CHAPTER I 



ADAPTATION TO ENVIRONMENT 



EVERYTHING in nature, living or not living, exists 

 and develops at the expense of some other thing, liv- 

 ing or not living. The plant borrows from the soil; 

 the soil from the rocks and the atmosphere ; men and 

 animals take from the plants and from each other the 

 elements which they in death return to the soil, the 

 atmosphere and the plants. Year after year, century 

 after century, eon after eon, the mighty, immeasurable, 

 ceaseless round of elements goes on, in the stupendous 

 process of chemical change, which marks the eternal 

 life of matter. No human imagination is powerful 

 enough to picture the vast, the infinite antiquity of the 

 tiniest particle of matter which composes our present 

 bodies and environment, or the varied and spectacular 

 trail of cosmic vicissitudes through which it has passed. 



To the superficial observer, nature in all her parts 

 seems imbued with a spirit of profound peace and har- 

 mony ; to the scientist it is obvious that every infin- 

 itesimal particle of the immense concourse is in a state 

 of desperate and ceaseless struggle to obtain such 

 share of the available supply of matter and energy as 

 will suffice to maintain its present ephemeral form 

 in a state of equilibrium with its surroundings. Not 

 only is this struggle manifest among living forms, 

 c 17 



