Conceptions of Vital Energy Reviewed 333 



We have already seen also that Claude Bernard, in 

 agreement with that, considers the sensibility of the ner- 

 vous substance as nothing else than a particular modality 

 of irritability, which would be a general property of 

 all living substance. "Sensibility," writes he, "considered 

 as a property of the nervous system, is only a higher 

 degree of a simpler property which exists everywhere 

 in all living substance both animal and vegetable. It 

 has nothing essential or specifically distinct. It is the 

 special irritability of the nerve just as the property of 

 contraction is the special irritability of the muscle, and 

 as the property of secretion is the special irritability of 

 the glandular element. These phenomena are so many 

 different degrees of one and the same elementary phe- 

 nomenon/' 251 



Bard also remarks that if the nature of the energy 

 constituting the basis of all vital phenomena must be 

 single, the infinitely varied modalities which the same 

 vital phenomena present must then be due to as many 

 corresponding modalities of this single energy. 



"In spite of the complexity and multiplicity of physio- 

 logical functions," he writes, "it is possible to refer them 

 fundamentally to a general function of the living cell, 

 namely the function of producing derived substances. 

 Cellular specificity can be explained and made compre- 

 hensible only as this single function is able to insure the 

 innumerable functions necessary for an entire organism. 

 The variety of derived substances is itself the effect and 

 the proof of the radically different vital properties of 

 the kinds of cells which create each of them." 



"It is necessary to establish an essential difference 



281 Claude Bernard: Legons sur les phcnomenes de la vie com- 

 muns aux animaux et aux vegetaux. P. 289 290. 



