22 



blood of the bullock, when burnt slowly, con- 

 stantly gives off carbonat of ammonia, although 

 it has been heated in an open vessel, and freely 

 exposed to the air. This indication of a greater 

 quantity of nitrogen e in the constituent parts of 

 the bodies of herbivorous animals, than in those 

 of the human body, is the more unexpected, as 

 the food of man, in general, contains more nitro- 

 gene ; whereas, on the contrary, nitrogene, which 

 has hitherto been considered as an elementary 

 body, is found but in small proportions in those 

 vegetables, which constitute the foorl of the bul- 

 lock. Our information on this subject will pro- 

 bably be considerably increased, by an examina-* 

 tion of the so much contested nature of nitro- 

 gene, 



The blood separates itself at the finest ramifi- 

 cations of the arteries, into a coloured portion, 

 which returns the suspended particles of the co- 

 louring matter through the veins, and a colour- 

 less portion, which penetrates the finest ramifi- 

 cations. These ultimate ramifications of the ar- 

 teries, we call, after BICHAT, capillary vessels. 

 The colouring matter changes, on this occasion, 

 its colour, and turns dark brown, or blackish ; 

 but it is entirely unknown to us what influence 



