112 BACTERIOLOGICAL METHODS 



The tubes must be fastened to suitable stands or supports to pre- 

 vent, as much as possible, the mechanical mixing of the contents 

 after the inoculations are made. It is perhaps self-evident that 

 concentrates or high contaminations are to be inoculated into the 

 tubes. The tubes should be large enough to hold at least 50 to 

 100 cc. of medium and suspected water in equal parts. 



12. Possible Contamination of Food Substances with the Cholera 



Bacillus 



In the United States the contamination of foods with the 

 cholera vibrio is far less hkely than the contamination with the 

 typhoid fever germ, yet it is a possibility to be reckoned with. 



Fig. 34. — Spirillum cholerm, from broth culture, stained with fuchsin (X looo). — 

 {Stitt, after Kolle and Wassermann.) 



The cholera germ is found in the feces (but not in the urine) of 

 patients and in the feces of carriers, in which regards it resembles 

 the typhoid bacillus. It is less resistent than the typhoid organ- 

 ism, disappearing rapidly from the stools, usually in 5 to 10 

 days. Under certain conditions (as in fresh water supplies) 

 the infection may endure for longer periods, for several months 

 and more. Like the typhoid germ, it shows some marked tend- 



