Darwinism and Deity. 35 



In the same way, diet and mode of life affect the body. 

 Each nation in Europe has its characteristics, and the 

 American people, though so recent, are already dis- 

 tinguishable from their ancestors. 



Now two facts are quite certain. One is, that no two 

 animals, even of the same species, are precisely alike. 

 Every individual has its own peculiarities. The other 

 fact is, that vastlv more are born than arrive at matu- 

 rity. If all animals born reached maturity, the world 

 would soon be heaped up with the crowd. Hence, there 

 is a continual competitive struggle for existence, and in 

 this struggle those mostly survive which are best fitted 

 to survive in the existing conditions of life. 



It, for example, various species should migrate to the 

 Arctic regions, the sustenance of animal heat would be- 

 come a matter of vital importance. White is the color 

 that protects against external heat or cold. Hence, those 

 animals which should happen to have white or nearly 

 white fur would, other things being equal, have the 

 best chance of surviving. Besides, a white-furred animal 

 would be least distinguishable on the snowy surface, 

 and so would have the best chance of escaping from its 

 pursuers, and at the same time, the best chance of 

 coming unperceived upon its own prey. These con- 

 stant chances operating through cycles would tend to 

 eliminate all dark-skinned animals, leaving only the 

 white to survive. So in animals that trust to speed, 

 either for their own safety, or for overtaking their prey, 

 the swiftest would have the best chance for life, and in 

 long course of ages, the swift-footed of those species 

 would tend to predominate, and the slow to disappear. 



So of an insect tribe infesting trees, if one should 



