644 PHILOSOPHICAL TRANSACTIONS. [anNO I78O. 



This reason is more specious than convincing; since it may be a poison when in- 

 troduced into the blood, even in the smallest quantity, and yet not be such when 

 taken in by the mouth, except the dose be very considerably increased. The 

 following are the experiments which I have made, the result of which is to 

 render us cautious of pronouncing, even after we have consulted experience itself. 



I made a young rabbit swallow 2 grs. of the poison, dissolved in water, and 

 then forced it to drink, a tea-spoonful of water, to wash all the poison out of its 

 mouth into its stomach. This animal showed no signs of suffering either then or 

 afterwards. In like manner I made another young rabbit drink 3 grs. of the 

 poison, and it suffered nothing, any more than the former had done. I made 

 another young rabbit drink 4 grs. of the poison, and it likewise suffered nothing. 

 I repeated the same experiments on 3 other young rabbits, to the last of which I 

 gave 6 grs. of the poison, but still without any effect. I then concluded that 

 these experiments were sufficient to assure me, that the American poison is in- 

 nocent when taken by the mouth, as the poison of the viper is; but I was de- 

 ceived. I had the curiosity to try it on a young pigeon, to which I gave 6 grs. 

 to drink, and it died in less than 20 minutes. I repeated the experiment on 2 

 other pigeons, and they both died within the i hour. 



These last experiments being contradictory to the former, obliged me to try 

 several over again on the rabbits and on the Guinea-pigs. I gave therefore to a 

 small Guinea-pig 5 grs. of the poison to drink, and I found it dead after 25 

 minutes. I then made a young rabbit drink 8 grs. of the poison: at the end of 

 the half hour it did not seem affected; but in half an hour more it tottered; 4 

 minutes after it fell down as if it were dead; and in 4 minutes more it was quite 

 dead. I made 2 other young rabbits, and 2 other small Guinea-pigs, drink 9 

 grs. of the poison: the 2 pigs died in 20 minutes, and 1 of the rabbits died in 

 less than 45 minutes. These experiments induced me to believe, that a greater 

 dose of the poison may prove still more certain death; and that the same quan- 

 tity of poison produced different effects in the same animals, according to the 

 state their stomachs happened to be in at the time, I had generally observed, 

 in making the experiments, that after swallowing the poison, those animals which 

 had their stomachs pretty full of meat either did not suffer any thing, or else 

 died with much difficulty. I was desirous of making this clearer, by experiments 

 on 3 rabbits and 2 pigeons, which I therefore first kept for a long time without 

 food. Three grs. of poison only killed each of them in less than 35 minutes. 

 I repeated the experiment on 5 other animals with full stomachs, and only 1 of 

 them died. 



Hence I deduce this certain fact, that the American poison, when taken in 

 by the mouth, is a poison; but that it requires a pretty large quantity of it to 

 kill even a small animal. The facts above related concerning the American poi- 



