STRUGGLE FOR EXISTENCE 77 



adaptations everywhere and in 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 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 principle, 

 by which each slight variation, if viseful, 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 re- 

 sults, 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 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 vv^ill 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 competition. In regard 

 to plants, no one has treated this subject with more spirit 

 and ability than W. Herbert, Dean of Manchester, evirlcntly 

 the result of his great horticultural knowledge. Nothing is 



