140 LIFE AND DEATH. 



cause. To these physiologists everything ingested is 

 called food, if it gives off heat within the body. 



To be heated by food is, indeed, an imperious 

 necessity for the higher animals. If this need be not 

 satisfied the functional activities become enervated ; 

 the animal falls into a state of torpor ; and if it is 

 capable of attenuated, of more or less latent, life it 

 sleeps in a state of hibernation ; but if it is not 

 capable of this, it dies. The warm-blooded animal 

 with a fixed temperature is so organized that this 

 constancy of temperature is necessary to the exercise 

 and to the conservation of life. To maintain this 

 indispensable temperature there must be a continual 

 supply of thermal energy. According to this, the 

 necessity of alimentation is confused with the 

 necessity of a supply of heat to cover the deficit 

 which is due to the inevitable cooling of the organism. 

 This is the point of view taken up by theorists, and 

 we cannot say that they have no right to do so. We 

 can only protest against the exaggeration of this 

 principle, and the subordination of the other roles of 

 food to this single r6le as a thermogen. It is the 

 magnitude of the thermal losses which, according to 

 these physiologists, determines the need for food, and 

 regulates the total value of the maintenance ration. 

 From the quantitative view it is approximately true. 

 From the qualitative point of view it is false. 



Such is the theory opposed to the theory ol 

 chemical and vital energy. It has on its side a large 

 number of experts, among whom are Rubner, Stoh- 

 mann, and von Noorden. It has been defended in an 

 article in the Dictionnaire de PJiysiologie by Ch. 

 Richet and Lapicque. They hold that thermogenesis 

 absolutely dominates the play of nutritive exchanges ; 



