xvi] VIBRIO AND SPIRILLUM 441 



remain longer and gain a footing in the intestine." This 

 conclusion appeared quite justifiable, inasmuch as by direct 

 experiment it had been proved that the contents of the 

 stomach pass too rapidly through the small intestine, and 

 since the comma bacilli could only unfold their poisonous 

 action, i.e., could multiply and produce the chemical poison, 

 if they had time to remain there and to multiply. Conse- 

 quently if they were not delayed on their passage through 

 the small intestine they would not multiply there, and once 

 in the CEecum, where the reaction is acid, they would 

 become harmless. 



In order to produce a condition similar to the one in the 

 above single successful experiment on the guinea-pig, Koch 

 injected tincture of opium into the peritoneal cavity after 

 the introduction of the sodium carbonate and the cultiva- 

 tion of the comma bacilli : this answered well for achieving 

 positive results. Immediately after the administration of 

 the 10 CO. of the culture of the comma bacilli, r cc. of 

 German tincture of opium for every 200 grms. of the 

 animal's body-weight were injected into the peritoneal cavity : 

 the animal became thereby narcotised for half an hour, and 

 died after one and a half to three days, with the same 

 S3'mptoms as the above guinea-pig. " Eighty-five guinea- 

 pigs have been infected in this way with cholera.'' 



Now the following criticisms can, I think, be justly 

 applied to these experiments: (i) According to Koch's 

 own showing, it cannot be the narcosis which is essential, 

 even allowing for the present that relaxation of the in- 

 testine may have been produced by the intraperitoneal 

 injection of opium tincture, since alcohol alone was in- 

 jected by Koch into the peritoneal cavity, and he says that 

 thereby " we were most successful in making the animals 

 susceptible to the cholera infection." (2) Can narcosis 



