anaerobic, liquefying, motile spirillum. Does not form
spores. Upon gelatin plates small, punctiform colonies
are formed at the end of twenty-four hours, which when
slightly magnified are seen to be circular in shape, with
sharply defined border and of a greenish-brown color
in the centre and paler toward the margins. Later,
when liquefaction has commenced, the sharp contour is
often lost. The liquefaction progresses more rapidly
than with the cholera bacillus, but not so energetically
as with the spirillum of Finkler and Prior. In gelatin
stick cultures after forty-eight hours a stocking-like
pouch is developed, the spirilla sinking to the bottom
SPIRILL UM METSCHNIKO VI. 593
of the liquefied gelatin in the form of a coiled mass,
while a thin, yellowish layer forms upon the surface ;
complete liquefaction usually occurs in about two weeks.
Upon the surface of agar a thin, yellowish layer is de-
veloped. Blood-serum is rapidly liquefied. The indol
reaction in peptone solutions is absent.
Pathogenesis. Somewhat pathogenic for guinea-pigs
when inoculated by Koch's method with previous ad-
ministration of soda solution and laudanum.
It is probable that this organism, from the locality in
which it is found and its behavior, is a saprophyte.
SPIRILLUM METSCHNIKOVI.
Discovered in 1888, in Odessa, by Gamalei'a in the
intestinal contents of fowls dying of an infectious dis-
ease which prevails in certain parts of Russia during
the summer months, and which presents symptoms
resembling fowl-cholera. GamaleiVs experiments show
that this organism is the cause of the disease mentioned.
It has since been found by Pf uhl and Pfeiffer in the water
of the Spree at Berlin, and in the Lahn by Kutchler.
Morphology. Morphologically this spirillum is almost
identical with the cholera spirillum; it forms curved
rods with rounded ends and spiral filaments, the curved
segments being somewhat thicker, shorter, and often
more decidedly curved than the comma bacillus. In
the blood of inoculated pigeons the diameter is some
times twice as great as that of the cholera spirillum,
and almost coccus-like forms are often found. A single,
long, undulating flagellum is attached to one end of the
spiral filaments or curved rods. In old cultures beau-
tiful long spiral filaments may be seen.
38
594 BACTERIOLOGY.
Stains with the usual aniline colors, but not by
Gram's method.
Biological Characters. An aerobic, liquefying, motile
spirillum. Upon gelatin plates the vibrio Metschnikovi
grows considerably faster than the cholera vibrio; small,
white punctiform colonies are developed at the end of
twelve hours; these rapidly increase in size and cause
liquefaction of the gelatin within twenty-four to thirty
hours. At the end of three days large, saucer-like
areas of liquefaction may be seen, the contents of which
are turbid, as a rule. Under the microscope the
colonies appear as yellowish-brown granular masses,
which are in active movement, and the margins are
surrounded by a border of radiating filaments. In
gelatin stick cultures the growth is almost twice as rapid
as the cholera bacillus. In bouillon at 37 C. devel-
opment is very rapid, and the liquid becomes clouded
and opaque, and a thin, wrinkled film forms upon the
surface. On the addition of pure sulphuric acid to
twenty-four-hour peptone cultures a distinct nitroso-
indol reaction is produced. Milk is coagulated and
acquires a strongly acid reaction. The spirillum does
not clump and lose its motility with the diluted serum
from an animal immunized to cholera.
Pathogenesis. The vibrio Metschnikovi is pathogenic
for fowls, pigeons, and guiaea-pigs. A small quantity
of a culture injected into the breast muscles of chickens
and pigeons causes their death with the local and gen-
eral symptoms of fowl cholera. At the autopsy the
most constant appearance is hypersemia of the entire
alimentary canal. A grayish-yellow liquid, more or
less mixed with blood, is found in considerable quan
tity in the small intestine; the spleen is not enlarged,
SPIRILL UM METSCHNIKO VI. 595
rather diminished in size, and the organs generally are
normal in appearance. In the watery fluid large num-
bers of spirilla are found; they are found in the blood
of pigeons always, but only in the blood of young fowls.
A few drops of a pure culture inoculated subcutane-
ously in pigeons cause their death in eight to twelve
hours. According to Gamale'ia, fowls may be infected
by giving them food contaminated with the cultures of
the spirillum, but pigeons resist infection in this way.
Infection may also be produced by way of the mouth
by Koch's method, a solution of carbonate of soda and
laudanum having been previously administered. The
animals then die with symptoms of acute gastro-
enteritis; the intestines are found to be highly inflamed
and their liquid contents contain numerous spirilla.
In contradistinction to the pathogenic virulence of
these spirilla for pigeons and guinea-pigs, the cholera
spirillum is much less pathogenic. Pigeons are not
killed by the intramuscular inoculation of pure fresh
cultures of the vibrio cholerse. Gamale'ia has claimed
that by passing the cholera spirillum of Koch through
a series of pigeons, by successive inoculation, its path-
ogenic power is greatly increased, and that when steril-
ized cultures of this virulent variety of the comma
bacillus are injected into pigeons they become immune
against the pathogenic action of the vibrio Metschni-
kovi, and the reverse. But Pfeiffer has shown that
this statement is not founded upon fact. The patho-
genic action of the vibrio Metschnikovi upon pigeons
and guinea-pigs, producing in these animals general
septicsemia and death, is, therefore, a characteristic point
of difference between this and the spirillum of Asiatic
cholera.
596 BACTERIOLOGY.
Within recent years numerous other vibrios, the so-
called " water vibrios," have been found while looking
for the cholera bacillus, the identity or variation of
which from the spirillum of cholera it has been ex-
tremely difficult to determine, as morphological, biolog-
ical, and pathogenical examinations have led to no posi-
tive results.
SPIRILLUM OBERMEIERI (Spirillum of Relapsing Fever).
First observed by Obermeier (1873) in the blood of
persons suffering from relapsing fever.
Morphology. Long, slender, flexible, spiral, or wavy
filaments, with pointed ends, from 16//to40// in length
and from one-quarter to one-third the thickness of the
cholera spirillum.
Stains readily with the ordinary aniline colors, es-
pecially with fuchsin, Loffler's solution of methylene-
blue and Bismarck-brown. Does not stain by Gram's
method.
Biological Characters. A motile spirillum which
has not been cultivated in artificial media. Spore
formation has not been demonstrated. In fresh prep-
arations from the blood the spirillum exhibits active
progressive movements accompanied by very rapid
rotation in the long axis of the spiral filaments or by
undulating movements. The spirilla are found exclu-
sively in the blood and spleen of persons suffering from
relapsing fever, never in the secretions, and only during
the fever, not in the intermissions, or at most singly at
the beginning of an attack. When preserved in blood-
serum or a 0. 5 per cent, solution of salt they continue
to exhibit active movements for a considerable time.
SPIRILLUM OBERMEIERI. 597
Efforts to cultivate this spirillum in artificial culture
media have thus far been unsuccessful, although Koch
has observed an increase in the length of the spirilla
and the formation of a tangled mass of filaments.
Pathogenesis. Inoculation experiments have been suc-
cessfully made on man and monkeys. Monkeys when
inoculated with human blood containing the spirilla
take sick after about three and a half days, but show
only the initial febrile attack; no relapses, such as are
characteristic of the disease in man. The organisms
are found in the blood, and at the height of the fever
in the other organs on autopsy. Extirpation of the
spleen renders the disease more dangerous for monkeys.
Blood from one animal, taken during the attack, in-
duces a similar febrile paroxysm when inoculated in
another monkey. One attack does not preserve the
animal experimented on from a second attack (Koch
and Carter).
Very little is known bacteriologically of this disease,
but from the fact that these peculiarly shaped organ-
isms are constantly and exclusively found in relapsing
fever, and that the disease can be transmitted to mon-
keys by inoculating them with the blood containing the
spirilla, it may be assumed that they are the true cause
of the disease.
CHAPTER XXXV.
GLANDERS BACILLUS.
BACILLUS MALLEI (Bacillus of Glanders).
THIS bacillus was discovered and proved to be the
cause of glanders by isolation in pure culture and com-
munication to animals by inoculation, by several bacte-
riologists almost at the same time (1882), viz., by the
investigations of Loftier, Schiitz, Israel, Bouchard,
Charrin, Weichselbaum, Kauzfeld, and Kitt. It is
found in the recent nodules in animals affected with
glanders, and in the discharge from the nostrils, pus
from the specific ulcers, etc., and occasionally in the
blood.
Morphology. Small bacilli with rounded or pointed
ends, from 0.25/* to 0.4^ broad and from 1.5// to 3//
long; usually single, but sometimes united in pairs, or
growing out to long filaments, especially in potato cul-
tures. Frequently breaks up into short, almost coccus-
like elements (Fig. 81).
The bacillus mallei stains with difficulty with the
aniline colors, best when the aqueous solutions of these
dyes are made feebly alkaline; it is decolorized by
Gram's method. This bacillus presents the peculiarity
of losing very quickly in decolorizing solutions the color
imparted to it by the aniline staining solutions. For
this reason it is difficult to stain in sections. Loffier
recommends his alkaline methylene-blue solution for
GLANDERS BACILLUS. 599
staining sections, and for decolorizing a mixture con-
taining 10 c.c. of distilled water, 2 drops of strong
sulphuric acid,, and 1 drop of a 5 per cent, solution of
oxalic acid; thin sections to be left in this acid solution
for five seconds.
FIG. 81.
Glanders bacilli. Agar culture. X 1000 diameters.
Biological Characters. An aerobic, non-motile bacil-
lus, whose molecular movements are so active that they
have often been taken for motility. It grows on vari-
ous culture media at 37 C. Development takes place
slowly at 22 C. and ceases at 43 C. It does not form
spores. Exposure for ten minutes to a temperature of
55 C., or for five minutes to a 3 to 5 per cent, solution
of carbolic acid, or for two minutes to a 1 : 5000 solu-
tion of mercuric chloride, was effectual in destroying
its vitality. As a rule, the bacilli do not grow after
having been preserved in a desiccated condition for a
week or two; in distilled water they are also quickly
destroyed. The bacillus does not grow in infusions of
BA CTERIOL OOY.
hay, straw, or horse-manure, and it is doubtful whether
it finds conditions in nature favorable to a saprophytic
existence. It grows well in the incubating oven on
glycerin-agar. Upon this medium at the end of twenty-
four to forty-eight hours, whitish, transparent colonies
are developed, which in six or seven days may attain a
diameter of 7 or 8 mm. On blood-serum a moist,
opaque, slimy layer develops, which is of a yellowish-
brown tinge. The growth on cooked potato is especially
characteristic. At the end of twenty-four to thirty-six
hours at 37 C. a moist, yellow, transparent layer de-
velops; this later becomes deeper in color, and finally
takes on a reddish-brown color, and the potato about it
acquires a greenish-yellow tint. In bouillon it causes
diffuse clouding, with ultimately the formation of a
more or less ropy tenacious sediment. Milk is coagu-
lated with the production of acid. It grows on media
possessing an acid reaction, and both with and without
oxygen.
Pathogenesis. The bacillus of glanders is pathogenic
for a number of animals. Among those which are most
susceptible are horses, asses, guinea-pigs, cats, dogs,
ferrets, moles, and field mice; sheep, goats, swine, rab-
bits, white mice, and house mice are much less suscep-
tible; cattle are immune. Man is susceptible, and in-
fection not infrequently terminates fatally.
When pure cultures of the bacillus mallei are injected
into horses and other susceptible animals true glanders
is produced. The disease is characterized in the horse
by the formation of ulcers upon the nasal mucous mem-
brane, which have irregular, thickened margins, and
secrete a thin, virulent mucus; the submaxillary lym-
phatic glands become enlarged and form a tumor, which
GLANDERS BACILLUS. 601
is often lobulated; other lymphatic glands become in-
flamed, and some of them suppurate and open exter-
nally, leaving deep, open ulcers; the lungs are also
involved, and the breathing becomes rapid and irreg-
ular. In farcy, which is a more chronic form of the
disease, circumscribed swellings, varying in size from
a pea to a hazel-nut, appear on different parts of the
body, especially where the skin is thinnest; these sup-
purate and leave angry- looking ulcers with ragged
edges, from which there is an abundant purulent dis-
charge. The bacillus of glanders can easily be obtained
in pure cultures from the interior of suppurating nod-
ules and glands which have not yet opened to the sur-
face, and the same material will give successful results
when inoculated into susceptible animals; but the dis-
charge from the nostrils or from an open ulcer contains
comparatively few bacilli, and these being associated
with other bacteria which grow more readily on the
culture media than the bacillus mallei, it is not easy to
obtain pure cultures by the plate method from such
material, and here animals are useful.
Of test animals guinea-pigs and field-mice are the
most susceptible. In guinea-pigs subcutaneous injec-
tions are followed in four or five days by swelling at
the point of inoculation, and a tumor with caseous con-
tents soon develops; then ulceration of the skin takes
place, and a chronic purulent ulcer is formed. The
lymphatic glands become inflamed and general symp-
toms of infection are developed in from two to four
weeks; the glands suppurate and in males the testicles
are involved; finally purulent inflammation of the joints
occur, and death ensues from exhaustion. The forma-
tion of the specific ulcers upon the nasal mucous mem-
602 BA CTER10L OGY.
brane, which characterize the disease in the horse, rarely
result from inoculation of the guinea-pig. The process
is often prolonged, or it remains localized on the skin.
Guinea-pigs succumb more rapidly to intraperitoneal
injection, usually in from eight to ten days, and in
males the testicles are invariably affected.
Glanders occurs as a natural infection only in horses
and asses; the disease is occasionally communicated to
man by contact with affected animals, and usually by
inoculation on an abraded surface of the skin. The
contagion may also be received on the mucous mem-
brane. Infection has sometimes been produced in
bacteriological laboratories. In the horse, the disease
may be localized in the nose (glanders) or beneath the
skin (farcy). The essential lesion is the granulomatous
tumor, characterized by the presence of numerous lym-
phoid and epithelioid cells, among and in which are seen
the glanders bacilli. These nodular masses tend to break
down rapidly, and on the mucous membrane form ulcers,
while beneath the skin they form abscesses. The glan-
ders nodules may also occur in the internal organs. An
acute and chronic form of glanders may be recognized
in man, and an acute and a chronic form of farcy. The
disease is fatal in a large proportion of cases. It is
transmissible also from man to man. Washer-women
have been infected from the clothes of a patient. The
infective material exists in the secretions of the nose,
in the pus of glanders nodules, and sometimes in blood;
it may occasionaly be found in the secretions of healthy
glands, as in the urine, milk, and saliva, and also in
the foetus of diseased animals (Bonome). From recent
observations it appears that glanders is by no means
an uncommon disease among horses, particularly in
GLANDERS BA GILL US. 603
southern countries, sometimes taking a mild course and
remaining latent for a considerable time (Semmer and
Babes). Apparently healthy horses, therefore, may pos-
sibly spread the disease.
Attenuation of virulence occurs in cultures which
have been kept for some time, and inoculations with
such cultures may give a negative result; or, when con-
siderable quantities are injected, may produce a fatal
result at a later date than is usual when small amounts
of a recent culture are injected into susceptible animals.
Several attempts have been made by investigators to
produce artificial immunity against glanders, but so far
with unsatisfactory results. According to Strauss, dogs
may be protected by intravenous inoculations of small
quantities of living bacilli against an injection with
large quantities which usually kill them. Fenger has
found that animals inoculated with glanders bacilli
react less powerfully to fresh injections; and that rab-
bits which have recovered from an injection of glanders
are subsequently immune, the immunity lasting for from
three to six weeks. Ladowski has obtained positive re-
sults also in rabbits and cats by intravenous injections
of sterilized cultures. Other observers have reported
not only the production of immunity, but also cures, by
the use of mallein. Mallein is produced by evaporat-
ing a six-weeks 7 old culture of the glanders bacillus in
5 per cent, glycerin nutrient veal bouillon to 10 per
cent, of its original bulk. It is made in the same way
as Koch's crude tuberculin from the tubercle bacillus
cultures. j % .
Differential Diagnosis. It is often difficult to demon-
strate microscopically the presence of the bacillus of
glanders in the nodules which have undergone purulent
CHAPTER XXXVI.
BUBONIC PLAGUE BACILLUS YELLOW FEVER
BACILLUS WHOOPING-COUGH BACILLUS.
BACILLUS OF BUBONIC PLAGUE (Bacillus Pestis
Bubonicse Kitasato ; Bacterium Pestis).
DISCOVERED simultaneously by Kitasato and Yersin
(1894) during an epidemic of the bubonic plague in
China. It is found in large numbers in the pus from
FIG. 82.
Bacillus of bubonic plague. X 1000 diameters.
the buboes characteristic of this disease and in the
lymphatic glands; more rarely in the internal organs
and in the blood, in which it occurs in acute hemor-
BACILLUS OF BUBONIC PLAGUE. 607
rhagic cases and shortly before death. It also occurs
in the feces of men and animals.
Morphology. Short thick rods, with rounded ends,
frequently occurring in short chains and often sur-
rounded by a capsule. When obtained from cultures
the bacilli present considerable spherical enlargement
(Fig. 82).
Stains readily with the ordinary aniline dyes, the
ends being usually more deeply colored than the central
portion; does not stain by Gram's method.
Biological Characters. An aerobic, non-motile bacil-
lus. Does not form spores. Grows on the usual culture
media. Does not liquefy gelatin. Grows best on blood-
serum in the incubator, the growth appearing on the
surface after twenty-four to forty-eight hours, in the
form of white, moist, transparent and iridescent col-
onies. It grows rapidly on glycerin-agar, forming a
grayish-white surface growth. In bouillon a very char-
acteristic appearance is produced, the culture medium
remaining clear while a granular or grumous deposit
forms on the walls and on the bottom of the tube.
Pathogenesis. This bacillus is pathogenic for rats,
mice, guinea-pigs, monkeys, rabbits, flies, and other
insects, which usually die within two or three days
after inoculation. Then at the point of inoculation is
found a somewhat hemorrhagic infiltration and rcdema,
with enlargements of the neighboring lymph-glands,
hemorrhages into the peritoneal cavity and parenchy-
matous congestion of the organs. The spleen sometimes
shows minute nodules resembling miliary tubercles.
Microscopically the bacilli are found in all the organs
and in the blood. The disease is rapidly communicated
from one animal to another, and thus its extension is
CHAPTER XXXVI.
BUBONIC PLAGUE BACILLUS YELLOW FEVER
BACILLUS W HOOPING-COUG H B A CILLUS.
BACILLUS OF BUBONIC PLAGUE (Bacillus Pestis
Bubonicae Kitasato ; Bacterium Pestis).
DISCOVERED simultaneously by Kitasato and Yersin
(1894) during an epidemic of the bubonic plague in
China. It is found in large numbers in the pus from
FIG. 82.
Bacillus of bubonic plague. X 1000 diameters.
the buboes characteristic of this disease and in the
lymphatic glands; more rarely in the internal organs
and in the blood, in which it occurs in acute hemor-
BACILLUS OF BUBONIC PLAQUE. 607
rhagic cases and shortly before death. It also occurs
in the feces of men and animals.
Morphology. Short thick rods, with rounded ends,
frequently occurring in short chains and often sur-
rounded by a capsule. When obtained from cultures
the bacilli present considerable spherical enlargement
(Fig. 82).
Stains readily with the ordinary aniline dyes, the
ends being usually more deeply colored than the central
portion; does not stain by Gram's method.
Biological Characters. An aerobic, non-motile bacil-
lus. Does not form spores. Grows on the usual culture
media. Does not liquefy gelatin. Grows best on blood-
serum in the incubator, the growth appearing on the
surface after twenty-four to forty-eight hours, in the
form of white, moist, transparent and iridescent col-
onies. It grows rapidly on glycerin-agar, forming a
grayish- white surface growth. In bouillon a very char-
acteristic appearance is produced, the culture medium
remaining clear while a granular or grumous deposit
forms on the walls and on the bottom of the tube.
Pathogenesis. This bacillus is pathogenic for rats,
mice, guinea-pigs, monkeys, rabbits, flies, and other
insects, which usually die within two or three days
after inoculation. Then at the point of inoculation is
found a somewhat hemorrhagic infiltration and oedema,
with enlargements of the neighboring lymph-glands,
hemorrhages into the peritoneal cavity and parenchy-
matous congestion of the organs. The spleen sometimes
shows minute nodules resembling miliary tubercles.
Microscopically the bacilli are found in all the organs
and in the blood. The disease is rapidly communicated
from one animal to another, and thus its extension is
608 BACTERIOLOGY.
facilitated. During epidemics, rats, mice, and flies, in
large numbers, become infected and die, and the disease
is apparently transmitted through them to man. The
organism is found in the feces of sick animals, in the
dust of infected houses, and in the soil.
The virulence of the bacilli in cultures and in nature
seems to vary considerably, and is rather rapidly lost
when grown on artificial media. The growth in cul-
tures becomes more abundant after frequent transplan-
tation. The virulence of the organism is increased by
successive inoculation in certain animal species, and
then its pathogenic properties for other species are less
marked.
Yersin, Calmette, and Borrel have succeeded in im-
munizing animals against the bacillus of bubonic plague
by inoculation, by the intravenous or intraperitoneal
injection of dead cultures, or by repeated subcutaneous
inoculation. They also succeeded in immunizing rab-
bits and horses, so that the serum afforded protection
to small animals, after subcutaneous injection of viru-
lent cultures, and even cured those which had been
inoculated, if administered within twelve hours after
injection. The serum has considerable antitoxic as
well as bactericidal properties. More recently this
serum has been applied by Yersin to the treatment of
bubonic plague in man, with very promising results.
Experience has shown that the treatment is more
efficacious the earlier the stage of the disease. When
treatment is begun in the first day of the attack, fever
and all alarming symptoms usually disappear with
astouishing rapidity. In cases treated at a later stage
larger doses of the serum are required, and even in the
favorable cases suppuration of the buboes is not always
BACILLUS ICTEROIDES. 609
prevented. In some of the early cases and in many of
the rather late ones the serum fails. When the disease