INOCULATION AGAINST THE VENOM OF SNAKES. 523 



into the mixture. The serum of a rabbit immunised against cobra or 

 viper venom acts indifferently upon all the venoms with which I have 

 experimented. 



The action of the serum is the same in the organism before or after 

 the poisoning as in vitro. If we inject, for instance, into the perito- 

 neum or under the skin of a fresh rabbit one c.c. of serum from an 

 animal immunised against a dose of venom one hundred times fatal, 

 and immediately afterwards inoculate into the muscles of the paw a 

 twice fatal dose of pure venom, the animal will not even bo ill ; and if, 

 after the injection of preventive serum, we wait twenty-four or forty- 

 eight hours before introducing the venom, we shall ascertain that this 

 also produces no toxic effect. Our rabbit is then immunised from the 

 first by the serum it has received. 



On the other hand let us inject into a second rabbit the twice fatal 

 dose of venom which will kill a control animal in about three hours. 

 Let us then, one hour or even an hour and a-half later, when the 

 symptoms of poisoning begin to be manifested (regurgitations, accelera- 

 tion of the heart's action, dyspnoea, slight paresis of the limbs) in- 

 ject into the peritoneum and under the skin at different points of the 

 body 2 c.c. or 3 c.c. of our immunising serum. 



The animal remains for a longer or shorter time in an alarming; 

 condition of malaise, characterised at first by a slight rise of tempera- 

 ture, then by a high fever. Its temperature rises from I to 5 degrees. 

 for 48 hours, then falls gradually to normal. From that time alL 

 danger is at an end. 



The serum of animals immunised against venoms is therefore, not 

 only capable of acting upon these venoms in vitro, but it is also pre-- 

 ventive and therapeutic, exactly like that of animals, immunised against, 

 diphtheria or tetanus. 



The antitoxic power in vitro and the preventive power naturally- 

 vary according to the dose of venom against which the animal which 

 furnishes the serum is immunised. 



The serum of the horse which we furnish at present at the Pasteur 

 Institute at Lille is active to the 20,000th— that is to say, that 

 l/10th c.c. of this serum injected, under the skin, of a rabbit weighing 

 two kilos, is sufficient to preserve it against the injection of a dose of 

 venom capable of killing a. rabbit of the same weight in-' less, thaa eight 



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