I 82 BACTERIA 



other members of this family, has no spores. It stains well with 

 the common dyes but not by Gram's method. Dilute fuchsin 

 stains it best. Occasionally involution forms are developed, which 

 do not stain well. So-called arthrospores are formed, according to 

 Hiippe. 



Habitat. It is said to exist constantly in the waters of the Gan- 

 ges in India. Is frequently found in contaminated drinking water, 

 from rivers, lakes, and wells; also in human feces, which, used as 



FIG. 64. Cholera spirilla. (Kolle and Wassermann.) 



manure, infests vegetables, and spreads the disease. It is found 

 in the intestines during cholera, and after death in other viscera. 



Vital Resistance. Is extremely sensitive to various deleterious 

 agencies. Minute quantities of mineral acids, and other chemical 

 disinfectants, as well as light, heat, and drying, quickly kill it; 

 one percent carbolic kills rapidly. A 1-2,000,000 solution of cor- 

 rosive sublimate destroys in from five to ten minutes. Its thermal 

 death-point is 60 C. for ten minutes (moist heat). 



Chemical Activities. It creates indol in large quantities, and 

 may be detected in peptone cultures merely by the addition of sul- 



