6d2 philosophical transactions. [anno 1780. 



In general I found, that it required a certain time for the American poison to 

 communicate itself to animals; that this time is much greater than that which 

 the poison of the viper requires to communicates itself; and that the effects of 

 the American poison on animals are more vague and more various; and that, 

 finally, animals may be cured of the effects of both these poisons by cutting 

 away the part in time, when it can be done without endangering the life of the 

 animal by the ojieration itself. 



In the course of my experiments on the poison of the viper, I found that it is 

 not poisonous to all animals; and that there are some cold-blooded animals to 

 whom it is quite innocent. I was curious to know if the case was the same with 

 the American poison. All the writers on the American poison tell us, that it is 

 poisonous to all animals; but assertions may be very different from facts. Many 

 experiments are necessary to evince this general conclusion, and it does not 

 appear that enough have been made to warrant it. I began by impregnating the 

 muscles of frogs with the poison, and they died in a little time. I then had 

 recourse to eels, into which I introduced the arrows, towards the lower or tail- 

 parts of them ; and they all died, though very slowly. 



I had found that the poison of the viper is quite innocent to the viper itself, 

 and to those serpents which in Tuscany are called binchi, and by the French, 

 couleuvres. Of these last I could procure no more than 2; for which 

 reason I could make but few experiments on them; but those I have 

 made I think quite decisive. I wounded one of them towards the tail with 

 an arrow well covered with poison of the thickness of syrup, and left the arrow 

 in the muscles. I had previously made an incision in the plane where I introduced 

 the arrow, that the dissolved poison on the arrow might easily enter the muscles 

 with the arrow. I also applied some more poison to the same part by means of small 

 incisions in the muscles. The serpent did not seem affected by the poison; but 

 for many hours was as well as ever. I locked it up in a box, which having 

 opened 6 hours after, I found that the serpent was gone, nor could I ever find 

 it again. I repeated the experiment many times, at different intervals, on 

 another rather smaller. The last time I introduced 2 poisoned arrows into the 

 muscles of the tail, and left them there for 24 hours. I frequently applied the 

 poison thickened to a syrup to the wounds, and introduced a great quantity into 

 them with a tooth-pick, yet, so far from dying, the animal was not sensibly 

 hurt. I have often made this same experiment on vipers, without any one of 

 them dying by the poison, though some were wounded in the muscles towards 

 the tail with many arrows well impregnated with poison thickened to a syrup. I 

 have left the arrows for 20 or 30 hours together in the muscles, ami yet none of 

 them have died. It is true indeed, that some few, after being operated on, 

 appeared less lively than before; and it seemed that the wounded parts, or the 

 lower half of the body, had sensibly lost some of its natural motion, and this 



