CHOLERA 



205 



Cultural Characters. — The bacillus grows readily on 

 almost all media, whether oxygen is admitted or not, and 

 after it has developed a saprophytic habit is much less 

 easily killed by disinfectants than when fresh from the 

 stool. 



The Finkler-Prior spirillum is one of the organisms which 

 is likely to be confounded with Koch's 'comma.' It is 

 occasionally found in the stools in English cholera 

 (cholera nostras), cholera infantum, etc. 



The general behaviour of the two organisms on different 

 media is distinctive, as is seen in the following table : 



The * comma ' bacillus produces sulphuretted hydrogen 

 in broth cultures. In examining a sample of stool sus- 

 pected to be choleraic, the microscopic appearance alone 

 is often sufficient to establish its true character, while in 

 other cases the culture test may yield positive results when 



* Care must be taken that the potatoes and broth are faintly 

 alkaline. 



