STRUGGLE FOR EXISTENCE. 55 



differ from each other far more than do the varieties of the 

 same species ? How do those groups of species, which con- 

 stitute 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, however 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 princi- 

 ple, 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 Survival 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. 



We 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 philosophically 

 shown that all organic beings are exposed to severe compe- 

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

 with more spirit and ability than W. Herbert, Dean of Man- 

 chester, evidently the result of his great horticultural knowl- 

 edge. 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 nature, with every fact on distribution, 

 rarity, abundance, extinction, and variation, will be dimly 

 seen or quite misunderstood. We behold the face of nature 

 bright with gladness, we often see superabundance of food ; 

 we do not see, or we forget, that the birds which are idly 



