21 



produce the same substances in the excretions, 

 or in the r^-produetion of solid parts, instead of 

 those which are decayed, or worn out. 



On accurately comparing human blood with 

 that of a bullock, I have found an astonishing 

 resemblance between the two. The same spe- 

 cific constituent parts in both, the same propoi%- 

 tions, and nearly the same chemical characters, 

 make it easy to explain the successful results of 

 several experiments that have been made, to 

 transfuse the blood of herbivorous animals into 

 human bodies, from which the blood had been 

 drawn at the time. I observed, however, a re- 

 markable difference in certain characters of the 

 constituents of the blood in man, from what I 

 found in that of the bnllock. The fibrin, as well 

 as the colouring matter, and the albumen, from 

 human blood, after they are dried, are much 

 more easily burnt to ashes ; and the charred hu- 

 man blood requires neither so strong, nor so pro- 

 tracted a heat, to be entirely reduced to ashes, 

 as that of the bullock. This difference in the fa- 

 cility of burning, indicates clearly a greater pro- 

 portion of nitrogene in the constituent parts of the 

 bullock's blood, which is still more clearly proVed 

 by the circumstance, that the charcoal of the 



