IN THE HERBIVORA. 141 



air, like resin, yields ammoniacal products, and, when 

 treated with acids, yields taurine and the products of 

 the decomposition of choleic acid ; when acted on by 

 alkalies, it yields ammonia and cholic acid. At all 

 events, the sugar of bile contains nitrogen, and much 

 less oxygen than starch or sugar, but more oxygen than 

 the oily acids. When, in the metamorphosis of sugar 

 of bile or choleic acid by alkalies, we cause the separ- 

 ation of the nitrogen, we obtain a crystallized acid, 

 very similar to the oily acids (cholic acid), and capa- 

 ble of forming with bases salts, which have the general 

 characters of soaps. Nay, we may even consider the 

 chief constituents of the bile, sugar of bile and choleic 

 acid, as compounds of oily acids with organic oxides, 

 like the fat oils, and only differing from these in con- 

 taining no oxide of glycerule. Choleic acid, for ex- 

 ample, may be viewed as a compound of choloidic acid 

 with allantoine and water : 



Choloidic acid. Allantoine. Water. Choleic acid. 

 C 72 H 66 12 + C 4 N 2 H 3 3 + H 7 7 = C 76 N 2 H 66 22 



Or, as a compound of cholic acid, urea, and water : 



Cholic acid. Urea. Water. Choleic acid. 



C 74 H 60 18 -f C 2 N 2 H 4 2 4- Ho0 2 = C 76 N 2 H 66 22 



45. If, in point of fact, as can hardly be doubted, 

 the elements of such substances as starch, sugar, &c., 

 take part in the production of bile in the organism 

 of the herbivora, there is nothing opposed to such a 

 view in the composition of the chief constituents of bile, 

 as far as our knowledge at present extends. 



If starch be the chief agent in this process, it can 



