310 



SNAKE- VENOM 



the same way against cobra-venom. He also made 

 experiments to ascertain whether the blood-serum of 

 these animals acted as an antidote to the venom. 

 Then came the work of Calmette, Fraser, Phisalix, 

 Bertrand, Martin (Australia), Stephens, and Meyers. 

 Professor Fraser's observations on the antidotal 

 properties of the bile are, of course, of the utmost 

 importance ; not only in preventive medicine, but 

 also in physiology. The results obtained by 

 Calmette are a good instance of the fineness and 

 accuracy of the experimental method. It is to be 

 noted that the animals were inoculated with a fine 

 needle, not thrust into cages with snakes, as at 

 zoological gardens ; and that an animal thus 

 poisoned has a painless death. The different 

 venoms were measured in decimal milligrammes, 

 and their potency was estimated according to the 

 body-weight of the animal inoculated. As with 

 tetanus, so with snake-venom, there must be a 

 standard, or "unit of toxicity": — 



" The following table gives the relative toxicity, 

 for i kilogr. of rabbit, of the different venoms that 

 I have tested. To denote this toxicity I use terms 

 such as Behring, Roux, and Vaillard used for the 

 toxin of tetanus, taking the number of grammes of 

 animal killed by one gramme of toxin : — 



1. Venom of naja 0.25 mgr. per kilogr. of rabbit. 



One gramme of this venom kills 4000 kilogrammes 



of rabbit ; it has, therefore, an activity of. 4,000,000 



2. Venom of hoplocephalus 0.29 mgr. ... 3,450,000 



3. Venom of pseudechis 1.25 mgr. ... 800,000 



4. Venom of pelias berus 4.00 mgr. ... 250,000 



