xvi] VIBRIO AND SPIRILLUM 439 



animals there which Hve together with human beings. 

 One would suppose, then, that in that country, where 

 cholera exists in all parts continually, animals must often 

 receive into their digestive canal the infectious matter of 

 cholera, and in just as effective a form as human beings, 

 but no case of an animal having an attack of cholera has 

 ever been observed there. Hence I think that all the 

 animals on which we can make experiments, and all those, 

 too, which come into contact with human beings, are not 

 liable to cholera, and that a real cholera process cannot be 

 artificially produced in them." 



Kochji starting from the idea that the comma bacilli are 

 killed by the gastric juice, and that in order to develop their 

 pathogenic powers they have to get unscathed and living 

 into the small intestine — their natural breeding-ground — it 

 occurred to him that this difficulty might be obviated by 

 first neutralising or making alkaline the contents of the 

 stomach, and introducing per os the comma bacilh. He 

 therefore kept guinea-pigs for twenty-four hours without 

 food, and then injected into their stomach per os 5 cubic 

 centimetres of a 5 per cent, watery solution of carbonate of 

 soda. This does not noticeably injure the stomach, and, 

 as direct observation proved, kept the contents of the 

 stomach in an alkahne condition for three hours. Some 

 minutes (twenty) afterwards he introduced by catheter 10 

 cubic centimetres of a cultivation of the comma bacilli in 

 meat infusion. 



The result is noteworthy. Seven guinea-pigs thus ex- 

 perimented upon remained perfectly well : " They were 

 killed after twenty hours," says Koch, "and the contents of 

 their stomach, intestine, and caecum were examined by 

 gelatine plate cultivations. In six of the seven animals the 



^ Second Conference on Cholera, Berlin, May, 18S5. 



