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 happen 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 formulae, 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 



