SPIRILLA RESEMBLING CHOLERA. 293 



This spirillum does not produce indol. 



Heider found the spirillum pathogenic for guinea-pigs. 



Spirillum I. of Wernicke. This organism is about 

 twice as large as the cholera spirillum, liquefies gelatin 

 more rapidly, produces indol, and is feebly pathogenic 

 for guinea-pigs. 



Spirillum II. of Wernicke. This spirillum is smaller 

 than the cholera spirillum, liquefies gelatin more slowly, 

 produces indol, and is highly pathogenic for rabbits, 

 guinea-pigs, pigeons, and mice. 



Spirillum Bonhoffi. This organism (Fig. 91) was 

 found in water by BonhofF. It has a decided resem- 



N&&&K 



*?&&&& 

 %^ v 



FIG. 91. Spirillum Bonhoffi, from a culture upon agar-agar; x 1000 (Itzerott 

 and Niemann). 



blance to the cholera spirillum, but is rather stouter 

 and less curved. Curved forms i. e. semicircles, sig- 

 moids, and spirals occur in old cultures especially. 



These organisms are colored badly with ordinary stains, 

 dahlia seeming to be the most appropriate color, and ac- 

 complishing the process better if warmed. The organ- 

 ism is motile, and has a long flagellum attached to one 

 end. 



The colonies develop slowly upon gelatin plates, first 

 appearing in forty-eight hours as little grayish points. 



