THE THEORY OF ENERGY AND THE LIVING WORLD. 531 



the phenomena of life are energetic metamorphoses in the same sense 

 as the phenomena of nature. 



The science which has been christened the u energetics of biology" 

 is not new. It is none other than the general physiology to which no 

 one in any country has contributed more for its foundation and enrich- 

 ment than Claude Bernard. It must be recognized, however, that 

 E. Mayer and Helmholtz have more distinctively characterized and 

 limited the field in defining it as "the study of the phenomena of life 

 from the standpoint of energy." 



A school of experimental zoologists, arisen within the last few years 

 in Germany, has attempted to monopolize and distort general physi- 

 ology by designating it simply as the study of cellular life. They have 

 affected to believe that physiology from the time of Galen down has 

 had no interest except in the working of the organs, and they oppose to 

 this "physiology of organs" their "physiology of cells." A qualified 

 scientist, J. Loeb, scarcely does justice to these preteusious. He shows 

 that "cellular structure" is in most cases a matter as completely of 

 indifference as the "structure of organs" in the action of vital forces; 

 and that it is necessary to banish this morphological notion of the phy- 

 sics of living matter as being nothing more to general physiology than 

 the physics of inanimate bodies. The determination of the vital energy 

 of plants and animals, the direct transformation of chemical energy of 

 nutrition into animal heat or into muscular energy, the chemical evolu- 

 tion of the aliment, and the study of the soluble ferments — these are 

 the things which in his view are likely to increase our knowledge of the 

 mechanism of life. It is these things which are most advanced by the 

 study of biological energetics. 



in. 



The equivalence or identity of the energies developed in the animal 

 with the universal forms of energy in nature has furnished the point 

 of departure for this doctrine. Two other principles go with this to 

 lay the foundation, to wit: That vital energy has its origin in some 

 form of external energy, and uot in all the forms as might be supposed 

 — but in one of them exclusively, chemical energy. This energy is 

 finally converted and issues forth in a few other well-determined forms. 



This is the importation, more precisely expressed in terms of energy, 

 of an idea similar to the vital vortex of Cuvier and the naturalists 

 in the order of matter. This idea of Cuvier defines life by its most 

 constant property, nutrition ; that is, by the existence of a current of 

 matter which the organism gathers from without by alimentation, 

 rejects by excretion; a current the complete interruption of which 

 even for a moment would be the signal of death. The circulation of 

 energy is the exact counterpart of this conception of the circulation of 

 matter. 



The second principle drawn from experience and made use of by 



