60 CHOLERA 



dies in the water of the Ganges, which is feebly acid. How quickly 

 it dies in stools depends on many conditions such as dampness and light. 



No lower animal, however intimate the contact with infected men 

 may be, is known to develop cholera. This disease seems to be, at 

 least under natural conditions, confined exclusively to the human 

 species. Furthermore, no one has succeeded in inducing a true cholera 

 in an animal by inoculation. However, some of the attempts to accom- 

 plish this purpose have been partially successful and are of sufficient 

 interest to justify brief review. Filter paper impregnated with cholera 

 cultures fed to mice induces diarrhea, but filter paper alone has the 

 same effect. Large quantities of cholera cultures fed to pigs cause 

 death, but cultures of many other bacteria produce like results. 



Nikali and Rietsch opened the abdominal cavities of guinea-pigs, 

 tied the bile duct in order to exclude the bactericidal action of this 

 fluid, and injected cholera cultures into the duodenum. In the intes- 

 tines of the recovered animals the cholera bacilli multiplied and the 

 epithelial lining of the intestines was found altered. Other bacteria 

 behave in a similar manner. Koch neutralized the stomach contents 

 with soda and then introduced cholera culture into this organ through 

 a tube. At the same time the animals were stupefied with opium from 

 which they soon recovered, but the next day became ill and died on 

 the second or third day in collapse. After death the intestine was 

 found to contain a colorless fluid consisting of a pure culture of the 

 comma bacillus. Like results may be secured with other vibrios. 

 Indeed, Metschnikoff did better in his experiments on rabbits with 

 the Vibrio Maszanah which is known to be quite different from Koch's 

 comma bacillus. He polluted the teats of a mother rabbit with this 

 culture and found that at least half of the nursing young died of a 

 choleraic diarrhea. Moreover, when the sick young rabbits were placed 

 in a cage with healthy fellows from another litter, many of the latter 

 became infected. Thomas injected cholera cultures into the ear veins 

 of rabbits. After a few days the animals died, and inflammatory 

 changes were found in the walls of the intestines and cholera bacilli 

 in the intestinal content. 



Many bacteria when injected intravenously find their way into 

 the intestine and may induce the same changes in the intestinal walls. 

 Cholera cultures injected into the abdominal cavities of guinea-pigs 



