26 Proceedings of Royal Society of Edinburgh. [sess. 
comitant of the collapse stage of Asiatic cholera in Europe, Egypt, 
India, &c. ; though it has not been found apart from the disease ; 
though it occurs in that part of the body specially affected, — the 
intestinal canal, — and disappears from it with the disease ; while it 
may he regarded as pathognomic, it has yet to be proved to be the 
cause of the disease. 
Many workers have failed to reproduce the disease. Nicati and 
Rietsch, believing that Koch’s organism did not reach the intestine 
alive when given by the mouth, opened the abdominal cavity of 
dogs, and injected cultivations of the bacillus into the duodenum, 
both with and without ligation of the bile duct. Under these con- 
ditions, they announced that they had reproduced the disease. Yan 
Ermengen, Koch, Watson Cheyne, and others repeated the experi- 
ments with the same results, but the operation was regarded by 
many as open to strong objection, and more probably the cause of 
death than cholera. The experiment is not free from objection. 
At the second Berlin Congress in 1885, Koch announced that he 
had succeeded in reproducing the disease in guinea pigs without 
opening the abdomen. Finding the reaction of the contents of the 
guinea pig’s stomach always strongly acid, he neutralised this 
reaction by injecting into the stomach a solution of soda. He then 
found that though the organism was thus enabled to pass through 
the stomach alive, no disturbance followed its presence in the small 
intestine. Many experiments of this kind failed ; only one animal 
took sick, and died with signs like those in cholera, and this animal 
had aborted shortly before the experiment. It was observed, too, 
that there was some degree of peritonitis present as one of the 
results of the abortion. Koch then made some experiments, observ- 
ing the condition of the animal’s digestion, more especially in the 
small intestine, when he found that its contents passed through that 
part of the gut in a very short time. Coloured foods were seen to 
pass from the stomach to the caecum in a few minutes. It occurred 
to him that, as in Nicati and Rietsch’s experiments, the more the 
bowel was handled the more successful they were, and vice versa, 
their success might be due to the lessening of the peristaltic action 
of the gut, in consequence of the handling. The success in the 
guinea pig that had aborted, and in which peritonitis was present 
— a condition, too, accompanied by interference with peristalsis — 
