64 THE FITNESS OF THE ENVIRONMENT 



acteristics of water and carbon dioxide and 

 of the compounds of carbon, hydrogen, and 

 oxygen favorable to a mechanism which must 

 be physically, chemically, and physiologi- 

 cally complex, which must be itself well regu- 

 lated in a well-regulated environment, and 

 which must carry on an active exchange of 

 matter and energy with that environment? 



The first step in seeking a solution must be 

 to review the data of physics and chemistry 

 which describe the properties of water and 

 carbonic acid, having due regard to their 

 meteorological significance. Such data of the 

 highest accuracy exist in great profusion, for 

 almost every conceivable property of these 

 substances has been studied with patient care. 

 Next, the properties of the compounds of 

 carbon, hydrogen, and oxygen must be con- 

 sidered, and some of the characteristics of 

 the chemical reactions into which they enter 

 must be discussed. For this examination the 

 unparalleled development of the science of 

 organic chemistry provides ample material. 

 All of these things must be scrutinized quan- 

 titatively as well as qualitatively, and here 

 again there is no lack of necessary information. 



Immediately one advantage of the method 

 here proposed becomes evident. We can deal 

 with the familiar abstractions of physical 



