PHILADELPHIA 
Social Science Association 
THE GERM THEORY OF DISEASE, 
AND 
ITS PRESENT BEARING UPON PUBLIC AND PERSONAL HYGIENE. 
READ BEFORE THE ABOVE ASSOCIATION, OCTOBER I7TH, 1878. 
JOSEPH G. RICHARDSON, M. D„ 
PROFESSOR OF HYGIENE AT THE UNIVERSITY OF PENNSYLVANIA. 
Reprint from PENN MON2 HL Y for November, 1878. 
PUBLISHED BY THE 
PHILADELPHIA SOCIAL SCIENCE ASSOCIATION, 
720 LOCUST STREET, PHILADELPHIA. THE FOLLOWING IS A LIST OF THE PAPERS READ BEFORE THE 
ASSOCIATION. 
187I?'- Compulsory Education. By Lorin Blodget. Out of print. 
'— Arbitration as a Remedy for Strikes. By Eckley B. Coxe. 
1 —* The Revised Statutes of Pennsylvania. By R. C. McMurtrie. Out of print. 
— Local Taxation. By Thomas Cochran. 
Infant Mortality. By Dr. J. S. Parry. 
1872.— Statute Law and Common Law, and the Proposed Revision in Pennsylvania. 
By E. Spencer Miller. Out of print. 
-—- Apprenticeship. By James S. Whitney. 
" —The Proposed Amendments to the Constitution of Pennsylvania. By Francis 
Jordan. 
Vaccination. By Dr. J. S. Parry. 
■«i ■ The Census. By Lorin Blodget. 
The Tax System of Pennsylvania. By Cyrus Elder. 
The Work of the Constitutional Convention. By A. Sydney Biddle. 
..1 m What shall Philadelphia do with its Paupers ? By Dr. Isaac Ray. 
.1 ■■ Proportional Representation. By S. Dana Horton. 
_ — Statistics Relating to the Births, Deaths, Marriages, etc., in Philaaelphia. By 
John Stockton-Hough, M.D. 
— On the Value of Original Scientific Research. By Dr. Ruschenberger. 
■— On the Relative Influence of City and Country Life, on Morality, Health, Fe- 
cundity, Longevity and Mortality. By John Stockton-Hough, M.D. 
The Public School System of Philadelphia. By James S. Whitney. 
.—- The Utility of Government Geological Surveys. By Prof. J. P. Lesley. 
—The Law of Partnership. By J. G. Rosengarten. 
Methods of Valuation of Real Estate for Taxation. By Thomas Cochran. 
—-The Merits of Cremation. By I’ersifor Frazer, Jr. 
_ Outlines of Penology. By Joseph R. Chandler. 
1875,- Brain Disease, and Modern Living. By Dr. Isaac Ray. Out of print. 
: Hygiene of the Eye, Considered with Reference to the Children in our Schools. 
By Dr. F. D. Castle. 
. _ — The Relative Morals of City and Country. By Wm. S. Pierce. 
Silk Culture and Home Industry. By Dr. Samuel Chamberlaine. 
1 — — Mind Reading, etc. By Persifor Frazer, Jr. 
— —Legal Status of Married Women in Pennsylvania. By N. D. Miller. 
— The Revised Statutes of the United States. By Lorin Blodget. 
l&f&t- Training of Nurses for the Sick. By John H. Packard, M.D. 
— The Advantages of the Co-operative Feature of Building Associations. By 
Edmund Wrigley. 
—— The Operations of our Building Associations. By Joseph I. Doran. 
-w—. Wisdom in Charity. By Rev. Charles G. Ames. 
Free Coinage and a Self-Adjusting Ratio. By Thomas Balch. 
_ Building Systems for Great Cities. By Lorin Blodget. 
■ ■Metric System. By Persifor Frazer, Jr. 
Cause and Cure of Hard Times. By R. J. Wright. 
House-Drainage and Sewerage By George E. Waring, Jr. 
■— A Ilea for a State Board of Health. By Benjamin Lee, M. D. 
__ , _ The Germ Theory of Disease, and its Present Bearing upon Public and Per- 
sonal Hygiene. By Joseph G. Richardson, M.D. THE GERM THEORY OF DISEASE, AND ITS PRESENT 
BEARING UPON PUBLIC AND PERSONAL 
HYGIENE.* 
THE devastating epidemic of yellow fever, now raging in some 
of our Southern States, has called forth so much discussion in 
regard to the nature of this and kindred maladies, that few persons 
of culture have failed to hear, more or less, in the last six months, 
of the Germ Theory of Disease. 
This hypothesis, of which, for more than ten years, I have been 
an earnest advocate, notwithstanding its unpopularity, both within 
and outside of the medical profession, has, in consequence of some 
recent discoveries, begun to be received into favor by many physi- 
cians, although many more still look upon it with distrust, if not 
with contempt. 
Hence, without endeavoring to convert you all to a faith in the 
absolute truth of its tenets, I believe the time has now come for me 
to point out exactly what its doctrines are, to enumerate the chief 
facts which form their support, and to indicate the precautions 
which, if we admit it is probably true, wisdom enjoins upon us 
towards preventing the propagation and spread of disease. 
In order to render myself clearly understood, I will begin by 
explaining, in the first place, that the Germ Theory of Disease, 
which was propounded by the celebrated Linnaeus more than a 
century ago, but has since been somewhat modified by its succes- 
sive advocates, professes to account for the phenomena of small-pox, 
typhoid fever, yellow fever, relapsing fever, measles, scarlatina, 
diphtheria, chicken-pox, erysipelas, etc., by attributing them to the 
more or less mechanical irritation and other disturbances set up by 
masses of spores and mycelial threads developing in the blood and 
in the affected tissues. The period of incubation (by which is 
meant the time between exposure to small-pox, for example, and 
the development of the complaint), is supposed to correspond with 
that required for the germination of these spores. The gradual in- 
crement of the symptoms is attributed to the progressive growth 
of the millions of minute fungoid plants whose period of greatest 4 
luxuriance marks the acme of the attack, and the death and de- 
struction of which correspond to the decline of the disease. The 
contagiousness of the communicable maladies is accounted for, as 
you see, very beautifully by the existence of the immense number 
of spores (the true seeds of disease) constantly produced, evolved 
from the affected individual, and carried through the air of a room 
or house, either alone or attached to some of the innumerable epi- 
thelial cells, which are constantly being rubbed off by millions 
from the surface of our bodies. The general absence of second at- 
tacks is admirably explained by the hypothesis that the parasitic 
fungus, on the first occasion, has exhausted all, or nearly all, of 
some peculiar (unknown) organic ingredient in our bodies, which 
is absolutely requisite for its support, according to the very same 
law that will cause, as every farmer knows, his wheat to fail if he 
plants it repeatedly in the same ground and neglects to secure a 
due rotation of crops. 
At the outset of my plea in favor of this doctrine, let me say 
that, in spite of the bold assertions of certain enthusiasts and savants, 
with whom zeal outruns knowledge, no really skilful microscopist 
will at present maintain that minute vegetable organisms, found in 
connection with contagious maladies, are as yet proved to have any 
definite relation to them as causes of disease. 
Nevertheless, the presumption that such causal relation does 
exist, is, in my opinion, so strong that I intend to ask you to accept 
my judgment that it will be demonstrated in the near future, and I 
therefore seek, in this address, tp popularize the conception that 
contagious diseases are conveyed from one person to another by 
the transplanting of microscopically visible spores, or seeds, which 
have a separate vitality of their own, each after its kind, and which 
are to be escaped, just as we would escape hordes of animal, or 
swarms of insect pests, by shutting them out or killing them before 
they can succeed in fastening upon our bodies. 
I urge upon you, gentlemen, and upon the community at large, 
such a practical recognition of this theory now, because I believe 
that before many years it will be, with perhaps slight modifications, 
fully and amply demonstrated from miscroscopical and clinical re- 
search, and all true philanthropists must, it seems to me, desire 
that humanity should benefit by this knowledge, even at the 
present hour, although the conservative opponents of the Germ 5 
Theory, whilst evidently wavering in their defense, are not yet 
driven into the last ditch on this side of complete surrender. 
I believe, as I wrote some years since, in regard to Favus, a 
parasitic skin disease of children, (.Hand-book of Medical Micro- 
scopy,, Philadelphia, 1871, p. 252,) “We see to-day the same old 
battle fought (now in regard to small-pox, diphtheria and their con- 
geners), which, fifty years ago, was so strenuously contested by 
Biett and Morgagni, on the one hand, and the microscopists on the 
other, in relation to scabies, or the itch, at present universally ad- 
mitted to be due to a minute insect, the Acarus Scabiei; and to the 
student of human nature it is a most interesting confirmation of the 
wise king’s dictum, “ There is no new thing under the sun,” to ob- 
serve how the same doubts, followed by the same objections, were 
urged against the parasitic character of the itch that are now put 
forward in opposition to the vegetable nature of the cause of ring- 
worm or favus. Thus, Biett, Cazenave, Lugol, etc., denied then, 
that, even with the aid of microscopes of high power, any insect 
whatever could be discovered. When, by a succession of lucky ac- 
cidents, so many observers blundered into seeing the insect, that 
this position was no longer tenable, opponents to the parasitic 
theory changed their base of operations, and admitting the occa- 
sional existence of the acarus, stoutly maintained that, instead of 
being the cause of scabies, it was a secretory product of that affection, 
and by no means a constant one. Finally, when proof that the 
whole disease could arise from the deposit of a single itch insect 
upon the skin of a previously healthy person, became incontestable, 
the anti-microscopists took refuge in the assertion that in such 
cases “ the insect, taken from the scabious vesicle, being charged 
with the virus, the fluid of the vesicle, by penetration of the cuticle 
inserted this virus and produced the disease,” as the inoculation of 
cow-pox is accomplished. 
One of the strongest arguments against the doctrine that living 
germs can enter human organisms from the alimentary canal, is 
that derived from the a priori probability that the solvent action 
of the gastric and intestinal juices must destroy all vitality in the 
microscopic organisms which on this hypothesis constituted the 
morbific matter, the contagium vivum of disease. A fundamental 
step towards establishing the Germ Theory, therefore, was mani- 
festly that of proving that Bacteria, or analagous low*forms of life, 6 
could penetrate from the stomach to the blood, to be thereby car- 
ried into all parts of the system, and this, I was, I believe, the first 
to demonstrate. My observations were detailed in the American 
Journal of the Medical Sciences for July, 1868, from which I ex- 
tract the following as the most important: 
Experiment 4th. At 7.45 P. M., May 17th, 1868, I drank 
four fluid ounces of water, similar to that employed in the preced- 
ing investigations and containing multitudes of Bacteria, estimated 
as numbering 27,000,000,000. At a quarter past eight, I examined 
a drop of blood drawn with the aid of a cataract needle from the 
tip of my finger and confined between a slide and cover cleaned 
with strong hydrochloric acid. Under the field of the one-twenty- 
fifth inch objective, the interspaces between the rows of blood cor- 
puscles were found to contain multitudes of apparently spherical 
molecules, in rapid and erratic motion, but so very minute as to 
readily escape notice even with this high power, except under the 
closest scrutiny; in the course of half an hour, not less than one 
hundred were observed. At 9 P. M., another drop of blood, ex- 
amined with the same precautions, exhibited, in addition to these 
minute particles, other bodies less active in their movements, of 
much greater magnitude, and which under an amplification of 
1,100 diameters, appeared precisely similar to the Bacteria I had 
been studying a few hours before in the identical decomposing beef 
juice imbibed. Five of them were thus enlarged so as to exhibit 
an unmistakable organized structure, totally different from their 
associated aggregations of Beale’s germinal matter. Three of these 
Bacteria were each about one-twelve-thousandth of an inch in 
length and one-twenty-five-thousandth of an inch in width, very 
distinctly constricted in the middle; a fourth was obviously com- 
posed of four, and a fifth of six joints, arranged in a straight line, 
the motion of which, was of that peculiar waving character so 
universal among the Oscillatoriacae. The last two were most 
clearly visible when they happened to lie vertically to the surface 
of the glass, and would probably escape observation under the 
one-eighth inch, except in that position, or be therefore mistaken 
for simple globular bodies, although in several cases I detected in 
the second and third experiments (with a lower power) a shadowy 
elongation of one diameter of the revolving molecules thus observed. 
These results of mine were corroborated soon after by the re- 7 
searches of Dr. Neftel of New York, upon some of the inferior 
animals, in regard to which, he informs us (N. Y. Medical Record, 
July 15th, 1868, p. 226;) “ My experiments so far me to the 
conclusion that the lower vegetable organisms can continue to live 
and multiply in the tissues of living animals, and that they can 
enter into the general circulation, either through the intestinal 
canal or respiratory organs, or by means of hypodermic injections. 
What is their ultimate fate in the animal organism, and what their 
importance in producing disease further investigation will have to 
show.” 
M. E. Semmer, in Virchow's Archives, April, 1870, in his paper 
on the “ Results of Injection of Fungous Spores and Fungous Cells 
into the Blood of Animals,” gives additional corroboration of the 
conclusion to which I arrived by personal experiments. 
Notwithstanding these and other investigations, the Germ 
Theory of Disease made but little real progress, at least in English 
speaking countries, until about three years since, when the re- 
searches of Professor Burdon Sanderson and E. Klein of London, as 
set forth in Mr. Simon’s Report for 1874, as Medical Officer of the 
British Privy Council, commanded much professional attention and 
doubtless led many who had previously ignored the theory to ex- 
amine anew its claims to credibility. 
In this report are endorsed the next two great steps towards 
the establishment of the Germ Theory, namely, the experiments of 
Oertel and Nassiloff, who showed that if the cornea of a rabbit is 
lightly pricked with a needle that has been thrust through diphthe- 
ritic false membrane, the wound does not heal up as similar tiny 
punctures with clean needles do, but becomes in a few days the 
centre of radiating streaks of brownish opacity, which under the 
microscope are seen to be made up of colonies of the vegetable 
spores (micrococci) of diphtheritic disease. The other important 
step was the detection by Obermeier of Berlin, of a minute fungoid 
growth (spirillum) in the blood of patients suffering with Relapsing 
Fever, a fact which Professor Strieker of Vienna, whose world- 
wide fame as a most skilful microscopist renders his testimony 
conclusive, told me only a few weeks ago he had fully confirmed. 
These and other researches, led Dr. William Roberts of Man- 
chester, England, in his Annual Address before the British Medical 
Association last year, to assert that the Germ Theory of Disease 8 
“ is now established upon a firm experimental basis, and if fairly- 
grasped in capable hands, will very soon give us most important 
aid in our struggle with disease ; ” and a recent eminent German 
writer on Pathology, Professor Orth, late of Berlin, now of Got- 
tingen, declares “ of all the modifications which the blood under- 
goes, the least understood and at the same time the most important, 
is unquestionably, that which is due to the admixture with low 
organisms. Recent researches leave no doubt whatever, that in 
some diseases the blood contains during life, though to a far higher 
degree after death, certain low forms of animal or vegetable life. 
Those organisms which have a thoroughly characteristic appear- 
ance can be detected without any great difficulty, with very high 
powers, provided the layer of blood which is examined be very 
thin, or that the red corpuscles have been destroyed with acetic 
acid or alkalies.” * 
The latest, and perhaps most important, advance toward actual 
proof of the Germ Theory, has just been made by my friend, Professor 
E. Klein, F. R. S., of London, who, in a series of admirable inves- 
tigations, partly communicated to the Royal Society in February 
1878, shows that a kind of bacterium found in the peritoneal exu- 
dation of pigs affected with a disease sometimes called typhoid 
fever (but more properly entitled Pneumo-enteritis contagiosa), may 
be cultivated in indifferent fluids outside the animal’s body for 
eight successive generations, and then produce the original malady 
in healthy animals upon which it is inoculated. 
The daily success of Lister’s Antiseptic Method of Dressing 
Wounds, now firmly established in the London and many of the 
Continental hospitals, is a further and almost unanswerable evidence 
of the infective power of germs, and the wonderfully lucid expla- 
nations and ingenious experiments of Professor Tyndall have done 
much to enable all to realize the intimate relation which exists be- 
tween Dust (which consists largely of germs), and Disease. 
It may not be amiss, before leaving this part of my subject, to 
* Dr. Orth describes the grey coating on wounds affected with Hospital Gangrene, 
and lining the uterus in puerperal fever, as being made up chiefly of micrococci and 
bacteria. He also asserts, what I long ago believed and taught, that in metastatic ab- 
scesses, and probably in carbuncles and boils* the starting point of the slough which 
forms the core, is found in a small artery plugged up by a little wandering mass of mi- 
crococci or fungous spores. 9 
reply to an objection which has been frequently offered to obser- 
vations upon Bacteria, met with in connection with various diseases, 
namely, that such organisms, apparently quite identical, are often 
detected in absolutely healthy animals, and therefore cannot be 
causes of disease. Those who urge this argument, however, seem 
to forget that since the Bacterial spores and rods are only the ana- 
logues of the seeds and roots of larger plants, and by no means 
entire organisms, it is, therefore, no more reasonable to expect us 
to distinguish the bacterium which develops into the cause of 
Yellow Fever, for instance, from that which produces simple putre- 
faction, than it is to demand we should discriminate at sight, the 
root and seed of a choke pear, from those of a seckle. In either 
case it may be only by cultivating the plant to its full perfection, and 
testing its ripe fruit, that we can determine its place in nature. 
Abandoning, as I said before, all claim at present to certainty 
that the Germ Theory of Disease is true, let us consider in conclu- 
sion, what modifications of the ordinary sanitary precautions we 
can wisely adopt in view of the probability that Bacteria, or closely 
allied organisms are the actual causes of constitutional diseases. 
In the first place, it seems to me that great benefit would re- 
sult from its being understood by every man, woman and child, that 
the contagion of small-pox, scarlet fever, typhoid fever, yellow fever, 
measles, diphtheria, cholera, etc., is probably composed of exceed- 
ingly minute spores, or seeds, so small, that 20,000 of them placed 
end to end, would measure less than one inch in length, and a mass 
the diameter of one of the periods (.) upon this printed page might 
contain 50,000,000. Each one of these 50,000,000 of seeds is ca- 
pable, under favorable circumstances, of reproducing its kind with 
almost inconceivable rapidity; so that, supposing, for example, the 
Zygodesmus of Professor Letzerich is really the morbific agent 
causing diphtheria, a particle of of the greyish false membrane of 
the size of the dot just mentioned, would contain separate seeds 
enough to infect every inhabitant of the whole continent of North 
America with diphtheritic disease. But, whilst this is the theo- 
retical possibility, practically, the same law of prodigality of nature 
exemplified in the spawn of the herring and salmon holds good, 
and not more than one spore in a thousand, a million, or a hundred 
million, perhaps, has an opportunity to reproduce its species. 
As there is no doubt that the contagion of the diseases just 10 
enumerated may penetrate into our systems by the air we breathe, 
the food we eat, and especially the water we drink, it is obvious 
that only the most scrupulous care can save us from these ex- 
tremely minute seeds, or insure their destruction after entrance into 
our bodies is accomplished. If these germs were singly dissemi- 
nated, it would be almost impossible to avert constant infection, 
but as they generally are carried about by winds or currents in ag- 
gregations of thousands or tens of thousands, of course the chance 
of imprisoning them, or otherwise shielding ourselves from them, is 
largely increased. It seems probable that the epithelial cells con- 
tinually shed from our integument and constantly floating about in 
the atmosphere in great numbers, and which, as shown in some 
observations of my own, upon the white incrustation upon brick 
house fronts, are met with in the dust deposited upon the highest 
points of four-story buildings in crowded thoroughfares, are often 
vehicles for small groups of these spores which adhere to them. 
The obvious deductions from these facts, tend to strengthen the 
urgent recommendations of sanitarians, that every effort should be 
made first, to prevent these morbific germs from being let loose upon 
the world, and second, when they have made their escape into the 
free air or water, to destroy all spores likely to come in contact 
with unprotected persons, that is to say, human beings from whose 
bodies one crop of small-pox (or cow pox) fungus, yellow fever 
bacteria, relapsing fever spirilla, etc., has not already been raised. 
Each individual affected with small-pox, scarlet fever, diphthe- 
ria, or any other of the diseases above mentioned, is, according to 
this theory, to be looked upon as a sort of hot bed or forcing 
house for the. seeds or spores of that malady. From his or her 
body are continually given off in all directions, by the skin, the 
breath, the perspiration and other secretions, millions of spores of 
the extreme minuteness I have described to you, each one of which, 
if it were received into a human system, under favorable circum- 
stances, would rapidly reproduce itself, and after a few days or 
weeks (corresponding, as already mentioned, to what is known as 
the period of incubation) give rise to a new case of the disease, 
again a new hot-bed of contagion for other unprotected organisms. 
Now these spores, just like the seeds of larger noxious weeds, 
which, when allowed to gain a foot-hold in our fields and gardens, 
propagate themselves with such immense rapidity, have no power 11 
to move of their own accord, and can only develop if they meet 
with air, moisture and congenial soil suited to their peculiar 
requirements. That is, if a small-pox patient is shut up in a germ- 
tight room so that the seeds cannot escape, or, if whilst in the 
open air that air is stagnant, so that no seeds are wafted away from 
the immediate neighborhood of the individual, or, if when carried 
along by the wind, they are blown away from any human habita- 
tions, are dessicated in a dry atmosphere, baked by the sun’s rays 
or artificial heat, frozen by extreme cold (as seems to be the case 
with yellow fever germs), or finally, if they happen to meet with 
no persons but those who have had small-pox or been sufficiently 
vaccinated, in other words, if they do not “ fall upon good ground,” 
all this wealth of provision by which nature tries so hard to secure 
the perpetuation of the poisonous plant, causing small-pox in our 
systems, becomes unavailing and her malevolent design against 
our race, carried out with such a prodigality of murderous weapons, 
utterly fails. 
This brings me to the notice of one of the most common and 
most mischievous popular errors which a general acceptance of the 
Germ Theory will necessarily subvert, namely, the belief that 
small-pox and other contagious maladies often arise without pre- 
vious exposure to the seeds of the disease. This doctrine, fre- 
quently advanced in private life as an excuse for neglect of proper 
care and caution in regard to children, etc., and occasionally sus- 
tained by public authorities as an apology for violation of quarantine 
and other sanitary regulations, is exceedingly pernicious, and our 
warmest gratitude would be due to the Germ Theory of disease, 
even should its establishment render no other service to humanity 
than the explosion of this fallacy. The fact is, as I firmly believe, 
that (inverting the Scriptural aphorism), we can no more gather 
thorns from grapes, or thistles from figs, than we can have, for in- 
stance, the germs of yellow fever growing from clean cotton, or 
those of cholera developing from uninfected rice. 
Putting aside the primary origin of diseases, which, with one or 
two doubtful exceptions, is a question of prehistoric time, the Germ 
Theory of Disease teaches us that every new case of the contagious 
maladies already enumerated, is the immediate off-spring of a pre- 
ceding case, and the direct result of exposure of an unprotected 
human being to the chance of having the spores or seeds of disease 12 
implanted in its system, an exposure which it only required suffi- 
cient knowledge, sufficient foresight and sufficient care to avoid. 
This pernicious belief, as I deem it, in the spontaneous endemic 
origin of the contagious diseases rests, at any rate, on entirely 
negative evidence, namely, the circumstance that cases do some- 
times spring up in which it is impossible to trace the affection back 
to a personal source of specific propagation, and yet, such an event 
is only what we have reason to expect from the very nature of these 
diseases, since the active principle of the poison is invisible to the 
naked eye. Hence, in the ordinary affairs of life, unless special 
precautions are resorted to, ways are open for the spread of these 
microscopic agents of propagation in a thousand unseen modes, so 
that, obviously, the precise source of infection and its track must 
often remain undiscovered by the best wisdom of man. I have 
seldom been more forcibly impressed with this truth than when, 
upon one occasion a few years ago, a stalwart man entered, in his 
turn, my prescribing-room in the Pennsylvania Hospital, and on his 
lifting his hat I saw his forehead was covered with well-filled pus- 
tules of small-pox, at about the sixth day of their development. In 
reply to my reproof for thus exposing other patients in the waiting 
room of the Hospital to this terrible disease, he assured me (men- 
daciously, I presume), that he did not know what was the matter 
with him, and that, being a stranger in the city, without home or 
friends, he had, when taken sick, come to the Hospital, since “ he 
must have some place to go to.” I hastened him off to the office 
of the Board of Health, whence he was doubtless forwarded to the 
Municipal Hospital; but the point of interest in this connection is, 
that if, as is probably often the case, there had happened to be in 
that waiting-room an unvaccinated child upon whom the infection 
from these pustules was propagated, no one connected with the in- 
fant could have suspected the source of contagion, as my small-pox 
patient had his hands concealed in gloves and wore a full, heavy 
beard, which, with a hat pulled low down over his eyes, effectually 
shielded his loathsome disorder from observation. 
Of course, this is not an isolated case, but only an example of 
what we all, young and old alike, are constantly exposed to in the 
streets, the cars, and all public places in a large city. I cannot but 
hope, however, that as soon as our legislators become convinced 
that the Germ Theory is true, we will have what our English 13 
cousins enjoy the advantage of, i. e., stringent laws to prevent such 
culpable injury to innocent persons. Meanwhile, our only safe- 
guard is to protect those under our care by the precautions of early 
vaccination and the most watchful seclusion from possible exposure 
to the sphere of influence of such contaminating individuals, who 
constitute, as I consider, hot-beds for generating the tangible seeds 
of disease.* 
In all such instances, indeed, isolation from unprotected persons, 
carried out with every due consideration and kindness, is, therefore, 
to be practiced, if possible, and under other conditions, means 
which will destroy the life of the spores, such as dry heat of high 
degree, super-heated steam, prolonged boiling in water, caustic 
acids or alkalies, are to be used, with a firm confidence that if they 
are employed thoroughly enough they will absolutely put a stop to 
all spread of the disease. 
A very important suggestion in regard to the use of disinfectants, 
arising from our knowledge of the Germ Theory, is, that since these 
spores doubtless float in the atmosphere, as do the seeds of the 
thistle or dandelion, and are no more susceptible to the action of 
chemicals, with which the air containing them is impregnated, it 
is useless to expect any certain and complete results from the 
milder aerial disinfectants, as usually employed, that is, by scent- 
ing the medium in which they are suspended with carbolic acid, 
camphor, acetic acid, and similar non-corrosive agents. 
As to the lesson we may deduce from these teachings in regard 
to Public Hygiene, I think its importance is only surpassed by its 
simplicity. 
For such contagious and infectious maladies it is : Avoid, at any 
cost, the entrance into communities of living spores or seeds of disease. 
And this should be insured, not as in former times, with the mere 
hope that somehow we might escape the visitation, but with the 
absolute certainty that with proper care infection cannot occur. 
No doubt many of us have smiled at the story of certain terror- 
* Some years ago a medical friend of mine attended, in a large town not a hundred 
miles from New York, two successive cases of small-pox in the house of a dealer in 
ready-made clothing. The whole stock of coats, pantaloons, etc., numbering many 
hundreds had an opportunity of being impregnated with the seeds of the complaint, and 
should have been disinfected with scrupulous care. They were, however, sold at retail, 
just as usual, and may have given rise to scores of cases of “ idiopathic ” (?) small-pox. 14 
stricken authorities in a German town, who, when a single potato- 
bug was discovered in a field near them, immediately covered the 
whole plantation with straw soaked in kerosene, and, setting fire to 
it, destroyed every vestige of animal and vegetable life for acres 
around. And yet, if we consider a moment, we realize the fact that 
this apparent waste of time, trouble, and potato vines, was the 
wisest and most economical expenditure that could possibly have 
been made. 
How much more, then, when our own lives and the lives of 
those that are dear to us, in addition to scores of millions of dollars 
are at stake, as they are now in the South, should sanitary 
authorities be armed with almost despotic power, in order that they 
may shut out, or kill every one of these actually visible and even 
tangible seeds of disease. Quarantine, disinfection and prolonged 
detention of persons, with disinfection, or frequently total destruc- 
tion of goods from infected districts, is, it appears to me, the right 
of the many at the expense of the few ; and even if, as I should ad- 
vocate, for the sake of strict justice, ample compensation for loss of 
time and loss of property were allowed by law to those who 
suffered, I believe the community at large would be tenfold better 
off pecuniarily, to say nothing of the far more important saving of 
human life and human suffering, which would be secured. PRESS OF EDWARD STERN & CO., 
I25 SOUTH SEVENTH STREET, PHILA.