VACCINATION AGAINST SNAKE-VENOM 251 



the first quality that an anti venomous seram ought to exhibit, 

 in order to be capable of being used in the therapeutics of 

 poisoning, is the possession of an antinetirotoxic power as high 

 as possible. This antineurotoxic power is easily obtained by 

 employing cobra-venom for the fundamental immunisation of the 

 horses destined for the production of the serum. 



Antineurotoxic serum thus prepared shows itself perfectly 

 capable of preventing all effects of intoxication from cobra-bites, 

 ■which are much the most frequent in India. In the same way 

 it shows itself quite sufficiently efficacious with regard to Colu- 

 BRINE and ViPERiNE venoms, the neurotoxic activity of which may 

 cause death. But it does not possess any preventive action upon 

 the local effects of hmmorrhagin, to which the noxiousness of 

 certain Vipeeine venoms — such as those of Lachesis — are almost 

 exclusively due. 



In countries in which Vipbrid.^; are very common, we must 

 therefore not confine ourselves to vaccinating the animals that 

 produce serum solely against the neurotoxin of cobra-venom, for 

 instance ; we must prepare these animals, after having immunised 

 them to cobra-venom, by injecting them with progressively increas- 

 ing doses of the various venoms derived from the snakes that are 

 most frequently met with in the district. 



Nothing, moreover, is easier than to train animals vaccinated 

 against cobra-venom to tolerate strong doses of the venoms of 

 Lachesis, Vipera russellii, Crotalus, Hoplocephalus, or Pseudechis. 

 In a few months we succeed in obtaining serums very active 

 against these different venoms. 



Utilising the horse as producer of antitoxin, I have prepared by 

 this method polyvalent serums capable of preventing the local 

 action of Viperinb venoms, and of suppressing in vitro their 

 coagulant and proteolytic effects upon the blood. 



Unfortunately, great as has been the kindness of the many 

 persons who have most obligingly given me their assistance in the 

 pourse of the fifteen years during which I have studied this ques- 



