532 THE THEORY OF ENERGY AND THE LIVING WORLD. 



general physiology may be thus enunciated: The maintenance of life 

 consumes no energy peculiar to and originating with the living being. 

 It borrows from the external world in the form of chemical potential 

 all that it requires. Such is a translation into the language of ener- 

 getics of results acquired in animal physiology within the last fifty 

 years. It is unnecessary for the commentator to emphasize the impor- 

 tance of such a principle; for it reveals the origin of animal activity — 

 the source from which proceeds the energy which at one point in its 

 transformation becomes the vital energy. 



The primum movens of vital activity is then, according to these 

 principles, the chemical energy stored up in the material composing 

 the organism. 



To attempt to follow out the movement it is necessary to be precise. 

 Let us suppose our attention concentrated upon a limited portion of 

 the organism — a certain tissue. We will come upon it in the uninter- 

 rupted course of its life at the given moment, and from this time on 

 examine its functions. The first effect we notice will be the liberation 

 of a portion of the potential energy lying concealed in the materials 

 put in reserve in the tissues. This disengaged material furnishes the 

 energy required for the continuance of the vital function of the tissues. 

 There is, then, at the beginning of its functional process, and as a neces- 

 sary part of this process, a liberation of chemical energy which can not 

 be brought about except by a decomposition of the immediate con- 

 stituents of the tissues or, following a customary expression, by the 

 destruction of organic material. Claude Bernard has stringently insisted 

 upon this consideration that vital activity is accompanied by a destruc- 

 tion of organic material. "When a movement takes place or a muscle 

 contracts, when the will or the emotions are excited, or the brain exer- 

 cised, or when the glands secrete, the substance of the muscles, the 

 nerves, the brain, or the granular tissue is decomposed, destroyed, and 

 consumed." The real reason of this coincidence between chemical 

 decomposition and functional activity, of which Claude Bernard had 

 nn intuition, has been made clear to us by energetics.. A portion of the 

 organic material being decomposed descends in the scale of chemical 

 complexity, and in so doing gives up its chemical potential energy. 

 In this store of energy lies the means for vital activity. . 



It is obvious that the store of reserve energy thus drawn upon must 

 be replenished if the organism is to preserve its equilibrium. Alimen- 

 tation provides for this by furnishing the materials. The action of the 

 digestive apparatus prepares them for assimilation; that is, it reduces 

 them to a convenient form to be incorporated in the reserve. This 

 replenishing of the reserves is not a chemical synthesis; it is, as Claude 

 Bernard has termed it, "synthesis of the organism." "The synthesis 

 of the organism," he says "remains hidden silent within, assembling 

 noiselessly the materials which it dispenses." 



This great physiologist divided the phenomena of animal life into 



