286 PATHOGENIC BACTERIA. 



the track of the wire, and forms a cloudy liquid which 

 precipitates at the apex in the form of a coiled mass. 

 Upon the surface a delicate imperfect yellowish myco- 



FlG. 85. Spirillum Denecke : gelatin puncture-cultures aged forty-eight and 

 sixty hours (Shakespeare). 



derma forms. Liquefaction of the entire gelatin gen- 

 erally requires about two weeks. 



Upon agar-agar this spirillum grows as a thin yellow- 

 ish layer which does not seem inclined to spread widely. 



The' culture upon potato is luxuriant if grown in the 

 incubating oven. It appears as a distinct yellowish moist 

 film, and when examined microscopically is seen to con- 

 tain long beautiful spirals. 



The organism sometimes produces indol, but is irreg- 

 ular in its action in this respect. 



The spirillum of Denecke is mentioned only because 

 of its morphological relation to the cholera spirillum, 

 not because of any pathogenesis which it possesses. It 

 probably is not associated with any human disease. Ex- 

 periments, however, have shown that when the spirilla 

 are introduced into the intestines of guinea-pigs whose 

 gastric contents are alkalinized and whose peristalsis is 



