454 CHOLERA 



eluding Koch. Thinking that probably the spirillum, when introduced 

 by the mouth, is destroyed by the action of the hydrochloric acid of 

 the gastric secretion, Koch first neutralised this acidity by administering 

 to guinea-pigs 5 c.c. of a 5 per cent, solution of carbonate of soda, and 

 some time afterwards introduced a pure culture into the stomach by 

 means of a tube. As this method failed to give positive results, he 

 tried the effect of artificially interfering with the intestinal peristalsis 

 by injecting tincture of opium into the peritoneum (1 c.c. per 200 grm. 

 Aveight), in addition to neutralising as before with the carbonate of 

 sodium solution. The result was remarkable, as thirty out of thirty- 

 five animals treated died with symptoms of general prostration and 

 collapse. Death occurs after a few hours. Post mortem the small 

 intestine is distended, its mucous membrane congested, and it contains 

 a colourless fluid with small flocculi and the cholera organisms in 

 practically pure cultures. Koch, however, found that when the spirilla 

 of Finkler and Prior, of Deneke, and of Miller (vide infra), were 

 employed by the same method, a certain, though much smaller, 

 proportion of the animals died from an intestinal infection. Though 

 the changes in these cases were not so characteristic, they were sufficient 

 to prevent the results obtained with the cholera organism from being 

 used as a demonstration of the specific relation of the latter to the 

 disease. 



Within later years some additional facts of high interest have been 

 established with regard to choleraic infection of animals. For example, 

 Sabolotny found that in the marmot an intestinal infection readily takes 

 place by simple feeding with the organism, there resulting the usual 

 intestinal changes, sometimes with hjemorrhagic peritonitis the 

 organisms, however, being present also in the blood. And of special 

 interest is the fact, discovered by Metchnikoff, that in the case of 

 young rabbits shortly after birth a large proportion die of choleraic 

 infection when the organisms are simply introduced along with the 

 milk, as may be done by infecting the teats of the mother. Further, 

 from these animals thus infected the disease may be transmitted to 

 others by a natural mode of infection. In this affection of young rabbits 

 many of the symptoms of cholera are present. Many of these experi- 

 ments were performed with the vibrio of Massowah, which is now 

 admitted not to be a true cholera organism, others with a cholera 

 vibrio obtained from the water of the Seine. 



It will be seen from the above account that the evidence 

 obtained from experiments on intestinal infection of animals, 

 though by no means sufficient to establish the specific relation- 

 ship of the cholera organism, is on the whole favourable to this 

 view, especially when it is borne in mind that animals do not in 

 natural conditions suffer from the disease. 



Experiments performed by direct inoculation also supply 

 interesting facts. Intraperitoneal injection in guinea-pigs is 

 followed by general symptoms of illness, the most prominent 

 being distension of the abdomen, subnormal temperature, and, 

 ultimately, profound collapse. There is peritoneal effusion, 

 which may be comparatively clear, or may be somewhat turbid 



