CHAPTER XVII. 

 CHOLERA. 



Introductory. It is no exaggeration of the facts to say 

 that previously to 1883 practically nothing of value was 

 known regarding the nature of the virus of cholera. In 

 that year Koch was sent to Egypt, where the disease had 

 broken out, in charge of a commission for the purpose of 

 investigating its nature. In the course of his researches 

 he discovered the organism now generally known as the 

 " comma bacillus " or the " cholera spirillum." He found 

 this organism in the discharges from the intestine, and also 

 post mortem in the intestinal contents and in certain parts 

 of the intestinal mucous membrane. Later he made more 

 extensive observations in India, and also investigated two 

 cases at Toulon, nearly 100 cases in all being examined, 

 and came to the conclusion that the association of this 

 organism with the disease was constant. The organism, 

 moreover, was one which was quite unknown before, and 

 numerous observations made in other diseased conditions 

 failed to show its presence. He also obtained pure cultures 

 of the organism from a large number of cases of cholera, 

 and described their characters. The results of his re- 

 searches were given at the first Cholera Conference at 

 Berlin in 1884. Next year he brought forward experi- 

 ments on animals which, he considered, supported his view 

 as to the relationships of the organism to the disease. The 

 general conclusions at which Koch arrived received, in the 



