410 FORMATION OF NEW RACES. CHAP. xxi. 



by the force of inheritance to their offspring, will constitute 

 new races, or what Mr. Darwin calls ( incipient species.' If 

 one variety, being in other respects just equal to its com 

 petitors, happens to be more prolific, some of its offspring 

 will stand a greater chance of being among those which will 

 escape destruction, and their descendants, being in like 

 manner very fertile, will continue to multiply at the expense 

 of all less prolific varieties. 



As breeders of domestic animals, when they choose certain 

 varieties in preference to others to breed from, speak techni 

 cally of their method as that of ' selecting,' Mr. Darwin calls 

 the combination of natural causes, which may enable certain 

 varieties of wild animals or plants to prevail over others of 

 the same species, e natural selection,' 



A breeder finds that a new race of cattle with short horns 

 or without horns may be formed, in the course of several 

 generations, by choosing varieties having the most stunted 

 horns as his stock from which to breed ; so nature, by altering, 

 in. the course of ages, the conditions of life, the geographical 

 features of a country, its climate, the associated plants and 

 animals, and, consequently, the food and enemies of a species 

 and its mode of life, may be said, by this means, to select 

 certain varieties best adapted for the new state of things. 

 Such new races may often supplant the original type from 

 which they have diverged, although that type may have been 

 perpetuated without modification for countless anterior ages 

 in the same region, so long as it was in harmony with the 

 surrounding conditions then prevailing. 



Lamarck, when speculating on the origin of the long neck 

 . of the giraffe, imagined that quadruped to have stretched 

 himself up in order to reach the boughs of lofty trees, until 

 ,by continued efforts, and longing to reach higher, he obtained 

 an elongated neck. Mr. Darwin and Mr. Wallace simply 

 suppose that, in a season of scarcity, a longer-necked variety, 



