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 septicaemia infection through umbilicus. 



Morphology. A short, thick bacillus, from 1 to 2 p. 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 aerobic and facultative anaerobic, 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, soft layer 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- 

 foetid 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 enormo'us numbers. At the point of 

 inoculation there is frequently a hemorrhagic oedema. 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 Fried lander'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 that it frequently gives rise to hernorrliagic extravasations in inocu- 

 lated animals. In 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 dj-es, the poles being stained darker 

 than the middle part, especially in blood preparations, and present- 

 ing a capsule sometimes well marked, sometimes indistinct. 



