THE CLASSIFICATION OF BACTERIA 21 5 



25. B. pestis (Lehmann-Neumann) 



Cocco-bacille de lapeste Yersin : Ann. Pasteur Inst., 1894. 666. 



Pest Bacillus Aoyama: Centralblatt f. Bakteriol., XIX, 1896; Zettnow, Zeitsch. Hygiene 



XXI. 1895-96, 165. 

 Bad. pestis Lehmann-Neumann : Bakt. Diag., 1896, 194. 

 B. pestis-bubonicce Kruse: Fliigge, Die Mikroorganismen, 1896, 429. 



Morphology. Bacilli short, ovals to longer rods, 4-5 times their breadth ; also- 

 chains of short elements. A uniform or polar stain. Flagella demon- 

 strated by Gordon, one at the end, often one at the side, long, spiral. 

 Grow better at room temperatures than at 37. 



Gelatin colonies. Deep: round, white to yellowish white. Surface: flat, with 

 a granular border; do not grow larger than a pin's head. According to 

 Klein, the colonies are small, gray, round to angular points, similar to 

 young colonies of B. vulgaris. 



Gelatin stab. In depth, growth often arborescent, like anthrax (Klein) ; 

 surface growth flat. 



Agar slant. Growth composed of confluent viscid colonies. 



Potato. A scanty growth, white to gray. 



Bouillon. Shows a turbidity of various grades, or with flocculent particles 

 adhering to walls of the tube. 



Milk. Not coagulated. 



Litmus milk. Reddened in 24 hours. According to Klein, unaltered. Indol 

 produced. Nitrates not reduced to nitrites. 



Pathogenesis. Pathogenic to mice, rats, guinea pigs, and rabbits. An oedema 

 at the point of inoculation ; swelling of lymph spaces and congestion of 

 the internal organs. Death in a few days ; bacilli in the blood and 

 organs. 



Habitat. Isolated from suppurating glands, etc., in bubonic plague. 



26. B. solitarius Ravenel 



I.e., 29. 



Morphology. Bacilli slender, straight, 3-7 times their breadth ; ends rounded ; 



occur singly. Aerobic. Bacilli rotatory, non-progressive ; flagella not 



demonstrated. 

 Gelatin colonies. Deep: round, white, slightly granular; margins notched. 



Later the colonies show a zoned and marmorated structure. Surface : 



round, grayish, floccose to filamentous. In 70 hours, the colonies have a 



