THE 
CHARACTER OF THE FLAGELLA 
ON THE 
BACILLUS CHOLERA SUIS (Salmon and Smith) 
BACILLUS COLI COMMUNIS (Escherich) 
AND THE 
BACILLUS TYPHI ABDOMINALIS (Eberth) 
BY 
VERANUS ALVA MOORE, B.S., M.D. 
REPRINTED FROM 
THE WILDER QUARTER-CENTURY BOOK 
ITHACA, N. Y. 
1893 THE CHARACTER OF THE FLAGELLA ON THE BA- 
CILLUS CHOLERAS SUIS (SALMON AND SMITH), 
BACILLUS COLI COMMUNIS (ESCHERICH), AND 
THE BACILLUS TYPHI ABDOMINALIS (EBERTH). 
f 
By VERANUS ALVA MOORE. 
Recent study of the morphology of bacteria has demon- 
strated the fact which Ehrenberg had foretold, that the motile 
forms are possessed of flagella. The further prophecy that in 
these minute hair-like appendages would be found vested the 
power of locomotion, was partially fulfilled as early as 1875 
by Dallinger and Drysdale, who saw these filaments con- 
stantly lashing on a living, moving germ (^Bacterium termo}. 
More recently Straus has made similar observations on several 
species of bacteria. Cohn, in 1872, and Koch, in 1877, 
stained the flagella on a few of the larger saprophytic bacte- 
ria, but the methods which they employed were so defective 
that for more than a decade no further knowledge was gained 
concerning the character or existence of these minute fila- 
ments. The recent development of staining methods by 
which the flagella can be demonstrated on all the motile 
bacteria, is therefore of considerable importance, in opening 
before us a hitherto unexplored field in the study of the mor- 
phology of an exceedingly large and prominent class of the 
Schizomycetes. 
Although considerable attention has been given to the 
character of the flagella, the greater part of the work which 
has been done on this subject has been directed to the devel- 
opment of methods for their demonstration rather than to the 
filaments themselves. As a natural result of this, our present 
knowledge of the flagella is exceedingly fragmentary, and the 
few statements concerning them are, in some instances, espe- 
cially with the typhoid and coli bacteria, contradictory. The 340 
Veranus Alva Moore 
intimate relation that exists between methods and results in 
the study of the morphology of bacteria will undoubtedly ex- 
plain many of these discrepancies. In the endeavor to bring 
out more fully the character of the flagella of the three species 
of bacteria in question, it is desirable, on account of their inti- 
mate association with the development of our knowledge of 
flagella, to consider first, in a general manner, the methods 
that have been proposed for their demonstration and to give a 
brief resume of our knowledge of these filaments and their 
accepted significance. I furthermore wish to acknowledge 
my indebtedness to the various writers on this subject for 
many valuable suggestions. 
A SUMMARY OF OUR RECORDED KNOWLEDGE OF THE FLAGELLA OF 
motile bacteria, (i) methods for their demonstration. 
(2) THEIR CHARACTER AND SIGNIFICANCE. 
Cohn1 and Koch3 appear to be the first who stained the 
flagella. The methods by which they demonstrated the ex- 
istence of these filaments have not been successfully applied 
to the smaller and especially the parasitic organisms. Al- 
though our instruments and methods have been much im- 
proved since Dallinger2 and Drysdale made their observa- 
tions, the detection of the flagella on living, moving bacteria 
is a result which has rarely if ever been attained with the 
small and pathogenic bacteria. From 1877 to 1889 no 
further knowledge of these filaments appears to have been 
acquired. 
In 1889 Loeffler6 succeeded in formulating a method by 
which he could stain the flagella on a considerable number of 
bacteria. The process, however, was not satisfactory, and a 
year later he published a second method9 which has since 
borne his name, and which he believed would, if properly 
carried out, be applicable in staining the flagella on all the 
motile bacteria. 
A few other methods* have been proposed, but Loeffler's 
*In an article'2 published in the American Monthly Microscopical 
Journal, (January, 1891), I reviewed the various methods that had been 
used in demonstrating the flagella on motile bacteria up to that time. 
See Literature, No. 5, 7, 10, and 11, at the close of this article. The Character of the Flagella 
341 
has appeared to be the most trustworthy, although its appli- 
cation to the different species of bacteria has been attended 
with much difficulty. It has frequently happened, even 
when the method was apparently strictly adhered to, that the 
outcome has been absolutely negative, while in other in- 
stances the result would be entirely satisfactory. 
Since the description of the original methods the literature 
on this subject has been exceedingly meager. In a commu- 
nication to the American Society of Microscopists13, in 1891, I 
pointed out several of the difficulties usually experienced in 
the application of Loeffler's method, and suggested certain 
modifications, more especially in the technique, which I had 
found would to a great extent overcome these objections. In 
the same paper it was also stated that the principle laid down 
by Loeffler "that an acid* producing germ required an alka- 
line mordant, and an alkali producing organism an acid mor- 
dant," need not be taken in a strict sense, as the flagella on 
certain of the acid and of the alkali producing bacteria could 
be stained by the use of either a neutral, acid, or alkaline 
mordant. 
Straus17 has recently reported a very simple methodf by 
which he could stain the flagella on certain living bacteria. 
The process has given in my hands universally negative 
results. 
Luksch15 has modified Loeffler's method principally by 
*In 1890, Dr. Theobald Smith {Centralblatt f. Bakteriologie u. Para- 
sitenkunde VIII, (1890), p. 389) pointed out the fact that liquid cultures 
of certain bacteria would be acid or alkaline, according as glucose or 
other sugars were present or absent. These undergo fermentation with 
the formation of acids. In liquids free from sugars the reaction re- 
mains alkaline. (See his paper in this volume.) Petruschky's (Ibid, 
VI, 1889) classification of bacteria as acid or alkaline producing is 
thus shown to depend largely on the presence or absence of carbo- 
hydrates in the culture medium. 
t The method is as follows : To a hanging drop preparation of the 
culture a drop of staining fluid consisting of carbol fuschin one part, 
and distilled water three parts, is added and the preparation examined 
at once. He states that the moving flagella can be observed for about 
15 minutes. 342 
Veranus Alva Moore 
using a stronger solution of tannic acid in the preparation of 
the mordant and by the use of acetic instead of sulphuric acid 
in acidifying it. A very few other minor modifications of 
Loeffler's and other processes have been suggested, but they 
have in no way brought out results which entitle them to a 
consideration. Brown's19 method is practically a modification 
of Trenkmann's process. 
During the brief period of time that the existence of flagella 
on the smaller and especially the pathogenic bacteria has 
been known, two valuable applications of this knowledge have 
been made : 
(i) Their use as a basis for a general classification of the 
Schizomycetes. Soon after the appearance of Loeffler's first 
method (1889) Messea8, an Italian investigator, proposed a 
new systematic classification* of bacteria based upon the num- 
ber and arrangement of the flagella. His classification is as 
follows : 
I. Gymnobacteria fion-motile}. 
II. Trichobacteria lynotile'). 
1. Monotricha. 3. Amphitricha. 
2. Lophotricha. 4. Peritricha. 
The Monotricha have one flagellum at one pole of the bacil- 
lus (Bacillus pyocyaneus}. The Lophotricha have a tuft or 
bunch of flagella at one pole of the bacillus (Bacillus of blue 
milk}. The Amphitricha have a flagellum at each pole 
(Spirillum volutans}. The Peritricha are provided with rows 
of flagella (Bacillus typhosus}. 
* Kruse (Centralblatt J. Bakteriologie u. Parasitenkunde, IX, (1891), 
p. 107) in reviewing Messea's classification, considers it of only second- 
ary importance. His reason for this is, that it is unnatural in that it 
places bacilli, spirilla, and a micrococcus together in one group (the 
Monotrichia'). It does not seem necessary to consider a pioneer classi- 
fication secondary merely because of an apparent inconsistency, espe- 
cially in a subject about which so little is known. Undoubtedly 
Messea's classification was based on too limited a number of examina- 
tions, and more extended investigations will probably cause many 
changes to be made. At present, however, it is the only classification 
which incorporates the complete morphology, as known at the present 
time, of motile bacteria. The Character of the Flagella 
343 
(2) Their assistance in differentiating closely allied species. 
Luksch15 in differentiating Bacillus typhi abdominalis and 
Bacillus coli communis made use of their flagella. He 
found from one to three flagella on the colon bacteria, but the 
typhoid bacilli were endowed with from 8 to 12 filaments, a 
difference sufficiently great to be of differential value. He 
experienced much more difficulty in staining the flagella on 
the colon germ than on any of the other motile bacteria. 
Tavel18 has recently made the statement that Bacillus 
coli communis has no flagella* but that the typhoid bacillus is 
provided with them. This statement is qualified by a preced- 
ing one, that Bacillus coli communis is a non-motile organ- 
ism, which would indicate that he was working with a differ- 
ent species. 
In the articles, already mentioned, on the demonstration of 
the flagella a brief description is given of the motile append- 
ages on the typhoid and a few other bacteria. Ballinger4 and 
Zettnow14 have discussed the flagella on a few species, more 
especially the saprophytic spirilla. In addition to these, there 
are brief mentions of the filaments on the typhoid and other 
species of bacteria scattered throughout the literature of the 
past three years, but so far as I am aware, they are too incom- 
plete to be considered of any specific value. 
THE COMPARATIVE DIFFERENTIAE VAEUE OF THE FEAGEEEA AND 
THE BIOEOGICAE PROPERTIES OF THE BACIEEUS CHOEER^E SUIS, 
B. COEI COMMUNIS, AND B. TYPHI ABDOMINAEIS. 
Bacteriology recognizes more fully, perhaps, than any other 
branch of biological science, functional properties in the forma- 
tion of species and varieties. There are writers on this sub- 
ject who consider every variation in the characters or proper- 
ties of bacteria of specific or varietal significance, while there 
are others who hold more rigidly to the morphology of these 
organisms in determining their specific differences. The 
question, therefore, are specific differences in bacteria deter- 
mined by their morphological characters or by their biological 
*In 1891 I published a brief description of the flagella on the colon 
bacteria (Proceedings of the Am. Soc. of Microscopists, 1891). 344 
Veranus Alva Moore 
(including etiological) properties, is one which, as yet, has no 
clearly defined and uniformly accepted answer. Messea's 
classification of motile bacteria is based on morphological 
characters only, and it recognizes genera, but not species. 
Luksch goes still further and points out a specific difference 
in the number of flagella of the typhoid and colon bacilli, two 
well recognized species of one genus. On the other hand, the 
more extended investigations of the biological properties of 
bacteria are continually bringing forth new facts, and reveal- 
ing variations in the properties of these organisms which are 
not explained by corresponding differences in their morpholo- 
gy. There are bacteria which possess marked difference in 
their biological manifestations which resemble each other so 
closely in their structure that, with our present knowledge, 
their differentiation by purely morphological characters, is 
practically impossible. In the group of bacteria which 
includes Bacillus cholera suis, Bacillus coli communis, and 
Bacillus typhi abdominalis we have an excellent illustration 
of this fact. These species resemble each other very closely 
morphologically but they are readily differentiated by means 
of their biological and etiological properties. In this group, 
therefore, is found a most rigid test for the differential value 
of the flagella. 
It may be assserted that these bacteria do not belong to the 
same group, and while in a narrow sense (considering their 
more characteristic physiological manifestations only) it may 
be true, yet morphologically they are small, motile bacteria 
belonging to the Peritricha (Messea) and, in certain other re- 
spects, they are closely enough related to one another to be 
enrolled in the same genus, while their physiological and eti- 
ological properties mark their specific differences. In order 
that the differential importance of the biological and etiolog- 
ical properties of these bacteria may not be overlooked in the 
subsequent consideration of the specific character of their 
flagella, a brief summary of the more important of these prop- 
erties for each of the germs in question, is appended : 
(a). Bacillus choleric suis is a small actively motile germ which 
is found in the organs of swine suffering from hog cholera. It The Character of the Flagella 
345 
has not been found outside of the diseased animal body (or its immedi- 
ate surroundings). It is fatal to experimental animals when injected 
beneath the skin in small numbers. In larger doses it will produce the 
disease in swine. It ferments glucose with the formation of gas. It 
does not coagulate the casein in milk. 
(b). Bacillus typhi abdominalis is slightly larger than the bacil- 
lus of hog cholera and not so uniformly actively motile. It is found 
in the intestines and organs of people suffering from typhoid fever and 
is generally accepted to be its cause. Like the hog cholera bacillus, its 
natural habitat outside of the diseased body is not known. It is not fa- 
tal to experimental animals when they are inoculated with moderate 
doses. It does not ferment glucose with the formation of gas*. It does 
not coagulate the casein in milk. 
(f). The Bacillus coli communis is a very feeble or more actively 
motile bacillus varying somewhat in size but usually about as large as 
the typhoid bacillus. It is found in the healthy intestines of both man 
and the lower animals. It does not appear to live in nature outside of 
the animal body. It is Jatal to rabbits when they are inoculated with 
large doses of the pure culture. It ferments glucose with the forma- 
tion of gas and coagulates the casein in milk. 
Another very important feature in the study of the relation, 
from a differential standpoint, that exists between the bio- 
logical properties and the character of the flagella of these 
bacteria, is the fact, which is verified by many observations, 
that these organisms exist in nature (f. e., the coli in the 
healthy intestines, and the hog cholera and typhoid bacteria in 
the organs of the victims of their respective diseases), in vari- 
ously modified forms in which the differences (biological and 
pathogenic) which separate the more typical species are very 
much diminished. This variation, especially in the patho- 
genic properties of the typhoid and colon bacteria, has given 
rise to a theory, advanced by Rodet and Roux16, that the 
typhoid germ is a modified form of the colon bacillus. In 
the investigation of animal diseases, hog cholera and colon 
bacteria have been found which varied in size and in their bi- 
ological and pathogenic properties to a marked degree from 
* The fact that the typhoid bacillus would not ferment glucose with the formation 
of gas, was first pointed out by Dr. Theobald Smith in 1890. {Centralblatt f. Baktevio- 
logie u. Parasitenkunde VII, 1890. p. 502). 346 
Ver anus Alva Moore 
the more typical forms of these species.* This would indi- 
cate that the evolutionary theory of Rodet and Roux is as 
applicable to the hog cholera germ as it is to the typhoid 
bacillus. Although the development of these specific patho- 
genic bacteria from a common intestinal germ is improbable, 
yet the possibility can not be gainsaid and the importance 
which this theory has in its bearing upon public health, as 
well as in its relation to pure bacteriology, renders its demon- 
stration of much interest. This, and many other interesting 
problems connected with the specific limitations of these bac- 
teria, emphasize the importance of determining as far as 
possible the extent to which their flagella may be deemed of 
differential value. In my efforts to do this, I have considered 
the flagella not only of the more typical species but also of a 
considerable number of modified forms (excepting the typhoid 
bacillus) of these bacteria. From these investigations, I have 
found their flagella to be much more constant than their bio- 
logical properties, but contrary to Luksch, I have not found 
them to be of specific differential importance. The evidence 
to support this conclusion is found in the subsequent descrip- 
tion of the character of the flagella. 
I have limited myself to a consideration of a very few of the 
many interesting questions which have presented themselves 
in the study of the flagella of these bacteria. A large amount 
of experimental work was necessary before a satisfactory 
method for their demonstration could be formulated. This 
being accomplished the specific objects which I endeavored 
to attain are : 
i. To complete as far as possible our knowledge of the mor- 
phology of each of these organisms. 
*In a communication to the Biological section of the American 
Association for the advancement of Science, in 1890 {New York Med. 
Journal LU (1890) p. 485). Dr. Theobald Smith described a hog cholera 
bacillus which was, " in every way nearer the saprophytic forms (coli) 
than the germ usually found in epizootics of that disease." I have 
found similar variations in the colon bacteria isolated from variously 
diseased organs of different animals. In an outbreak of swine disease 
in 1892, I isolated several colon bacteria which approached in their bio- 
logical characters very closely to the hog cholera organism. The Character oj the Flagella 
347 
2. To determine whether or not there is a difference in the 
number or character of the flagella of the modified forms of 
these bacteria corresponding with the variations that are found 
to exist in their physiological and etiological manifestations. 
3. To determine the significance of the flagella in classifying 
motile bacteria, as illustrated by a comparative study of these 
filaments on three typical species, representing morphol- 
ogically three closely allied groups*, and biologically three 
distinct groups, of bacteria. 
It was my opinion in 1891 that there was a well marked 
specific difference in the flagella of these species, but more ex- 
tended investigations have caused me to recede somewhat from 
that opinion and to call attention at this time, in accordance 
with the results of my observations, to the similarity which 
exists between them. 
method for staining the feageeea. 
The difficulties which have been experienced in the demon- 
stration of the flagella both by myself and others, necessitate 
a somewhat careful consideration of the method which has 
been followed in obtaining the results herein recorded. As I 
have been unable to detect the flagella on living bacteria, my 
descriptions apply to stained preparations only. With the ex- 
ception of certain modifications, Loeffler's method has been 
followed. The advantages that are claimed for the modified 
method over the original process are : (i) the preparations are 
more uniformly free from a deeply stained background which 
conceals entirely or renders indistinct the individual filaments ; 
(2) there is a better distribution of bacteria on the cover-glass ; 
(3) the application is more simple and the results more trust- 
worthy. The majority of the changes which I have made 
were fully described in a previous article13. The others are 
incorporated here. The method as I have used it, is as follows : 
the principle that is involved in staining the flagella is 
simply the one employed in the use of a mordant or fixative. 
The methods which have been at all successful (beyond the 
experience of the originator) in staining the flagella require a 
* Group is here taken in a narrow sense, signifying a species and its 
varieties only. 348 
Veranus Alva Moore 
mordant which contains tannic acid. The other elements 
have varied. The technique of the method therefore consists 
in treating the cover glass preparations of the bacteria with a 
mordant prior to, or together* with, the application of the 
staining fluid. 
The mordant :f 
A 20 per cent, solution of tannic acid 10 cc. 
A cold saturated solution of sulphate of iron 5 cc. 
A saturated alcoholic solution of fuchsin 1 cc. 
If possible chemically pure tannic acid should be used. 
This mordant can be used in staining the flagella of these 
three species of bacteria, but slightly better results appear to 
be obtained with the typhoid and colon bacteria when a few 
drops of a 10 per cent, solution of sulphuric or acetic acid are 
added. With the hog cholera bacteria a mordant containing 
a 10 per cent, solution of tannic acid gave equally good results. 
The staining fluid For this I have used carbol fuchsin 
prepared after Ziehl's formula. 
*1 have found, since the greater part of the work on this article was 
completed, that certain staining fluids (alcoholic solutions) could be 
mixed with the mordant thus eliminating their subsequent application. I 
have not perfected the formula for this combination but have obtained 
excellent results with a fluid composed of a 20 per cent, solution of 
tannic acid 2 cc., saturated solution of sulphate of iron 1 cc., and a sat- 
urated alcoholic solution of fuchsin 1 cc.. filter and apply in the same 
manner as the mordant, but for a much longer time. 
tThis is Loeffler's standard or neutral mordant. It is successfully 
employed in staining the flagella on many motile bacteria. The 
addition of a few drops of a 10 per cent, solution of sulphuric acid or a 
similar quantity of a 1 per cent, solution of sodium hydrate appears to 
give better results, if indeed it is not absolutely necessary, with certain 
other species. My personal experience tends to prove that no sharp 
and fixed lines can be determined for the preparation of a universal 
mordant. I have been unable, however, to stain a single flagellum by 
the use of a mordant not containing tannic acid, although I have tried 
nearly all of the known "fixatives." As I have stated elsewhere13 a 
weaker solution of tannic acid can sometimes be used with advantage. 
J I have stained the flagella with nearly all of the basic aniline dyes 
ordinarily used in bacteriological work. The carbol fuchsin gives a 
deeper stain and consequently a clearer definition of the filaments is 
obtained. The Character of the Flagella 
349 
Fuchsin i gram 
Absolute alcohol io cc. 
A 5 per cent, solution of carbolic acid 100 cc. 
The fuchsin is dissolved in the alcohol, after which the acid 
solution is added. 
The cover-glass preparations: The cover-glasses must be 
perfectly clean. The desired number of cover-glasses are 
then arranged on a level tray. A large drop of ■warm water 
(distilled or hydrant) is placed upon each cover-glass by 
means of a sterile pipette. If the cover-glass is properly 
cleaned * the drop of water will spread over its entire surface. 
The point of a cooled, flamed platinum wire is very gently 
touched to the surface growth of the germ on agar or gelatine 
and carefully immersed in the water near the center of the 
cover-glass. A sufficient number of bacteria will adhere to 
the wire to make from six to ten preparations. The tray with 
the cover-glasses is then placed in an incubator at a tempera- 
ture of about 36° C. until the water is evaporated. Many of 
the bacteria on account of their power of locomotion, and by 
means of the currents produced in the liquid during its evap- 
oration, will be found, in the dried preparations, to be isolated 
from the clumps of bacteria that were introduced with the 
wire and distributed very evenly over a large portion of the 
surface of the cover-glass. This natural distribution prevents, 
to a marked extent, the breaking off of the flagella which 
occurs when the distribution is made by mechanical means 
in a smaller quantity of the diluent. If the water to be used 
* Weber {Fortschritte der Medicin Bd. XI. (1893), p. 49) has found 
that when the percentage of calcium is too small in proportion to the 
alkalies (sodium and potassium) in the composition of the glass, the 
atmosphere will produce a chemical change in the glass which gives its 
surface a peculiar moist condition. This may explain to some extent 
the cause of the deeply stained background where the proper precau- 
tions were taken to prepare the cover-glasses. I have frequently no- 
ticed that in the use of cover-glasses that had been cleaned and ex- 
posed to the atmosphere for a considerable time prior to their use, the 
water would " roll up " in drops, as though the surface was covered with 
a film of oil, and when stained they would invariably exhibit a deeply 
stained background. 350 
Ver anus Alva Moore 
on the cover-glasses is heated to a temperature of about 
40-450 C. and the preparations placed at once in the incubator, 
the bacteria are more evenly distributed. 
After the preparations have dried the bacteria are fixed to 
the cover-glass by heat. This can be accomplished either by 
passing them, film upward, twice through the flame of a spirit 
lamp or Bunsen burner, or by heating them from I2o°-i4o° C. 
for from five to ten minutes in a hot air chamber. The latter 
is to be recommended when facilities will permit. 
The application of the mordant and staining fluid: In ap- 
plying the mordalit the preparations are completely im- 
mersed in the fluid. In place of a watch glass as formerly 
recommended, I have used a large (one inch) test tube for 
this purpose. From three to four c. c. of the mordant is placed 
in the tube into which the cooled, heated cover-glass prepara- 
tion is dropped. The tube is held over a flame until steam is 
given off when it is removed. The mordant should be fre- 
quently agitated by gently shaking the tube. After from five 
to ten minutes the cover-glass is removed by the use of a wire 
hook on the end of a glass rod and with a pair of fine forceps. 
The cover is thoroughly rinsed in clean water, or better, in a 
stream from a spigot or wash bottle. If there is a grayish 
film on the preparation it can usually be removed by rinsing it 
in strong alcohol and again in water. 
The staining fluid is applied in a test tube in precisely the 
same manner as the mordant. It is allowed to act for from 
one to three minutes. 
The mordant should be fresh and always filtered before it is 
used. The carbol fuchsin can be kept in stock solution for a 
considerable time. The success of the operation depends 
very largely upon the care with which it is performed. The 
method as described gives excellent results with the three 
species of bacteria under consideration, and it has been suc- 
cessfully applied to a few others.* 
*In the application of the method to other bacteria whose flagella 
will not stain by the use of a neutral solution, trials must be made with 
acid and alkaline mordants, and possibly with mordants containing 
different quantities of tannic acid, until a successful combination is 
found. The Character of the Flagella 
351 
Cultures used: In this work, agar cultures have been em- 
ployed. Unfortunately the staining method is not so appli- 
cable to preparations of bacteria from bouillon cultures on 
account of the presence of organic substances in the bouillon, 
which form a deeply stained back ground. I have, however, 
succeeded in making a few quite satisfactory preparations from 
these cultures. Gelatin and potato can be used, but with our 
present methods the surface of inclined agar appears to be the 
most satisfactory sub-stratum upon which to grow the bacteria 
for this purpose. 
A DESCRIPTION OF THE COMMON AND MORE SPECIFIC CHARACTERS OF 
THE FLAGELLA ON THE BACILLUS CHOLERA SUIS, B. COLI COMMUNIS, 
AND B. TYPHI ABDOMINALIS. 
In stained preparations for the exhibition of the flagella on 
these bacteria, there are so many variations and exceptions to 
what might be termed a typical presentation of the body of 
the germ and its motile appendages, that at present, a formula 
for their description can not well be written. In order to 
avoid repetition I shall first describe in a general way, such 
characters of the flagella as are common to the three species.* 
The staining process necessary to bring out the flagella 
increases to a slight extent the size of the body of the germs. 
This is probably due either to the staining of a " capsular " 
substance which may surround the bacteria, and which is not 
brought out by the ordinary staining methods, or to the swell- 
ing of the cellular substance on account of the action of the 
mordant.f 
* Iii this discussion the well-known morphological characters (size 
and form) of these bacteria are omitted. The rod-shaped forms will be 
spoken of as the body of the germ wherever it is necessary to distin- 
guish between it and the flagella. The terms motile appendages, and 
filaments are used synonymously with flagella. 
f Zettnow14 holds with Klebs and Biitschli, that the part of the germ 
which is easily brought out by the ordinary staining methods is the 
nucleus only, and that the additional part which is demonstrated by the 
use of Loeffler's method is a plasma which surrounds the nucleus. 
Wahrlich (Article reviewed in Centralblatt f. Bakteriologie u. Par- 
asitenkunde XI, (1892) p. 49) found two substances in bacteria cells, (1) 
the basis, a substance which gave the micro-chemical reaction of linen, 
and (2) a chromatine substance or nucleus which is contained within 
the meshes of the basis. 352 
Ver anus Alva Moore 
In the microscopical examination of well-executed prepara- 
tions for exhibiting the flagella three conditions have been 
universally observed: (i) In certain fields there were a 
greater or less number of bacteria which exhibited no flagella; 
(2) there were a considerable number of detatched or free fla- 
gella lying between the bacteria ; and (3) the numbers of fla- 
gella on the different bacilli were not constant. On the other 
hand, however, fields could be selected in which there were no 
detatched filaments and where every germ was provided with 
motile appendages. 
The flagella appear as hair-like appendages or filaments, 
which radiate from the bacteria. They are given off from the 
cell wall of the germs of which they appear to be continua- 
tions or projections. This can be clearly shown by their re- 
action to the following staining fluid. If to 3 c. c. of the mor- 
dant 1 c. c. of a saturated alcoholic solution of fuchsin is added 
and the preparation treated in the usual way with this solu- 
tion for about five minutes, the flagella and periphery of the 
bacteria will be stained with equal intensity, while the central 
portion of the cells will remain unstained. By allowing the 
reagent to act for a much longer time or by applying the usu- 
al stain, the entire organism will become deeply tinted. This 
would indicate that the cell wall and flagella were alike in 
their composition, or at least in their reaction to a certain 
staining fluid, and that the contents or nucleus was different. 
The sharp outlines of the flagella as observed in stained prepa- 
rations, would indicate that they are organized elements. I 
have been unable to make out any differentiation of their 
structure. 
The appearance of shorter and longer free flagella and the dif- 
ference in the length of those still attached to the body of the 
germs is due apparently to their detachment and breaking dur- 
ing the separation of the individual bacteria from the closely 
packed masses in which they grow on solid media. In these 
cultures the long filaments on the different individuals ap- 
pear to become entangled with each other, causing the 
separation of the bacteria to be accomplished with difficulty 
and presumably with more or less injury to their organs of The Character of the Flagella 
353 
locomotion. This is suggested by watching the clumps of 
bacteria in a hanging-drop preparation. The germs at the 
edge of these masses, when about to separate themselves from 
the others, exhibit first a trembling motion, then a jerking, 
reeling and pitching movement, until finally they are free * 
and move across the field. 
Furthermore, in the examination of a hanging drop prepa- 
ration made from a bouillon culture the bacteria are observed 
to move much closer to each other than the length of their 
flagella, and it seems highly probable that detachment or 
breaking of the appendages is produced during these volun- 
tary movements, by their contact and possible entanglement 
with each other. Free flagella have been found to be numer- 
ous in stained preparations made from liquid cultures. For 
the ultimate settlement of these questions a method must be 
devised by which the motile appendages can be observed on 
the living and moving germs. At present we are forced to be 
content with the study of the appearances that are presented 
in stained specimens, presuming that as the conditions of 
preparation are the same the characters that are revealed will 
be correspondingly similar in the different species. 
The length of the flagella as seen in stained preparations 
varies to a marked degree. The longest I have measured wms 
18 p or about nine times the length of the body of the 
bacillus (hog cholera). 
The diameter of the flagella varies in different preparations 
and frequently in the same specimens, to a marked degree. 
In a deeply stained preparation they are occasionally 0.4 p 
in diameter, or about one-third of the diameter of the body of 
the germ. More commonly they are about o. 2 p in diameter, 
or about one-sixth the thickness of the organism. Again they 
may appear as extremely delicate lines, so fine that it is with 
difficulty that they can be seen at all. Usually, however, 
they are about 0.2 p in diameter. The unexpected appear- 
ance of these variations has thus far baffled an explanation, 
* It is an observable fact that the character of the movement of the 
individual germs is somewhat varied. This may be due to the loss of 
certain of their motile appendages. 354 
Veranus Alva Moore 
although many series of preparations have been carefully 
made to discover the cause. I believe, however, that the fail- 
ure is due to the technique rather than to a variation in the 
filaments. The diameter of the flagella is appreciably the 
same at the distal end as at the union with the body of the 
germ. Occasionally, however, the distal portion appears to 
be very slightly tapering. 
Among the free flagella is sometimes observed what appears 
to be a strand or bunch of twisted filaments, varying from one 
to two p. in width, which presents a uniformly, deeply stained 
appearance. At one or both ends the filaments are separated 
from each other, giving the appearance of the frayed end of a 
cord. In preparations from old cultures several flagella which 
radiate from the same point are frequently observed. They 
present the appearance of the filaments of a single germ. 
These are occasionally observed in preparations from young 
cultures. 
Frequently a flagellum will present throughout the greater 
part of its length a very close, wavy condition. There are in 
addition to these many other anomalous appearances which 
have as yet no clearly defined significance. 
In the study and comparison of the flagella, I have em- 
ployed cultures varying in age from sixteen hours to three 
days. There appeared to be no difference in the character of 
the flagella on the bacteria in cultures of these ages, but in 
preparations made from those of a longer growth there was 
usually a much larger number of broken and detached fila- 
ments. 
The exact arrangement of the flagella on the body of the 
germ is hard to determine. In stained preparations the or- 
ganisms are dried to the cover-glass with the filaments in such 
positions that they seem to radiate from the outer edges of the 
germs as they appear in the stained specimen. Frequently 
they all appear to come from a very small arc on the circum- 
ference. This is undoubtedly due to our inability to detect 
the filaments as they cross the body of the germ. The fla- 
gella are given off from both extremities, and at variable 
points along the intervening portion of the body of the germ, The Character of the Flagella 
355 
although a single bacillus which exhibits this uniform radia- 
tion of motile appendages is rarely observed in stained prepa- 
rations. The flagella are usually more or less wavy, and it is 
the rule, though it has many exceptions, that the waves in a 
single flagellum are uniform. 
I have studied very carefully the flagella on several hog 
cholera bacteria. These were obtained from different sources 
(outbreaks of hog cholera) and a few of them exhibited slight 
variations in their biological characters and more marked dif- 
ference in their virulence. So great have been these varia- 
tions in a few cases that the bacteria have been deemed modi- 
fied forms. I have also studied a larger number (about 20) of 
colon bacteria isolated from variously diseased organs of differ- 
ent animals and from the human intestine. These have also 
shown a marked difference in their properties. The twro cul- 
tures more specifically described represent (1) the more typical 
form (2) a somewhat modified form. Of the typhoid bacteria, 
only two cultures have been at my disposal. All of these 
bacteria have been carefully studied and their identification 
clearly established. In these examinations I have been un- 
able to detect any constant, specific difference in the character 
of the flagella on the germs from the different cultures of the 
same species. On this account bacteria from only two cultures 
of each species will be considered in the more specific descrip- 
tion of the flagella. 
The flagella on Bacillus cholera suis. (Plate 1, Fig. 1.) 
(1) A culture of hog cholera bacteria which was obtained from 
a pig that died in an outbreak of hog cholera in the State of 
Illinois in the fall of 1891. An examination of the bacteria in 
a hanging drop preparation showed them to be universally 
actively motile. They were virulent. 
The number of flagella on the different germs, as observed 
in the stained preparations, was variable. The most usual 
number was from two to five. A few germs have been found 
upon which nine filaments could be counted, but it is the ex- 
ception to find more than eight. Frequently the filaments are 
bent upon themselves in such a way that it is very difficult to 
determine the exact number, especially when it is large. In 356 
Ver anus Alva Moore 
a few instances I have thought it possible for as many as 
twelve filaments to be present. In order to estimate the most 
usual number an actual count of the flagella on a large num- 
ber of germs was made. These were taken from somewhat 
ideal fields on a considerable number of preparations. In 
these fields there were from 2 to io bacteria which were well 
separated * from each other and on each of which all of the 
flagella could be counted ; that is, there were no clumps of 
bacteria present. Care was always taken to avoid extreme 
conditions. 
Of these the number of flagella on two hundred individual 
germs was as follows, 12 had no flagella, 23 had one, 30 had 
tw'O, 47 had three, 39 had four, 22 had five, 12 had six, 8 had 
seven, 5 had eight and 2 had nine. In many of the fields 
there were no free filaments, while in others there was a vari- 
able number. 
The longest flagellum that I measured was i8/x.f The 
usual length was from 7 to 12 p.. Shorter ones were quite 
common. Occasionally the ends of the filaments were curved 
into nearly or quite perfect circles or rings with a diameter of 
about 1.5 p.. These were not uniformly present but in occa- 
sional preparations they were quite conspicuous. 
(2) A culture obtained from an outbreak of hog cholera in 
the State of Maryland. A microscopical examination of a 
hanging drop preparation showed the bacteria to be actively 
motile. They were less virulent than those in the previous 
culture. Cover-glass preparations treated and stained as in 
the preceding case revealed no appreciable difference in their 
staining properties, the number, arrangement, and character 
*This is very important, for the tendency of the bacteria to be 
united in twos or small clumps which might easily be mistaken for a 
single germ is very marked, and the flagella which belong to two germs 
could be readily considered as those of a single individual. This is 
especially true where the bacilli are united end to end. 
t In measuring the length of the flagella the distance from the body 
of the germ to the distal end of the filament along its general course 
was taken, without allowance for the minute curves or waves which 
would in some instances, if considered, add an appreciable amount to 
the recorded length. The Character of the Flagella 
357 
of their flagella. To complete the comparison the number of 
flagella on 200 germs is recorded. Of these, 10 had no 
flagella, 33 had one, 33 had two, 45 had three, 38 had four, 19 
had five, 6 had six, 8 had seven, 6 had eight; and 2 had nine. 
The longest flagellum observed measured 11 The usual 
(about 75 per cent.) length was from 6 to 8/x. The small 
circles at the distal ends were also present but in small num- 
bers. 
Flagella on Bacilhis coli comm/unis. (Plate 1, Fig. 2). A 
culture of the bacillus coli communis, obtained by Dr. Theo- 
bald Smith from the human intestine. A microscopical ex- 
amination of a hanging drop preparation from an agar culture 
of this species showed comparatively few of the germs to be in 
motion. Upon watching it carefully for several minutes, 
many of the individual germs which were first at rest ex- 
hibited an active motility. 
The diameter and arrangement of the flagella on this species 
do not differ to any appreciable degree from those on the hog 
cholera bacteria. The number of filaments on the individual 
germs varied considerably. Seven was the maximum number 
found on a single organism. As before, an actual count of 
the flagella on 200 individual germs selected from representa- 
tive fields was made. Of these, 9 exhibited no motile ap- 
pendages, 33 had one, 58 had two, 44 had three, 34 had four, 
15 had five, 4 had six and 3 had seven. The number of the 
free flagella in many of the fields averaged about one to each 
germ. This is unimportant as in other parts of the prepara- 
tions the number was greater and in still others less. The 
length of the filaments varied from 2 to 12 p. The greatest 
number (66 per cent, of a large number measured) were from 
5 to 7 p. It is of interest to note that the number of individual 
bacteria which exhibited no flagella was no larger in this 
species than in the preparations of the hog cholera bacteria 
where apparently every germ was actively motile. A very 
few of the flagella formed nearly or quite perfect circles or 
rings at their distal ends. Their existence, even in small 
numbers eliminates their specific value when compared with 
hog cholera and typhoid bacteria. 358 
Veranus Alva Moore 
(2). A culture Bacillus coli communis obtained from the 
pectoral muscle of a pig which died in an outbreak of swine 
disease in 1892. The motility of the bacteria in this culture 
was less marked than in those from the previous culture. 
The flagella extended out from the body of the bacteria in 
delicate, more or less wavy filaments. In diameter, course, 
and general appearance they differed in no perceptible manner 
from the flagella on the previously described germ. The 
maximum number of filaments that was found on an indi- 
vidual was one less than in the previous case, and the num- 
ber which possessed but one flagellum was proportionally 
larger. The number of detached filaments was not in excess 
of those in the preparations of the colon bacteria from the 
human intestine. In order to arrive at a more accurate com- 
parison, the flagella on 200 individual bacteria from selected 
fields were counted. Of these, 11 showed no flagella, 83 had 
one, 55 had two, 29 had three, 13 had four, 6 had five, and 3 
had six. The maximum length of the filaments measured 
was 15 p.. The length of the greatest number varied from 5 
to 9 p. 
Flagella on Bacillus typhi abdominalis.-(Plate I, Fig. 3). 
For my cultures of typhoid bacilli I am indebted to Dr. Theo- 
bald Smith. These cultures were from two to four years 
old. Unfortunately I have no knowledge of the history 
of these cultures prior to their arrival in our laboratory. 
(1) A culture obtained from the Johns Hopkins Hospital, 
Baltimore, Md. When examined in a fresh condition (hang- 
ing drop) the majority of the bacilli were observed to be in 
active motion. 
The arrangement of their flagella was not perceptibly dif- 
ferent from those on the hog cholera and colon bacteria. In 
the examination of different preparations of this bacillus a 
considerable variation was found to exist in the appearance of 
its flagella. A certain number of the bacilli were provided 
with long, nearly straight or wavy filaments which extended 
in various directions from the body of the germs, while the 
motile appendages on the greater number of the organisms 
were shorter, more curved, and intertwining, presenting a The Character of the Flagella 
359 
somewhat bushy appearance about the body of the germs. 
In many specimens there was an exceedingly large number of 
flagella which were bent at their distal ends, if attached to 
the germ, into nearly or quite perfect circles or rings varying 
from 1.2 to 2 in diameter, while other filaments were curved 
to such an extent that the free ends passed either above or 
below the body of the germ. In many preparations I have 
found fields in which one or more of the filaments on nearly 
every germ exhibited these circles or rings. Their formation 
is somewhat curious and their significance is as yet specula- 
tive. Frequently many of the "rings" are broken from the 
flagella. The filaments were usuallly bent at right angles to 
their course at the point where the curve begins. This gave 
them the appearance of the ends of certain screw hooks. 
Less frequently the rings were formed by the distal part of 
the filaments bending to one side, forming perfect or nearly 
complete circles. In some preparations a considerable num- 
ber of bacilli were observed around which were from one to 
four rings or inbending filaments with few, if any, extended 
flagella. The terminal rings and incurved flagella on the 
typhoid bacilli were very marked, but their differential value 
is destroyed by the fact that they occasionally appeared in 
preparations of the other bacteria. 
The detached filaments vary in number, as in the case of 
the previously described organisms. The number of flagella 
on the individual germs also varied ; ten was the maximum 
number that I was able positively to determine on a single 
germ ; Luksch found twelve ; and according to Sternberg20, 
Babes found as many as twenty on a single germ. In the 
photographs of typhoid bacillus published by Fraenkel and 
Pfeiffer21, and Migula22, showing their flagella, ten is the 
largest number positively represented as belonging to a single 
germ. In these photographs, clumps and pairs of bacilli 
show a much larger number. A count of the flagella on 200 
germs in well selected fields showed 9 bacilli to be without 
motile appendages, 23 had one, 39 had two, 45 had three, 27 
had four, 15 had five, 23 had six, n had seven, 3 had eight, 
3 had nine, and 2 had ten. The length of the filaments 360 
Ver anus Alva Moore 
varied considerably. The maximum length of those meas- 
ured was 11 /x ; 78 per cent, of a large number that were 
measured varied in length from 3 to 6 p. 
(2). A culture which was obtained from Koch's Laboratory 
(Germany). The bacteria were not quite so actively motile 
as the hog cholera germs. They stained readily and the fla- 
gella differed in no appreciable manner from those on the bac- 
teria from culture (1). There were a large number of short 
flagella and rings. The number of flagella on the individual 
germs was estimated in the manner heretofore described. 
Seventeen of the 200 germs exhibited no flagella, 43 had one, 
42 had two, 45 had three, 24 had four, 18 had five, 5 had six, 
3 had seven, and 3 had eight. It is possible that a few bacte- 
ria had nine filaments each, but there was a doubt as to the 
exactness of the count. The longest filament measured was 
13 p. A large majority of those measured varied from 3 to 7 
P in length. 
From the detailed descriptions of the flagella on these three 
species of bacteria a few comparisons may be made. These 
can be stated best in tabulated form : 
A COMPARISON OF THE NUMBER OF FLAGELLA ON THE INDIVIDUAL 
GERMS. 
Bacillus. 
Cul- 
ture 
The Number of Flagella. 
Total 
number of 
bacteria. 
Average 
number of 
flagella on 
each germ 
0 
1 
2 
3 
4 
5 
6 
7 
8 
9 
Cholerae suis . 
(I) 
12 
23 
30 
47 
39 
22 
12 
8 
5 
2 
200 
3-3 
<< u 
(2) 
IO 
33 
33 
45 
3« 
19 
6 
8 
6 
2 
200 
3-1 
Coli communis 
(I) 
9 
33 
5« 
44 
34 
15 
4 
3 
200 
2.6 
a it 
(2) 
11 
83 
55 
29 
'3 
6 
3 
(■•) 
200 
1.8 
Typhi abdomi- 
nalis .... 
(I) 
9 
23 
39 
45 
-7 
i5 
23 
11 
3 
3 
200 
3-5 
(( K 
(2) 
17 
43 
42 
45 
24 
18 
5 
3 
3 
3 
200 
2.6 
In comparing the figures in the tables the fact should 
be kept clearly in mind that they have only a relative 
significance. The large number of preparations examined 
and the number of counts and measurements made give them, The Character of the Flagella 
361 
A COMPARISON OF THF LENGTH, DIAMETER AND CHARACTER OF THE 
FLAGELLA. 
Bacillus. 
Cul- 
ture 
Length of 
longest 
fllagellum. 
Lgth. of 
70 per ct 
or more 
of the 
flagella. 
Usual 
diame- 
ter of 
flagella. 
Appearance of flagella. 
Cholerae suis 
(I) 
18 /z 
7-12 /z 
0.1-0.2/z 
Usually extended, wavy, 
cc cc 
(2) 
ii n 
6-8 /z 
O.I-O.2/Z 
few terminal rings, 
cc cc CC 
Coli communis 
(I) 
12 /z 
5-7 /< 
0.1-0.2/z 
cc cc c c 
4 4 CC 
(2) 
15 A 
5-9 H 
0.1-0.2 ii 
CC CC CC 
Typhi-abdom- 
inalis . . . 
(I) 
II /z 
3-6 /z 
0.1-0.2/z 
Many incurved, wavy, 
c c cc 
(2) 
13 P- 
3-7 A 
0.1-0.2 /z 
large number of ter- 
minal rings. 
CC cc cc 
however, a good representative value. To illustrate this 
point and to show how easily different results could be ob- 
tained, especially in reference to the number of flagella, by 
considering a smaller or possibly larger number of bacteria, I 
have appended the results of the count of the flagella of 200 
individual germs. Here also a further difference of opinion 
as to the fields to be selected might vary the final result. My 
counts in this case were made from eight preparations. 
Bacillus 
Number 
of fields 
Number of Plagella. 
number 
of 
:teria. 
number 
?teria in 
field. 
Choeerae Suis. 
examined. 
5 
U M 
0123456789 
0 
<! 0 
Preparation I. 
5 
3628712 
32 
6.4 
" II. 
4 
2157524x21 
30 
7-5 
" III. 
6 
1 12 10 613131 
29 
4.8 
" IV. 
3 
22181 
14 
4.6 
" V. 
8 
2686551 
35 
4-3 
" VI. 
7 
23264111 
20 
2.8 
" VII. 
3 
1 5 3 7 7 3 1 
27 
9 
" VIII. 
2 
22213321 
15 
7-5 
122330473922 12 8 5 2 
200 
In comparing the specific characters of the flagella of the 
three species, it will be observed that while there are manifest 362 
Ver anus Alva Moore 
differences there are likewise striking resemblances. A few 
of the more important facts which have been brought out in 
this study to illustrate their differences and similarities are 
appended. 
Their difference is shown from the observation, (1) that the 
length of the greater number of the flagella is greatest on the 
hog cholera and least on the typhoid bacilli, while those of 
the colon bacteria are of intermediate length ; (2), that the 
average number of flagella on the colon bacteria is less than 
that on either of the other species ; and (3), that the terminal 
and free rings are much more numerous in the preparations of 
the typhoid bacillus than in those of the other bacteria. This 
is also true of the incurving flagella. 
Their similarity is illustrated by the fact (1), that the num- 
bers of flagella on the individual bacteria vary in the different 
fields in the preparations from the same species as much as in 
those from different species, excepting in the maximum num- 
bers ; this is also true of the length of the flagella ; (2), that 
the diameter of the flagella on the three species is identical; 
(3), that the position of the flagella on the body of the germ 
is the same ; and (4), that fields could be selected in prepara- 
tions from the three species in which no difference could be 
detected in the character of the flagella. 
CONCLUSIONS. 
The foregoing examinations and the results of a careful 
comparative study of the flagella of these three species of 
bacteria appear to sustain the following conclusions : 
i. These three species of bacteria belong to the Peritricha 
(Messea). 
2. There are apparently slight differences in their flagella, 
but the differences are not marked enough to be deemed of 
differential value. This is evidenced by the fact that the 
flagella in different preparations from the same species exhibit 
quite as marked variations. 
3. There is no difference in the flagella of modified forms of 
the same species to correspond with the difference in their 
physiological and etiological manifestations. The Character of the Flagella 
363 
4. Until further facts are determined, the character of the 
flagella will not furnish a means for specific differentia- 
tion. The species and varieties must be determined by their 
physiological and pathogenic properties while the genera may 
be fixed by the character of the flagella. 
5. The proposition that the Bacillus typhi abdominalis is a 
modified form of Bacillus coli communis cannot be justly 
refuted on their morphological characters. The similarity in 
the structure (as it is now understood) of these bacteria in- 
creases the importance, from a differential standpoint, of the 
differences found to exist in their biological and etiological 
manifestations. 
Washington, D. C., 
July 31, 1893. literature. 
i. Cohn, F. Untersuchungen iiber Bacterien. Beitrage zur Bio- 
logic der Pflanzen, Bd. I (1872), S. 126. 
2. Dallinger, W. H., and Drysdale, J. J. On the existence of fla- 
gella in Bacterium termo. The Monthly Microscopical Journal, (Lon- 
don), vol. XIV (1875), p. 105. 
3. Koch, Robert. Untersuchungen iiber Bacterien. Beitrage zur 
Biologie der Pflanzen, Bd. II (1877), S. 416. 
4. Dallinger, W. H. On the measurement of the diameter of the 
flagella of Bacterium termo. Jour, oj the Royal Mic. Society, vol. 1, 
(1878), p. 169. 
5. Neuhauss, R. Ueber die Geisseln an den Bacillen der Asiati- 
schen Cholera. Centralblatt f. Bakteriologie u. Parasitenkunde, Bd. 
V, (1889), S. 81. 
6. Loeffler, F. Ein neue Methode zum Farben der Mikroorganismen 
im besonderen ihren Wimperhare und Geisseln. Centralblatt f. Bak- 
teriologie u. Parasitenkunde, Bd. VI, (1889), S. 209. 
7. Trenkmann, Dr. Die Farbung der Geisseln von Spirillen und 
Bacillen. Ibid., Bd., (1889), S. 433. 
8. Messea, A. Contribuzione allo studio delle ciglia dei batterii e pro- 
posta di una classificazione. Rivista d'igiene e sanita publica, No. 14, 
(1889), p. 513. 
9. Loeffler, F. Weitere Untersuchungen iiber die Beizung und Far- 
bung der Geisseln bei den Bakterien. Centralblatt f. Bakteriologie u. 
Parasitenkunde, Bd. VII, (1890), S. 625. 
10. Trenkmann, Dr. Die Farbung der Geisseln von Spirillen und 
Bacillen. Ibid., Bd. VIII, (1890), S. 385. 
11. Dowdeswell, G. F. Note surles flagella du microbe du choldra. 
Annales de Micrographie, T. II, (1890), p. 377. 
12. Moore, V. A. A review of the methods of demonstrating the 
flagella on motile bacteria, with special reference to the staining pro- 
cesses. American Monthly Microscopical Journal, vol XII, (1891), p. 
15- 
13. Moore, V. A. Observations on staining the flagella on motile 
bacteria. Proceedings of the Am. Soc. of Microscopists, (1891), p. 86. 
14. Zettnow, E. Ueber den Bau der Bakterien. Centralblatt f. Bak- 
teriologie u. Parasitenkunde, Bd. X, (1891), S. 6. 
15. Luksch, L. Zur Differenzialdiagnose des Bacillus typhi abdomi- 
nalis (Eberth), und des Bacterium coli communis (Escherich). Cen- 
tralblatt f. Bakteriologie u. Parasitenkunde, Bd. XII, (1892) S. 427. The Character of the Flagella 
365 
i6. Rodet, A., et Roux, G. Bacille d'Eberth et bacillus coli. Experi- 
ences comparatives sur quelques effets pathogenes. Archives de med. 
Experimentale, T. IV. No. 3, (1892), p. 317. 
17. Straus, I. Sur un proc€de de coloration, a 1'dtat vivant des cils 
ou flagella de certaines bacteries mobiles. Comp. Rend. Societe de 
Biologic, T. IV, (1892), No. 23. p. 542. 
18. Tavel, E. Caracteres difKrentiels du bacterium coli commune et 
du bacille typhique. La Semaine Med. T, No. 8, (1892), p. 52. 
19. Brown, A. P. Stdining bacteria to demonstrate their flagella. 
The Observer, vol. Ill, (1892), p. 298. 
20. Sternberg, G. M. Manual of Bacteriology. (1892), p. 346. 
21 Fraenkel, C., and Pfeiffer, R. Atlas der Bakterienkunde. Tafel 
LIV, (1891), No. 11. 
22. Migula, W. Bacteriologisches Practicum, (1892). DESCRIPTION OF PLATE. 
The figures in the plate are to illustrate the flagella on these three 
species of bacteria as they appeared in stained cover-glass preparations. 
The drawings were made by the aid of a Zeiss apochromatic objective, 
2 mm., 1.30 n. a. and the measurements were made with the com- 
pensating micrometer ocular No. 6. Each germ and its flagella were 
carefully measured and in the drawings each micromillimetre is rep- 
resented by a millimeter, thus giving a magnification of a thousand di- 
ameters. The curves in the flagella were carefully counted and repro- 
duced as accurately as it was possible by freehand drawing. The posi- 
tion of the flagella was also carefully determined. In the preparation 
of the plate care has been taken to avoid extremes. Individual bacteria 
have been selected from different fields to represent the various number, 
lengths and position of the filaments on the body of the germs as they 
appeared in the preparations. A few free, or detached flagella are also 
indicated. The drawing of each germ is practically equivalent to a photo- 
graph. It is possible to find all of the structures represented in a few 
fields of the microscope in a well executed preparation. The germ in 
the center of each figure represents the maximum number of flagella on 
a single individual. In the left lower corner of each is a drawing of a 
clump of bacteria with their flagella. There are a few drawings of bac- 
teria (a) with only their periphery and flagella stained. 
Fig- I. Bacillus cholera: suis. Drawings made from preparations of 
the culture of hog cholera bacteria obtained in the State of Illinois, (d) 
A bunch or strand of flagella. 
Fig. 2. Bacillus coli communis. Drawings made from preparations 
from the culture obtained from the human intestine. 
Fig. 3. Bacillus typhi abdominalis. Drawings made from prepara- 
tions of the typhoid bacillus which was obtained from the Johns Hopkins 
Hospital. The upper right hand corner, enclosed in dotted lines, rep- 
resents all of the bacteria and flagella from a single microscopic field. 1 
2 
3 
FLAGELLA OF BACTERIA-MOORE. The Wilder Quarter=Century Book. 
A collection of original papers dedicated to Professor Burt 
Green Wilder at the close of his twenty-fifth year of service 
in Cornell University (1868-1893), by some of his old students. 
8V0, 493 PP-> Portrait (Japan proof), 26 plates, and 36 figures 
in the text. Price, $5.00. Address the 
COMSTOCK PUBLISHING CO., Ithaca, N. Y. 
TABEE OB CONTENTS AND OF CONTRIBUTORS. 
PAGE. 
Portrait of Professor Burt Green Wieder. Engraved by 
John P. Davis, Secretary of the Society of American Wood- 
Engravers Frontispiece. 
List of the more important scientific publications of Professor 
Wilder 1 
TabeE showing the number of students taught by Professor Wilder 9 
David Starr Jordan, LL.D., President of the Leland Stanford* 
funior University. Temperature and Vertebrae-A Study in 
Evolution, Being a Discussion of the Relations of the Numbers 
of Vertebrae among Fishes to the Temperature of the Water 
and to the Character of the Struggle for Existence 13 
Anna Botsford Comstock, B.S., Member of the Society of 
American Wood-Engravers, Natural History Artist. I. En- 
graving of a Cat (following page 36). II. Engravings of Moths 
(Plate I, illustrating the Essay on Evolution and Taxonomy). 
John Henry Comstock, B.S., Professor of Entomology and Gen- 
eral Invertebrate Zoology in Cornell University, and Professor 
of Entomology in The Leland Stanford funior University. 
Evolution and Taxonomy. An Essay on the Application of 
the Theory of Natural Selection in the Classification of Ani- 
mals and Plants, Illustrated by a Study of the Evolution of the 
Wings of Insects, and by a Contribution to the Classification of 
the Lepidoptera, (with three plates, and thirty-three figures in 
the text) 37 
Eugene Roeein Corson, B.S., M.D., Physician and Surgeon, 
Savannah, Ga. The Vital Equation of the Colored Race and its 
Future in the United States 115 
Leeand O. Howard, M.S., First Assistant Entomologist, U. S. 
Department of Agriculture, Washington, D. C. The Corre- 
lation of Structure and Host-Relation among the Encyrtinae . 177 
Theobaed Smith, Ph.B., M.D., Chief of the Division of Animal 
Pathology, Bureau of Animal Industry, U. S. Department 
of Agriculture, Professor of Bacteriology and Hygiene in the 
Medical Department of the Columbian University, Washing- 
ton, D. C. The Fermentation Tube with Special Reference to 
Anaerobiosis and Gas Production among Bacteria, (with one 
plate) 187 Table of Contents 
William Christopher Krauss, B.S., M.D., Physician, Professor 
of Pathology, Medical Department of Niagara University, Buf- 
falo, N. Y. Muscular Atrophy Considered as a Symptom, 
(with one plate and three figures in the text) 235 
Susanna Phelps Gage, Ph.B. The Brain of Diemyctylus viride- 
scens, from Larval to Adult Life, and Comparisons with the 
Brain of Amia and of Petromyzon, (with eight plates) .... 259 
Hermann Michael Biggs, A.M., M.D., Professor Materia Medi- 
ca, Therapeutics, and Nervous Diseases, Bellevue Hospital 
Medical College, Visiting Physician and Pathologist, Belle- 
vue Hospital, Neurologist and Pathologist to the Hospital 
of the Work House and Alms House, Chief Inspector Div. 
Path. Bad. and Disinfection, N. Y. City iTealth Department. 
A Bacterial Study of Acute Cerebral and Cerebro-Spinal Lepto- 
Meningitis 315 
John Casper Branner, Ph.D., Professor of Geology in the Le- 
land Stanford Junior University. Observations upon the Ero- 
sion in the Hydrographic Basin of the Arkansas River above 
Little Rock 32 
VER anus Alva Moore, B.S., M.D., First Assistant in the Di- 
vision of Animal Pathology, Bureau of Animal Industry, U. 
S. Department of Agriculture, Assistant Demonstrator of 
Pathological Histology in the Medical Department of the Col- 
umbian University, Washington, D. C. The Character of the 
Flagella on the Bacillus Cholera? Suis (Salmon and Smith), 
Bacillus Coli Communis (Escherich), and the Bacillus Typhi 
Abdominalis (Eberth), (with one plate) 339 
Grant Sherman Hopkins, D.Sc., Instructor in Anatomy, Micro- 
scopy, and Embryology in Cornell University. The Lympha- 
tics and Enteric Epithelium of Amia calva, (with two plates) 367 
Pierre Augustine Fish, B.S., Instructor in Physiology, Verte- 
brate Zoology, and Neurology in Cornell University, and In- 
structor in Zoology, Marine Biological Laboratory at Wood's 
Holl. Brain Preservation, with a Rdsum€ of some Old and 
New Methods, (with one plate) 385 
William Russell Dudley, M.S., Professor of Botany in the Le- 
land Stanford Junior University. The Genus Phyllospadix, 
(with two plates) 4°3 
Simon Henry Gage, B.S., Associate Professor of Anatomy, His- 
tology, and Embryology in Cornell University. The Lake and 
Brook Lampreys of New York, Especially those of Cayuga and 
Seneca Lakes, (with eight plates) 421