VOL. LXi.J PHILOSOPHICAL TKANSACTIONS. 647 



and beasts, it may be concluded, that the American poison applied to the skin 

 slightly scratched may be fatal, though it is not so always, nor in all circum- 

 stances. The larger animals more easily resist the action of the poison, and 

 when the more feeble animals did not die, in a little time they were as well 

 as ever. 



I was desirous to know what quantity of the poison was necessary to kill an 

 animal. I had made a like inquiry concerning the poison of the viper, and had 

 determined the quantity of that poison requisite to kill the different animals. 

 I might indeed have safely concluded, that a very small quantity of the American 

 poison is sufficient to kill a small animal, since 1 or 2 small drops applied to the 

 skin just scratched, had proved fatal to more than one; but I wished for some- 

 thing more positive. ■ I steeped a very small bit of cotton in about one-fiftieth 

 of a little drop of poison dissolved, which could scarcely be the 50th part of 

 the whole drop. This I introduced into a muscle of the thigh of a pigeon, but 

 the animal was not affected by it. Two hours after, I put into another muscle 

 an atom of the dry poison, scarcely perceptible to the eyes: this likewise did not 

 affect the pigeon. I repeated the experiment with the dry poison on 3 other 

 pigeons; but none of them died or was sick, though in one of the cases the bit 

 of dry poison was very perceptible. I made the same experiment on 3 Guinea- 

 pigs, and on 1 small rabbits, still with the same success, none of them being at 

 all afi^ected. It must be observed, that the poison was not dissolved by the 

 humours of the wound, and I found the bits of it quite entire. 



I put to the muscle of another pigeon a bit of cotton much larger than before, 

 impregnated with about 8 times as much poison as in the former case: in Q 

 minutes time the pigeon fell down, and died soon after. To the muscles of i 

 Guinea-pigs I applied bits of cotton steeped in much the same quantity of poison 

 as above: one of them died in 12 minutes, and the other fell down, as if dead, 

 in 6 minutes, but it recovered a little time after. From these experiments I con- 

 clude, that above -j-J-^ part of a grain is requisite to kill a small animal; and that 

 it is necessary that the poison be dissolved, for it to prove fatal, or to cause any 

 alteration in the animal economy. 



I have made various experiments to determine whether the American poison 

 be fatal or hurtful when applied to the wounded combs of poultry, or to the ears 

 of quadrupeds slightly wounded. The poison of the viper is not commonly fatal 

 in those parts, nor is there any visible disorder in the poisoned comb, though 

 there is in the wattles, which swell horribly, so as sometimes to kill the animal. 

 I wounded the comb of a fowl in many parts, and twice applied to it the Ameri- 

 can poison by means of cotton well soaked in it; but without being able to 

 produce any disorder. But the experiment succeeded better when tried on the 

 ears. After having made many fruitless trials to communicate the poison by 



