LIBRARY 



N. C. State College 



PREFACE 



Darwinian fitness is compounded of a 

 mutual relationship between the organism 

 and the environment. Of this, fitness of en- 

 vironment is quite as essential a component as 

 the fitness which arises in the process o* or- 

 ganic evolution ; and in fundamental charac- 

 teristics the actual environment is the fittest 

 possible abode of life. Such is the thesis 

 which the present volume seeks to establish, 

 This is not a novel hypothesis. In rudimen- 

 tary form it has already a long history behim 

 it, and it was a familiar doctrine in the early 

 nineteenth century. It presents itself anew 

 as a result of the recent growth of the science 

 of physical chemistry. 



About fifteen years ago I first became inter- 

 ested in the connection between physical and 

 chemical properties of simple substances and 

 the organic functions which they serve. At 

 that time the applications of the new physical 

 chemistry to physiology were only just begin- 

 ning, and the older speculations of natural 

 theology upon such subjects had long since 



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