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THE AMEBIC AN NATURALIST [Vol. XL VII 



putting fitness by the side of adaptation as a coordinate 

 factor in causing the marvels of life, it is hard to believe 

 that they would have been so long neglected. In the sec- 

 ond place there is nothing comparative about such in- 

 formation. Water is indeed a wonderful substance which 

 fills its place in nature most satisfactorily, but would not 

 another substance do as well? Is not ammonia, for 

 example, a possible substitute? And are there not many 

 other chemical bodies which might, in a very different 

 world, serve equally useful purposes? Perhaps, too, the 

 great variety of carbon compunds which are known to 

 the chemist are known only because the vital processes 

 furnish an abundance of material with which to experi- 

 ment. Is it not possible, therefore, that another element, 

 perhaps for instance silicon, may enter into even greater 

 varieties of compounds? It is such questions, ever pres- 

 ent in the minds of men of science yet never yet care- 

 fully scrutinized to see if an answer be possible, which, I 

 suspect, have long deflected attention from this subject. 



Clearly, therefore, it will be necessary to compare the 

 properties of water and carbonic acid and of the carbon 

 compounds with those of other substances. It will be 

 necessary to find out whether these substances are not 

 only fit but fittest— and this no doubt is a task of a very 

 different sort. It may even seem, at first sight, an im- 

 possible one, but I hope to show that this is not the case, 

 and that in spite of the incompleteness of our physical 

 and chemical knowledge, it may be pressed to a satis- 

 factory issue. 



The very constant temperature of the ocean is a most 

 important factor in the economy of nature. It consti- 

 tutes, for example, a vital regulation of the environment 

 of a large proportion of all the living organisms of the 

 world, and it has many other important "functions." 

 This constancy of temperature is in large part due to the 

 magnitude of the specific heat of water. Other things 

 being equal the greater the specific heat of water the more 

 constant must be the temperature of the ocean. If then 



