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SNAKE-VENOM 



neutralise in vitro (in a glass test-tube) the toxicity 

 of i mgr. of naja- venom." 



By 1894 he had found that the serum of an 

 animal, thus immunised by graduated doses of one 

 kind of venom, neutralised other kinds of venom : — 



" If 1 mgr. of cobra- venom, or 4 mgr. of viper- 

 venom, be mixed, in a test-tube, with a small 

 quantity of serum from an immunised rabbit, and 

 a fresh rabbit be inoculated with this mixture, it 

 does not suffer any discomfort. It is not even 

 necessary that the serum should come from an 

 animal vaccinated against the same sort of venom 

 as that in the mixture. The serum of a rabbit 

 immunised against the venom of the cobra or the 

 viper acts indifferently on all the venoms that I have 

 tested.'' 



In 1894 ne na d prepared enough serum for the 

 treatment to be tried by his own countrymen 

 practising in some of the French colonies. In 

 April 1895, ne gave the following account of his 

 work : — 



" I have immunised two asses, one having re- 

 ceived 220 mgr. of naja- venom from 25th September 

 to 31st December 1894, an d the other 160 mgr. 

 from 15th October to 31st December. The serum 

 of the first of these two animals has now reached 

 this point, that half a cubic centimetre destroys 

 the toxicity of 1 mgr. of naja-venom. Four cubic 

 centimetres of this serum, injected four hours before 

 the inoculation of a dose of venom enough to kill 

 twice over, preserve the animal in every case. It 



