VEGETABLE POISONS. ^^ 



black colour, it may naturally be afked, from 

 whence it arifes. Does putrefadlion occalioa 

 it ? if it does, why does not putrefadion al- 

 ways give rife to this appearance ? Why is hot 

 the body in general of the fame complexion ? 

 Is putrefadion, different in kind or degree, 

 dependent on the different texture of the 

 parts ? certainly not : putrefadlion is univer- 

 fally the fame, and nature is always fimple 

 and uniform in her operations. The black- 

 Hefs of the face is occafloned by putrefadlon, 

 but not by putrefadion only : if convulfions 

 precede death, and the body becomes very 

 putrid after it, the effect may be produced. 

 I {hall attempt to explain it, by firft eftablifh- 

 ing two fads (clear and demonftrable as the 

 two firft propofitions of Euclid) upon vi'hich 

 I mean to reafon. 



The firft propofition, then, which I fliali 

 make, is this : As foon as an animal has 

 breathed, and the foramen ovale is confe- 

 quently fliut up, the blood muft pafs from 

 the right fide of the heart, through the lungs ^ 

 to the left fide of the heart, before it can cir- 

 culate to any other part of the body. 



F The 



