1888 - 89 .] Messrs Macleod and Milles on Asiatic Cholera . 27 
suggested the same explanation, viz., that the normal peristalsis in 
this animal did not afford sufficient time for the multiplication of 
the organisms, so that they and their products might he hurried 
through the small gut before they had multiplied to the extent 
necessary to set up the changes constituting the disease, and from 
the acid reaction of the contents of the caecum they were unable to 
multiply and do mischief in that part of the bowel. Recognising 
in opium a drug that would lessen the peristalsis of the small gut, 
he made experiments with it, and finally decided that the injection 
of opium tincture into the peritoneal cavity was the surest means of 
bringing about this loss of peristalsis, without otherwise injuring 
the animal. In this way Koch claims that he has reproduced the 
disease, but his experiments are not as yet regarded in this country 
as sufficient, and the objections urged are : — 
1. The symptoms produced in the guinea pig are not those of 
cholera in man, there being no purging, vomiting, or cramps. 
There seems to be little doubt that Pasteur has produced hydro- 
phobia both in dogs and rabbits by material taken from the disease 
in man ; but there seems to be as little doubt that the symptoms of 
that disease in man, the dog, and the rabbit, do not correspond in 
any two out of the three. Is it to be expected that cholera in the 
guinea pig will present the same symptoms as in man ? Will any 
one maintain that a given case in man without vomiting, purging, 
or cramps is not one of Asiatic cholera? Such cases are certainly 
met with in man, and what is here the exception may be the rule 
in the guinea pig. 
2. It is objected that death and the post-mortem appearances 
in the animal experimented with may be the result of some other 
cause than cholera. 
There is some truth in this objection, as animals may die, for 
instance, from mechanical injuries with the catheter used to inject 
the stomach; from the injection of fluid into the windpipe; from 
needle injuries in the abdomen ; from an overdose of opium ; from 
peritonitis or septicaemia. Animals dying from these causes, and 
even those presenting any injury which might not have been of 
itself sufficient to cause death, have been rejected from the experi- 
ments recorded below. Such accidents might have been passed 
over without comment ; but in the interest of any one having to 
