PATHOGENIC BACTERIA, 



much resembles cholera. It was first isolated by Heider 

 in 1892. In appearance it is rather delicate and decidedly 

 curved. It is often united in sigmoid and semicircular 

 forms, and exhibits long spirals in old cultures. It is 

 actively motile, each organism presenting a terminal 

 flagellum. 



The growth upon gelatin plates is rapid. Small light- 

 gray colonies, resembling those of cholera, but exhibit- 

 ing a dentate margin, are observed. The growth in 

 gelatin punctures also much resembles cholera, and the 

 agar-agar growth can scarcely be distinguished from it. 



The potato growth has a distinct yellowish-brown 

 color. 



Milk is coagulated in three or four days. 



FIG. 93. Spirillum Danubicus, from an agar-agar culture; x 1000 (Itzerott and 



Niemann). 



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, 



