Chap. 111.] STRUGGLE FOR EXISTENCE. 49 



genera, and which differ from each other more than do the speciea 

 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 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 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, as we shall hereafter see, is a power inces- 

 santly 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 arc 

 exposed 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 have 

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

 unless it be thoroughly engrained in the mind, the whole economy 

 of nature, with every fact on distribution, rarity, abundance, extinc- 

 tion, 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 net 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, though 

 food may be now superabundant, it is not so at all seasons of each 

 recurring year. 



