VOL. LXX.] PHILOSOPHICAL TRANSACTIONS. 657 



in multiplying my experiments, and varied them in proportion as I found less 

 agreement in the results. To this perseverance, or obstinacy as I may call it, I 

 chiefly owe the new discoveries which, I believe, I have made, concerning the 

 2 poisons of the viper and the Ticunas. 



Having laid bare the sciatic nerve of a rabbit, I passed under it a fine rag 

 several times doubled, and put on the nerve a little cotton well soaked in the 

 American poison, thickened to a syrup. I covered the nerve with the same rag 

 that the poison might not run over the opened muscles of the animal, and sewed 

 up the skin as usual. After 10 minutes the rabbit began to have convulsions 

 and to totter; it then fell, with all the signs accompanying the effects of the 

 poison, and died soon after. I repeated the same experiment on another rabbit 

 and took care to wrap up the poisoned nerve with rags still better than before. 

 This 2d rabbit showed no signs of being affected for 10 hours, during which I 

 observed it; but looking at it after 2 hours more, I found it had been dead a 

 little while, as it was still warm. 



I suspected that the poison applied to the nerve, which was considerable in 

 quantity, might at length have penetrated through the rags, and, uniting with 

 the humours of the parts cut, have extended its action to the muscles, and the 

 adjacent parts. I was under the necessity therefore, of either diminishing the 

 quantity of poison, or increasing the rags, to prevent any diffixsion of the poison 

 through them : I adopted the latter as the more secure way. I detached the 

 sciatic nerve of a rabbit as usual, and introduced below it a very fine rag, often 

 doubled. I put the bit of cotton, well soaked in the poison, on the nerve, and 

 covered every thing well with the lappets of the rag. This rabbit lived 24 hours, 

 and only showed signs of being ill in the last hour, nor was there any reason to 

 think that it died of the effects of the poison. 



I prepared the sciatic nerve of another rabbit in the same manner, covering 

 it with the poison and rags as before. This rabbit died 40 hours after, without 

 any symptoms of being poisoned. I made the same experiment on the sciatic 

 nerve of 3 other rabbits, having taken all possible care that the poisoned nerve 

 should be well covered with rags, that there might not be any reason to suspect 

 the poison might penetrate through them. One of them died 3 days after, but 

 the other 2 were still living at the end of 8 days. I also prepared the nerves of 

 2 other rabbits exactly as above, but without the poison, to serve as a kind of 

 comparative experiment to the former. One of these rabbits died in 36 hours, 

 and the other was still living 8 days after. 



These experiments seemed sufficient ground to determine, whether the 

 American poison, when applied externally to the nerves, is capable of producing 

 any malady or disorder in animals. But it remained to be tried, whether it be 

 equally inactive when ap[)lied to wounded nerves, as also to the pulp of the 



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