ARE ACQUIRED CHARACTERS INHERITED ? 329 



Argument from tlie Giraffe. 



The only other argument of importance adduced by Mr. 

 Spencer is that drawn from the giraffe. This argument 

 was first stated at some length in his essay on The Factors 

 of Organic Evolution, in 1886 ; and it is now repeated and 

 enforced by some additional considerations, although, Mr. 

 Spencer says, he has met with nothing that can be called 

 a reply ; and he adds, that my contention (in Darwinism) 

 that what he alleges cannot be done by natural selection has 

 been done by artificial selection — assumes a parallelism 

 that does not exist. I therefore propose to examine this 

 case more carefully, and shall show that the parallelism I 

 assume is a very close one, and that natural selection is, as 

 Darwin himself believed, fully competent to account for 

 the facts.^ 



Mr. Spencer's argument is, briefly stated, that to develop 

 such an animal as the giraffe from some antelope-iike 

 ancestor requires many coincident and co-ordinate varia- 

 tions of different parts — each increase in the length of the 

 neck, of the head, of the fore or hind limbs, or of either of 

 the bones composing them, requiring corresponding in- 

 crease of muscles, nerves, and blood-vessels, not only of 

 such as are immediately connected with the enlarged 

 limb, but often in remote parts of the body whose motions 

 are necessarily co-ordinated with it. He maintains that 

 any increase of one part without the adjusted increase of 

 other parts would cause evil rather than good ; and that 

 want of co-adaptation, even in a single muscle, would 

 cause fatal results when high speed had to be maintained 

 while escaping from an enemy. Then, again, not only the 

 sizes but the shapes of the bones have to be altered as the 

 muscles are increased in size and the motions of the 

 various parts of the body change ; and this introduces 

 fresh difficulties which are, again and again, declared to 

 be insurmountable. And after elaborating all these 

 alleged difficulties at great length, he arrives at the con- 

 clusion that, unless the increase or modification of parts 



^ Origin of Species, p. 177, and more fully and with admirable force 

 and clearness in Animals and Plants under Domestication, vol. ii. p. 221. 



