PATHOGENIC BACTERIA. 403 



those of the spirillum of cholera, and the margin is almost 

 absolutely smooth and circular. As the colonies become older 

 they assume a more irregular and lobulated appearance, but 

 are still more finely granular than the colonies of the cholera 

 spirillum. Gelatin is very slowly hquefied. Its growth on the 

 other culture-media is not remarkable. It forms indol in pep- 

 tone solution, and it increases in the upper layers of the fluid. 



^ u 



Fig. 105. — Spirillum of relapsing fever in the blood. Sketched 

 from a stained specimen. 



When guinea-pigs are inoculated in the peritoneal cavity, death 

 occurs in one to two days. This organism was discovered in 

 the water-supply of Berlin. 



Other spirilla have been isolated rom water by Giinther 

 (Vibrio aquatilis in Spree water); by Dunbar from the Elbe 

 River; by Russell from the Gulf of Naples; by Heider from the 

 water of the Danube Canal; and in America, by Abbott, from 

 the water of the Schuylkill (Vibrio Schuylkiliensis) ; and many 

 others have been described to which the limits of this work 

 will not permit of further allusion. 



