INOCULATION AGAINST TUB VENOM OF SNAKES. 521 



travelling in Africa, I was again stung by a scorpion winch caused me so 

 much pain, that for eight days I thought I should die or lose my arm.' 



In France, in the departments where vipers are very numerous, 

 certain individuals who have a reputation for their skill in catching 

 these reptiles enjoy a complete immunity against their bites. One of 

 these snake-hunters, who lives in the Jura and to whom I am indebted 

 for a portion of the venom used in my experiment, can allow himself 

 to be bitten several times in the same summer with impunity. Each 

 season he intentionally gets bitten once or twice in order to preserve 

 his immunity; if he did not take this precaution, he would expose 

 himself, he asserts, to grave risks. Thus it is possible for man, under 

 certain circumstances, to acquire the power of resisting the poisonous 

 effects of snake-bite. We shall see that the same is true of animals. 



As far back as 1887 Sewall (Journal of Physiology) had shown that 

 the organism can become gradually resistent to the action of snake- 

 poison just as to that of infectious virus such as charbon. By inject- 

 ing very small quantities of poison he succeeded in rendering animals 

 refractory to the effects of doses large enough to kill rapidly animals 

 which had not been thus prepared. 



Somewhat later, in 1 889, Kaufmann obtained the same result in the 

 course of his studies upon the poison of the viper. He succeeded in 

 getting animals to stand quantities of poison two or three times fatal. 



In a communication to the Society of Biology (February 10th 9 

 1894) I mentioned the methods by which I succeeded in rendering 

 rabbits and guinea-pigs really immune to considerable doses of poison, 

 and I demonstrated that an animal which is immune to the poison of 

 the cobra, for instance, is so also to that of the viper or Hoplocepkalus 

 and vice versa, 



M.M. Phisalix and Bertrand also announced {Acad, des 

 Sciences, February 5th, and Soc. de Biologie, February 10th, 1894) 

 that they had been able to secure to the guinea-pig immunity against 

 the poison of the viper by means of preventive inoculations of this 

 same poison heated to 80? in a bain marie for 10 to 15 minutes. 



One can, therefore, render animals refractory to the inoculation of a 

 fatal dose of venom either by accustoming them to it by repeated 

 doses, or, as I have pointed out, by mixing alkaline hypochlorites or 

 chloride of gold with the venom, or by the venom modified by heat. 



