19-2 VENOMS 



Antivenomous anticoliihrine serara, that is to say, that fur- 

 nished by horses vaccinated against the venoms of the Cobra and 

 the Krait, does not prevent coagulation by coagulant venoms. 

 This need not surprise us, since the coagulant substances in venoms 

 are destroyed by heating, and the animals vaccinated in order to 

 obtain antitoxic serum are usually inoculated exclusively with 

 heated venoms. 



It is easy, however, to obtain active serums specific against 

 the coagulant venoms ; it is sufficient to treat these animals by 

 inoculation with progressively increasing doses of the same venoms 

 unheated. I have had no difficulty in achieving this result with 

 small laboratory animals (guinea-pigs and rabbits) and also with 

 the horse, but I have never had at my disposal a sufficient amount 

 of the venoms of Lachesis or Vipera riis>ieUii to undertake with 

 them the regular acquisition of large quantities of horse-serum, 

 at once antlneurotoxlc and anticoagukoif. Tlie preparation of such 

 a serum, nevertheless, presents much interest for certain countries, 

 such as Burma, where the Daboia (^Vipera m.^.'^ellii} is almost as 

 common as the Cobra, and Brazil, where nearly all the casualties 

 due to venomous snakes are produced by Lachesis.^ 



II. — ANTICOAGULA.NT VeNOMS. 



Contrary to what is observed with the venoms of VirEiiiD.E in 

 general, all the venoms of Colubrid.e and, as exceptions to the 

 rule, the venoms of some North American Crotalin^ {Ancistrodon 

 contortrix and A. pisclvorus) suppress the coagulability of the 

 blood in vivo and in vitro. It is, however, important to observe 

 that, in vivo, the blood remains fluid after death only if the dose of 

 venom absorbed has been sufficient. In vitro this phenomenon is 

 easier to study, and has been the subject of several important 

 memoirs. 



' At the Serum-therapic Laboratory of Sfio Paulo (Brazil), Dr. Vital, Brazil, 

 is at the present time preparing serum specific against Lachesis-yQuonx 



