68o Bacillus Suipestifer 



They are rarely larger than 0.5 mm. in diameter and are 

 homogeneous throughout. The superficial colonies have 

 little tendency to spread upon the gelatin. They rarely 

 reach a greater diameter than 2 mm. The gelatin is not 

 liquefied. 



Upon agar-agar they attain a diameter of 4 mm. and 

 have a gray, translucent appearance with polished surface. 

 They are round and slightly arched. 



Gelatin. In gelatin punctures the growth takes the form 

 of a nail with a flat head. There is nothing characteristic 

 about it. The medium is not liquefied. 



Agar-agar. Linear cultures upon agar-agar present a 

 translucent, circumscribed, grayish, smeary layer without 

 characteristic appearances. 



Potato. Upon potato a yellowish coating is formed, 

 especially when the culture is kept in the thermostat. 



Bouillon. Bouillon made with or without peptone is 

 clouded in twenty-four hours. When the culture is allowed 

 to stand for a couple of weeks without being disturbed, a 

 thin surface growth can be observed. 



Milk is an excellent culture-medium, but is not visibly 

 changed by the growth of these bacteria. Its reaction re- 

 mains alkaline. 



Vital Resistance. The bacillus is hardy. Smith found 

 it vital after being kept dry for four months. It ordinarily 

 dies sooner, however, and I have experienced difficulty in 

 keeping it in the laboratory for any length of time unless 

 frequently transplanted. The thermal death-point is 54 C., 

 maintained for sixty minutes. 



Metabolic Products. Gas Production. The hog-chol- 

 era bacillus is a copious gas-producer, capable of break- 

 ing up dextrose and lactose into CO 2 , H, and an acid, which, 

 formed late, eventually checks its further development. It 

 does not ferment saccharose. 



Indol. No indol and no phenol are formed in the culture- 

 media. 



Toxin. In pure cultures of the hog-cholera bacillus 

 Novy* found a poisonous base with the probable composition 

 C 16 H 26 N 2 , which he gave the provisional name "susotoxin." 

 In doses of 100 mg. the hydrochlorid of this base causes con- 

 vulsive tremors and death within one and one-half hours in 



* "Medical News," 1900, p. 231. 



