ix LIMITS OF NATURAL SELECTION IN MAN 197 



the accumulation of variations from a hairy ancestor. The 

 evidence all goes to show that such variations could not have 

 been useful, but must, on the contrary, have been to some 

 extent hurtful. If even, owing to an unknown correlation 

 with other hurtful qualities, it had been abolished in the 

 ancestral tropical man, we cannot conceive that, as man 

 spread into colder climates, it should not have returned under 

 the powerful influence of reversion to such a long persistent 

 ancestral type. But the very foundation of such a supposi- 

 tion as this is untenable, for we cannot suppose that a 

 character which, like hairiness, exists throughout the whole 

 of the mammalia, can have become, in one form only, so 

 constantly correlated with an injurious character as to lead to 

 its permanent suppression a suppression so complete and 

 effectual that it never, or scarcely ever, reappears in mongrels 

 of the most widely different races of man. 



Two characters could hardly be wider apart than the size 

 and development of man's brain and the distribution of hair 

 upon the surface of his body, yet they both lead us to the 

 same conclusion that some other power than natural selec- 

 tion has been engaged in his production. 



Feet and Hands of Man, considered as Difficulties on 



the Theory of Natural Selection 



There are a few other physical characteristics of man that 

 may just be mentioned as offering similar difficulties, though 

 I do not attach the same importance to them as to those I 

 have already dwelt on. The specialisation and perfection of 

 the hands and feet of man seems difficult to account for. 

 Throughout the whole of the quadrumana the foot is pre- 

 hensile, and a very rigid selection must therefore have been 

 needed to bring about that arrangement of the bones and 

 muscles which has converted the thumb into a great toe, so 

 completely, that the power of opposability is totally lost in 

 every race, whatever some travellers may vaguely assert to 

 the contrary. It is difficult to see why the prehensile power 

 should have been taken away. It must certainly have been 

 useful in climbing, and the case of the baboons shows that it 

 is quite compatible with terrestrial locomotion. It may not 

 be compatible with perfectly easy erect locomotion ; but, then, 



