STRUGGLE FOR EXISTENCE 49 



each other far more than do the varieties of the same species? How 

 do those groups of species, which constitute what are called dis- 

 tinct 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, however slight and from what- 

 ever 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 sur- 

 vive. 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 exp ression 

 often used by Mr. Herbert Spencer, of the Survival of the. Fittest, 

 is mure 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 accumula- 

 tion 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. 



We will now discuss in a little more detail the struggle for exist- 

 ence. 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 philosophically shown that all organic beings are ex- 

 posed to severe competition. In regard to plants, no one has treated 

 this subject with more spirit and ability than W. Herbert, Dean 

 of Manchester, evidently the result of his great horticultural 

 knowledge. Nothing is easier than to admit in words the truth of 

 the universal struggle for life, or more difficult — at least I found 

 it so — than constantly to bear this conclusion in mind. Yet unless 

 it be thoroughly ingrained in the mind, the whole economy of na- 

 ture, with every fact on distribution, rarity, abundance, extinction, 

 and variation, will be dimly seen or quite misunderstood. We be- 

 hold the face of nature bright with gladness, we often see super- 

 abundance of food; we do not see, or we forget, that the birds 

 which are idly singing round us mostly live on insects or seeds, 

 and are thus constantly destroying life; or we forget how largely 

 these songsters, or their eggs, or their nestlings, are destroyed by 

 birds and beasts of prey; we do not always bear in mind, that, 



