58 JSTE UG GLE FOR EXISTENCE. 



short, we see beautiful adaptations everywhere and iu every 

 part of the organic world. 



Again, it may be asked, how is it that varieties, which I 

 have called incipient species, become ultimately converted 

 into good and distinct species, which in most cases 

 obviously differ from each other far more than do the 

 varieties of the same sj^ecies? How do those groups of 

 species, which constitute what are called distinct genera 

 and which differ from each other more than do the species 

 of the same genus, arise? All these results, as we shall 

 more fully see in the next chapter, follow from the struggle 

 for life. Owing to this struggle, variations, hoAvever slight 

 and from whatever cause proceeding, if they be in any 

 degree profitable to the individuals of a species, in their 

 infinitely complex relations to other organic beings and 

 to their physical conditions of life, will tend to the 

 preservation of such individuals, and will generally be 

 inherited by the offspring. The offspring, also, will 

 thus have a better chance of surviving, for, of the many 

 individuals of any species which are periodically born, 

 but a small number can survive. I have called this 

 principle, by which each slight variation, if useful, is 

 preserved, by the term natural selection, in order to 

 mark its relation to man^s power of selection. But the 

 expression often used by Mr. Herbert Spencer, of the Sur- 

 vival of the Fittest, is more accurate, and is sometimes 

 equally convenient. We have seen that man by selection 

 can certainly produce great results, and can adapt organic 

 beings to his own uses, through the accumulation of slight 

 but useful variations, given to him by the hand of Nature. 

 But Natural Selection, we shall hereafter see, is a power 

 incessantly ready for action, and is as immeasurably superior 

 to man's feeble efforts as the works of Nature are to those 

 of Art. 



AVe will now discuss in a little more detail the struggle 

 for existence. In my future work this subject will be 

 treated, as it well deserves, at greater length. The elder 

 De Candolle and Lyell have largely and philosophicajly 

 shown that all organic beings are exposed to severe compe- 

 tition. In regard to plants, no one has treated this sub- 

 ject with more spirit and ability than W. Herbert, Dean 

 of Manchester, evidently the result of his great horticul- 



