FORMATION OF BILE IN HERBIVORA. 149 



constituents of bile, as far as our knowledge at 

 present extends. 



If starch be the chief agent in this process, it 

 can haj^i^en in no other way but this — that, as when 

 it passes into fat, a certain quantity of oxygen is 

 separated from .the elements of the starch, which, 

 for the same amount of carbon (for 72 atoms), con- 

 tains five times as much oxygen as choloidic acid. 



Without the separation of oxygen from the ele- 

 ments of starch, it is impossible to conceive its 

 conversion into bile ; and this separation being ad- 

 mitted, its conversion into a compound interme- 

 diate in composition between starch and fat offers 

 no difficulty. 



47. Not to render these considerations a mere 

 idle play with formuloe, and not to lose sight of our 

 chief object, we observe, therefore, that the consi- 

 deration of the quantitative proportion of the bile 

 secreted in the herbivora leads to the following 

 conclusions : — 



The chief constituents of the bile of the herbi- 

 vora contain nitrogen, and this nitrogen is derived 

 from compounds of proteine. 



The bile of this class of animals contains more 

 carbon than corresponds to the quantity of nitro- 

 genised food taken, or to the portion of tissue that 

 has undergone metamorphosis in the vital process. 



A part of this carbon must, therefore, be derived 

 from the non-nitrogenised parts of the food (starch, 

 sugar, &c.) ; and in order to be converted into a 



