180 THE ORIGIN OF SPECIES 



lished cases than can be found in any other work known to me. 

 My judgment may not be trustworthy, but after reading with 

 care Mr. Mivart's book, and comparing each section with what I 

 have said on the same head, I never before felt so strongly con- 

 vinced of the general truth of the conclusions here arrived at, 

 subject, of course, in so intricate a subject, to much partial error. 



All Mr. Mivart's objections will be, or have been, considered in 

 the present volume. The one new point which appears to have 

 struck many readers is, "That natural selection is incompetent to 

 account for the incipient stages of useful structures." This subject 

 is intimately connected with that of the gradation of the charac- 

 ters, often accompanied by a change of function, for instance, the 

 conversion of a swim-bladder into lungs, points which were dis- 

 cussed in the last chapter under two headings. Nevertheless, I 

 will here consider in some detail several of the cases advanced by 

 Mr. Mivart, selecting those which are the most illustrative, as 

 want of space prevents me from considering all. 



The giraffe, by its lofty stature, much elongated neck, fore legs, 

 head, and tongue, has its whole frame beautifully adapted for 

 browsing on the higher branches of trees. It can thus obtain food 

 beyond the reach of the other Ungulata or hoofed animals in- 

 habiting the same country; and this must be a great advantage 

 to it during dearths. The Niata cattle in South America show 

 us how small a difference in structure may make, during such 

 periods, a great difference in preserving an animal's life. These 

 cattle can browse as well as others on grass, but from the projec- 

 tion of the lower jaw they cannot, during the often recurrent 

 droughts, browse on the twigs of trees, reeds, etc., to which food 

 the common cattle and horses are then driven; so that at these 

 times the Niatas perish, if not fed by their owners. Before coming 

 to Mr. Mivart's objections, it may be well to explain once again 

 how natural selection will act in all ordinary cases. Man has 

 modified some of his animals, without necessarily having attended 

 to special points of structure, by simply preserving and breeding 

 from the fleetest individuals, as with the race-horse and grey- 

 hound, or as with the game-cock, by breeding from the victorious 

 birds. So under nature with the nascent giraffe, the individuals 

 which were the highest browsers and were able during dearths to 

 reach even an inch or two above the others, will often have been 

 preserved; for they will have roamed over the whole country in 

 search of food. That the individuals of the same species often 

 differ slightly in the relative lengths of all their parts may be 

 seen in many works of natural history, in which careful measure- 



