ASIATIC CHOLERA 149 



and by 60 C. (140 F.) in ten minutes ; neither do 

 they retain their vitality for any length of time in 

 soil or water. They may retain their vitality for 

 several days upon the surface of fruit and vege- 

 tables, if kept in a cool, moist place. Whether 

 there is any multiplication of cholera spirilla in im- 

 pure water is still a matter of doubt, although there 

 can be no doubt that they retain their vitality in 

 impure water for several days, as cholera-infected 

 drinking water is the usual source of infection. 



Cholera Infection in Man. The proof of the con- 

 nection of the cholera spirillum with Asiatic cholera 

 in man has been demonstrated several times in 

 laboratory workers who by accident or design have 

 become infected by the materials with which they 

 were working; all of these instances occurring when 

 no cholera existed in the country. 



The spirilla are found in the intestines, but do not 

 enter the blood or internal organs. The small intes- 

 tines are mostly affected, the epithelium being shed, 

 and the characteristic " rice-water" discharges con- 

 taining enormous numbers of spirilla, almost pure 

 cultures. Like typhoid fever, cholera is contracted 

 largely through polluted drinking water, i.e. the 

 spirilla must enter the alimentary tract, and in- 

 fected drinking water is the common source. Un- 



