650 PHILOSOPHICAL TRANSACTIONS. [aNNO 1780. 



it many times to several animals in various parts of their skin; but none of them 

 were hurt by it. It appears therefore, that the mineral acid destroys the noxious 

 quality of the American poison : I only say, it appears, because it may perhaps 

 be suspected, that, as there remained a little of the acid mixed with the poison 

 after evaporation, it was this that produced the usual alteration in the vessels of 

 the skin. I ought to have made some other experiments with it washed several 

 times in water, and rendered quite insipid; but at that time I was in want of 

 animals to ascertain the truth of this suspicion, and I have not had time since 

 to resume the subject. With respect to the alkaline salts, I may say that I have 

 not discovered that they alter the poison, or render it in the least less noxious. 

 It is true indeed that I have not so often repeated the experiments, nor so much 

 varied them, as I ought to, and as I should have done, if I had not found a 

 great difficulty in procuring animals, and if I had not had in view other experi- 

 ments much more important. 



It was natural for me to think, that as the acids hinder the action of that poison 

 on animals, they might also be a remedy against that poison. I prepared there- 

 fore, in the usual way, the skin of a Guinea-pig, and covered it with the poison; 

 and about 40 seconds after I washed it with the nitrous acid, and afterwards with 

 pure water: the animal suffered nothing. Two hours after I introduced the poison 

 into a muscle, and immediately applied the nitrous acid to the part; but the 

 animal fell in a moment convulsed, and was quite dead in 1 minutes. I repeated 

 this experiment on the muscles of another Guinea-pig, and as soon as I had 

 applied the poison, washed it with the nitrous acid, and a little after with water. 

 It fell convulsed in 1 minutes, and was quite dead in 4. 



1 poisoned, in like manner, the muscles of 4 pigeons, and the moment after 

 I washed them with the nitrous acid: they died in 1 minute. Suspecting that it 

 might be owing to the nitrous acid, rather than to the poison, I next made use 

 of nitrous acid, much diluted, on 4 other pigeons; but they all 4 died, though 

 much more slowly. Being desirous of knowing whether the simple application 

 of the nitrous acid to the muscles could kill pigeons and small Guinea-pigs, I 

 made the trial on 1 of each sort: the pigeons both died soon after; but neither 

 of the pigs, though one of them was very sick. 



It appears, therefore, that acids are not only useless as a remedy; but some- 

 times dangerous, when applied to the poisoned muscles of animals. I shall not 

 say any thing of any other remedy which I have tried, because I hav$ found by' 

 experience that they are all useless, whether they are applied soon or late, or whe- 

 ther externally or internally. When the poison is introduced deeply, and has al- 

 ready insinuated itself into the humours, every remedy comes too late and is useless. 



There yet remained to be made a further very nice inquiry, and which might 

 in some cases too have turned out a very useful one. My experiments on the 



