132 LIFE AND DEATH. 



and after having taken part in the vital operations. 

 The chemical potential only passes into thermal 

 energy after having passed through a certain inter- 

 mediary phase of vital energy. This is the normal 

 case, tJie regular type of alimentary evolution. It may 

 be said in this case that the food has fulfilled the 

 whole of its function, it has served for the vital 

 functional activity before producing heat. It has 

 been biothermogenic. 



The irregular or pure thermogenic type. — And now 

 let us conceive of the most simple irregular or 

 aberrant type. Food passes from the initial to the 

 final state without incorporation in the living cells of 

 the organism, and without taking part in the vital 

 functional activity. It remains confined in the blood 

 and the circulating liquids, but it undergoes in the 

 end, however, the same molecular disintegration as 

 before, and sets free the same quantity of heat. 

 Its chemical energy changes at once into thermal 

 energy. Food is a pure thermogen. It has fulfilled 

 only one part of its work. It has been of slight 

 vital utility. 



Does this ever occur in reality? Are there foods 

 which would be only pure thermogens — that is to 

 say, which would not in reality be incorporated with 

 the living anatomical elements, which would form no 

 part of them either in a state of provisory constituents 

 of the living protoplasm, or in the state of reserve- 

 stuff; which would remain in the internal medium, in 

 the blood and the lymph, and would there undergo 

 their chemical evolution? Or again, if the whole of 

 the food does not escape assimilation, would it be 

 possible for part to escape it ? Would it be possible 

 for one part of the same alimentary substance to be 



