Pseudotuberculosis 761 



no spores. Upon gelatin and agar-agar circular colonies 

 with a dark nucleus surrounded by a transparent zone are 

 formed. In gelatin punctures the bacilli grow all along the 

 line of puncture and form a surface growth with concentric 

 markings. The gelatin is not liquefied. The bacilli grow 

 readily upon agar and on potato, but without character- 



Fig. 248. Bacillus pseudotuberculosis from agar-agar. X 1000 

 (Itzerott and Niemann). 



istic appearances. In bouillon a diffuse turbidity occurs, 

 with floating and suspended flakes. Milk is not altered. 



Pathogenesis. The bacillus is fatal to mice, guinea- 

 pigs, rabbits, hares, and other rodents in about twenty 

 days after inoculation. At the seat of inoculation an abscess 

 develops, the neighboring lymphatic glands enlarge and 

 caseate, and nodules resembling tubercles form in the 

 internal organs. Similar bacilli studied by Pfeiffer were 

 isolated from a horse supposed to have glanders. 



