Pseudo-tuberculosis 351 



which could easily be stained by ordinary methods (Fig. 

 i oo) . When introduced subcutaneously into guinea-pigs, the 

 original disease was reproduced. 



Morphology and Cultivation. Bacillus pseudo-tubercu- 

 losis is characterized by Pfeiffer as follows : The organism is 

 rod-shaped, the rods varying in length (0.4 to 1.2 p) and 

 sometimes united in chains. They may be almost round, 

 and then resemble diplococci. They stain by ordinary 

 methods, but not by Gram's method. They are motile and 



"r %% \" V" V '' NV/ r> .** v V 



^^^^Ki^fe? 



Fig. 100. Bacillus pseudo-tuberculosis from agar-agar. X 1000 

 (Itzerott and Niemann). 



have flagella like the typhoid and colon bacilli. They form 

 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- 

 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, and 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. 



