ALIMENTARY ENERGETICS. 133 



incorporated, and for the rest to be kept in the blood 

 or the lymph, in the circulating liquids ad liniina 

 corporis, so to speak ? In other words, can the same 

 food be according to circumstances a biotJiermogen or 

 a pure thermogen ? Some physiologists — Fick of 

 Wurzburg, for instance — have claimed that this is 

 really the case for most nitrogenous elements, carbo- 

 hydrates, and fats; all would be capable of evolving 

 according to the two types. On the other hand, Zuntz 

 and von Mering have absolutely denied the existence 

 of the aberrant or pure thermogenic type. No sub- 

 stances would be directly decomposed in the organic 

 liquids apart from the functional intervention of the 

 histological elements. Finally, other authors teach 

 that there is a small number of alimentary substances 

 which thus undergoes direct combustion, and among 

 them is alcohol. 



Liebig's Superfluous Consumption. — Liebig's theory 

 of superfluous consumption and Volt's theory of the 

 circulating albumen assert that the proteid foods 

 undergo partial direct combustion in the blood vessels. 

 The organism only incorporates what is necessary 

 for physiological requirements. As for the surplus 

 of the food that is offered it, it accepts it, and, so 

 to speak, squanders it ; it burns it directly ; and 

 we have a "sumptuary" consumption, consumption 

 de luxe. 



In this connection arose a celebrated discussion 

 . which still divides physiologists. If we disen- 

 {;age the essential body of the discussion from all 

 that envelops it, we see that it is fundamentally a 

 question of deciding whether a food always follows the 

 same evolution whatever the circumstances may be, 

 and particularly when it is introduced in great excess. 



