154 SODA ESSENTIAL TO THE 



share in these metamorphoses, is opposed to the 

 supposition that a part of the carbon of the non- 

 azotised food enters into the composition of the bile. 

 52. Fat, in the animal body, disappears when 

 the supply of oxygen is abundant. When that sup- 

 ply is deficient, choleic acid may be converted into 

 hippuric acid, lithofellic acid, (37) and water. Li- 

 thofellic acid is known to be the chief constituent 

 of the bezoar stones, which occur in certain herbi- 



vorous animals : 



C 2 at. hip. acid C^H^Ou 

 2 at.chole 1 cac 1 dC 76 N 2 H 66 0, = f iat>lit ^ ac . d ^ 



\14 at. water ... H M O M 



53. For the production of bile in the animal 

 body a certain quantity of soda is, in all circum- 

 stances, necessary ; without the presence of a com- 

 pound of sodium no bile can be formed. In the 

 absence of soda, the metamorphosis of the tissues 

 composed of proteine can yield only fat and urea. 

 If we suppose fat to be composed according to the 

 empirical formula C n H 10 0, then, by the addition of 

 oxygen and the elements of water to the elements 

 of proteine, we have the elements of fat, urea, and 

 carbonic acid. 



Proteine. Water. Oxygen. 



2 (C^NeHsA.,) -f 12 HO + 14 O = C 96 N 12 H 84 O M = 

 r 6 at. urea ......... = C 12 Ni 2 H 24 O 12 



= ) Fat ............... = CBS HeA, 



I 18 at. carbonic acid = C 18 O 3S 



