70 STRUGGLE FOR EXISTENCE. Cuap. III. 



good and distinct species, which in most cases obviously differ 

 from each oilier far more than do the varieties of the same 

 species? How do those groups of species, wliich 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. 0\\4ng to this struggle, 

 variations, however slight, and from whatever cause proceed- 

 ing, 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, wUl thus have a better 

 chance of surviving, for, of the many individuals of an}^ species 

 Avhich 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 expres- 

 sion often used by Mr. Herbert Spencer of the Survival of the 

 Fittest is more accurate, and is sometimes equally convenient. 

 'SVe 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 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 Ijyell have largely and philosophically shown that all 

 organic beings are exposed to severe competition. In regard 

 to plants, no one has treated this subject Avith more spirit and 

 ability than AV. 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 con- 

 stantly to bear this conclusion in mind. Yet unless it be 

 thoroughly engrained in the mind, the whole economy of 

 Nature, with every fact on distriljution, rarity, abundance, ex- 

 tinction, and variation, will be dimly seen or quite misunder- 

 stood. We behold the face of Nature bright Avith gladness, 

 Ave often sec superabundance of food ; Ave do not see, or Ave 



