1 52 BACTERIA. 



Asia Minor and in Europe, that many observers should be 

 anxious to find out the ultimate cause of the disease, and 

 as early as 1848 Virchow, and in 1849 PoUchet, Brittan, and 

 Swaine found numbers of vibriones in the discharges of 

 choloraic patients, without, however, being able to assign 

 to them or prove for them any specific r6le in the causation 

 of the disease. 



Following up these researches Philippe Pacini, setting 

 himself to look for a causal agent, frequently found in 

 cholera stools small micro-organisms which were charac- 

 terized by active and peculiar movements. These observa- 

 tions, however, as well as those of Klob, who looked upon 

 the cause of cholera as an accumulation of fungi in the 

 intestines, and those of Boehm and Hallier (all published 

 in 1867), who believed that they had found the cause in a 

 peculiar fungus which was found to grow in certain forms 

 of grain imported from India, not only did not receive 

 adequate proof, but were, like all preceding observations, 

 entirely unreliable. Then followed the experiments by 

 Hayem and Raynaud, carried on during the epidemic of 1873, 

 which, however, again were equally futile and without definite 

 results, and it was not until Koch, going out with the 

 German Cholera Commission to Egypt and India, was able 

 to demonstrate a peculiar species of bacterium as the causal 

 agent that any definite proof of the micro-organismal nature 

 of the contagium of the disease could be obtained. 



Since that time, however, the amount of work published 

 on the subject has been so great that cholera has now a 

 special " literature " of its own. The report of the German 

 Commission was speedily followed by that of the French 

 Government, who sent out MM. Straus, Roux, Nocard, and 

 Thuillier, the last of whom fell a victim to his assiduity and 

 zeal in carrying on the work of investigation in Egypt. In 

 this country Klein and Heneage Gibbes, Cunningham and 

 Lewis, Roy, Graham Brown and Sherrington, Watson 

 Cheyne, and Macleod have, with very different voices, some 

 supporting Koch's verdict, others opposing it, reported on 

 the subject ; with the general result that until further and 

 more convincing opposing evidence is forthcoming, Koch's 

 comma bacillus, of which the following is a brief descrip- 

 tion, must be looked upon as the causa causans of the 

 disease. 



