52 ARBOREAL MAN 



this fate only to become quadrumanous. Four feet do 

 not lead far in the struggle for mammalian supremacy, 

 four hands do not lead a great deal farther. It was the 

 differentiation into two hands and two feet that provided 

 the great strength of the stock from which Man arose. 



The active specialization of the fore-limb did much, 

 but it could not do all, without the accompanying passive 

 specialization of the hind-limb. Mere ability in climbing, 

 which usurped the power of any real ability to walk, 

 was but a poor accomplishment, for to complete the whole 

 story of evolution the animal which climbed up the tree 

 had still to walk down — and the Old-World apes still 

 show in caricature how this was done. 



