244 



VENOMS 



or colleagues, and on the other to the valuable co-operation of the 

 Colonial Governments of Indo-China, the French Settlements in 

 India, and Martinique, I soon received poisonous snakes and dried 

 venom in abundance. 



Fig. 93. — Vaccinatikg a Hoese against Venom at the Pasteur Institute at Lille. 



After this I was not long" in pushing the vaccination of a few 

 horses until I made them resist, in a single injection, 2 grammes of 

 dry cobra-venom, a dose about eighty times lethal ; for I was able 

 to satisfy myself that about 0"0'25 gramme of cobra-venom was 

 sufficient to kill fresh horses in from twelve to twenty-four hours. 



The immunisation of horses to this very high degree of tolerance 

 of venom is not obtained without difficulties; many animals sue- 



