J94 ESSAYS AND OBSERVATIONS 



But, as thefe experiments are made on 

 frogs, it may be necefTary, before enter^ 

 ing upon the particular detail of them, to 

 obviate a doubt, which, to fome, may 

 prefent itfelf, concerning the propriety of 

 applying to the human body experiments 

 made on any other animal, efpecially on 

 one that differs much from man in its 

 way of life, confidering the more fudden 

 and greater effedls certain medicines are 

 obferved to have on fome fpecies of ani- 

 mals than on others. 



Werr I to fuppofe the effedls of me- 

 dicines on different animals to agree in 

 every circum{lance,my conclufions would 



be juflly queftionable. Bat I am far 



from attempting to make the application 

 in this way. I am fenfible that the effeds 

 of a medicine may be much more fpeedy 

 and violent on one fpecies of animals, 

 than on another, owing to the different 

 degrees of delicacy of their frame in ge- 

 neral, or of that particular part to which 

 the medicine is applied. So that all I con- 

 tend for is, that, if two fpecies of anir 



mals, 



