1895.] Zoology. 937 
dose until, in time, he can inject fifty times the minimum lethal dose 
into the animal’s blood without producing any bad effects. This ani- 
mal is immunized, and its blood serum, injected into another animal 
of the same size and weight, will prevent the action of snake poison 
when injected. This immunized blood serum is called, by its discoverer, 
antivenine. 
In experimenting with rabbits it was found that the blood serum of 
one which had received thirty times the minimum lethal dose was as 
effective in its antitoxic properties as that of one which had received 
fifty times the minimum lethal dose. 
The antivenine obtained from a horse was found to be twice as pow- 
erful as that from the rabbit. In immunizing a horse the same 
method is adopted as is used for the rabbit, viz.: to begin by injecting 
a small dose; then to give regularly increasing doses, every few days, 
until fifteen times the minimum lethal dose is administered. The blood 
serum from from a horse thus immunized is found to be so powerful 
an antivenine that a hundredth, and even the thousandth part of a 
cubic centimeter per kilogramme of animal was sufficient to prevent 
death from the minimum lethal dose of the venom. For a horse to 
arrive at this stage of immunism requires four months and a half. 
The antivenine can be kept for use in two forms, liquid and dry, of 
which the latter is preferable as less liable to decomposition. 
In the course of his experiments, Prof. Fraser discovered that dietary 
has an effect upon venom poisoning. Ifa herbivorous animal be put 
upon a flesh diet, the effect of venom upon it is lessened. 
Through another set of experiments Prof. Fraser concludes that the 
deadly effects of serpents’ venom is due to its action on the blood. 
Venom is almost inert when introduced into the stomach. Neverthe- 
less, an animal may be immunized by the administration of poison into 
its stomach. This fact is due to the absorption of the poison by the 
blood. This may account for the immunity from snake-bites said to 
be enjoyed by some of the snake-charmers of India, who eat the poison- 
glands of the snakes. 
Snakes themselves have been noticed to be impervious to the effects 
of the poison. This may probably be due to the absorption of venom 
shed from poison-glands through the mucous surfaces of the mouth, or 
by the blood-vessels and lymphatics passing to and from the glands. 
In some cases it may be secured by serpents devouring other members 
of their tribe. 
It is now within the range of certainty that, at no distant date, Dr. 
Fraser will be able to have sufficient quantities of antivenine from the 
