I4O ESSENTIALS OF BACTERIOLOGY 



Staining. Gram positive, easily stained with ordinary dyes. 



Growth. Strictly anaerobic. Forms abundant gas in glu- 

 cose, gelatin, and liquefies cultures, producing butyric acid 

 odor. Best temperature between 20 and 30 C. 



Pathogenesis. Produces a powerful toxin in the tissues, 

 like the tetanus bacillus. This toxin may be present in the 

 affected meat without causing decomposition, and thus give 

 rise to poisoning. 



Bacillus enteritidis of Gartne'r has likewise been considered 

 a cause of meat and sausage poisoning. 



CHAPTER XIX 



PATHOGENIC BACTERIA (Continued) 



Spirillum Choleras (Koch) (Comma Bacillus of Cholera) . 



Origin. Koch, as a member of the German expedition 

 sent to India, in 1883, to study cholera, found this micro-organ- 

 ism in the intestinal contents of cholera 

 patients, and by further experiments 

 identified it with the disease. 



Form. The spirillum as seen ordi- 

 narily appears as a short, arc-like body, 

 about half the size of a tubercle bacillus, 

 but when seen in large groups, spirals 

 are formed, each little arc appearing 

 Fig. 71. Comma ba- then as but a segment, a vibrio; each 



cillus, pure culture (x 600). . ,. , ., 



arc is about three times as long as it 



is broad, and possesses a flagellum at one or more, rarely 

 both, ends. 



Properties. The spirilla are very motile; liquefy gelatin. 

 They are easily affected by heat and dryness. Spores have not 

 been found, though some (Hiippe) claim arthrospores, but these 

 bodies represent only degenerative changes. 



Growth. At ordinary temperatures on all nutrient media 



