully protected during the period of their full de- 
velopment, in order that they may come to maturity in a fit condition 
to take on the responsibilities of the family. 
Inattention to the very great importance of conserving the health of 
women and children is bound sooner or later to result in degeneration, 
and this fact has received the attention of the law-making bodies of 
all, or nearly all, civilized countries. In this country, it is constitution- 
ally a matter for legislation by individual states, in many of which not 
only is their physical welfare protected, but the moral aspects of trades 
as well receive due attention. 
By legal enactment, the employment of women in certain kinds of 
work is absolutely prohibited and in many others is restricted as to 
number of hours according to the nature of the work. The very great 
value of most of the legislation regulating labor by children and 
women is too clear to need demonstration. CHAPTER XIV. 
VITAL STATISTICS. 
The science of vital statistics comprises the analysis and synthesis 
of facts concerning the life-history of populations. It points out where 
and to what extent disease and death are on the increase, and suggests, 
therefore, the inauguration of combative sanitary effort, the efficiency 
of which it enables us to measure. It furnishes the basis for the study 
of all the various social problems which affect increase and diminution 
in numbers. 
It is axiomatic that the facts employed must be numerous and ac- 
curately stated and classified, in order that the information supplied 
therefrom shall be trustworthy and of value. These facts comprise 
those which are yielded by the census, as numbers, age, sex, color, oc- 
cupation, and conjugal relations, and those reported to and recorded by 
local and central authorities concerning infectious diseases, marriages, 
births, and deaths. 
The study of these facts and their correct interpretation are by no 
means simple. In census years, it is not difficult to obtain practically 
accurate information of the size of the population and the ratios of 
births, marriages, and deaths, and at all times to know the degree of 
prevalence of notifiable diseases; but the intelligent interpretation of 
these facts is often, if not usually, a most complex problem. In the 
hands of those who understand the fallacies, the numerous sources of 
error, the corrections to be applied, and the comparative values, statis- 
tics can be made to yield knowledge of immense value to sanitary 
science ; but in the hands of the unskilled or unscrupulous, they may be 
more productive of harm than absolute ignorance, for it is better not 
to know at all than to be misinformed. 
It is well known that it is often possible apparently to prove two 
direct opposites with the same statistics, the fallacies being unobserved, 
and to this fact is due the low estimate in which all statistical studies 
are held by those incapable of distinguishing the false from the true. 
Statistics may be made to lie while they appear to tell the truth, and 
they have been raised to superlative rank, therefore, among falsifiers 
of all degrees. 
As has been said already, the interpretation of statistics is no simple 
matter. It requires, in fact, a mind not only naturally logical, but 
trained in drawing scientific inferences, in the recognition and avoid- 
ance of the influence of fallacy, and in the correct estimation of the 
value of different factors and disturbing influences. But even with 
several such minds working on the same mass of material, decided THE CENSUS. 
673 
differences may be found in their respective conclusions, some appa- 
rently small fact being overlooked by one or being credited with un- 
due importance by another. Therefore, in publishing facts and in- 
ferences, it is well to give as much as possible of the details and to 
bring out clearly the thread of the reasoning leading to the final con- 
clusions, for then, other analysts may, by pointing out debatable issues, 
assist in deducing the absolute truth. 
The Census.-The very foundation of vital statistics is a knowledge 
of the size of the population and of the ages of the units of which it is 
composed. In census years this may be regarded as substantially ac- 
curate, but in the intervening years it is necessary to make estimates 
based on past and present indications, which may lead to wide varia- 
tions from the truth, not susceptible of correction until the next 
enumeration. The census is taken in all civilized countries at stated 
intervals, usually of five or ten years. In France and in Germany, it 
is taken every five years; in this country and in Great Britain, every 
ten years. In this country, many of the individual States have an in- 
dependent enumeration in the middle of the intercensal period, so that 
the census is virtually quinquennial. The census gives the population 
of each community and important facts as to age distribution, sex dis- 
tribution, race, occupations, and civil state. 
From the very nature of the work, dealing in a very short time with 
vast numbers of individual sources of information, no census can be 
absolutely accurate, but under present methods the results obtained 
may be regarded as being as nearly accurate as possible. It is prob- 
able that in a large degree the errors counterbalance one another, but 
how far, can be only a matter of conjecture. 
The sources of error in census taking are intentional frauds and neg- 
ligence on the part of the enumerators, ignorance and wilful misstate- 
ment on the part of those interrogated, absence of residents when called 
upon, and inclusion of transient visitors. In 1890, it is well known, 
in certain cities gross frauds were practiced in " padding " the re- 
turns so as to increase the fees due the individual enumerators con- 
cerned. In one case, a hotel register, running back seven years, is 
known to have served as an aid in the manufacture of population re- 
turned. During the same census, many complaints were made that 
whole streets and districts were omitted altogether, the inference being 
that the enumerators either did not regard the work as sufficiently 
remunerative, or made up their reports regardless of the facts and 
without the disagreeable necessity of going from house to house for in- 
formation only slowly obtained. 
Ignorance on the part of the person questioned is doubtless a more 
fruitful source of error than intentional misstatement. Many persons 
do not know their age and give, therefore, only a guess, which is most 
commonly expressed in multiples of five and ten, more especially the 
latter. This tendency appears, in general, only after the twenty-fifth 
year, and is shown graphically by means of the accompanying diagram 
(Fig. 100) by Mr. R. H. Hooker, taken from Newsholme's Vital Sta- 674 
VITAL STATISTICS. 
tistics. Again, many data concerning the occupants of a house are 
given by persons not qualified to know; thus, the returns for a whole 
family may be based upon the statement of a servant not long in the 
place. 
Intentional misstatement is most common with regard to age and 
occupation, many wishing to appear younger, others older than they 
really are, and many being reluctant to state correctly the occupations 
of themselves and of members of their households, preferring, perhaps, 
to record others more " genteel " or important. Other wilful misstate- 
ments are very commonly due to that over-development of the sense 
of humor that disposes its unfortunate possessor to regard extravagant 
lying as the acme of wit. 
The intentional misstatement of age is more commonly a fault of 
women than of men. Women are prone to understate their age after 
Fig. 100. 
Number of persons in Tasmania living at each year of age, according to the census schedule, showing 
the tendency to cluster at round decennial periods. 
passing twenty-five; with men, the tendency is to add rather than 
subtract. After twenty-five, many women become sensitive and give 
their ages as under that age, and do not progress for several years. 
This is shown statistically by the British census returns, from which it 
appears that the girls of 10 to 15 years of one census, who become 
women of 20 to 25 years of the next census, reach these latter age 
periods without suffering any loss in number through death and emi- 
gration, but, on the contrary, with an augmentation, while the women 
of 20 to 25 years, who become 30 to 35 years old at the next census, 
show a very great diminution in number. 
Thus, as shown by Dr. Farr, the Registrar-General, in 1841 the 
number of girls of 10 to 15 years was 1,003,119, and in 1851, the 
number of women of 20 to 25 years was 1,030,456, or 27,337 more, ESTIMATED POPULATION. 
675 
while the women of 20 to 25 years in 1841 numbered 973,696 and 
yielded in 1851 only 768,711-a loss of 204,985. It is inconceivable 
that the losses among the younger group, due to death and emigration, 
should have been more than offset by immigration to the extent of 
27,337, and that the same influence should have failed to the extent 
of 204,985 to do the same thing for those of the later age periods. 
This discrepancy is said to be capable of demonstration by comparison 
of the returns of any two consecutive subsequent enumerations. • Chil- 
dren's ages are very commonly overstated in the earliest years; then, as 
the limit of age for free transportation in public conveyances is passed, 
they are understated as long as possible. Finally, when the statutory 
minimum of age is the only bar to the utilization of children in the 
various trades, the years held back are restored with some additions. 
Estimated Population.-In intercensal years, it is necessary to esti- 
mate as nearly as possible the growth or decline of a population, making 
use of such factors as can be obtained by comparison of the two preced- 
ing enumerations and from other observed influences. This is very 
commonly done by dividing the difference between the figures of the 
two by the number of years of the interval, thus obtaining the yearly 
increase or diminution, and reducing it to a percentage which is assumed 
to be the rule obtaining until the next census. This, of course, is 
merely a guess which may be near or very wide of the truth, since 
very many influences may be in operation to bring about conditions 
actually very different. But one must work with the best data avail- 
able and eliminate as much of error as possible, hence the ratio of in- 
crease or diminution is assumed to hold until the next census, and in 
the meantime errors must be diminished as much as possible. 
One of the first errors into which one falls is in assuming a fixed 
ratio, based upon the above-mentioned method of calculation. Let it 
be assumed, for example, that the annual increase in the population of 
a city of 100,000 inhabitants, determined by a comparison of the two 
preceding enumerations, is 2 per cent.; if we reckon that in 5 years' 
time the population will have increased 5 times 2 per cent., that is to 
say, from 100,000 to 110,000, we fall at once into error, for the in- 
crease proceeds not by simple but by compound interest, since in reckon- 
ing by simple interest no allowance is made for the augmentation of 
capital, so to speak, due to the annual increase in the number of per- 
sons arriving at the nubile period. 
The method generally adopted is, therefore, based on the assump- 
tion that population increases in geometrical rather than arithmetical 
progression, and the formula employed is P' = P(l + ry in which P' 
represents the estimated population, P the population according to the 
last census, r the annual rate of increase per unit of population, ascer- 
tained by comparison of two successive enumerations, and n the num- 
ber of the intercensal year in question. On the basis of a 2-per-cent. 
annual increase, the population at the end of the first year would be 
102,000; at the end of the second, it would be 102,000 plus 2 per 
cent., or 104,040; at the end of the third, 106,121 ; at the end of 676 
VITAL STATISTICS. 
the fourth, 108,243 ; and at the end of the fifth, 110,408, or an in- 
crease of 408 over the original estimate. 
As an illustration of the manner of applying this formula in the 
estimation of the population at the expiration of the fifth intercensal 
year, in this instance of an original population of 100,000 increasing 
at the rate of 2 per cent., the following may serve. The formula 
is P' = 100,000 x (1 + .02)5; (1 + .02)5 = 1.10408. 100,000 x 
1.10408 = 110,408 = P' as given above. Much time is saved in the 
calculation by recourse to logarithms. For a proper estimation of 
the population at any particular period in the year on this basis, due 
allowance must be made for the fraction of the uncompleted year. 
Population is sometimes estimated by using as a factor the average 
number of persons per habitation according to the preceding census 
returns, and multiplying this by the number of houses found to be 
occupied at the time. Sometimes, also, the number of registered voters 
is used as a basis of calculation, and again the birth rate, and again 
the number of children in attendance at the several schools. These 
methods, however, are very faulty and often even quite valueless. 
Whatever the method adopted and notwithstanding the calculations 
of the amount of influence exerted by emigration, immigration, unusual 
prevalence of or freedom from infective diseases and other factors, 
estimation of population is very frequently wide of the truth. Within 
recent years, for example, the most careful estimate of the population 
of London by the Registrar-General was found by the census returns 
to be no less than a quarter of a million in excess of the truth. With 
errors in estimation come necessarily errors in all the ratios of births, 
marriages, and deaths, and these must, therefore, undergo correction at 
the proper time. 
Increase of Population.-The growth in population due to excess 
of births over deaths is known as the natural increase. That which is 
due to excess of births plus immigration over deaths plus emigration, 
is known as the actual increase. Fluctuations in natural increase are 
caused by changes in mortality and birth rates ; thus, a decline may 
be due to a diminution in the number of births, or to an increase in 
the number of deaths, or, more markedly, to both. Fluctuations in 
actual increase are caused by the same influences plus those of immi- 
gration and emigration. Growth may, therefore, be slow or fast, and 
steady or varied and spasmodic, according to ever possible changing 
conditions, governed largely by commercial prosperity or depression. 
Decline in population may be due to excess of deaths over births, but 
is commonly the consequence of emigration. 
Population Constitution.-What is known as the constitution of 
a population shows the relative proportions of males and females and 
of persons of different age periods. These facts are obtained only from 
the census returns, and are commonly accepted as holding good until 
the next census gives different figures. In cities and large towns, 
the proportion of females is generally considerably higher than that 
of males, while in country districts the reverse is true or the excess is REGISTRARS' RETURNS. 
677 
slight. This is explained in several ways : In the first place, women 
are, in general, longer lived than men ; in the second, men are more 
prone than women to return, when advanced in years, to country dis- 
tricts from which they originally sprang; and again, men wear out 
under the conditions obtaining in crowded communities more rapidly 
than women. In the population at large, males are more numerous than 
females. 
Age distribution has a very important bearing on the death rate, 
since, as is well known, the highest death rates, so far as age is con- 
cerned, occur always in the earlier age periods. Therefore, the prepon- 
derance of individuals of one and another age period has a very great 
influence in demonstrating apparent differences in salubrity of different 
localities, when the actual sanitary conditions are identical. With such 
agreement in sanitary conditions, a community which includes a much 
larger proportion of young children will show a larger death rate and 
a smaller marriage rate than another in which the population is more 
largely made up of young adults. In consequence, it is necessary, in 
instituting comparisons between two localities, to take into account (and 
make corrections therefor) the differences in age distribution, and to 
reduce the respective populations to a common standard. 
Registrars' Returns.-Returns concerning births, marriages, deaths 
and causes thereof, and cases of infective diseases are made to local au- 
thorities, such as boards of health, and city or town clerks or regis- 
trars. In conjunction with census returns or estimates of population, 
they reveal the sanitary and sociological conditions obtaining from 
week to week, month to month, and year to year, in any community 
in which they are made. Through them we are enabled to watch the 
death rate from all causes and from any one cause, the amount of pre- 
ventable disease, the probable fluctuations in populations, and other facts 
of interest concerning communities and groups thereof. They convey 
information as to sanitary conditions and suggest wherein improvement 
in various directions is possible. 
The individual facts must, of course, be accurately observed and 
stated. This is particularly true of causes of death and distribution 
of infective diseases. The importance of proper groupings is well 
shown by the worthlessness of the lax returns not infrequently ob- 
served. For example, it is not unusual, especially in the older tables, 
to find " dropsy" standing side by side with "heart disease," "kidney 
disease," Bright's disease, and other general or vague terms. 
The value of the aggregate facts depends very largely upon the 
length of time during which they have been gathered, since only with 
the lapse of time can comparisons be instituted and the influence of 
temporary conditions eliminated or minimized. They must be suffi- 
ciently numerous to yield correct averages, for the larger the number 
of facts, the smaller the fluctuations caused by individual units, and 
conversely, the smaller the number, the greater the influence of single 
units, and the greater the chance of error; or, more definitely stated, 
accuracy increases as the square root of the number of units. Thus, 678 
VITAL STATISTICS. 
400 units will yield but half the error of 100, and 900 will yield 
but a third. In no way, perhaps, can the great influence of individual 
components of a small aggregate and the small influence of the unit when 
the aggregate progressively increases be better illustrated than by the 
daily fluctuations in the comparative standing of a number of athletic 
organizations, such as ball clubs and bowling clubs, in competition 
among themselves for a prize or championship. In the beginning, 
single events may cause entire rearrangement, and the fluctuations are 
wide and the curves most irregular; then, as the number of events in- 
creases, the fluctuations are less abrupt and the changes in the curves 
are gradual. 
In order that statistics may be useful, they must admit of compar- 
ison with similar figures obtained in other years and also at other 
places. But correct deductions can be drawn only when the condi- 
tions are at least apparently the same or when there is but one essen- 
tial difference. One may not, for example, compare the death rate of 
New York for the winter of 1898 with that of Detroit for the summer 
of 1875, and expect to obtain thereby any information of value. In 
order to measure the full influence of any one important condition, the 
other conditions must be in agreement or it must be possible to make 
correct allowance for any degree of divergence. 
Again, one must not ignore the effect of temporary local conditions, 
such, for example, as an accident in a small community whereby a num- 
ber of persons are killed at once and others die later from the effects of 
their injuries. The death rate of that town for that year would be ab- 
normally high, and the sanitary condition of the place might be made 
by figures to appear much inferior to that of an adjoining one where 
sickness and death from preventable diseases are much higher all the 
time. 
Marriage Rates.-Statistics as to marriage vary considerably from 
year to year, according to various circumstances and especially with 
changing conditions in the prosperity of the general population. The 
rate is commonly greater in cities and towns than in country districts, 
not that country-bred people are less inclined to marry, but because 
large numbers of them are attracted to populous centers after arriving 
at the wage-earning age, and there they marry. 
The marriage rate is usually expressed as so many per 1,000 of pop- 
ulation, but this is commonly open to objection, in that it may convey 
false impressions concerning inclination or disinclination to assume the 
new responsibilities, and also concerning the communal prosperity. 
Here, the importance of the population constitution as to age periods 
and sex is very clear, for in a community made up largely of old per- 
sons, young children, and domestic servants from without, the number 
of marriages occurring among the marriageable element might be very 
considerable and yet the rate per 1,000 of population would be low. 
Therefore, a more instructive method of expression would be a state- 
ment of the rate obtaining among those of marriageable age. Again, 
the number per 1,000 of population does not admit of proper compari- BIRTH RATES. 
679 
son of different communities in this particular, unless their population 
constitution is substantially the same. 
Fluctuations in marriage rates are due to other causes than com- 
mercial prosperity and depression. It has been observed, for example, 
that a condition of war diminishes the rate by withdrawing from the 
marriageable ranks of wage-earners large numbers of able-bodied active 
men. With return of peace and its attendant release of the troops to 
civil life, the rate is augmented. Thus, during 1870, when France and 
Germany were at war, the marriage rates sank respectively to 12.1 and 
14.8 ; two years later (1872) they advanced to 19.5 and 20.7. Age 
constitution, too, has necessarily an important influence in causing fluc- 
tuations. Thus, in a community largely made up of youths and maid- 
ens, the time comes when an unusual amount of marriageable material 
becomes available, and the rate at once advances. 
A period of unusual increase in the rate, from whatever cause, is com- 
monly followed by a corresponding decline, just as business prosperity 
and depression are marked by regular waves. But the general trend is 
unmistakably toward a diminution. For nearly 30 years, a very grad- 
ual decline has obtained in nearly all highly civilized countries. 
That more women marry than men, sounds paradoxical, but is, never- 
theless, true; for men are more prone than women to second and third 
marriages, and statistics show that the tendency of widowers to marry 
spinsters is much more marked than that of bachelors to marry widows. 
The age at which marriage occurs has a very important bearing on 
the natural increase of population, since whether a woman marries early 
or late in the child-bearing period, determines, other conditions being 
the same, the extent of fruitfulness and, more particularly, the interval 
between successive generations. Statistics indicate that among the 
native-born of this country, particularly in those parts longest settled, 
and in Great Britain and other countries in which the highest degree 
of civilization has been reached, the average age at marriage is steadily 
increasing. This has been attributed to an intelligent selfishness, 
tending to defer the assumption of responsibility for the maintenance 
of others, thus ensuring an unrestricted enjoyment of the fruits of 
labor; and to the wider opportunities for profitable employment of 
women, with consequent lessened dependence upon marriage as a 
means of support. 
Birth Rates.-Statistics as to births are expressed in the same 
manner as those concerning marriage; namely, as so many per 1,000 of 
population. This ratio is known as the crude birth rate and conveys 
no information concerning the proportion of women of the child-bear- 
ing age who have added to the population. Here, again, a more ac- 
curate and instructive method of expression might be based upon a 
comparison of the number of legitimate births with the number of 
married women below 45 years of age, and of the number of illegit- 
imate births with the number of single women of the same limit of 
age. Under any system, still-births are not included in either the 
births or deaths, though they are certified. 680 
VITAL STATISTICS. 
Birth rates naturally vary very greatly in different communities, 
the same as marriage rates, and for the same reasons. Ordinarily, 
they are higher in cities than in the country, and during and immedi- 
ately following periods of prosperity than during times of depression. 
A higher rate is to be expected of a manufacturing and commercial 
center than of a purely residential town, where a large number of 
unmarried domestics, employed by the well-to-do and rich, swell the 
population and lower the rates of both marriages and births in the 
manner already mentioned. In the latter case, the married inhab- 
itants may be unusually prolific, and the birth rate, expressed per 
1,000 of married women below 45, would be very high ; yet, the 
crude birth rate would be low. So, in comparing two communities in 
respect to births, accuracy demands that they shall be reduced to a 
common basis. 
The higher birth rate in cities and large towns is due to the greater 
proportion of women of child-bearing age, the higher marriage rate, 
and the earlier marriage age that there obtain among people of the 
lower classes. 
Since the proportion of deaths in the earliest years of childhood is 
very high, it follows that a high birth rate is always associated with a 
higli death rate, but at the same time, a high birth rate implies a large 
proportion of married persons in the full vigor of life at that age period 
which is associated with a low rate of mortality, and thus the influence 
on the death rate is more or less corrected. A continued high birth 
rate necessarily implies a large proportion of growing children who, 
year by year, swell the ranks of the reproductive. 
A low birth rate, by causing a relative increase in the proportion of 
persons of the age periods of low mortality, may bring about a low 
death rate, but if it continues long enough to bring the population to 
a high average age, it will be succeeded by a rapid increase in the death 
rate due to diseases of advancing years. 
The birth rates of many countries, like the marriage rates, have for 
some years shown a steady decline. This is due somewhat to the in- 
creasing average age at marriage, which reduces the period of repro- 
duction, but largely to artificial restrictions and economic considera- 
tions. The great decline in the birth rate of France has attracted 
widespread attention and become the subject of grave concern to the 
authorities and other thinking people of that country. A hundred 
years ago, over a quarter of the population of what are known as the 
Great Powers was French ; to-day, notwithstanding the marked disin- 
clination of that people to emigrate and seek new homes, the propor- 
tion has fallen to about one-eighth. In 1891, according to census re- 
turns, of every hundred families, 22 had but two children, and 24, but 
one, apiece. The decline in births is not due to poverty, for it is 
among the poorest there, as elsewhere, that the largest families are 
raised. The same influences appear to have been in operation for 
some years in England and Wales, where, since 1876, when the birth 
rate was 36.3, it fell progressively in 20 years to 29.7, and showed in DEATH EATES. 
681 
the last years of the century a more striking decrease than in any other 
country of Europe. 
In our own country, among the descendants of the original colonists 
and earlier immigrants, the same decline is most evident. Whereas in 
colonial times and in the earlier years of national independence, fam- 
ilies of a dozen, fifteen, and more were exceedingly common, nowa- 
days, one of six or eight becomes a subject for comment, surprise, and 
even ridicule. The large families of to-day are mainly those of the 
more recently arrived immigrants and their first generation. In Mas- 
sachusetts, the statistics for 1898 show that the greatest proportion of 
the number of births belongs to the foreign-born, the children of 
native parentage on both sides representing 32.36, those of mixed 
parentage, 19.42, and those of foreign-born parentage, 48.22 per cent, 
of the total births. The crude birth rate was 27.37. 
Death Rates.-Death rates are calculated in the same way and ex- 
pressed in the same terms as birth and marriage rates, that is, by mul- 
tiplying the number reported by 1,000 and dividing the product by 
the population, or by dividing the reported number by the number of 
thousands of population, the result in either case being the rate per 
1,000 of population. This is known as the general, gross, or crude 
death rate, and is affected by so many factors that, without careful 
study and due allowance for disturbing influences, it may prove to be a 
very faulty index of the health of the people and of the sanitary con- 
dition of the place. When used as a basis for comparison of different 
places, the death rates must first be corrected by making careful 
allowances for differences in age, sex, and race distribution, and for 
abnormal influences. 
Influence of Sex.-Sex exerts a decided influence, since, in general, 
females live longer than males and their mortality is lower at all age 
periods, excepting from the tenth to the twentieth year. So, of two 
places equal in sanitary and all other conditions excepting sex consti- 
tution, the one with the greater proportion of females will have the 
lower death rate. Except in newly-settled places, there is, as a rule, 
a preponderance of females over males, although everywhere the births 
of males exceed in number those of females, the preponderance being 
the result of the higher mortality that obtains among males, except at 
the age periods above mentioned. 
Influence of Age.-The influence of age distribution is far greater 
than that of sex, since, for example, the mortality per 1,000 of children 
under 5 years of age is more than ten times that of persons between 5 
and 25, and more than six times that of adults between 25 and 45. 
Thus it may be seen that the greater the proportion of population be- 
longing to the earliest and latest periods of life, the higher will be the 
death rate. One would expect, for example, a higher mortality in a 
community made up largely of elderly people or young children than 
in one unusually rich in young adults, or, to reduce the matter to its 
simplest terms, in a foundling asylum or retreat for the aged than in a 
college of young men. 682 
VITAL STATISTICS. 
Influence of Race.-To a certain extent, racial peculiarities have an 
influence on vitality and especially on susceptibility to certain diseases. 
Thus, the negro is far less prone to some and far more susceptible to 
other morbid influences than the white. As between different peoples 
of the same race, the differences are not so wide. In those parts of 
this country where the negro population is considerable or preponder- 
ant, this influence can never be disregarded, and, indeed, it is commonly 
the practice to calculate separate rates for the whites and for the blacks. 
According to Hoffman,1 the mortality of whites and blacks in ten south- 
ern cities, including Baltimore, Washington, Richmond, Memphis, 
Louisville, Atlanta, Savannah, Charleston, Mobile, and New Orleans, 
during the years 1890-94, was expressed as 20.1 and 32.6 respectively. 
This divergence, it is pointed out, would be still greater, if correction 
were made for age distribution. 
The excess of negro mortality obtaining at all age periods is especially 
noticeable in the earlier ones. Thus, in 1890, in Washington and 
Baltimore, the death rates of negro children under 5 and between 5 
and 15 years of age were more than double those of white children of 
the same age periods; in the age periods from the fifteenth to the forty- 
fifth year, the rates for both races naturally diminish very much, but 
the ratio is nearly the same. After the forty-fifth year, the difference 
begins to be much less, but the excess is always with the negro. 
As instances of the differences in white and black death rates, the 
following are presented : 
New Orleans December, 1899, White, 23.49; Colored, 28.59 
January, 1900, " 28.28; " 44.80 
March, 1900, " 22.50; " 39.60 
Baltimore November, 1899, " 13.42; " 22.30 
December, 1899, " 15.00; " 29.38 
January, 1900, " 17.90; " 30.60 
Charleston, 5 wks. ending Jan.6, 1900, " 15.70; " 33.23 
4 " " Feb. 3, " " 12.60; " 27.50 
2 " " Feb. 24, " " 19.81 ; " 32.94 
The difference between white and black mortality is believed to be 
due more largely to race degeneration than to sanitary conditions. In 
the North, the negro shows an excess of deaths over births and holds 
his own only by influx of recruits from the South. 
From what has been said, it must be evident that crude death rates 
cannot be relied upon as a basis of mortality comparison of two places, 
unless the respective populations are in substantial agreement in age, 
race, and sex constitution, nor for comparison of the conditions obtain- 
ing at the same place in different years, unless these factors are prac- 
tically unchanged. 
Other Influences.-Crude death rates are influenced by errors in es- 
timated population, by the presence of various kinds of public insti- 
tutions, such as hospitals, state almshouses, and asylums for foundlings 
and the aged ; by migratory movements ; by density of population, and, 
1 Race Traits and Tendencies of the American Negro. Publications of the Amer- 
ican Economic Association, New York, 1896. DEATH RATES. 
683 
as has been stated already, by the birth rate. An important source of 
error lies in the return of persons afflicted with incurable diseases to 
their old homes, where they die; their deaths are registered there, in- 
stead of at the places where the causes thereof had their origin or 
where the sanitary conditions were such as to favor susceptibility. 
Influence of Density.-Death rates, especially those of the very 
young, are much higher in crowded localities than where the population 
has plenty of room, and it is commonly accepted that, other things being 
equal, increased density means increased mortality. To a certain ex- 
tent this is undoubtedly true, particularly where increased density 
means overcrowding, but it is not necessarily true of a large population 
spread out over a territory capable of accommodating twice as many 
people very comfortably. Thus, in Massachusetts, for example, where, 
in 1855, the population averaged 136 to the square mile, the general 
death rate was about the same as obtained 40 years later, when the 
average population per square mile had more than doubled, the slight 
difference being in favor of the later period. During the decennium 
just prior to the outbreak of the civil war, the average rate was 18.25 ; 
during the period 1887-1897, it was about 19.50 ; and in 1898, it was 
but 17.55, which was the lowest annual rate for 32 years. 
In densely populated overcrowded localities, such as the slums of large 
cities, we find all the conditions which favor a high mortality ; namely, 
poverty, immorality, ignorance, intemperance, unsanitary habitations, 
high birth rate, carelessness, filth, and improper and insufficient food. 
In fact, the slums are, in very great measure, the cause of the differences 
observed in the death rates of small and large communities. In 
country districts, small towns, large towns, and cities situated within 
the same district, where climatic and other natural conditions are es- 
sentially the same, it is commonly observed that the higher average 
rates obtain in the larger communities, and the lower in the smaller 
places where slums are unknown, while the very highest occur in 
manufacturing centers where the main population consists of mill oper- 
atives, who work by day under unsanitary conditions and pass their 
nights in crowded tenements. So, also, higher rates obtain in old man- 
ufacturing places, in which a larger proportion of population of a weak 
and degenerated type is to be found, than in others more recently es- 
tablished. 
Weekly Death Rates, Etc.-The death rate for any particular week 
is obtained by multiplying the number of deaths occurring during 
that period by 52.14 (the number of weeks in 365 days) and dividing 
the product by the number of thousands of population as estimated 
for the middle of the year.1 The same method of reckoning may be 
employed for determining the rates for other fractions of a year, and 
for rates of birth, marriage, zymotic disease, and other matters of sta- 
1 Many statisticians employ the factor 52.17747, the number of weeks in the solar year 
of 365 days, 5 hours, 48 minutes and 46 seconds. This exaggeration of exactness in 
small things seems all the more absurd when we consider that the estimation of popu- 
lation at the middle of the year is nothing more than a fairly reasonable guess, which 
often proves to be wide of the truth. 684 
VITAL STATISTICS. 
tistical interest. These weekly and other periodical rates are highly 
unreliable data upon which to base comparisons with those of other 
places and other parts of a year, since seasonal influences and tem- 
porary conditions must not be ignored; their principal value is in 
comparing the rates obtaining at the same place at corresponding 
periods of different years. 
In the same way, the weekly death rate from any given cause, or the 
weekly number of cases of any particular notifiable disease, such as 
diphtheria, scarlet fever, or measles, may be determined. 
Zymotic Death Rate.-The zymotic death rate is the death rate due 
to the seven principal so-called zymotic diseases; namely, smallpox, 
scarlet fever, measles, diphtheria, whooping-cough, typhoid fever, and 
diarrhoeal diseases. It is expressed in terms per 1,000 of population, 
like the gross death rate. The rate for any disease can be similarly 
obtained and expressed. 
Infantile Death Rate.-The infantile mortality is not expressed in 
terms per 1,000 of the whole population, but as the number of deaths 
of children under one year of age to each 1,000 births registered dur- 
ing the year. It is assumed that the efflux of living children whose 
births have been registered with the local authorities is counterbalanced 
by the influx of others whose births are registered elsewhere. 
Infantile mortality is always high, owing to a variety of causes, and 
it is particularly high in slums and in manufacturing towns where 
women are largely employed in factories and so are unable, even though 
so inclined, to give that personal attention to their offspring as is be- 
stowed by mothers whose lives are purely domestic. In Massachusetts, 
for example, the infantile death rate averaged, in the decade 1881-1890, 
174.9 in the cities and 129.5 in the country, and the extremes for the 
cities were 239.7, at Fall River, preeminently a "mill town," with all 
that the term implies, and 111.9, at Newton, where manufacturing is 
at a minimum and overcrowding practically unknown. Lowell and 
Lawrence, also "mill towns," showed respectively 222.5 and 213.9, 
while Boston, commercial, manufacturing, and residential, showed 
188.2. 
In the three cities with the highest rates, Fall River, Lowell, and 
Lawrence, the population is largely French Canadian operatives of 
cotton and woolen mills, housed in crowded tenements. The so-called 
"shoe towns," Haverhill, Marlboro, Brockton, and Lynn, have a very 
different kind of population, much better paid and not inclined to a 
tenement-house life, and show respectively 157.1, 154.6, 146.9, and 
140.7, all of which rates are below that of the State at large, 160.4.1 
Similarly, in England and Wales, where in 1894 the rate was 137, and 
in 1896, 147.5, Preston, which can claim one of the blackest records 
in all respects among mill towns, showed, in the former year, 229, and 
in the latter, 262, while in London the rate was but 159. 
1 These figures are taken from a communication by Dr. S. W. Abbott, Secretary of 
the State Board of Health of Massachusetts, on "Infant Mortality in Massachusetts." 
Journal of the Massachusetts Association of Boards of Health, December, 1898, p. 134. DEATH RATES. 
685 
The chief factors in the causation of high infantile mortality are 
premature births, heredity, intemperance, early marriages, neglect, 
carelessness, ignorance, improper food, unsanitary surroundings, indus- 
trial conditions, illegitimacy, and, perhaps, infant life insurance. The 
immediate causes are chiefly inanition, diarrhoeal diseases, measles, 
whooping-cough and other infective diseases, and violence. The influ- 
ence of premature birth, heredity, neglect, carelessness, ignorance, and 
unsanitary surroundings needs no elucidation. Industrial conditions 
figure largely in the neglect of infants, since mothers in employment 
return as soon as possible after confinement to their work and entrust 
their offspring to the care of older children and others, by whom they 
are improperly fed and looked after. During pregnancy, also, the 
woman remains at her work up to the last possible moment, so that her 
absence is limited to that period during which she is absolutely in- 
capacitated. 
The age of the parents has much influence on the vitality of infants, 
those of mothers under 20 dying off appreciably faster than those of 
others between 20 and 30. Between 30 and 35, the vitality of the off- 
spring is still greater, but after this age period it begins to decline. 
The first children of very young fathers also are, as a general rule, 
weaker than those begotten later. To this influence of the parents' 
age, conjoined with that of ignorance and inexperience, may be attributed 
the excessive mortality which obtains among the first-born. 
Illegitimacy has a very great influence on the chance of survival to 
even the early period of childhood, for the infant is in an unfavorable 
position as regards care and home surroundings from the beginning. 
Abandoned by the mother to the care of whomsoever may be willing 
to accept the charge, or "farmed out" among persons whose interest 
in its welfare is wholly financial and subject to immediate decline on 
the cessation or tardiness of payments, it has even less chance, perhaps, 
than when kept at home, an unwelcome addition both to the family 
circle and to the expense account. 
Infant insurance is generally believed to be an influence in diminish- 
ing the amount of care and solicitude for the health of the very young, 
and, therefore, has been the subject of considerable legislation, by which 
the maximum amount of the policy is kept at a low figure, as, for 
instance, the actual expense of burial. Whether insurance really has 
more than an insignificant bearing, cannot be determined by any trust- 
worthy statistics. 
Beyond doubt, the most fruitful single cause of high infant mortality 
is improper feeding, due partly to the necessity of supplying an artificial 
substitute for breast milk and partly to ignorance. The breast-fed in- 
fant, carelessly looked after, has a far better chance than the bottle-fed 
more carefully tended. The former receives its natural food at a uni- 
form temperature and practically sterile ; the latter is fed upon another 
kind of milk, differently constituted and of a different degree of digesti- 
bility, which, under the best of circumstances, is comparatively rich in 
ordinary bacteria and administered at different temperatures, sometimes 686 
VITAL STATISTICS. 
very hot, sometimes cold. With lack of care, the danger is increased, 
for the milk may be stale and dirty and act as the vehicle for the exciting 
cause of cholera infantum, which is responsible to a greater extent than 
any other morbid condition for the deaths in mill towns of infants 
whose mothers are employed in the various industries. Besides dirty 
and stale cow's milk, a variety of cereal and sugar substitutes are pro- 
vided, which may or may not be digestible and nutritious. 
Ignorance of what is proper for introduction into an infant's stomach 
is responsible for much infantile mortality, even when breast-feeding 
is followed. Who has not seen fond, but ignorant, mothers, in public 
conveyances, keeping their infants quiet with bananas, seed cakes, 
cookies, and other food materials unsuited to a digestive system which 
can have difficulty enough with milk alone? It seems unlikely that 
such practices are restricted to the time spent in travel, when con- 
sideration for the comfort of strangers suggests the avoidance of fret- 
ting and crying. 
Death rates of children under five years of age are expressed in the 
same terms as infantile mortality, that is to say, as the proportion of 
deaths per 1,000 children of that age period. 
High and Low Death Rates.-In the absence of any unusual general 
unsanitary condition or of unusual prevalence of epidemic diseases, 
an abrupt rise in, or a very high, death rate is not infrequently only 
apparent, being based upon an underestimated population. A very 
low death rate is always open to suspicion, though sometimes, as in 
newly settled communities with a very high proportion of young male 
adults, for a limited term of years, it is perfectly possible and natural. 
A rate of 15 per 1,000, for example, in large cities, is so low as to 
suggest that the population has been very much overestimated. Within 
very recent years, the authorities of a rapidly growing Western city 
noted with great pride the gigantic strides in the estimated population 
and were naturally much elated to find that the death rate based 
thereon entitled the city to a position in the first rank of the cities, 
large and small, of the whole world. The census of 1900 dispelled 
the illusion, for the population had been grossly exaggerated and the 
actual death rate was comparatively high. 
Death rates as low as 10 and 12 are sometimes noted. A continued 
rate of 10 in a stationary population would mean that the inhabitants 
would average 100 years of age at death; one of 12 would mean an 
average age of over 83 ; one of 15 would mean an average of nearly 67. 
As examples of high and low death rates, the following for the same 
quarter of the same year (1897) may be cited : 
High. 
Dublin 39.9 
Moscow 36.9 
Bucharest 33.2 
Belfast 31.3 
St. Petersburg 31.0 
Low. 
Frankfort a/M 15.6 
The Hague 16.2 
Berlin 17.0 
Christiania 17.7 
Amsterdam .17.8 
The influence of improved sanitation in the lowering of the morta - DEATH RATES. 
687 
ity of any given place cannot be disputed, but in attributing the whole 
or even the greater part of the difference in the rates of any two places 
or of the same place in different years, one must be careful not to 
ignore factors, already mentioned, that exert influences beyond the con- 
trol of sanitary authorities. Permanent decline in mortality rate is a 
matter of slow growth and is the combined result of sanitary effort and 
mitigation of the occupational and social conditions tending to lower 
vitality. In Elizabethan times, the death rate of London was about 
40 ; at the beginning of the reign of Victoria, it was 24, and at the end 
of the century, about 19. 
Correction of Death Rates.-The impossibility of making a fair com- 
parison of the death rates at different places without taking into con- 
sideration the constitution of the respective populations as to age, sex, 
and race, has been already sufficiently pointed out, and since two places 
absolutely alike with regard to occupational influences, wealth, density 
of population, climate, soil, water supply, sanitary administration, and 
general sanitary condition, but discrepant as regards the distribution 
of the sexes, age periods, and race, may show very different death 
rates, perhaps magnifying the salubrity of the one and exaggerating the 
unhealthiness of the other, it becomes necessary to have some method 
of bringing them to a common basis. In the matter of race influence, 
the best plan is to separate the statistics absolutely, having one set for 
the white and another for the colored population, and compare white 
with white and negro with negro. 
The method commonly recommended for correcting according to 
sex and age is the one in use in the office of the Registrar-General for 
England and Wales; this may be briefly described as follows. 
The mean annual death rate of the country for each sex at each of 
the eleven age periods, namely, below 5, 5-10, 10-15, 15-20, 20-25, 
25-35, 35-45, 45-55, 55-65, 65-75, and 75 and upwards, during 
the last preceding 10 years, is obtained and multiplied by fhe number 
of those of each sex at each corresponding age period in the territory 
under consideration, according to the returns of the last preceding 
census. Each product thus obtained, divided by 1,000, gives the cal- 
culated number of deaths for the respective sex and age periods. 
These 22 results, added together, represent the calculated number of 
deaths for the place in question in one year. The total calculated 
number of deaths, divided by the number of thousands of population 
or multiplied by 1,000 and divided by the population, gives the stand- 
ard death rate. 
The next step is to obtain a factor for correction, by determining the 
ratio which the standard death rate of the place bears to the death 
rate of the whole country. This is obtained by the rule of simple 
proportion, the second mean being unity. The recorded death rate 
for the year, multiplied by this factor, gives the corrected death rate, 
which will, therefore, be above or below the recorded rate, according 
as the factor is above or below unity. By dividing the corrected 
death rate by the death rate of the whole country and multiplying the 688 
VITAL STATISTICS. 
quotient by 1,000, the comparative mortality figure is obtained ; that is' 
to say, the number of deaths which will occur in the same number of 
the local population as, in the general population, will yield 1,000 
deaths. 
Classification of Causes of Death.-In the registration of causes of 
death, a certain amount of error is inevitable, for several reasons. In 
the first place, even the most competent practitioners are not infallible 
in diagnosis, and it is not always possible, when one pathological state 
is complicated by the advent of another, to determine which was the 
actual cause of the fatal termination. Next, the nomenclature of 
diseases is faulty, though ever tending toward ultimate perfection. 
Again, the true cause of death is frequently intentionally misrepre- 
sented for private or family reasons ; thus, apoplexy, instead of suicide, 
and peritonitis, when the actual cause of the peritonitis is criminal in- 
terference. 
Lastly, it is sometimes the case that no cause whatever is assignable, 
even after careful autopsy, and, obviously, such cannot be classified. 
With the existence of an indeterminate amount of error, it follows 
that caution must be exercised in comparing results representing a 
series of years, and allowances must be kept in mind with changes in 
nomenclature, when drawing deductions from what has been described 
as the classification of the more or less reliable guesses of a large num- 
ber of more or less skilled observers. 
Registration of Sickness, if it were possible, would afford a far more 
efficient index of the sanitary condition of the population than the 
registration of deaths, which gives us simply the number of cases of 
sickness which ended fatally, but no idea of the duration thereof or of 
the number of persons temporarily incapacitated. A disease ordinarily 
regarded as fairly dangerous may prevail very extensively in a mild 
form and be attended by a very low death rate, and again may exist 
to a lesser extent, but in an unusually severe form, with a high propor- 
tion of fatalities. Many diseases, again, are temporarily disabling and 
often widely prevalent, but play a small part in mortality returns. 
Tonsillitis, for example, is responsible for much discomfort and lost 
time : its prevalence has some meaning, but its death roll is exceedingly 
small. Rheumatism is much more widespread than mortality returns 
would imply; chickenpox is relatively unimportant, but in some 
places its notification is required as a safeguard against the spread of 
smallpox incorrectly diagnosed as varicella ; gonorrhoea, without being 
fatal, does more harm than is commonly supposed, and syphilis, also 
not immediately and directly fatal, sends its victims into the mortality 
returns through various avenues. 
But however desirable such registration may be, the obstacles in the 
way of its accomplishment are too numerous to admit even of hope, and 
excepting in the case of infective diseases, which law requires shall be 
reported, there is no satisfactory method of obtaining an accurate idea 
of the health of a community. 
Duration of Life.-Several expressions and methods are employed DURATION OF LIFE. 
689 
to denote and measure the duration of life, a problem with which the 
science of vital statistics is largely engaged. One of the most fallaci- 
ous indications of longevity and sanitary condition is the Mean age at 
Death or Mean Lifetime, which is the sum of the ages at death divided 
by the number of deaths. This is unreliable, because it fluctuates very 
widely, according to age distribution ; for in a community containing a 
large proportion of children and in which the birth rate and, conse- 
quently, the infantile mortality are high, the average age at death will 
be lower than in another, equally healthy, in which these conditions do 
not obtain. Hence, it can only be employed with any degree of safety 
where the population constitution is uniform in all respects and when 
the observations are carried along over a long period. The mean age 
at death, not of a few hundreds or thousands of individuals, but of an 
entire generation of population, is necessary to show accurately the mean 
duration of life, and this is determined only by means of life tables. 
Probable Duration of Life signifies the age at which half of any num- 
ber of children born will have died, so that they have equal chances 
of dying before and after that age. It is also called the vie probable 
and the equation of Life, but all of these terms are ill-chosen, for every 
possible duration of life has a certain probability, which may be de- 
termined by life tables. 
Mean Duration of Life is another ill-chosen term with which the last- 
mentioned is often confounded, but which has an entirely different 
meaning. It is meant to express the probable duration of life from 
the date of birth. In an ordinary population, subjected to the usual 
disturbing influences of migration, it means present age plus the prob- 
able length of life after passing a given point, and is commonly called 
the expectation of life or mean after-lifetime. It is a term which, by 
reason of its indefiniteness and looseness of application, it would be well 
to eliminate altogether. 
Expectation of Life, or Mean After-lifetime, is the average number of 
years which an individual at any given age will continue to live, as 
shown by a life table. As applied to whole communities, it is the 
mean duration of life of a generation of individuals from birth to death 
and is regarded as the only true measure of the health of entire 
populations. Like others which have gone before, it is an unfortunate 
expression tending to confusion. " The term does not imply that an 
individual may reasonably expect to live a given number of years. 
The excess of those who die late is distributed among those who die 
early, 1 those who live longer enjoying as much more in proportion to 
their number as those who fall short enjoy less of life.' Thus the ex- 
pectation of life has no relation whatever to the most probable lifetime 
of any given individual." (Newsholme.) 
"Expectation of life is an incorrect term : the time which it is expected 
a person will live is the time which it is an even chance he will live; 
it is the vie probable of the French, and is correctly expressed by 
* probable lifetime.' The after-lifetime can only be the same as the 
probable lifetime on Demoivre's hypothesis-that the surviving form 690 
VITAL STATISTICS. 
an arithmetical progression. The term 'expectation of life,' first used 
by Demoivre, is correct, on that supposition, which is, however, in 
itself quite erroneous. The idea intended to be expressed by 'expec- 
tation of life ' is the mean time which a number of persons at any in- 
stant of age will live after that instant: it is the French vie moyenne ; 
and this technical idea is strictly and shortly expressed by afterlifetime, 
a pure English word, formed on the same analogy as afterlife, after- 
times, after age, afterhours. The afterlifetime of men at the age of 30 is 
33 years by the English Life Table: 33 years is not the precise time 
probably that anyone of that age will live, but the average time that 
a number of men of that age will live, taken one with another. 
Age + afterlifetime = Lifetime. At 30 this is 30 4- 33 = 63, the 
average age which men now aged 30 will attain. At birth this is 
0 + 40 = 40 ; when lifetime and afterlifetime are the same thing. 
" The lifetime simply, without the addition at a given age, will serve to 
express in one word what is improperly called the expectation of life at 
birth; thus the lifetime of males in England is 40 years, the lifetime of 
males in Manchester is 24 years. Those who, from habit, prefer " ex- 
pectation of life, can always substitute it for afterlifetime; from the 
use of which, in this paper, no ambiguity can arise." (Dr William 
Farr, Eighth Annual Report of the Registrar-General, p. 279.) 
Life Tables.-A life table, according to Dr. Farr, is an instrument 
of precision. " It may be called a biometer, for it gives the exact 
measure of the duration of life under given circumstances. * * * A 
life table represents a generation of men passing through time; and time 
under this aspect, dating from birth, is called age. In the first column 
of a life table, age is expressed in years, commencing at 0 (birth), and 
proceeding to 100 or 110 years, the extreme limit of observed lifetime." 
In order to construct a life table, it is essential to have, as material, 
a knowledge of the size of the population and its age and sex distribu- 
tion, and the returns of death for a year, or a series of years, arranged 
according to age at death and sex; and for tools, certain abstruse mathe- 
matical formulae which it is hardly necessary to consider here. The 
principle upon which the tables are based is that if a large number of 
persons, 100,000 for instance, born at the same time, were followed from 
birth to the grave and their deaths recorded in the usual manner, 
the average age lived could be obtained by dividing the sum of their 
ages at death by their original number, and the number of deaths and 
of survivors at each period would be known. Another lot of the same 
size, observed elsewhere and living under different conditions, would 
give different results, and thus the influence of the discrepant condi- 
tions could be measured. 
To ensure as great accuracy as possible in constructing life tables, it 
is best to take the death returns for the entire intercensal period of 5 
or 10 years and the mean population, for the experience of a single 
year may be very exceptional. Tables can be constructed comprising 
each year of life or according to quinquennial periods, and are made 
for each sex. From them one determines the probable proportion of LIFE TABLES. 
691 
a given number that will arrive at different ages, the probability of 
living a given time at each year or period of age, the mean afterlife- 
time at the end of any given year or period, and the aggregate future 
lifetime of the survivors at the end of each year or age period, or what 
is known as the life capital of the entire community. 
The probability of living a given time for each year of life or age 
period equals the number of survivors at the beginning, into the num- 
ber at the end of the year or period. The probable number of surviv- 
ors at each year or period is obtainable directly. The mean afterlife- 
time at the end of any given year or period is obtained by adding 
together the years lived by the whole life-table population beyond the 
year or period, and dividing the sum by the number of survivors at 
that particular time. The life capital of a community, divided by the 
population, gives the average future lifetime ; and into a hundred times 
the population, gives the percentage of annual expenditure of life capi- 
tal, since the mean population equals years of life expended in a year. 
For further information concerning this branch of vital statistics, 
and for further consideration of statistical methods, values, and errors, 
the reader is referred to the many standard works dealing with the 
subject. CHAPTER XV. 
PERSONAL HYGIENE. 
In addition to the barriers which public hygiene interposes for the 
protection of the health of communities by protecting water supplies, 
disposing of sewage and other wastes, excluding exotic diseases by 
means of quarantine, providing for isolation of communicable diseases, 
destroying infectious matter by disinfection, regulating the conduct of 
dangerous occupations, providing for the inspection of foods, and throw- 
ing out other safeguards, the individual owes it to himself and to the 
community, of which he constitutes a more or less valuable unit, to 
erect such other barriers for his own protection as he can, by due re- 
gard to such habits of life as conduce to a healthy existence. It is his 
duty to maintain habits of personal cleanliness, to regulate his diet, 
avoiding all excesses in eating and drinking; to protect his body by 
suitable clothing ; to take sufficient exercise in the open air; to keep his 
system in perfect working order throughout; to devote a sufficient 
part of each twenty-four hours to needful rest of mind and body; and 
to keep his immediate surroundings in as cleanly a state as his own 
person. This is the domain of personal hygiene. 
Section 1. CARE OF THE PERSON. 
It is hardly necessary to impress upon intelligent people the impor- 
tance of personal cleanliness, for with such it is a matter almost of in- 
stinct. In the case of the naturally dirty, the attempt to educate in 
this particular is, as a rule, a hopeless task, and with such, the mainte- 
nance of cleanliness of body and surroundings can be obtained only by 
compulsion. There is in every civilized community an all-too-large 
proportion of persons who never bathe, and, indeed, regard a bath as 
a positive danger to health, as every physician who has had an experi- 
ence as a hospital interne or in practice among the ignorant poor can 
abundantly testify. 
Bathing is of importance to health, both for its action in removing 
dirt and infectious matter of external origin and for its influence in 
keeping the skin free from waste products of the system and in a con- 
dition for the proper exercise of its natural functions; for the skin is 
one of the most important natural defenses. 
Baths.-By an arbitrary division of temperatures, cold baths are 
those in which the water has a temperature below 65° F.; cool, be- 
tween 65° and 80° ; tepid, between 80° and 90° ; warm, between 90° CARE OF THE PERSON. 
693 
and the normal temperature of the body; and hot, above this limit as 
high as the system can bear. Cold bathing is essentially stimulant : 
the cutaneous vessels contract at once, and send the superficial blood 
supply inward; the respiration is momentarily gasping in character, and 
then slowed and increased in depth. The whole nervous system and 
all of the mental faculties receive an immediate powerful stimulus. 
The pulse is somewhat slowed. On emerging from the cold water, the 
respiration and pulse return to their normal rates, the cutaneous vessels 
relax and dilate, and the return of the blood in increased volume to the 
surface gives a sensation of warmth, which is increased by the process 
of " rubbing down." This is known as the " normal reaction." 
The cold bath is best taken in a tub in which the whole body can be 
immersed, but in default of the necessary means, a sponge, saturated 
with water, applied repeatedly to the various parts and squeezed out, 
forms a desirable substitute. A shower bath is still better, especially 
one admitting of regulation of the temperature. 
The proper time for cold bathing is on rising in the morning ; never 
on retiring for the night. Cold baths should not be taken by those 
advanced in years, in whom the arteries are atheromatous, nor by those 
with abnormal circulation, who do not quickly react. 
Not the least in importance of the effects of cold bathing is the im- 
munity which its devotees appear to enjoy against taking cold. Many 
of those who practice cold bathing the year round have no experience 
whatever with colds and can withstand exposure which, to others, is 
productive of much illness. 
In sea bathing, the element of enjoyment has a most important influ- 
ence. The salts are commonly supposed to be the chief source of bene- 
fit, and in consequence of this belief, many persons are in the habit of 
dissolving in their daily bath in the household a quantity of more or 
less dirty material, sold at a price which insures at least a fair pecuni- 
ary return, and known as sea salt. The influence of the salts contained 
in sea water is really nil, and the benefits of sea bathing are the result 
of the physiological action of cold, the attendant exercise of swimming, 
the pure air, the absence of domestic and business cares (if on vaca- 
tion), and the sense of enjoyment. 
Warm and hot bathing cause a dilatation of the cutaneous vessels 
and more or less profuse perspiration. Respiration and pulse are in- 
creased in frequency, and a general soothing effect is produced. Hot 
bathing is a most grateful means of reducing soreness of the muscles 
after violent exercise and a valuable assistant in the treatment of 
insomnia. For purposes of personal cleanliness, warm and hot baths 
are more suited than cold, since they can be longer borne with comfort 
and the relaxation of the skin which they induce is more favorable to 
complete removal of the adherent matters. 
If means for complete bathing are not at hand, the individual should 
in any event give daily attention to careful cleansing of the axillae, 
groins, genitals and feet, as well as the hands and face. 694 
PERSONAL HYGIENE. 
Section 2. REGULATION OF THE DIET. 
It is obviously impossible to formulate any system of rules, applic- 
able to all classes, for the selection of diet and the regulation of hours 
with reference to the daily duties of life, but general rules concerning 
some aspects of the question may be laid down. The suggestion of 
light breakfasts, somewhat more substantial luncheons, and hearty din- 
ners at close of day, with periods of mental and physical rest after each 
meal, is easy to make, but the busy lives which the great majority of 
the population lead and the widely different conditions of life and oc- 
cupation make its general acceptance and adoption quite beyond the 
bounds of possibility. It is a common habit of writers on personal 
hygiene to compose menus for the several daily meals, to suggest the 
amount of time which should be devoted to the consumption of each, 
and to recommend the avoidance of physical or mental labor for vary- 
ing periods of time before and after each meal, in order that the diges- 
tive apparatus may proceed with its work under the most favorable 
conditions for its uninterrupted completion. 
The adoption of most of such recommendations, however, presup- 
poses a curious state of the conditions of life, including an absence of 
any marked preferences in the matter of articles of diet, a complete 
mastery of one's time without reference to the demands of occupation, 
and pecuniary independence. 
General rules may be offered to the effect that the diet should con- 
sist of wholesome articles of food ; that these should be consumed in 
sufficient, but not excessive, amounts ; that they should not be hurriedly 
bolted, and that as much time as is consistent with the needs of one's 
occupation should be allowed after each meal, before proceeding to a 
continuance of work. Obviously, in these particulars each person must 
be a law unto himself, and the greater the observance of general hy- 
gienic principles, the better the physical and mental well-being. 
Section 3. REST AND RECREATION. 
For the repair of the daily wear and tear of a busy life, a reasonable 
period of rest of body and mind is indispensable. Nervous and mental 
breakdown result from overwork and absence of recreation, but it is 
impossible to make any rule as to what may be regarded as a safe 
limit of the amount of work which may be performed. Monotony of 
life is, perhaps, as potent a factor in mental breakdown as overwork, as 
is evidenced by statistics showing the high percentage of insanity among 
farmers and farmers' wives in sparsely settled districts. Mental worry, 
also, is far more potent than mere mental activity in causing physical 
and mental degeneration. Recreation is a most important remedy, 
therefore, for the breaking of monotony and worry. 
It is impossible to lay down any rule, governing the amount of sleep, 
that can apply to all persons indifferently, since active minds may need 
much less than what is commonly regarded as a minimum general re- PHYSICAL EXERCISE. 
695 
quirement, and persons of conspicuously low mental capacity may re- 
quire much more. It is generally accepted, however, that for the 
repair of waste, the average man needs to pass at least one-third of his 
time, namely, eight hours a day, in sleep. 
Section 4. PHYSICAL EXERCISE. 
It is essential to the maintenance of a completely healthy condition 
that a well-nourished body shall be properly exercised in all its parts. 
The muscular effort involved in what we designate as physical exercise 
and in the pursuit of certain callings which necessitate bodily activity 
affects not alone the general musculature, but all the organs of the 
body as well; the heart, the lungs, the digestive apparatus, the skin, 
the kidneys, the brain, and, in short, every part. The heart and lungs 
being stimulated to increased action, an increased supply of oxygen- 
ated blood is sent to every part, bringing with it the essentials to full 
nutrition and conveying to the eliminative channels the ultimate prod- 
ucts of metamorphosis. The special stimuli of the various organs 
are excited, and thus the several functions are maintained in a normal 
state of activity. 
In order to gain a full appreciation of the benefits of physical exer- 
cise, one needs but to compare the rugged condition of the well-nour- 
ished laborer in the fields or of the student or man of business, who, 
in the intervals away from his daily work, seeks recreation in outdoor 
exercise or indoor gymnastics, with that of the pent-up sedentary 
operative or the indolent seeker after pleasures involving inaction. 
Whether the work of the individual be that of the hands or brain, it 
is better sustained, if the system is kept active in all its functions and 
parts. 
Effects of Active Exercise. 
Circulation and Respiration.-Muscular effort causes the heart to 
beat more rapidly and with greater force, so that more blood is sent 
through the lungs and all parts of the body, including the substance of 
the heart itself. Unless the exercise is excessive in duration or vio- 
lence, the increased action is regular and equal, and cessation of the 
exercise is followed by gradual slowing, until the rate is below the nor- 
mal ; and then by return to the natural rate. With excess of muscular 
effort, the pulse becomes quick, small, and, often, more or less irregular, 
and even during the fall in rate in the interval of rest, may be inter- 
mittent. Excessive rapidity, irregularity in pulsation, and inequality 
of volume are indicative of the necessity of rest and of danger from 
continuance. 
The increase in the pulmonary circulation is accompanied by in- 
crease in respiratory action, so that a larger volume of blood is forced 
through the lungs and comes in contact with an increased air supply, 
from which it receives the necessary increase in oxygen for convey- 
ance to the tissues, and to which it gives up its carbon dioxide, aque- 696 
PERSONAL HYGIENE. 
ous vapor, and other waste products, for removal from the body. Ac- 
cording to the researches of Pettenkofer and Voit, the oxygen absorbed 
during an ordinary working day, with the usual interval for rest, is 
about one-third greater in amount than during a day of inaction, and 
the carbon dioxide produced and eliminated is increased about two- 
fifths. During exertion, the action of the chest should be impeded as 
little as possible by tightly fitting clothing and other restrictions. 
Excessive exercise causes labored breathing and sighing, which are 
indications that the lungs are too much congested and that rest is re- 
quired. 
Continued excessive exercise may bring about palpitation, dilatation, 
hypertrophy, and even valvular lesions of the heart, and congestion of 
the lungs, accompanied, sometimes, by haemoptysis. Sudden unusual 
effort may cause rupture or other injury of the blood vessels and, rarely, 
even rupture of the heart. 
Deficient exercise favors weakening of the heart's action, dilatation, 
and fatty degeneration; and in those with inherited predisposition, the 
preparation of suitable soil for the reception and development of the 
organism of tuberculosis. 
Skin.-In consequence of the increased blood supply sent through 
the cutaneous vessels, the latter dilate and the skin becomes reddened. 
Heat is brought from the interior of the body and radiated from the 
surface, and a further cooling effect is caused by the evaporation of the 
sweat which is poured out by the sweat glands. Thus the excess of 
heat produced in the system through exercise of its various parts is 
eliminated and the body temperature kept in a state of equilibrium. 
The amount of water given off by the lungs and skin during a day of 
average work was shown by Pettenkofer and Voit to be nearly twice 
and a half that eliminated during the same period of rest. 
With the water of the sweat, the body loses salts, especially sodium 
chloride, and fatty acids and other organic substances. 
During exercise, while the skin is active, there is but little danger of 
chill, even though the skin be lightly covered or even exposed, but as 
soon as the body rests, the temperature falls, and sweating and evapo- 
ration continue, so that it is important to protect the body against sud- 
den checking of the skin's action and chilling of the surface. This is 
best done by means of clothing of low heat conductivity, preferably 
woolen. 
With normal action of the skin, the body temperature remains fairly 
constant, the heat of the blood, even during most violent exercise, 
rarely rising much more than a degree Fahrenheit above the normal. 
During work, a decided rise in temperature indicates lessened evapora- 
tion from the skin and points to possible danger from heat apoplexy. 
Nervous System.-It is a common belief that exercise has no effect 
in increasing the powers of the mind, this belief being based on the 
supposition that the greater expenditure of nervous energy called for 
in the exercise of the muscles is opposed to intellectual development or 
accomplishment. In support of the idea that great muscular power 697 
PHYSICAL EXERCISE. 
and exertion are incompatible with marked mental attainments, the 
fact is often cited that trained athletes, as pugilists and wrestlers, are 
conspicuously stupid. But admitting that this is true, it may also be 
said that these persons are stupid in spite of rather than because of 
their physical development and training, and the fact may be pointed 
out that in our schools and colleges the chosen athletic representatives 
rank, as a class, even higher than the average of their non-athletic 
brethren. Intellectual ability is incompatible with the embracing of 
pugilism as a calling, but is quite consistent with a high degree of 
physical perfection and bodily exercise. Furthermore, a reasonable 
degree of activity appears to be necessary to the performance of men- 
tal labor, for without proper nutrition and exercise of the system, the 
nerves and nerve centers must suffer with other parts, even as they 
must share in the benefits of healthy and vigorous living. 
One part of the general system cannot monopolize the benefits of 
training : the muscles, for example, cannot be trained without the par- 
ticipation of the nervous system in the good results, nor, on the other 
hand, can they be abused without injury to other parts as well, for 
motor activity is the result of nervous energy, and all fatigue is nerv- 
ous fatigue. As evidence of the beneficial influence of exercise on 
the nerves may be cited the greater readiness with which trained mus- 
cles respond to volition. 
Deficient exercise is a common cause of morbid excitability, mani- 
fested by irritability of temper, sensitiveness, and that form of nervous 
unrest commonly known as fidgets. 
Digestive Apparatus.-The great increase in the excretion of car- 
bon dioxide and in general cellular activity causes a demand for food, 
and the appetite is increased, especially for proteid matter and fats. 
Digestion is assisted, and absorption is hastened. The volume of the 
excreta is lessened by reason of a diminished content of water, due to 
increased elimination through the skin and lungs. 
Lack of exercise, on the other hand, tends to diminish appetite and 
the powers of digestion. 
Kidneys.-The amount of urine is lessened by reason of increased 
loss of water through the skin and lungs. The inorganic salts are com- 
monly increased, both relatively and absolutely. Urea is not increased 
and may even be diminished, as shown by Pettenkofer and Voit, in 
which case, a more than compensatory increase occurs during the inter- 
val of rest. 
Effect of Exercise on Weight.-The effect of systematic regular 
exercise on weight is by no means constant, but is influenced by the 
condition of the body in the beginning and by the amount and variety 
of the food ingested. Many persons shortly after beginning a course 
of training for the reduction of weight or, more correctly, of size, find 
that a reduction in girth is accompanied by an increase rather than a 
diminution in weight. This means simply that the system has drawn 
upon its stored fat for fuel, this fat being most conspicuously placed 
in the vicinity of the waist line, and has built up tissues elsewhere for 698 
PERSONAL HYGIENE. 
the increased work of moving the various levers of the body. This in- 
crease has its limitations, and when the maximum has been reached, 
the fall in weight, due to utilization of surplus fat, may continue until 
a point is reached when the curve of weight approximates a horizontal 
line, and the person may be said to be in perfect physical condition. 
The marked losses in weight which occur during violent exercise are 
soon counterbalanced by ingestion and absorption of food and drink. 
Amount of Exercise Required.-Since in the ordinary routine 
of life, a considerable and varying amount of physical work is per- 
formed, it is impossible to fix any rule concerning the exact daily 
amount of exercise which a healthy normal adult should take. With 
the vast majority of persons, all the exercise needed is taken as an in- 
separable element of their regular occupation, and any additional work 
is performed as a means of recreation. On no other ground can be 
explained, for example, the evening bicycle ride of the letter carrier 
after the monotony of his daily rounds on foot, or the game of ball be- 
gun at the close of the day's work by the hands from the mill or foun- 
dry. 
A fair day's work for an adult may be said to be equivalent to 
about 300 foot-tons, a hard day's work to 400, and a very hard day's 
work to 500 foot-tons. The latter is about the amount of work per- 
formed by a soldier of average weight marching at ease with his kit 
twenty miles over a level surface at the rate of three miles an hour. 
It has been reckoned by Haughton that, in walking on the flat, one 
performs an amount of work equivalent to raising a certain proportion 
of his weight through the distance traveled, the proportion varying 
according to speed. The work performed is reckoned by the follow- 
ing formula : 
(TP+Jp/)XD 
- 240 X o - number of foot-tons. 
W = weight of the person. 
W ' = weight carried. 
D = distance in feet. 
2,240 ■= number of pounds in a long ton. 
C - coefficient of traction. 
The coefficients of traction, as determined by Haughton for different 
rates of speed, are as follows : 
Miles per hour. 
Coefficient. 
1.818 
1 
28.27 
4 353 
1 
15.70 
10.577 
1 
7.51 
From these, the coefficients for any rate can be determined. For 
two, three, four, and five miles per hour, they are approximately 
2^, 2V? tV? and respectively. Thus, a man weighing 175 pounds, PHYSICAL EXERCISE. 
699 
walking 10 miles at the rate of four miles per hour and carrying 25 
pounds, would, according to the formula, do nearly 300 foot-tons of 
work- 
(175 4- 25) X 52,800 1 _ 
2,240 Xjg- 295.25. 
In ascending a height, a man lifts his entire weight through the 
vertical distance travelled. Thus, the same man, carrying the same 
weight, climbing six flights in an ordinary office building, would do 
about eight foot-tons of work, reckoning the distance climbed as 90 feet. 
For those who do no regular, ordinary, physical labor, it has been 
estimated by different authorities that exercise equivalent to from 100 
to 150 foot-tons is sufficient for the maintenance of a fair state of 
health. But this should not be pushed to the extent of being exhaust- 
ing or irksome. When, in the course of exercise, the body begins to be 
fatigued or the heart and respiration to be embarrassed, rest is required ; 
for excessive exercise ceases then to be a benefit. Severe prolonged 
exercise may cause dilatation of the heart, aneurysm, and respiratory 
disorders. 
Kinds of Exercise.-Exercise as a hygienic measure may be divided 
into outdoor work, including walking, riding, and athletic sports, and in- 
door work, or systematic gymnastic exercises. The former, preferred by 
all English-speaking people, are carried on under far more healthy con- 
ditions and bring with them a much greater measure of enjoyment 
than the latter, which are preferred on the Continent, more especially 
by Swedes and Germans. Indoor work in the gymnasium is, as a 
rule, purely work, without the element of pleasure either in anticipation 
or during its continuance, and is performed as a serious duty. It is 
carried out from day to day for a longer period, if done in company 
with others, as in a class ; in which case, emulation may stand in the 
place of actual enjoyment. But ordinary indoor exercise with Indian 
clubs, dumb-bells, chest-weights, and similar appliances, carried on 
alone in one's room, is usually most unsatisfactory in its results. 
There are some, doubtless, who regularly take a certain amount of 
this class of exercise, enjoy it, and profit by it; but commonly, the en- 
thusiasm which attends the purchase of the appliances declines in a 
marked degree by the end of the third or fourth day of use and has 
disappeared in a week. Then the exercise, now simply a duty, de- 
velops speedily into a bore, for the monotony of this kind of work, into 
which no sense of achievement enters, except that from the accomplish- 
ment of a wearisome round of strokes measured by hundreds, produces 
a distaste; and soon the work becomes spasmodic, the intervals grow- 
ing longer and longer, and finally is completely abandoned. 
Golf.-This exceedingly popular game appears to be an ideal form 
of exercise for all ages above early childhood and particularly for those 
whose lives are essentially sedentary or whose age precludes them 
from following the more violent games. The amount of work per- 
formed in going once over a course is very considerable, but it is done 700 
PERSONAL HYGIENE. 
in such a way and under such surroundings, with ever-changing scene, 
that, at the time, it is hardly appreciated. The mind is pleasantly en- 
gaged in speculation as to the possibility of achieving certain results 
and is filled with pleasurable emotions when the effort is crowned with 
success ; the body is gently exercised in all its parts by a form of work 
performed because it is so essentially a means of enjoyment. It cannot 
be abused as are so many other sports, and there is no necessity for 
quick and violent action, as in tennis and football. 
Wheeling.-Wheeling involves very largely the entire muscular sys- 
tem and brings into play groups of muscles, the existence of which 
have not before been appreciated by the beginner. With the wheel, 
one can take any desired amount of gentle, moderate, or violent exer- 
cise. It gives a constant change of scene and the pleasurable sense of 
motion, both of which are of value to the tired mind. It is not the 
particular form of muscular exertion that is the incentive to long exer- 
cise on the wheel, but the pleasure which it gives, for no more monoto- 
nous exercise can be devised than riding a stationary bicycle in a 
gymnasium, while, on the other hand, many who would regard an 
errand, involving a walk of a mile, as a hardship, will, without demur, 
wheel five times that distance for the same end. 
Tennis, etc.-Tennis, football, baseball, and other outdoor sports are 
comparatively violent for the majority of people. They bring the 
whole body into action and are valuable, if not pushed too far. They 
do not admit of varying the pace according to the fatigue of individual 
players, in which respect golf and wheeling possess an advantage. 
Rowing is also a very healthful form of exercise, but the violent 
exertion required in the sustained effort of racing is not always a 
benefit. 
Section 5. CLOTHING. 
The objects of clothing are, aside from motives of decency, to pro- 
tect the body from the sun's rays in hot weather, from the chilling in- 
fluence of winds in all weathers, from rain and other forms of wet, 
and from mechanical and other external injuries and discomforts ; to 
conserve the body temperature and prevent interference with the 
natural functions of the skin ; and, finally, to adorn the person. The 
proper fulfillment of these various objects is dependent upon the nature 
of the material, the looseness of its texture, its color, its hygroscopicity 
and heat conductivity, and its special adaptability to some particular 
purpose. 
Color.-The heat of the sun's rays is absorbed to the greatest ex- 
tent by black materials and least by white. Next to black come the 
dark shades of blue, and then in order, green, red, and yellow. Heat 
is reflected most by white, and then in order, the light shades of yellow, 
red, green, and blue. The color of undergarments (not exposed to the 
rays of the sun) exercises no influence whatever. 
Texture.-The looser the texture, the greater the amount of air in 
the interstices ; and air being a very poor heat conductor, other things CLOTHING. 
701 
being equal, a loosely woven fabric prevents loss of body heat in a still 
air more than one of closer texture. Thus it is that a thin loosely 
woven garment of woolen is warmer to the body in a still cold atmos- 
phere than an equal amount of closely woven material of the same or 
other kinds. The same result is attained by wearing a number of gar- 
ments, one over another, so that, having layers of confined air between, 
they act in the same way as double windows on a house. The value 
of furs as conservators of heat is largely due to the large amount of 
air retained between the individual hairs. 
Impermeable materials, being absolutely wind-proof and hence per- 
mitting no natural ventilation through their substance, are very warm, 
but have serious disadvantages, the most important of which is the reten- 
tion of the transpired moisture of the body, which collects on the surface 
and is absorbed only in part by the clothing next thereto. Against 
rain and cold winds, impermeable materials afford very great protection. 
Winds act in two ways to chill the body : by constant removal of the 
air in contact with the body and warmed by reason of contact, and by 
hastening evaporation of the moisture within the substance of the 
clothing. 
Heat Conductivity.-Materials vary widely in their power of heat 
conduction. Among the textiles, linen and cotton are by far the best 
conductors, and wool the poorest; but since the conductivity of a gar- 
ment is governed mainly by the looseness of texture, it follows that 
the same amount of a high conductor, loosely woven, may be warmer 
than wool woven very closely. But the fabrics made of the best con- 
ductors are commonly very closely woven, and of wool are of varying 
degrees of looseness. 
Hygroscopicity.-Fabrics hold moisture in two ways : first, by re- 
taining it in the interstices between the fibers; and second, by absorp- 
tion directly into the substance of the fibers. The moisture held in 
the interstices gives the sensation of dampness or wetness and can be 
largely removed by pressure, as in wringing; that absorbed into the 
fiber may be very large in amount without giving any sensation of 
dampness, and it cannot be expelled by pressure. The latter is known 
as hygroscopic moisture. 
Materials of animal origin are more hygroscopic than those from the 
vegetable world, and while they absorb water readily, they part with it 
more slowly by evaporation. Thus it happens that a person, sweating 
to the same extent and under the same general conditions, feels less 
sensation of chill on resting from his exercise or work when clothed 
in woolen, than when his dress is linen or cotton. In the latter in- 
stance, the moisture is held more largely in the interstices, and the 
garment may be distinctly wet and then adheres to the skin, which, as 
evaporation proceeds, becomes chilled through rapid abstraction of the 
heat required in the process ; whereas, in the former, the evaporation 
is gradual and the chilling much less perceptible or quite unnoticeable. 
But here again, a hygroscopic material, very closely woven, maybe in- 
capable of holding as much moisture without imparting the sensa- 702 
PERSONAL HYGIENE. 
tion of distinct wetness, as one of a loosely woven substance of low 
hygroscopicity. 
Materials. 
The materials employed in the making of clothing come mainly from 
the animal and vegetable worlds; from the former are derived the 
wools of various kinds, silk, furs, feathers and down, and leather; 
from the latter, the principal derivatives are cotton and flax (linen), 
and, of lesser importance, straw, hemp, jute, and rubber. 
Wool.-Wool of various kinds is yielded by a number of different 
genera of animals. That in commonest use and to which the name 
is very generally restricted is derived from the sheep. Other kinds 
include mohair from the Angora goat, kashmir, or cashmere, from 
the Thibet goat, camel's hair, and alpaca, from Auchenia pacos, a 
cameloid ruminant of South 
America. But the terms mohair, 
cashmere, and alpaca commonly 
refer to cotton and sheep's wool 
imitations containing no trace of 
either of these more expensive 
wools. 
Under the microscope, the fibers 
of wool are seen to be cylindrical 
and translucent and covered with 
small imbricated scales which, like 
those of a fish or the feathers of a 
bird, run all in the same direction. 
They are sharpest and smallest, and 
hence most numerous, in the finest 
sorts; as many as 2,800 and as 
few as 500 to the inch have been 
counted respectively in the best 
and very inferior kinds. They give 
to the fibers the tenacity with which they cling together when woven, 
and the readiness with which, when wet and subjected to pressure, as 
rubbing or wringing, they mat together and cause a shrinking of the 
fabric. They are shown in Fig. 101, which is drawn from a specimen 
of fine Saxony crewel. 
Woolen goods, being poor conductors and containing much enmeshed 
air, are the most valuable of all textiles for general purposes in all 
climates, and particularly in those in which abrupt wide changes in 
temperature occur. In very hot climates, they are inferior as outer 
garments to cotton and linen, which, being better conductors and re- 
flectors, assist more in keeping the body comfortably cool. But for 
undergarments, wool is much better as a protection against chilling 
after active exercise, on account of its hygroscopic properties ; the vapor 
from the body is condensed and absorbed, and the heat, which becomes 
latent when the moisture is vaporized, is set free, and the evapora- 
Fig. 101. 
Woolen fibers. 703 
CLOTHING. 
tion from the fabric to the external air proceeds slowly and without 
the chilling effect observed when one sits in clinging wet cotton or 
linen, which feels cold in proportion to the rapidity with which it dries. 
Woolen fabrics are much subject to adulteration with cotton and 
other cheaper materials. What are known as flannelettes are very 
commonly made wholly of cotton or with a very small percentage of 
wool, though the name is intended to convey the idea that wool is the 
sole or chief material used. What some are pleased to designate 
"sanitary flannel" is often largely or wholly cotton. Shoddy is a 
fabric made with varying proportions of old ravelled woolen and other 
cloths with a minimum of new wool. It has, as may be supposed, a 
much inferior tensile strength and less uniformity of texture than 
woolen of good quality. 
Silk.-Silk is the spun fiber produced by a number of species of 
insects, especially the larvae of the bombycid moths, called silkworms, 
to form cocoons or protective coverings when about to assume the 
chrysalis stage. The cocoon in which the chrysalis is killed yields an 
exceedingly fine thread, consisting of two agglutinated filaments. This 
thread, when unwound, measures over two miles in length, and when 
spun, yields in the neighborhood of 500 yards of silk thread. The 
outer part of the cocoon is of inferior quality and is known as floss. 
Silk is very hygroscopic. It is a poor heat conductor and a perfect 
non-conductor of electricity. It has 
a great affinity for anilin and other 
dyes. 
Under the microscope, the fibers 
appear as structureless tubes and 
show no scales or surface markings, 
such as are seen on wool. They 
are represented in Fig. 102. Be- 
fore being woven into fabrics, silk 
is commonly weighted with salts 
of tin and iron, with which it 
forms stable chemical compounds. 
Weighted silk, subjected to the ac- 
tion of a Bunsen flame, parts with 
its organic constituents, but retains 
its structural appearance. 
Silk is very subject to adulteration with other fibers and to complete 
substitution by artificial preparations. One «form of artificial silk, in- 
vented, in 1884, by a Frenchman, Count Chardonnet, is made from pre- 
pared cotton or wood fiber. It possesses a very silky lustre and was 
at first very inflammable and even explosive, being practically nitro- 
cellulose ; but later, the product was subjected to further chemical 
process and made harmless. Another form, invented by Fremery and 
Urban, is made from cotton waste and is produced much more cheaply. 
Still another form, invented by Professor Hummel, of Leeds, is made 
from gelatin at an expense of about $1.15 per pound. It has a low 
Fig. 102. 
Silk fibers. 704 
PERSONAL HYGIENE. 
tensile strength, but can be employed in a mixture with genuine silk 
or fine linen or cotton thread to make a durable fabric. 
Silk is used chiefly in the manufacture of silks, satins, velvets, crape, 
and plush. 
Cotton.-Cotton is the soft woolly fibers appendant to the seeds of 
the cotton plant ^Gossypium^, consisting of cellulose, and varying in 
length from a half to two inches. It is contained with the seeds 
within the boll, which, when ripe, bursts open and allows it partially to 
escape. Microscopically, the fibers appear flattened and twisted ; they 
have somewhat thickened borders, and some show a central canal. 
They are shown in Fig. 103. They are freed from the seeds by the 
cotton-gin, then cleaned and spun into thread and woven into fabrics 
of various kinds, including what is commonly known as " cotton cloth," 
sheeting, towelling, jean, drill, and others. For the purpose of giving 
weight, stiffness, and improved appearance, starch and other materials 
Fig. 103. 
Cotton fibers. 
are commonly employed in finishing. Cotton is employed also with 
wool and other materials as an adulterant or to combine the useful 
properties of each, as, for example, in merino, which is much used in 
the manufacture of underclothing and stockings. Cotton is very 
durable and hard, has low hygroscopicity and high heat conductivity, 
does not shrink in washing, and is particularly adapted as a material 
for outer garments for hot weather. 
Linen.-Linen is a fabric woven from the soft silky fiber obtained 
from the outer covering of the stalks of the flax plant (Linum usitatis- 
simum) which are allowed to rot until the proper stage of decomposition 
is attained, when they are beaten and carded. They yield about a six- 
teenth of their weight of fiber. Microscopically, the fibers appear as 
cylinders marked at regular intervals by striae indicating cell divisions. 
(See Fig. 104.) Twisted into thread, they are used in weaving various 
fabrics known as linen, cambric, damask, diaper, lawn, and huckaback. CLOTHING. 
705 
Linen goods are smooth and lustrous, heavier than cotton, durable and 
hard, of low hygroscopicity and high heat conductivity. They are 
especially suited for shirtings, sheetings, and outer garments for hot 
climates. 
Rubber.-India rubber is a product derived from the milky juice 
of various tropical plants. It is soluble in ether, naphtha, chloroform, 
and carbon disulphide. Its elasticity is impaired and destroyed by 
long exposure to the air and by extremes of atmospheric temperature, 
but is made lasting by the addition of a small amount of sulphur in the 
process known as vulcanizing, 
discovered by Goodyear in 
1844. This process, in addition, 
ensures increased durability, 
flexibility and impermeability 
to air and moisture. To the 
latter quality, rubber owes its 
extensive employment in arti- 
cles of dress, including galoshes 
and other foot coverings, and 
outer garments made of rubber- 
sheeting or waterproof cloth, 
known as mackintosh. The 
latter is made by applying a solution of rubber in successive layers to 
cotton or other fabric, so that it shall be made impermeable to water. 
Rubber garments are a very useful protection against wind and rain, 
but are objectionable on the score of being hot and confining the 
watery vapor given off by the skin, thus bringing about a condition of 
great discomfort. They should, therefore, be ventilated as much as is 
practicable, especially if worn in moderate or warm temperatures. 
Clothing can be made waterproof and, at the same time, permeable 
to air, by a number of processes, and such material has an obvious ad- 
vantage over ordinary mackintosh and other impermeable fabrics. 
Leather.-Leather is the skins of animals, chiefly the ox, calf, horse, 
sheep, and goat, prepared by tanning and tawing. In tanning, the 
skin is soaked in vats containing an infusion of oak bark rich in tannic 
acid, which causes the formation of tough insoluble tannates of the 
gelatinous and albuminous constituents of the skin. In tawing, 
mineral astringents are used instead of oak bark ; the end is more 
quickly attained, but the product is of inferior quality. After the 
process of tanning or tawing is completed, the skin, now tough and 
stiff, is subjected to a series of processes, collectively known as curry- 
ing, whereby it is made soft, smooth, pliable, and ready for use. 
Leather, being hygroscopic, takes up perspiration from the foot and 
gives it off to the outer air, but if it is made impermeable as in the 
case of the so-called " patent leather," the latter office cannot be per- 
formed. That the perspiration of the foot is given off through the 
boot, is sufficiently proven by the dampness and dull appearance of the 
leather of a well-polished boot after half a day's confinement in a rub- 
Fig. 104. 
Linen fibers. 706 
PERSONAL HYGIENE. 
her overshoe. Though permeable to this extent, leather is sufficiently 
waterproof for ordinary use and can be made more so by the external 
application of grease. 
Fur.-Fur as au article of clothing presents the great advantage of 
impermeability to wind with that of very low heat conductivity, due 
in greatest part to the large volume of air retained between the hairs. 
No other kind of material is comparable as a protection against wind 
and cold. 
Felt.-Felts are made from the hairs of various animals, but the 
best, such as are used for hats, both soft and stiff (the Derby, for ex- 
ample), are made from the hairs of the cony. They are made without 
weaving, the hairs being blown against a revolving, perforated, metallic 
cone of large size, connected with an exhaust blower. When a thin coat- 
ing has formed, a jet of steam is directed against the cone, and then the 
felt in its first stage is stripped off in a coherent mass, held together 
by the minute imbrications on the individual hairs. By means of fur- 
ther processes of steaming and steeping, the mass is reduced in size and 
increased in wall thickness through shrinkage. 
Fabrics are much subject to adulteration by admixture of fibers of 
lower value, as of cotton or shoddy to wool, and by starch and mineral 
matters to give weight. Many of the cheapest of cotton fabrics are so 
heavily sized that a single washing will convert a stiff apparently 
close-woven piece of goods into a worthless, coarse, flimsy material fit 
only for sieves. 
Chemical analysis of fabrics is not always to be relied upon, al- 
though fibers of vegetable origin behave very differently from those from 
the animal world ; and any attempt on the part of an inexperienced 
person to determine the percentage of different kinds of fiber in a mix- 
ture is sure to lead him to two conclusions, namely, that he has wasted 
his time, and that much of what has been written concerning the be- 
havior of different fibers when treated with strong chemicals is re- 
markable only for its small measure of truth. 
Microscopical examination is a far simpler and much more satis- 
factory method of determining the composition of a fabric. A few 
threads, teased apart and examined with a moderately high power, will 
reveal the nature of the fibers and yield approximately accurate quan- 
titative results. Shoddy commonly shows fibers of wool of different 
shades of color, but this finding is by no means to be accepted as con- 
clusive evidence that a specimen of fabric under examination is shoddy, 
since only plain goods of a solid color yield fibers all of one shade. 
But if the fibers show abrupt changes in diameter and partial obliter- 
ation of the imbrications, it may be safely concluded that the specimen 
is shoddy, since fresh wool is fairly regular in diameter and shows 
sharply marked imbrications. 
Poisonous Dyes.-In the dyeing of textiles and other articles of 
Adulteration of Clothing. SELECTION OF CLOTHING. 
707 
clothing, a great variety of substances of vegetable and mineral origin 
are used, and many of them have been known to produce serious re- 
sults. Among them may be mentioned potassium dichromate, zinc 
chloride, compounds of arsenic and antimony, and certain of the 
anilins. An outbreak of 34 cases of acute dermatitis, occurring among 
a number of workmen who had just donned new overcoats, is reported 
by Taunton.1 On the first wet day, when the coats were worn, the 
wrists, where they came in contact with the edges of the wet sleeves, 
became inflamed. In one case, the legs were similarly affected, the 
trousers being wet and rubbed against by the skirt. In three cases, 
the arms were affected. On soaking the cloth in water, it yielded free 
zinc chloride. 
A far more serious case of poisoning by anilin black is quoted by 
Cartaz 2 from a report of Landouzy and Brouardel to the Academy of 
Medicine of Paris. A child of 17 months became suddenly uncon- 
scious and apparently asphyxiated, and though restored, remained very 
ill for 48 hours. Then the brother of the child and a number of 
other children were seized in the same way. All of the victims wore 
shoes which gave off a peculiar penetrating odor and were found to 
have been dyed with anilin black. Animal experimentation proved 
that absorption of this by the skin may bring about alteration of the 
blood corpuscles and asphyxia, and is favored by heat and moisture, 
which conditions are present in a tightly laced shoe. 
It is commonly believed that arsenic in dyed and printed textiles is 
present as an accidental impurity of various anilins, but this is far from 
being the truth, since white arsenic itself is used in several processes for 
the purpose of adding brilliancy to the colors. Thus, in the so-called 
arsenite of alumina process, the dye, dissolved in acetic acid or water, is 
mixed with acetate of aluminum and white arsenic in glycerin, and the 
mixture is employed in printing the pattern ; next, the printed fabric 
is subjected to moist heat, and the anilin in combination with the arsen- 
ite of aluminum formed is fixed in the fibers in an insoluble form. 
Selection of Clothing.-The properties of the various materials 
used in the manufacture of textiles have been already given in some 
detail, and further consideration of underclothing and outer garments, 
beyond a word of caution against unnecessary weight of clothing and 
undue constriction of any part of the body, is, therefore, unnecessary. 
In the matter of constriction, no part of the human body is so abused 
as the foot, especially that of woman. Boots, shoes, and stockings 
should fit the foot and there should be no such thing as the agony 
which many people expect as a matter of course in the process of 
" breaking in." The toe should be neither pointed nor cut square, and 
the whole sole should follow the natural outline of the foot. The sole 
should project a reasonable distance from the upper, in order to give 
firmer support and increased protection to the soft parts from contact 
with loose stones and other objects. The heels should be low and 
1 The Lancet, December 6, 1898. 
2 La Nature, August 4, 1900. 708 
PERSONAL HYGIENE. 
broad. High heels are worn, not for comfort in walking, but to increase 
the height of the body and diminish the apparent length of the foot. 
For purposes of successful deception, they take about equal rank 
with hair dyes and artificial complexions. Their use conduces to 
weakness of the arch, atrophy of the muscles of the leg, and a variety 
of other abnormalities. The heel of the foot should fit snugly in its 
place within the shoe, but the toes should have sufficient room for 
freedom of movement, yet not enough to cause chafing and excoriations. 
The upper should fit snugly, but not too tightly, about the ankle and 
over the instep; otherwise, the foot will drive forward and cramp the 
toes. CHAPTER XVI. 
VACCINATION. 
Prior to the discovery of vaccination by Jenner, toward the close 
of the eighteenth century, smallpox was one of the principal scourges 
of the world. It killed, on an average, nearly half a million people in 
Europe alone, and about once in three years was more than ordinarily 
severe. In England, Germany, France, Sweden, and other countries 
of Europe, the yearly mortality from smallpox was about two thousand 
per million inhabitants. More than half the cases of blindness through- 
out Europe were attributed to the disease, and about a third of the 
population showed in their faces evidences of having had it. 
It was well known that those who recovered enjoyed protection from 
recurrence of the disease, and consequently it had long been the prac- 
tice to produce immunity by causing the disease intentionally by in- 
oculation when it prevailed in a modified form, favorable to recovery. 
For more than a thousand years, the Chinese and other Eastern peoples 
had produced the disease by blowing dried smallpox matter in 
powdered form into the nostrils. The discovery that the inoculation 
of material from a smallpox pustule was more certain and quick in its 
results led to the widespread practice of inoculation. This was begun 
in England in 1721, and towards the end of the century was very ex- 
tensively practiced; and even after the discovery of the beneficent re- 
sults of vaccination, was practiced to a certain extent, until, in 1840, 
it was prohibited by law. 
Jenner discovered that a pustular disease of cows, when transferred 
by inoculation to human beings, produced an immunity to smallpox in 
apparently the same way as the inoculation of the real disease. In 
May, 1796, he performed his first successful vaccination. After some 
very strong opposition, intelligent people began to adopt the practice, 
and the uneducated classes began to fall gradually into line. The 
practice was adopted in America, France, Germany, and, in fact, the 
entire civilized world, and everywhere proved to be of the greatest 
benefit. In 1802, the English Parliament awarded Jenner 4,000 
pounds sterling, and later, a still larger grant was made. 
In this country, the practice was first followed by physicians in and 
about Boston. In 1806, Thomas Jefferson, who was the first to intro- 
duce the practice in the South, wrote to Jenner, " You have erased 
from the calendar of human afflictions one of its greatest. Yours is 
the comfortable reflection that mankind can never forget that you have 
lived. Future nations will know by history alone that the loathsome 
smallpox has existed, and by you has been extirpated." 710 
VACCINATION. 
In England, the mortality rate fell during the period of permissive 
vaccination from about 2,000 to 417 ; in 1850, vaccination was made 
compulsory and the rate then fell to 53. During the third quarter of 
the seventeenth century, the average annual deaths from smallpox per 
million inhabitants in London was 4,000 ; a hundred years later, be- 
tween 1770 and 1780, it was over 5,000; in the first years of vacci- 
nation it was over 2,000; by the middle of the nineteenth century it 
had fallen to about 500, and in the last decade of the century, to less 
than 75. In Sweden, the mortality from smallpox was even greater 
than in England, but before 1817, when vaccination became compul- 
sory, the rate had fallen to 480,. and since then, to about 150. In 
Prussia, too, the mortality was over 2,000, but fell during the period 
of permissive vaccination to about 300, and since being made compul- 
sory after the epidemic of 1870-71, it has virtually disappeared. 
In all countries where vaccination has, at different periods, been op- 
tional and then required, a remarkable drop has occurred both in mor- 
bidity and mortality rates, and those countries in which, to-day, vacci- 
nation is not compulsory, suffer periodical visitations of the disease 
and lose thousands of lives. In 1889, for instance, the death rate from 
smallpox in Spain, where vaccination was not compulsory, was nearly 
as great as obtained a century before in the principal countries of 
Europe, while in the same year, in Germany, the disease was practically 
non-existent. In France, vaccination is not compulsory, and in the 
twenty-five years from 1870 to 1895, over 20,000 people died from 
smallpox in Paris alone, the epidemics of 1871 and 1872 being excep- 
tionally severe and fatal. No epidemic has occurred in Germany since 
1871, when the disease was brought in by French prisoners, though a 
few scattered cases have occasionally appeared. 
In spite of the remarkable testimony concerning the value of vac- 
cination in making a rarity of what was once one of the principal 
scourges, there are in this country and others where laws compelling 
vaccination have been enacted, numerous misguided individuals who 
band themselves together into anti-vaccination leagues and attempt to 
create a popular antagonism to the practice and to effect the repeal of 
existing laws. In England, they have already been partially success- 
ful in compelling the passage of a law which exempts parents who 
have " conscientious scruples " against having their children vaccinated. 
In progressive Japan, where the government has decided to compel 
vaccination after the age of ten months and revaccination at the age 
of six and again at twelve, the anti-vaccinationist is unknown. 
It cannot be claimed that vaccination confers absolute immunity 
against smallpox, but it is true that those who have been vaccinated 
and then acquire the disease have it in a much milder form and are 
more likely to recover than those who have not been vaccinated. In- 
vestigation of 11,036 cases of smallpox in England showed that, for 
unvaccinated and vaccinated cases, the rates of mortality were respec- 
tively 36.6 and 5.2 per cent., and that for all cases in children under 
ten, the rates were respectively 36.2 and 2.7 per cent. Among those VACCINATION. 
711 
stricken during the epidemic at Warrington, England, in 1891-92, 
21.8 per cent, of the cases in vaccinated persons were confluent, while 
among the unvaccinated cases, the percentage was 70.6. In the Shef- 
field epidemic of 1887-88, 1.55 per cent, of vaccinated and 9.7 of un- 
vaccinated persons were attacked. Among the former, the death rate 
was 0.7, and among the latter, 48 per thousand. Among children 
under 10, the rate of attack was 5 and 101 per thousand respectively 
for vaccinated and unvaccinated, and the death rate was 0.09 and 44. 
The protection conferred by vaccination is greatest during the year 
succeeding the operation, and appears to diminish gradually during the 
succeeding five or six years ; but the modifying power does not di- 
minish equally fast. The protective influence can be reestablished by 
a repetition of the operation, and during epidemics, or when about to 
visit countries where vaccination is not practiced and smallpox is en- 
demic, revaccination is always advisable. If the operation is negative 
in its results, the individual is regarded as immune or partially pro- 
tected, but in the case of a first vaccination, it is customary to repeat 
the operation until success is attained. In most civilized countries, 
vaccination is not postponed until an outbreak of smallpox occurs, 
but is attended to in the first few months of life. 
Successful primary vaccination within three days after exposure to 
existing cases of smallpox will prevent the development of the disease, 
and as late as the fifth or sixth day will either prevent or modify an 
attack. This fact has been utilized in many cases where smallpox has 
broken out among unprotected people with a prospect of unlimited 
spread, and has been the means of stopping epidemics with some sud- 
denness. Thus, for example, at Gloucester, England, in 1895, after 
eight years of practical abandonment of compulsory vaccination, that 
is to say, of neglect on the part of the authorities to enforce the law, 
an epidemic of smallpox occurred in what was practically an unvac- 
cinated community. The cases increased at such a rate that great 
alarm was felt and extensive measures were taken for general vaccina- 
tion. In the closing weeks of 1895, 31 cases occurred. In January, 
28 more were reported. In February, the number suddenly increased 
to 146, and during March, to 644. Toward the last of that month, 
the authorities gave directions for enforcement of the law, and work 
was begun ; but during the following month, no less than 744 cases oc- 
curred. 
During the last days of April, a committee undertook general vac- 
cination of the city, and within a very few days, every house had been 
visited ; by the end of June, the city had been converted from a prac- 
tically unvaccinated city to the best vaccinated in the country. Nearly 
36,000 persons were operated upon; the epidemic began at once to de- 
cline, and before August had disappeared. Nearly 450 persons, how- 
ever, had died, and 1,600 others who survived, bore the usual lasting 
evidence of the disease in their faces. 
As showing the influence of revaccination, the following figures 
from a study of the statistics of the Sheffield epidemic are presented: 712 
VACCINATION. 
Persons not vaccinated 94 
Persons once vaccinated 19 
Persons twice vaccinated 3 
Rates of attack per 1,000 persons. 
Persons not vaccinated 51 
Persons once vaccinated 1 
Persons twice vaccinated 0.08 
Death rates per 1,000 persons. 
Similar facts are yielded by investigation of all epidemics where 
there is a large class of vaccinated and another of unvaccinated per- 
sons, and yet anti-vaccinationists still agitate and find sympathetic lis- 
teners to their arguments. One of their favorite charges is that vac- 
cination not only has had nothing to do with the decline in the amount 
of smallpox, but, on the contrary, gives rise to other diseases. 
It is, indeed, true that syphilis has been conveyed from one to an- 
other through the practice of vaccination, but at the present time the 
danger is practically nil, since arm-to-arm vaccination has fallen into 
disuse ; but while the arm-to-arm practice was continued, there were 
occasional instances of grave injury. Thus, some years since, it hap- 
pened that a company of French infantry, prior to being sent to 
Algiers, was vaccinated by the arm-to-arm method and very many of 
the men were thereby inoculated with syphilis. 
Parents are prone to ascribe to vaccination every disturbance which 
a child may suffer, particularly if there be any cutaneous eruption. 
Sometimes a vesicular or pustular rash may occur and spread from the 
vaccinated arm to other parts of the body; sometimes, erysipelas and 
other infections occur at the point of vaccination ; but these are no 
more likely to occur as a result of vaccination than of any other inter- 
ference with the integrity of the skin. Persons of dirty habits, living 
in unclean surroundings, are more likely than others to suffer from 
ulceration of the vesicle and from other local disturbances not due to 
the influence of the virus itself. At the present time, instead of using 
crusts and arm-to-arm vaccination, lymph is collected on the sixth day 
after inoculation of the calf and is mixed with water and glycerine 
and stored in small vials with all antiseptic precautions. The glycer- 
ine not only does not injure the lymph, but, on the contrary, appears to 
increase its power. The yield of lymph from one calf is sufficient to 
prepare enough glycerinated lymph for at least 4,000 vaccinations. 
In revaccination, if the individual has become again wholly sus- 
ceptible, the local manifestations occur earlier than in the primary vac- 
cination and the general symptoms are usually much more marked. 
Other Preventive Inoculations. 
It was nearly one hundred years after the first operation of vaccina- 
tion by Jenner before any progress was made toward the conferring of 
immunity from other diseases through similar means. In 1880, Pasteur 
discovered accidentally that chickens could be rendered immune to 
chicken cholera by preventive inoculation, and it was this work which OTHER PREVENTIVE INOCULATIONS. 
713 
led Haffkine, in 1890, to the discovery of preventive inoculation for 
Asiatic cholera. He first experimented on himself and then made 
70,000 injections on over 40,000 people in India within a period of 
two years. By inoculating only a part of any given population where 
cholera was raging, he was sure of a control by which he could judge 
of the value of the work. The rate of attack among those inoculated 
fell to about one-twentieth and the mortality in about the same propor- 
tion. Preventive inoculation has been very extensively tried, and gen- 
erally with at least fair results. 
It is to Haffkine also that the prophylactic treatment for bubonic 
plague is due. He discovered that immunity could be attained by in- 
jecting dead cultures of the specific organism. The dead bacteria them- 
selves without the culture medium excite a marked local reaction with 
slight constitutional disturbances, and injection of the culture medium 
from which the dead bacilli have been removed causes the opposite 
effect. In practice, the entire sterilized culture is employed. While 
the treatment appears to confer some degree of immunity, the duration 
of immunity is thus far unknown. 
According to a report of the Plague Commissioners in India, of 4,296 
persons inoculated once, only 45 contracted the disease, and of 3,387 in- 
oculated twice, two were seized. Fifteen of the former and one of the 
latter died. At the same time, among the non-inoculated persons, no 
less than 657 per thousand died in a single week (the third week in 
September, 1899). At Kirkee (India) the plague broke out in a small 
camp; 671 persons were inoculated and 859 were left unprotected. 
Thirty-two cases occurred among the inoculated and 143 among the 
uninoculated. The mortality among the inoculated was 2.05 and 
among the uninoculated, 11.40 per cent. In another camp, 324 
persons were inoculated and 300 left unprotected. Fourteen cases oc- 
curred among the uninoculated and none among those protected. 
Preventive serum treatment for protection of children in institutions 
against diphtheria has been extensively practiced, but the immunity thus 
conferred is very transient, lasting but three weeks. In a children's 
hospital in which an outbreak of diphtheria occurred, Lohr 1 immu- 
nized 460 inmates and the epidemic was checked, no cases occurring 
within three weeks of the operation. Later on, a few cases occurred, 
which illustrated the temporary nature of the immunity. Of 99 cashes 
of measles treated because of the special danger of diphtherial super- 
vention, not one was attacked. 
Recently, preventive inoculation against typhoid fever has been ex- 
tensively practiced upon soldiers bound for South Africa and other 
countries, but the reports of results at the time of writing are so 
meager and contradictory as to afford no real information as to the 
value of the practice. As a matter of fact, the subject of protective 
inoculation, except so far as it relates to smallpox, is as yet only in its 
infancy, but at the same time is one of the most promising fields of 
scientific research. 
1Jahrbuch fur Kinderheilkunde und physische Erziehung, Sept., 1896, XLIIL, 
No. 1. CHAPTER XVII. 
DISPOSAL OF THE DEAD. 
The public health requires that the bodies of the dead shall be dis- 
posed of in such a way as not to be a menace to the living and as soon 
as possible, with due consideration of the feelings of those bereaved. 
In the case of those dead of infectious diseases, disposal should not be 
delayed by sentimental considerations, but should be accomplished with 
as little delay as possible, on account of the risk to which the living 
are subjected by the retention of the body in the home. 
Concerning methods of disposal, consideration may be limited to the 
two in use by most civilized peoples and by most others as well; 
namely, earth-burial and cremation. 
Earth-Burial.-Interment of the dead in the soil has ever been the 
principal mode of disposal among Christians, Jews, and Mussulmans. 
Within comparatively recent years, the results of overcrowding of 
ancient churchyards and cemeteries and the necessity of dedicating 
great areas of valuable land to be held in perpetuity for the accommo- 
dation of the dead have brought about an economic sentiment against 
the practice, and to it has been added a feeling of danger to the public 
health from the decomposing tissues, particularly of those who have 
died of infectious diseases. 
Buried in soil of suitable character, a body gives off for a number 
of months-six to nine may be regarded as reasonable limits-foul 
gases of decomposition which are not evolved in the later stages. The 
rate of decomposition is influenced not alone by the nature of the soil, 
its pore volume, and its degree of moisture, but by the character of the 
coffin, the depth of interment, and the processes to which the body has 
been subjected before burial. After some years, the period varying 
within very wide limits according to circumstances,1 decomposition is 
complete and but little remains besides bones, more or less crumbly in 
character. 
It is charged against earth-burial, that the places used for the pur- 
pose are offensive ; that the air becomes poisoned ; that the soil becomes 
laden with disease germs of all descriptions, which are preserved in- 
definitely, and that water supplies are converted to dilute poisons of 
great potency ; that is to say, that cemeteries predispose to and act as 
direct causes of disease. As proof, numerous cases which will not bear 
close scrutiny are cited, but the whole mass of what is regarded as evi- 
dence of the connection of cemeteries with the outbreak of disease has 
but little real weight and is quite unconvincing. It has been said, for 
1 See case cited on page 273. EARTH-BURIAL. 
715 
example, that typhus and other fevers were prevalent in the immedi- 
ate neighborhood of old overcrowded churchyards in London when it 
was customary to keep disturbing the soil for new interments, regardless 
of the number and condition of those already buried. Even though 
the supposed connection were anything more than mere coincidence, it 
may be said that nothing of the sort has been noticed within recent 
years, and never anywhere except in densely populated neighborhoods, 
in which densely crowded cemeteries happen to be located. 
Cases of cholera, yellow fever, scarlet fever, and other diseases have 
been attributed to the opening of old graves. In one case often quoted 
in all seriousness, a number of persons came down with scarlet fever 
supposedly from digging up the surface of a burial ground where, 
no less than thirty years before, a number of victims of that disease 
had been buried. Sir Henry Thompson has said, " The poisons of 
scarlet fever, enteric fever, smallpox, diphtheria, malignant cholera, 
are undoubtedly transmissible through earth from the buried body by 
more than one mode. And thus by the act of interment we literally 
sow broadcast throughout the land innumerable seeds of pestilence ; 
germs which long retain their vitality, etc., many of them destined at 
some future time to fructify in premature death or ruined health to 
thousands." 
Such broad statements are easy to make, but exceeding difficult or, 
indeed, impossible to substantiate. If true, it would appear that the 
earth, instead of being the great natural resolvent and disinfectant of 
all forms of dead organic matter deposited below the surface, is a mine 
of septic matter, in spite of which, the world at large continues to in- 
crease in health and the average length of life to extend little by little 
with every decade. 
It is also said that the spores of all known species of pathogens 
are very resistant and retain their virulence indefinitely. But even 
granting that this is true, it is not shown that the spore bearers in the 
body go on after death occurs to form spores. As a matter of fact, the 
basis of the bacterial scare concerning the dangers of earth-burial rests 
on no more solid foundation than the instance, quoted in the chapter 
on Soils, of the anthrax spores supposed to have been brought to the 
surface by earthworms that had acquired them from a cow buried two 
meters below, which instance has no value as evidence for reasons al- 
ready explained. 
Coming to a consideration of the actual dangers arising from earth- 
burial and from the proximity of cemeteries, it must be admitted at the 
outset that merely stinking gases are incapable of transmitting disease, 
and are, moreover, absorbed and deodorized by the soil itself. The 
same class of foul odors are borne without injury by those engaged in 
the numerous offensive trades. There is no ground for supposing that 
the emanations from the graveyard soil are dangerous to health, for 
if they were, their effects should be most marked among the grave- 
diggers, a class, who, like the workmen in sewers, are obstinately 
healthy in spite of all a priori reasoning to the contrary. 716 
DISPOSAL OF THE DEAD. 
Whether the soil becomes seriously polluted, is a question which 
bears on the possible contamination of the ground-water. This possi- 
bility certainly exists, but it is as nothing in comparison with the pol- 
lution of the soil and its contained water by leaching cesspools, into 
which man casts yearly several times his weight of liquid and solid 
excreta from his own body, and there is recorded no single well- 
authenticated case of outbreak of disease due to water contaminated by 
the drainage of a graveyard. 
On general principles, the drainage of a cemetery should not be 
allowed to run into streams used as water supplies, and wells should 
not be located in close proximity to the boundaries of land used for 
interments. 
While burial too near the surface must be avoided on account of the 
possibility that they may be exhumed by dogs and other animals, it is 
to be borne in mind that the nearer the body is to the surface, the 
more rapid will decomposition occur. In order to shorten as much as 
possible the time required for complete resolution, the coffin, which 
should not be of too permanent material, should be placed in immedi- 
ate contact with the earth and not in a bricked enclosure or vault. 
The use of wicker coffins is urged, since they offer less obstacles to the 
natural processes of resolution than any other. Metallic coffins which 
retain the products of decomposition indefinitely should be prohibited. 
The top of the grave should be a mound of earth capable of support- 
ing a fairly luxuriant growth of vegetation, which assists in draining 
the soil and makes use of the products of decay. 
Sites for Cemeteries.-In the selection of a site for a cemetery, 
particular attention should be given to the nature of the soil. This 
should be dry and permeable to air; the ground-water level should 
normally be well below the bottom of the deepest grave; the surface 
should be of rich loam, which acts as a powerful deodorant and pro- 
vides for an abundant growth of vegetation. Clay soils are objection- 
able on account of dampness and impermeability, which prevent rapid 
decomposition of the bodies. Rocky soils are objectionable on account 
of their drainage and the obstacles to the digging of graves. 
Much has been written concerning the danger of pollution of water 
supplies by the drainage of cemeteries, and this danger should be kept 
in mind, but it is unlikely that, with proper locations well away from 
habitations, serious pollution will occur. Where land is abundant and 
cheap, the immediate neighborhood of cemeteries for purposes of resi- 
dence is generally avoided, but it is always well to pay attention to the 
proper drainage of lands devoted to burial purposes and to consider the 
possibility of the fouling of any wells already existing or likely to be 
sunk in the surrounding soil. 
Cremation.-Disposal of the dead by burning was practiced in very 
early times as a mark of respect by some, or of dishonor by others, or 
from motives of expediency after great slaughter in warfare; but the 
practice of incineration, based on economic and sanitary considerations, 
is of quite recent origin among Christian peoples. The arguments 717 
HISTORY OF MODERN CREMATION. 
urged in its favor from an economic standpoint are indisputable, for 
not only can the dead be thus disposed of much more cheaply, but the 
necessity of devoting large tracts of valuable land for purposes of 
burial is done away with. 
From a sanitary standpoint, the arguments are not so strong and, in 
fact, are easy of refutation. It is urged that earth-burial is a menace 
to public health, and a number of supposedly convincing instances are 
cited as proof of this statement; but these cannot withstand the test 
of careful examination and weighing of evidence, and it must be ad- 
mitted, even by the strongest advocates, that there is no definite statis- 
tical evidence that the general death rate or any special death rate has 
ever been influenced by earth-burial. 
It is also urged that earth-burial is repulsive in idea and horrible in 
practice, and while, in the minds of many, this statement is very true, 
it is to be said, on the other hand, that in the minds of far more, the 
argument applies with greater force to the practice of incineration. 
From the time of the early Christians, who practiced interment by 
stealth, earth-burial has ever been the one method of disposal, and the 
sentiment in its favor, fostered through nineteen centuries of practice, is 
a powerful obstacle to the general adoption of cremation and can only 
slowly be overcome. A strong feeling that cremation is opposed to 
Christian doctrine concerning the resurrection of the body can only be 
overturned by the influence of the clergy, many of whom, including 
Protestants and Roman Catholics of eminence, have already done much 
in advocacy of the practice as a rational, economic, and sanitary means 
of disposal. 
Aside from religious feeling, the strongest argument urged against 
cremation is the destruction thereby of evidence of poisoning in cases 
in which, after disposal of the body, suspicion of foul play may arise; 
but when one considers the very great infrequency of exhumations on 
this ground and the still greater infrequency of positive results there- 
from, this objection can hardly be regarded as entitled to much weight. 
In the case of the metallic poisons, the evidence would still be present 
in most cases in the ashes ; in the case of the organic compounds, it 
must be borne in mind that, under most favorable conditions, beginning 
the analysis before the onset of putrefaction, their detection in the small 
amounts commonly employed is by no means easy, and afterwards is 
extremely difficult and more often impossible. 
Furthermore, it must be borne in mind that, unless suspicion arises 
before or immediately after death, chemical analysis is commonly viti- 
ated by the universal practice of embalming the body with strong solu- 
tions containing the very substances sought. In every case of doubt 
as to the cause of death, the body should be subjected at once to proper 
examination. In some States, legal provision has been made, forbidding 
embalming in case of death by violence, until the body has been 
" viewed " by the proper authority, and providing for proper certifica- 
tion before incineration. 
History of Modern Cremation.-According to Japanese authorities, 718 
DISPOSAL OF THE DEAD. 
cremation, as at present practiced among civilized nations, had its origin 
in their country many years ago. Until 1871, however, no special 
crematories were installed, the body in its coffin being placed on stones 
surrounded by wood or other inflammable material. In that year, 
crematories were erected ; and since then, the practice of incineration has 
increased to such an extent that, in 1897, in Tokio, of 34,000 persons 
who died, 15,000, or 44 per cent., were cremated. In 1898, the per- 
centage was about the same. 
In this country, the first movement in favor of cremation occurred 
in New York, in 1873, but the first crematory was not erected until 
1876. This was built at Washington, Pa., by Dr. J. T. LeMoyne, for 
the disposal of his own body, and was the only one in the country until 
1884, when another was established at Lancaster, Pa. During this 
interval of 8 years, the use of his crematory was allowed by Dr. Le- 
Moyne for others, and 25 in- 
cinerations were performed. 
Between 1884 and 1900, the 
number of crematories in- 
creased to 26, which growth 
indicates a steady increase in 
public sentiment in favor of 
the process. The number of 
cremations performed in the 
United States from 1884 to 
1899 is shown by the follow- 
ing diagram from the mono- 
graph by Dr. Samuel W. 
Abbott,1 contributed by the 
Commonwealth of Massachu- 
setts to the United States 
Social Economy Exhibit at 
the Paris Exposition. Dur- 
ing this period, 8,885 crema- 
tions occurred. 
The first table on page 719, 
from the same monograph, 
shows the progress of the 
movement in the entire 
country. 
Next to the United States in the number of crematories stands Italy, 
where, in 1898, 22 were in operation. The movement began in Italy 
in 1857, but nothing was accomplished until 1897, three years after 
legal sanction was obtained. Germany had, in 1898, four establish- 
ments, the first of which was installed at Dresden in 1874 ; France 
had twTo, and Great Britain four, the first of w'hich was established in 
London in 1885. The second table shows the growth of the movement 
in Great Britain to 1899. 
Fig. 105. 
ANNUAL NUMBER OF CREMATIONS. 
Diagram showing number of cremations in the United 
States. (After Abbott. ) 
1 The Past and Present Condition of Public Hygiene and State Medicine in the 
United States, Boston, 1900. 719 
HISTORY OF MODERN CREMATION. 
Crematories. 
Date 
Estab- 
lished. 
1876 
to 
1883 
1884 
1885 
1886 
1887 
1888 
1889 
1890 
1891 
1892 
1893 
1894 
1895 
1896 
1897 
1898 
Total. 
New York City (U. S. Cremation Co.)... 
1885 
9 
77 
67 
83 
106 
160 
187 
186 
232 
243 
296 
330 
331 
466 
2773 
Buffalo, N. Y 
1885 
1 
8 
17 
16 
23 
30 
38 
27 
30 
31 
41 
28 
44 
40 
374 
Troy, N. Y 
1890 
4 
10 
14 
15 
12 
10 
18 
14 
13 
110 
Swinburne Island, N. Y 
1889 
2 
60 
28 
8 
1 
1 
3 
3j 
106 
Waterville, N. Y.'. 
1893 
1 
1 
6 
5 
4 
4 
21 
St. Louis, Mo 
1888 
21 
20 
42 
60 
64 
72 
87 
96 
86 
118 
109 
778 
Philadelphia, Pa 
1888 
14 
28 
31 
51 
62 
68 
74 
88 
78 
114 
69-3 
San Francisco, Cal. (Odd Fellows') 
1895 
66 
101 
214 
260 
641 
Boston, Mass 
1893 
1 
87 
88 
135 
160 
167 
638 
Cincinnati, 0 
1887 
11 
21 
34 
45 
43 
34 
42 
38 
66 
46 
71 
59 
51 0 
San Francisco, Cal. (Cypress Lawn). .. 
1893 
42 
111 
88 
70 
54 
65 
430 
Chicago, Ill 
1893 
6 
42 
66 
54 
82_ 
130 
380 
Los Angeles, Cal 
1887 
7 
5 
12 
17 
29 
41 
37 
38 
37 
37 
34 
58 
352 
Detroit, Mich 
1887 
3 
10 
14 
24 
21 
33 
47 
22 
31 
29 
44 
51 
329 
Pittsburg, Pa 
1886 
14 
9 
11 
8 
9 
13 
14 
13 
10 
13 
14 
w 
23 
167 
Baltimore, Md 
1889 
3 
5 
12 
16 
22 
15 
11 
17 
21 
14 
136 
Lancaster, Pa 
1884 
3 
36 
14 
13 
6 
1 
3 
1 
3 
5 
2 
1 
1 
1 
2 
92 
Davenport, la 
1891 
6 
7 
13 
8 
8 
9 
23 
17 
91 
Milwaukee, Wis 
1895 
21 
34 
30 
85 
Washington, D. C 
1896 
25 
38 
63 
Pasadena, Cal 
1895 
4 
14 
13 
24 
55 
Washington, Pa 
1876 
25 
13 
1 
1 
2 
42 
St. Paul, Minn 
1897 
2 
11 
13 
Fort Wayne, Ind 
1895 
5 
1 
6 
Middletown, Conn. (Asylum) 
1897 
Mt. Auburn, Mass. (Cambridge) 
1900 
Totals 
.... 
25 
16 
47 
114 
127 
190 
249 
372 
471 
561 
674 
831 
1017 
1101 
1391 
1699 
8885 
Crematories. 
1885 
8 
1886 
1887 
13 
1888 
1889 
1890 
1891 
1892 
1893 
1894 
1895 
1896 
1897 
1898 
Total. 
Glasgow 
Liverpool 
London (Woking) 
Manchester 
10 
28 
46 
■ 1 
99 
104 
3 
101 
30 
125 
47 
1 
150 
58 
10 
2 
137 
52 
16 
10 
173 
51 
12 
27 
240 
62 
39 
39 
1283 
303 
Totals .. 
8 
10 
13 
28 
46 
54 
99 
107 
131 
172 
209 
201 
250 
341 
1664 
TABLE OF CREMATIONS IN THE UNITED STATES, 1876 TO 1899. 
TOTAL YEARLY CREMATIONS IN GREAT BRITAIN. 
In the destruction of the body, the heat employed is so intense and 
the apparatus so constructed that, while reduction to ashes is complete 
within three hours, no offensive fumes are given off. Commonly, the 
body, inclosed in a simple wooden coffin, is placed in the retort, which 
is then intensely heated by an oil flame, with which air under pressure 
is mixed by a blower. INDEX. 
4 BDOMINAL bands, 588 
A Acetylene gas, 429 
Acid, carbolic, 509 
Acids, mineral, as disinfectants, 508 
organic, in foods, 22 
Adulteration of beer, 165 
of butter, 112 
of cheese, 121 
of clothing, 706 
of cocoa, 160 
of coffee, 157 
of flour, 129 
of honey, 152 
of milk, 82 
of tea, 156 
of wine, 177 
Aeration of water, 307 
Aerobioscope, 248 
Ague, brass founders', 660 
Air, 207 
ammonia in, 212 
amount of necessary for ventilation, 
403 
analysis of, 231 
aqueous vapor in, 212 
argon in, 209 
as a carrier of disease, 226 
bacteria in, 216 
and moulds in, 224 
bacteriological examination of, 248 
carbon dioxide in, 209 
monoxide in, 217 
composition of, 206 
disinfection of, 535 
dust in, 215 
effect of bad, 222 
filtration of, 421 
hydrogen peroxide in, 212 
nitrogen in, 208 
organic matters in, 222 
oxygen in, 206 
ozone in, 211 
respired, toxicity of, 224 
sewer, 219 
soil, 263 
tester, Fitz's, 244 
Wolpert's, 243 
Albuminoid ammonia, 309 
determination of, 377 
Alcohol as a disinfectant, 513 
determination of, in beer, 165 
in wine, 178 
in milk, 77 
in soldiers' ration, 598 
Alcohol tables, 166 
use of, in the tropics, 643 
Alcoholic beverages, 160 
Alcohols, toxicity of, 182 
Ale, 160 
Allspice, 190 
Almonds, 138 
Alum, purification of water by means of, 
330 
Aluminum chloride as a disinfectant, 506 
Ammonia, in air, 212 
albuminoid, 309 
determination of, in water, 377 
in soils, 252 
in water, 308 
Anchylostomum duodenale, 375 
Animal foods, 23 
Annatto, detection of in milk, 105 
Anopheles, relation of, to spread of ma- 
laria, 282 
Anthrax, relation of soil to, 285 
transmission of, by meat, 43 
Antiseptics, 488 
in milk, 81 
Apples, 145 
Apricots, 145 
Aqueous vapor, 212 
capacity of air for, 213 
determination of, 232 
influence of, 214 
Argand burner, 426 
Argon, 209 
Arrowroot, 138 
Arsenic fumes, influence of, on health, 660 
Artesian wells, 321 
Artichokes, 143 
Ascaris lumbricoides, 374 
Asparagus, 144 
Aspiratory force in ventilation, 408 
Asthma, grinders', 664 
Autoclaves, 520 
Babcock fat tester, 101 
Bacteria bed, Dibdin's, 480 
in air, 216, 224 
in soils, 274 
in water, 351 
influence of, in sand filtration, 338 
Bacteriological examination of air, 248 
of soils, 296 
of water, 392 
Bakers' chemicals, 186 
Baking powders, 191 
Bananas, 147 X 722 
INDEX. 
Barley, 131 
Barracks, 608 
Bathing, 692 
Bathtubs, 460 
Beans, 136 
Beef, composition of, 27 
poisoning by, 63 
Beer, 160 
adulteration of, 165 
analysis of, 165 
composition of, 164 
manufacture of, 162 
Beets, 143 
Beet tops, 144 
Berries, 148 
Beverages, 153 
Bilharzia haematobia, 375 
Bills of health, 544 
Birth rates, 678 
Boiling water, disinfection by, 496 
Books, disinfection of, 539 
Borax, detection of, in milk, 107 
effects of, on the system, 198 
in foods, 198 
Boric acid, effects of, on the system, 198 
in foods, 198 
Botulism, 49 
cause of, 61 
Brandy, 182 
Brass founders' ague, 660 
Bread, 126 
Broad irrigation, 474 
Bromine, disinfection by, 502 
influence of, on health, 657 
purification of water by means of, 331 
Brussels sprouts, 144 
Buckwheat, 134 
Burgundy, 176 
Burial, earth, 714 
Butter, 110 
adulteration of, 112 
analysis of, 115 
composition of, 111 
transmission of disease by, 114 
Butyrorefractometer, 118 
CtABBAGE, 144 
V Caffeine, 157 
Caisson-workers' disease, 669 
Calcium oxide, disinfection by, 504 
Cameron's septic tank, 480 
Camp sewerage, 614 
Camps, 606 
of detention, 573 
inspection of, 616 
sanitary police of, 616 
Candies, 152 
Cane sugar, 21, 149 
Canned foods, 194 
Caramel, detection of, in milk, 106 
Carbohydrates, 21 
Carbolic acid, 509 
Carbon dioxide, absorption of, bv plants, 
210 
in air, 209 
determination of, in air, 237 
Carbon dioxide, determination of, in soil 
air, 295 
effects of, 211, 225 
elimination of, 209 
permissible amount of, in air, 210 
• sources of, in air, 209 
in water, 307 
Carbon disulphide, influence of, on health, 
657 
monoxide, determination of, in air, 
245 
influence of, on health, 657 
poisonous action of, 218 
sources of, in air, 217 
Carrots, 143 
Cassia, 190 
Cauliflower, 144 
Cayenne pepper, 191 
Celery, 144 
Cellulose, 22 
Cemeteries, 716 
Census, 673 
Cereals, 124 
Cerebro-spinal meningitis, transmission 
of, through air, 229 
Chamberland-Pasteur filter, 334 
Champagne, 176 
Cheese, 119 
adulteration of, 131 
analysis of, 122 
composition of, 121 
poisoning by, 122 
Cherries, 146 
Chest capacity, 582 
Chestnuts, 139 
Chicory, 158 
Chloride of lime, disinfection by, 501 
Chlorine, determination of, in water, 382 
disinfectant action of, 500 
influence of, on health, 656 
purification of water by means of, 331 
Cholera, infantum, spread of, by milk, 93 
propagation of, in India, 371 
relation of soil to spread of, 277 
water to spread of, 357, 369 
spread of, through milk, 90 
transmission of, by flies, 626 
through the air, 229, 230 
Chromates, detection of, in milk, 109 
Cider, 181 
vinegar, 187 
Cinnamon, 190 
Claret, 176 
Clay soils, 250 
Clothing, 700 
adulteration of, 706 
disinfection of, 534 
influence of color of, 586 
selection of, 707 
in the tropics, 645 
Cloves, 190 
Coal gas, 427 
Cocoa, 158 
adulteration of, 160 
Cocoanuts, 139 
Coflee, 156 INDEX. 
723 
Coffee, adulteration of, 157 
Colostrum, 77 
Condensed milk, 83 
Condiments, 186 
Conduction, 415 
Confectionery, 152 
Convection, 415 
Copper in foods, 202 
sulphate, disinfection by, 506 
Cordon, sanitary, 572 
Corn, 132 
sweet, 133 
Corned beef, poisoning by, 64 
Corrosive sublimate, disinfection by, 507 
Cotton, 585, 704 
dust, influence of, on health, 666 
Cotton-seed oil, 140 
Cowls, 408 
Cream, 84 
detection of gelatin in, 110 
Cremation, 716 
Creolin, 512 
Cresols, 511 
Cucumbers, 144 
Cysticercus bovis, 39 
cellulosse, 39 
Dandelions, 144 
Dead, disposal of, 714 
Death rates, 681 
correction of, 687 
Deodorants, 488 
Dextrine, 21 
Dextrose, 21, 150 
Diarrhoeal diseases, transmission of, 
through the air, 230 
Dibdin's bacteria bed, 480 
Diet, regulation of, 694 
Diets, standard, 18 
Diphtheria, preventive inoculation, 713 
relation of soil to, 280 
spread of, by milk, 90 
transmission of, through the air, 228, 
229 
Disinfectants, 488 
chemical, 497 
physical, 489 
Disinfection, 488 
plants, 493 
portable apparatus, 493 
practical, 532 
Disposal of dead, 714 
garbage, 484 
sewage, 469 
Distilled alcoholic beverages; 181 
Domestic filters, 333 
Dracunculus medinensis, 374 
Drain, main, 433 
Drainage area of wells, 323 
of soils, 276 
Dust, 215 
cotton, influence of, on health, 666 
determination of, in air, 247 
flax, influence of, on health, 666 
irritating, 664 
poisonous, 661 
Dust, relation of, to disease, 228 
to rain and fog, 215 
Dyes, poisonous, 706 
Dysentery, relation of water to, 357 
PARTH burial, 714 
Ij Earthworms, action of, on soils, 262 
Egg plant, 144 
Eggs, 71 
composition of, 71 
Electric lighting, 431 
Exercise, 695 
amount of, required, 698 
kinds of, 699 
Erysipelas, transmission of, through the 
air, 229 
Eucalyptol, 514 
PjECES, disinfection of, 533 
I Eat, determination of, in milk, 99 
Fats, 20 
Feet, care of, 594 
Felt, 706 
Fermented beverages, 160 
Feser's lactoscope, 95 
Figs, 147 
Filaria sanguinis hominis, 375 
File making, 663 
Filter beds, 336 
galleries, 325 
Filters, Chamberland-Pasteur, 334 
domestic, 333 
Fischer plaque, 542 
mechanical, 341 
Filtration of air, 421 
of sewage, 478 
of water, 333, 336 
proper rate of, 339 
value of, in diminishing disease, 
358 
Fish, 32 
classification of, 34, 36 
composition of, 33, 36 
digestibility of, 33 
keeping qualities of, 33 
parasitic diseases from, 39 
poisoning by, 48 
poisonous, 32 
transmission of disease by, 43 
tuberculosis in, 47 
Fitz's air tester, 244 
Flax dust, influence of, on health, 666 
Flies, agency of, in transmission of dis- 
ease, 626 
Flour, adulteration of, 129 
"mixed," 130 
wheat, 125 
Fluorides, detection of, in beer, 173 
Flushing apparatus, 456 
Fog, influence of, on health, 230 
Foods, 17 
amount of, necessary, 18 
animal, 23 
borax in, 198 
boric acid in, 198 
canned, 194 724 
INDEX. 
Foods, carbohydrates of, 21 
composition of, 19 
contamination of, by metals, 202 
copper in, 202 
fats of, 20 
general consideration of, 17 
inorganic salts of, 22 
lead in, 204 
nickel in, 205 
nutritive value of, 17 
organic acids in, 22 
preservation of, 193 
preservatives in, 196 
proteids of, 19 
salted, 194 
smoked, 194 
tin in, 205 
vegetable, 123 
zinc in, 205 
Formaldehyde, 518 
amount of, necessary for room disin- 
fection, 531 
as a food preservative, 201 
conditions favoring action of, 528 
detection of, in milk, 108 
wines, 180 
disadvantages of, 531 
germicidal properties of, 524 
lamps for generating, 519 
in milk, 81 
penetrating power of, 527 
toxicity of, 529 
Formalin, 519 
Fruits, 145 
Fur, 706 
Furnaces, 417 
n ALACTOSE, 22 
VI Galvanized iron, action of water on, 
350 
Garbage, disposal of, 484 
Gas, acetylene, 429 
burners, 426 
coal, 427 
gasolene, 429 
illuminating, varieties of, 427 
pipes, 430 
water, 427 
Gasolene, 429 
Gelatin, detection of, in cream, 110 
Gin, 185 
Ginger, 191 
Glaisher's table, 234 
Glucose, 21, 150 
wholesomeness of, 164 
Glycoformal, 524 
Goitre, relation of water to, 355 
Grape sugar, 21 
Grapes, 146 
Grease traps, 443 
Grinders' asthma, 664 
Ground-water, 264, 299, 317 
level, 267, 299 
movement of, 301 
sources of, 269 
Habitations, 399 
Ham, poisoning by, 57, 59 
Hands, disinfection of, 535 
Hardness (water), 313 
determination of, 384 
removal of, 342 
Heat apoplexy, 642 
Heat, conducted, 415 
convection of, 415 
disinfectant properties of, 498 
radiant, 414 
Heating, 402 
methods of, 416 
Herrings, poisoning by, 52 
Hominy, 132 
Honey, 151 
poisoning by, 151 
Hops, substitutes for, 164 
Horse meat, composition of, 30 
consumption of, 31 
detection of, 31 
poisoning by, 66 
Hot water heating, 418 
Humidifier, 421 
Humidity, absolute, 214 
relative, 214 
Humus, 251 
Hydrochloric acid fumes, influence of, on 
health, 656 
Hydrogen peroxide, disinfectant properties 
of, 500 
Hygrophant, 236 
ICE, 375 
1 Indian meal, 133 
Inoculation, diphtheria, 713 
plague, 713 
typhoid fever, 713 
Inorganic salts in foods, 22 
Inosite, 22 
Iodine, disinfectant properties of, 502 
Iron, action of water on, 349 
determination of, in water, 389 
purification of water by means of, 332 
removal of, from water, 343 
salts as disinfectants, 505 
[AMS, 153 
f' Jellies, 153 
Kefir., 84 
Kjeldahl process, 104 
Koumiss, 84 
Kummerbund, 589 
[ ACTODENSIMETER, 95 
L Lactoscope, 95 
Lactose, 22 
Lager beer, 160 
Lake waters, 316 
Lamb, composition of, 29 
Lamps, formaldehyde, 519 
paraform, 522 
Lard, 72 INDEX. 
725 
Lead, action of water on, 344 
determination of, in water, 387 
influence of, on health, 661 
presence of, in foods, 204 
Leather, 705 
Leeks, 144 
Legumes, 135 
Lemon juice, 188 
Lentils, 137 
Lettuce, 144 
Life, duration of, 688 
expectation of, 689 
mean duration of, 689 
probable duration of, 689 
tables, 690 
Light, action of, on bacteria, 489 
Lighting, 424 
artificial, 424 
electric, 431 
natural, 424 
Lime, chloride of, as disinfectant, 501 
disinfectant properties of, 504 
juice, 188 
Linen, 585, 704 
Liqueurs, 185 
Loams, 250 
Lysol, 512 
Macaroni, 129 
Mace, 191 
Madeira, 176 
Malaria, relation of mosquitoes to, 282 
of soil to, 282 
of water to, 357 
Malignant oedema, relation of soil to, 285 
Malt vinegar, 187 
Maltose, 22 
Maple sugar, 149 
Marching, 589 
Marine hygiene, 629 
Marls, 251 
Marriage rates, 678 
Matchmaking, 660 
Mean afterlifetime, 689 
Measly meat, 39 
Mechanical ventilation, 414 
Meat, characteristics of good, 26 
extracts, 30 
inspection, 69 
poisoning, 48 
powder, 30 
transmission of disease by, 43 
Meats, 23 
comparative digestibility of, 26 
composition of, 26 
digestibility of, 24 
effects of cooking on, 25 
flavor of, 24 
measly, 39 
parasites in, 39 
texture of, 24 
Melons, 147 
Menthol, 514 
Mercuric chloride, disinfectant proper- 
ties of, 507 
Mercury, influence of, on health, 659 
Mess, consolidated naval, 631 
Military hygiene, 574 
Milk, 73 
abnormal forms of, 76 
adulteration of, 82 
analysis of, 94 
bacteria in, 79 
changes in, through boiling, 78 
composition of, 73 
condensed, 83 
detection of annatto in, 105 
of borax in, 107 
of caramel in, 106 
of chromates in, 109 
of cooked, 109 
of formaldehyde in, 108 
of salicylic acid in, 108 
determination of ash of, 104 
of fat of, 99 
of proteids of, 104 
of specific gravity of, 96 
of sugar of, 103 
of total solids of, 102 
diseased, 85 
elimination of alcohol through, 77 
fat of, 74 
infected, 89 
mineral matter of, 76 
pasteurized, 80 
poisonous, 85 
preservation of, 79 
preservatives in, 81 
proteids of, 75 
reaction of, 76 
specific gravity of, 76 
spread of cholera by, 90 
of infantum by, 93 
of diphtheria by, 90 
of diseases by, 84 
of scarlet fever by, 91 
of tuberculosis by, 87 
of typhoid fever by, 92 
sterilized, 80 
sugar of, 22, 75 
determination of, 103 
Mineral acids, disinfectant properties of, 
508 
Mixed flour, 130 
Molasses, 150 
vinegar, 187 
Moselle wines, 176 
Mosquitoes, agency of, in spread of ma- 
laria, 282 
of yellow fever, 288, 624 
Moulds, number of, in air, 224 
Muscle sugar, 22 
Mushrooms, 148 
Mussels, poisoning by, 51 
Mustard, 189 
Mutton, composition of, 29 
V APHTHA, fumes of, in relation to 
health, 658 
poisoning by, 658 
Natural ventilation, 409 
Naval hygiene, 629 726 
INDEX. 
Nickel in foods, 205 
Nitrates, determination of, 381 
presence of, in soils, 252 
water, 310 
Nitric acid, presence of, in soils, 252 
Nitrification, 338 
Nitrites, determination of, 381 
presence of, in water, 310 
Nitrogen, absorption of, by plants, 208 
amount of, in air, 208 
presence of, in soils, 252 
Norton tube well, 320 
Nutmeg, 191 
Nuts, 138 
OATMEAL, 132 
Oats, 131 
Occupations, classification of, 653 
hygiene of, 648 
Offensive trades, 668 
Oils, essential, as disinfectants, 514 
Oleomargarine, 112 
Olive oil, 139 
Onions, 144 
Open fires, 416 
Oranges, 146 
Organic acids, 22 
matter in soils, 253 
in water, 307 
Overcrowding, 222 
extreme cases of, 223 
relation of, to phthisis, 223 
Oyster plant, 143 
Oysters, poisoning by, 54 
transmission of disease by, 47 
Oxygen, atmospheric, 206 
disinfectant properties of, 499 
presence of, in the tissues, 207 
required, determination of, 385 
Oxyuris vermicularis, 374 
Ozone, 211 
determination of, 246 
disinfectant properties of, 499 
origin of, 211 
purification of water by means of, 332 
1)AIL system of sewage disposal, 470 
Paraform, 519 
Parasites in water, 374 
Parsnips, 143 
Pasteurization, 80 
Peaches, 145 
Peanuts, 139 
Pears, 145 
Peas, 136 
Peat, 251 
Pectin, 22 
Pectose, 22 
Pepper, 190 
Perflation, 408 
Permanganate, purification of water by 
means of, 330 
Permeability of soils to air, 254 
to water, 257 
Peroxide of hydrogen, 212 
Perry, 181 
Person, care of the, 692 
in the tropics, 646 
Personal hygiene, 692 
Phenol, 509 
Phosphorus, influence of, on health, 659 
Phthisis, relation of overcrowding to, 223 
of soil to, 277 
transmission of, through the air, 227 
Physical exercise, 695 
Pimento, 190 
Plague, preventive inoculation against, 
713 
relation of rats to spread of, 280 
of soil to, 280 
transmission of, through clothing, 
229 
Plumbing, 431 
methods of testing, 466 
Plums, 145 
Pneumonia, transmission of, through the 
air, 229 
Poisoning by beef, 63 
by cheese, 122 
by corned beef, 64 
by ham, 57, 59 
by herrings, 52 
by honey, 151 
by horse meat, 66 
by mussels, 51 
by naphtha, 658 
by oysters, 54 
by pork, 56 
by ptomaines, 49 
by salmon, 53 
by sausages, 66 
by veal, 54 
Poisonous milk, 85 
Population, 675 
Pore volume of soils, 253 
determination of, 290 
Pork, composition of, 28 
measly, 39 
poisoning by, 56 
trichinae in, 41 
Port, 176 
Porter, 160 
Potatoes, 141 
Potters, lead poisoning in, 662 
Poultry, composition of, 30 
Preservatives in foods, 196 
Preventive inoculation, 712 
Proof spirit, 185 
Proteids, 19 
Psych rometer, 233 
Ptomaines, 49 
Pumpkin, 144 
Purification of water, methods of. 329 
Quarantine, 540 
interstate, 570 
municipal, 572 
state, 570 
law, 541 
regulations, 553 
Quicklime, disinfectant properties of, 504 INDEX. 
727 
DADI ANT heat, 414 
It Radishes, 143 
Rags, disinfection of, 551 
Rain, 215 
relation of, to dust, 215 
stored, 314 
Rates, birth, 678 
death, 681 
zymotic, 684 
marriage, 678 
Ration, adequacy of U. S., 600 
alcohol in, 598 
Austrian, 601 
British, 600 
French, 600 
German, 601 
Italian, 601 
naval, 630 
Russian, 601 
Spanish, 601 
suitability of U. S., to the tropics, 602 
United States army, 596 
Rats, relation of, to plague, 280 
Recreation, 694 
Recruits, 576 
age of, 577 
examination of, 581 
grounds for rejection of, 583 
height of, 580 
naval, 629 
weight of, 581 
Registration returns, 677 
Respirators, 655 
Rest, 694 
Rhabdonema intestinale, 375 
Rhine wines, 176 
Rice, 134 
River water, 316 
Rivers, self-purification of, 328 
Rooms, disinfection of, 536 
Rubber, 705 
Rum, 185 
Rusks, 128 
Rye, 130 
^AGO, 137 
kj Sailors, diseases of, 634 
sleeping quarters of, 633 
Salicylic acid, detection of, in beer, 173 
in milk, 108 
in wines, 180 
use of, as a food preservative, 200 
in milk, 81 
Salmon, poisoning by, 53 
Salt, 189 
Samp, 132 
Sand filtration, 336 
Saprol, 512 
Sausages, 30 
composition of, 31 
poisoning by, 66 
Sauterne, 176 
Scarlet fever, spread of, through milk, 91 
School furniture, 401 
Schools, 399 
Sea bathing, 693 
Sedgwick's aerobioscope, 248 
Self purification of soils, 262 
of water, 328 
Septic tank, Cameron's, 480 
Sewage, 466 
chemical treatment of, 471 
filtration of, 478 
methods of disposal of, 469 
value of, 467 
Sewage farming, 474 
irrigation, 474 
influence of, on health, 476 
Sewer air, 219 
bacteria in, 219 
relation of, to typhoid fever, 220 
" gas," 219 
Sewerage of camps, 614 
Sheep rot, 42 
Sherry, 176 
Ships, disinfection of, 550, 557, 567 
general hygiene of, 636 
ventilation of, 635 
Sickness, registration of, 688 
Silk, 703 
Sinks, 462 
and latrines, 615 
Slaughtering, 69 
Jewish method of, 70 
Soaps, 515 
medicated, 517 
Soil air, 263 
determination of CO2 in, 295 
dampness, relation of, to disease, 276 
reduction of, 276 
moisture, influence of vegetation on, 
269 
pipes, 433 
water sources of, 269 
Soils, 250 
action of earthworms on, 262 
bacteria of, 274 
bacteriological examination of, 296 
capacity of, for water, 258 
classification of, 250 
constituents of, 251 
determination of capillarity of, 294 
of permeability of, to air, 291 
to water, 292 
water capacity of, 293 
permeability of, to air, 254 
to water, 257 
physical examination of, 288 
properties of, 253 
pollution of, 272 
relation of, to diseases, 275 
self-purification of, 262 
temperature of, 260 
water-retaining capacity of, 258 
Soja beans, 137 
Soldier, clothing of the, 585 
diseases of the, 622 
hygiene of the, 584 
rations of the, 596 
work of the, 589 
Solutol, 513 
Solveol, 513 728 
INDEX. 
Spaghetti, 129 
Spices, 186 
Spinach, 143 
Spirit, proof, 185 
vinegar, 187 
Spirits, 181 
Springs, 317 
Sputum, disinfection of, 534 
Squash, 144 
Starches, 21 
Steam, disinfection by, 491 
heating, 418 
Stout, 160 
Stoves, 416 
ventilating, 417 
String beans, 137 
Sucrose, 21 
Sugar, 148 
maple, 149 
Sugars, 21 
Sulphites, detection of, in wines, 180 
use of, in foods, 200 
Sulphur dioxide, disinfectant properties 
of, 503 
influence of, on health, 657 
Sunlight, disinfectant properties of, 489 
Sunstroke, 625, 642 
Surface waters, 298, 316 
Sweat, toxicity of, 225 
Sweet potatoes, 142 
TANKS, house service, 463 
1 Tape worms, 39 
Tapioca, 138 
Tea, 153 
Tensions, table of, 235 
Tents, 610 
Tetanus, relation of soil to, 285 
Theine, 154 
Thymol, 514 
Tin, action of water on, 351 
detection of, in water, 389 
presence of, in foods, 205 
Toast, 128 
Tokay wines, 176 
Tomatoes, 144 
Trades, offensive, 668 
Traps, 436, 439 
Trichina spiralis, 40 
Trichinosis, 40 
Trichocephalus dispar, 374 
Tropical diseases, 646 
hygiene, 639 
Tropics, care of the person in the, 646 
clothing in the, 645 
diet in the, 643 
habits of life in the, 641 
residence in the, 641 
use of alcohol in the, 643 
Truffles, 148 
Tube wells, 320 
Tuberculosis in armies, 622 
in cattle, 44 
in fish, 47 
overcrowding as a cause of, 222 
relation of soil to, 277 
Tuberculosis, transmission of, by air, 226 
by butter, 114 
by meat, 44 
by milk, 87 
Turnips, 143 
. Typhoid fever, epidemics of, due to water, 
364 
in armies, 623 
preventive inoculation against, 
713 
relation of sewer air to, 220 
soil to, 277 
water to, 357 
transmission of, by dust, 228 
by milk, 92 
by oysters, 47 
infection of water, 359 
rates, classification of cities according 
to, 362 
influence of introduction of 
water supplies on, 360 
Tyrotoxicon, 78 
in cheese, 123 
ITRINALS, 458 
U Urine, disinfection of, 534 
VACCINATION, 709 
' Veal, composition of, 29 
poisoning by, 54 
Vegetable fats, 139 
foods, 123 
Vegetation, effects of, on soils, 269 
Ventilation, 402 
amount of air necessary for, 403 
determination of, 422 
mechanical, 414 
natural, 409 
forces in, 405 
of ships, 635 
space required for, 404 
Ventilating cowls, 408 
stoves, 417 
Vermicelli, 129 
Vinegar, 187 
Vital statistics, 672 
WALNUTS, 139 
Waring system of irrigation, 477 
Wash basins, 458 
Waste pipes, 438 
Water, 297 
action of, on galvanized iron, 350 
on iron, 349 
on lead, 344 
on tin, 351 
aeration of, 307 
ammonia in, 308 
analysis of, 377 
bacteria in, 351 
bacteriological examination of, 392 
carbonic acid in, 307 
chemical purification of, 330 
classification of, 297, 326 
closets, 449 
disinfection of, 539 INDEX. 
729 
Water, color of, 302 
filtration of, 333, 336 
gas, 427 
gases in, 306 
ground, 264, 299, 317 
hardness of, 313 
lake, 316 
mineral matter in, 312 
nitrates in, 310 
nitrites in, 310 
odor of, 303 
organic matter in, 307 
parasites in, 374 
physical characteristics of, 301 
purification of, 328 
by boiling, 333 
by means of alum, 330 
bromine, 331 
chlorine, 331 
distillation, 333 
metallic iron, 332 
permanganate, 330 
ozone, 332 
reaction of, 302 
relation of, to cholera, 357, 369 
to dysentery, 357 
to goitre, 355 
to malaria, 357 
to typhoid fever, 357 
removal of hardness of, 342 
of iron from, 343 
supplies, 314 
surface, 298, 316 
table, 299 
taste of, 306 
treatment of, by alum, 330 
typhoid epidemics due to, 364 
infection of, 359 
Water, well, 318 
Wells, 318 
artesian, 321 
bored, 320 
drainage area of, 323 
driven, 320 
dug, 318 
location of, 323 
pollution of, 323 
tube, 319 
Welsbach burner, 427 
Wheat, 124 
flour, 125 
Whiskey, 183 
Wines, 174 
adulteration of, 177 
analysis of, 178 
classification of, 175 
composition of, 176 
detection of coal tar colors in, 179 
of formaldehyde in, 180 
of salicylic acid in, 180 
of sulphites in, 180 
Wine vinegar, 187 
Wolpert's air tester, 243 
Wool, 585, 702 
Woolsorter's disease, 667 
VELLOW fever, agency of mosquitoes 
1 in spread of, 288, 624 
relation of soil to spread of, 287 
ZINC, action of water on, 350 
detection of, in water, 389 
presence of, in foods, 205 
disinfectant properties of salts of, 505 
Zymotic death rates, 684 UUtfllogtu of Souks 
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