120 THE BACTERIA IN ASIATIC CHOLERA. [CH. 



experiment was therefore modified by introducing the 

 substances direct into the intestines of the animals. The 

 belly was opened, and the liquid was injected immediately 

 into the small intestine with a Pravaz's syringe. The 

 animals bore this very well, but it did not make them ill. 

 We also tried to bring the cholera-dejecta as high as possible 

 into the intestines of monkeys by means of a long catheter. 

 This succeeded very well, but the animals did not suffer 

 from it. I must also mention that purgatives were previously 

 administered to the animals in order to put the intestine into 

 a state of irritation, and then the infecting substance wasgiven, 

 without producing any different result. The only experi- 

 ment in which the comma- bacilli exhibited a pathogenic 

 effect, which therefore gave me hope at first that we should 

 arrive at some result, was that in which pure cultivations 

 were injected directly into the blood-vessels of rabbits or into 

 the abdominal cavity of mice. Rabbits seemed very ill after 

 the injection, but recovered after a few days. Mice, on the 

 contrary died from twenty-four to forty-eight hours after the 

 injection, and comma-bacilli were found in their blood. Of 

 course they must be administered to animals in large quan- 

 tities ; and it is not the same as in other experiments 

 connected with infection, where the smallest quantities of 

 infectious matter are used, and yet an effect is produced. 

 In order to arrive at certainty as to whether animals can be 

 infected with cholera, I made inquiries everywhere in India 

 as to whether similar diseases had ever been remarked 

 amongst animals. In Bengal I was assured such a pheno- 

 menon had never occurred. This province is extremely 

 thickly populated, and there are many kinds of animals there 

 which live together with human beings. One would suppose, 

 then, that in this country, where cholera exists in all parts 

 continually, animals must often receive into their digestive 



