THE PHYSIOLOGICAL ACTION OF SNAKE-VENOMS 173 



fightinf^^ fishes, tliat the natives of Annam rear in aquariums in 

 order to witness their combats and make bets on them. The 

 fislies died five liours after intramuscular inoculation with a dose 

 which kills a pigeon in twenty minutes. 



]Many invertebrates, such as leeches, crayfish, and gastropod 

 molluscs (snails), are killed by inoculation with very small quantities 

 of venom. 



C. — Deteuminatiox of the Lethal Doses of Venom fou 

 Different Species of Animals. 



It is very difficult to specify, even within broad limits, the dose 

 of venom necessary to kill a hunmn being. The quantity of poison 

 introduced by the bite of a venomous snake depends, as has alreadv 

 been stated, upon a large number of factors, and, very fortunately, 

 this quantity is not always sufficient to cause death. Thus in 

 India, that is to say in the region in which snakes are most 

 numerous and^ most dangerous, the mean mortality seems scarcely 

 to exceed 85 to 40 per cent., so far as it is possible to judge from 

 ofticial statistics. But, by experimenting upon animals, and com- 

 mencing with known doses of venom, which has first been dried 

 and then dissolved again in always the same quantity of physio- 

 logical saline solution or sterile distilled water, we can determine 

 exactly, for each kind of venom and for each species of animal, 

 the minimum lethal dose per kilogramme of animal. 



The entire series of data collected by investigators who have 

 devoted themselves to this study may be summed up as follows : — 



Minimal doses lethal in twenty-four hours for a guinea-pig 

 weighing from 600 to 700 grammes :-- 



COL UBRID.-E. 



Venom of Naja tripudiauH ... ... ... 0-0002 f,n-ainnir 



,, BiDu/arns ctcrnh'u.'i ... ... O'OOOG ,, 



,, Naja haje ... ... ... ... U'OO.'J ,, 



