Cultivation 



547 



They are actively motile and possess long flagella (peritricha), 

 easily demonstrable by the usual methods of staining. No 

 spore-production has been observed. In general the bacillus 

 resembles that of typhoid fever. It stains readily by the 

 ordinary methods, but not by Gram's method. 



Cultivation. No trouble is experienced in cultivating 



Fig. 157. Ulceration of the intestine in atypical case of swine-fever 

 (Crookshank). 



the bacilli, which grow well in all the media under aerobic 

 and anaerobic conditions. 



Colonies. Upon gelatin plates the colonies become 

 visible in from twenty-four to forty-eight hours, the deeper 

 ones appearing spheric with sharply defined borders. The 



