BACTERIUM PESTIS. 213 



Bacterium pseudotuberculosis rodentium. Preiss. 



(L. and N.) 



Si/nonym. — Bacillus pseudotuberculosis A. Pfeiffer. 

 Entire Literature. — Delbanco (Ziegler's Beitrage XX, 477). 



Microscopic. — Plump, short rods, motility absent or 

 doubtful, flagella not found, often arranged in short chains 

 in cultures, stain best with alkaline methylene-blue, not by 

 Gram's method. 



Cultures. — Somewhat like Bact. coli, grow readily and 

 luxuriantly upon most nutrient media (only upon potato 

 poorly), forming yellowish -white to salmon-colored and 

 yellowish-brown growths. Bouillon is first diffusely cloudy, 

 then presents a thick sediment, but no pellicle. Abundant 

 formation of crystals in the cultures from the formation 

 of alkali (basic phosphate). No fermentation of sugar 

 with formation of gas. Milk is not coagulated. No 

 indol. 



Distribution. — Frequently found as the cause of tuber- 

 culous-like, caseous, granulation swellings (especially in 

 the abdomen) of rodents (rabbits, guinea-pigs). Appears 

 widely distributed; may also cause epidemics. 



Detection. — The organism may be easily found in 

 stained smears from the swellings. Growth occurs read- 

 ily, and thus it is differentiated from tuberculosis. 



Bacterium pestis. 1 (Kitasato, Yersin.) L. and N. 



(Plate 13.) 



Literature. — Yersin (A. P. VIII, 662); Aoyama (C. B. XIX, 481); 

 O.uata contra Kitasato (C. B. xxi, 771). Much newer literature is 

 cited in the text. Especially important is : Gaffky, E. Pfeiffer, Dieu- 

 donne. Sticker. Report of the German Pest Commission (A. G. A. 

 xvi, 1899). 



Microscopic Appearance. — Short rods with rounded 

 ends, two to three times as long as thick, here and there 

 united in pairs (13, x a). In smear preparations from ex- 



1 We have had at our disposal for study and illustrating, through 

 the great kindness of Dr. Dieudonne, besides the living cultures, also 

 a scries of preserved original Indian cultures and original prepara- 

 tions. 



