1896.] on Immunisation against Serpents' Venom. 123 



administered, reserving, for a few minutes, a description of the 

 results that were obtained when the venom itself was used. 



The first experiments were made with the object of determining 

 if, by repeating the process followed in the production of immunity, 

 with the exceptions that the administrations were by the stomach, 

 and that antivenene was substituted for venom, an animal could be 

 protected against the poisonous effects of venom. With this object, 

 a white rat received on alternate days during several weeks, doses of 

 antivenene, which were gradually increased from 1 to 10 c.c. per 

 kilogramme, and then, by subcutaneous injection, one-and-a-half the 

 minimum-lethal doses of cobra venom ; with the result that death was 

 not produced. Other white rats received 10 c.c. per kilogramme on 

 each of four days, and on the fifth day 15 c.c. i3er kilogramme of 

 antivenene, and still recovery took place when one-and-a-half and 

 one-and-three-quarters the minimum-lethal dose of venom was injected 

 under the skin. To other white rats, 10 c.c. and 15 c.c. of antivenene 

 were given by the stomach, on two successive days, and on the 

 second day, one-and-a-half the minimum-lethal dose of venom, 

 and the result also was that death was prevented. It was thus 

 suggested that a single administration of antivenene might be as 

 efficacious as a succession of administrations ; and accordingly, the 

 antidotal efficiency of single doses of 7 and of 10 c.c. per kilogramme 

 was tested, in some instances three hours, in others two days, and 

 of 15 c.c. three days before one-and-a-half the minimum-lethal dose 

 of venom was subcutaneously injected ; and in all cases the animals 

 recovered. When, however, 5 c.c. j)er kilogramme of antivenene 

 was thus administered three hours before, and 10 c.c. per kilogramme 

 three days before, one-and-a-half the minimum-lethal dose of venom, 

 the animals died. 



The experiments have not as yet been carried farther, but I hope 

 to continue them so that the limits of the antidotal power of the 

 antivenene, and the duration of the protection after single doses of 

 antivenene, may be defined. Enough has, however, been done to 

 prove that the stomach administration of antivenene, equally with its 

 subcutaneous administration, confers protection against lethal doses 

 of serpents' venom, and to justify the use of antivenene by the former 

 and more convenient method for the purpose of securing protection 

 for, at least, a period of several days after a single administration 

 of the protecting antidote. 



The facts hitherto narrated are sufficient to establish that the 

 protection acquired by animals as a result of the administration of 

 venom is not chiefly, or even to any important degree, caused by the 

 venom having produced a tolerance by accustoming the body, as it 

 has been expressed, to the presence of the venom — alth<;ugh a certain 

 degree of this protection may possibly be due to such accustoming — 

 but rather to the presence in the body, as a result of the introduction 

 into it of venom, of a definite substance having antivenomous qualities. 

 Notwithstanding the powerful protective and antidotal action of this 



