CHOLERA. 165 



stomach to the caecum in a few minutes ; the peristaltic 

 action of the intestine causing such rapid passage of the 

 bacillus that it was completely powerless to produce any 

 characteristic symptoms of cholera, a fact the importance of 

 which was accentuated when it was found that the only 

 guinea pig in which any choleraic symptoms were observed, 

 and in which there was any increase in the number of bacilli 

 in the small intestine, was probably suffering from an attack 

 of peritonitis, due to the animal having aborted just previous 

 to the experiment a condition in which, as has long been 

 recognized, there is invariably interference with the peristaltic 

 action of the intestine. It was possible, then, that this second 

 factor might be neutralized by the introduction into the 

 peritoneal cavity of some reagent, which would by its 

 action cause partial or complete paralysis of the small 

 intestine. For this purpose he first used opium, but he 

 afterwards found that alcohol was equally efficacious. After 

 administering the soda solution, and injecting into the 

 stomach of the guinea pig 10 c.c. of broth, to which one or 

 several drops of a pure cultivation of bacilli had been added, 

 he injected into the abdominal cavity tincture of opium, in 

 the proportion of i c.c. to every 200 grammes of the animal's 

 weight ; the results he obtained were indeed startling. 



Of course objections were raised to the method, and it was argued that some 

 of the animals died from an overdose of opium, some from blood poisoning, 

 and so on. Subsequent observers found, indeed, that the dose of opium 

 was somewhat too large, as some animals experimented on never awoke 

 from the opium sleep. Macleod, of Shanghai, found that he obtained the 

 best results by giving " repeated doses of I c.c. or less of the tincture till 

 the animal was stupefied sufficiently to lie on the side or back for ten 

 minutes when placed in that position." " Several times," he says, "the full 

 dose recommended by Koch had to be given, but usually a smaller one 

 sufficed." Control-animals treated, according to Macleod's method, and in 

 all respects in the same way, with the exception that they received sterilized 

 broth instead of cholera material, always recovered. 



The contents of the bowel or dejecta from cholera patients 

 passed into the stomachs of guinea pigs so prepared, pro- 

 duced cholera symptoms and death. Giving the results of 

 of his experiments, Macleod states that from one of the 

 animals that died after a dose of cholera material, the small 

 gut contents were collected into a sterilized vessel, and 

 injected (by means of a fine indiarubber flexible catheter) 

 in doses of 2 c.c. into the stomach of two other animals. 



