CAUSED BY NATURAL SELECTION. 275 



no reason, if my theory is true, why brown 

 bears are not still occasionally taking to a Polar 

 life, catching seals and turning white " (?) 

 The answer is easy ; the ground is already 

 occupied by the variety of bear formed by 

 Nature, acting through the process of natural 

 selection, for catching seals. The seals are so 

 shy that even the existing white bears have 

 difficulty in living, and a brown bear, although 

 he may eke out his means of subsistence by 

 occasionally still catching a seal on the shores 

 of Siberia, would have no chance of succeeding 

 in the struggle for life if he were to set off on 

 a seal-hunting expedition, and to enter into 

 competition with his white congeners, who are 

 already formed and fitted by Nature, through 

 countless generations, for that particular mode 

 of life.* 



I think the appearance and the very existence 



* It will be obvious to any one that I follow Mr. Darwin 

 in these remarks : and although the substance of this 

 chapter was written in Spitzbergen, before the " Origin of 

 Species " was published, I do not claim any originality for 

 my views ; and I also cheerfully acknowledge that, but for 

 the publication of that work in connection with the name 

 of so distinguished a naturalist, I never would have ven- 

 tured to give to the world my own humble opinions on the 

 subject. 



I 2 



