150 RELATION OF STARCH, &c. TO BILK 



From 6 at. starch = 6 (C 12 H 10 O 10 ) = C 72 U K) O 60 

 Subtract 44 at. oxygen i _ HO 



4 at. water \ 



Remains choloidic acid = C 72 H 66 O 12 ; 



that, finally, choloidic acid, ammonia, and taurine, if 

 added together, contain the elements of choleic acid ; 



] at. choloidic acid = C 72 H S6 O 12 

 1 at. taurine . . -. = C 4 N H 7 O 10 

 1 at. ammonia . . = N H 3 



1 at. choleic acid . = C 76 N 2 H 66 O 22 ; 



if all this be considered, every doubt as to the possi- 

 bility of these changes is removed. 



58. Chemical analysis and the study of the living 

 animal body mutually support each other ; and both 

 lead to the conclusion, that a certain portion of the 

 carbon of the non-azotized constituents of food (of 

 starch, &c., the elements of respiration) is secreted by 

 the liver in the form of bile ; and further, that the 

 nitrogenized products of the transformation of tissues in 

 the herbivora do not, as in the carnivora, reach the 

 kidneys immediately or directly, but that, before their 

 expulsion from the body in the form of urine, they take 

 a share in certain other processes, especially in the 

 formation of the bile. 



They are conveyed to the liver with the non-azotized 

 constituents of the food ; they are returned to the cir- 

 culation in the form of bile, and are not expelled by the 

 kidneys till they have thus served for the production 

 of the most important of the substances employed in 

 respiration. 



59. When the urine is left to itself, the urea which 



