562 PATHOGENIC AEROBIC BACILLI 
CAPSULE BACILLUS OF VON DUNGERN. 
Obtained by von Dungern (1893), post mortem, from a new-born child 
which died of hemorrhagic septicemia—infection through umbilicus. 
Morphology.—A short, thick bacillus, from 1 to 2 » long and half as 
broad, surrounded by a capsule which is slightly stained by gentian violet— 
best seen in the body of infected mice; sometimes seen in pairs or in chains 
of four elements; also grows out into filaments, especially in bouillon. 
Upon potato usually only small spherical elements, resembling micrococci, 
are seen. Does not stain by Gram’s method. 
Biological Characters.—An aérobic and facultative anaérobic, non- 
motile, non-liquefying bacillus. Does not form spores. Coagulates milk, 
in which it causes an abundant development of gas at 38°C. Has feeble 
indol reaction. Grows well at room temperature, more rapidly in incubator. 
Upon gelatin plates the deep colonies at end of twelve hours are the size of a 
pin’s head, finely granular, spherical, and sharply defined. Upon the sur- 
face, porcelain-like, elevated, white colonies are developed, which in two or 
three days attain the size of lentils. In gelatin stab cultures development 
occurs all along the line of puncture, frequently with formation of gas bub- 
bles. Upon agar a thick, softlayer of a white color is developed. In bouil- 
lon, at 38° C., there is considerable development of gas. Upon potato the 
growth is very abundant, of a pale yellowish-white color, thick, soft, some- 
what sticky, and filled with gas bubbles. A great portion of the surface is 
covered by this growth at the end of twenty-four hours, even at the room 
temperature. These cultures give off a peculiar odor, sometimes aromatic- 
feetid and sometimes recalling that of fresh bread. Some of the cultures on 
potato soon become cream-like in consistence. At first they have an alkaline 
and later an acid reaction, when they have the odor of acetic acid. 
Pathogenesis.—Very pathogenic for white mice. The bacilli are found 
in the blood and in all the organs in enormous numbers. At the point of 
inoculation there is frequently a hemorrhagic cedema. The spleen is greatly 
enlarged. Also pathogenic for guinea-pigs when injected into the cavity of 
the abdomen—less pathogenic for rabbits. 
According to von Dungern, this bacillus can not be distinguished by its 
morphological and biological characters from Friedlander’s bacillus, Bacil- 
lus capsulatus of Pfeiffer, or Bacillus canalis capsulatus of Mori. But it is 
distinguished from these by greater virulence, especially for rabbits, and by 
the fact thatit frequently gives rise to hemorrhagic extravasations in inocu- 
lated animals. ln our opinion the characters given do not justify the view 
that this bacillus is a distinct species from the bacilli above mentioned. 
BACILLUS PESTIS (Kitasato and Yersin). 
Discovered by Kitasato (1894) in the blood of living patients, and 
in the buboes, blood, and organs of those who had recently died from 
the infectious malady known as bubonic plague. Kitasato was sent 
to Hong-Kong by the Japanese Government for the purpose of inves- 
tigating this disease. According to Lowson the bacilli are found in 
the faeces, in the contents of the buboes, and in the blood. 
Morphology.—In his preliminary note, Kitasato described the 
plague bacilli as “rods with rounded ends,” which are readily 
stained by the ordinary aniline dyes, the poles being stained darker 
than the middle part, especially in blood preparations, and present- 
ing a capsule sometimes well marked, sometimes indistinct. 
