292 SECRETS OF ANIMAL LIFE 



Touch is separated off from the nose and snout, and 

 is specialized in the hand. " It is the freed hand 

 which is permitted to become the sensitive hand, 

 which now, so to speak, goes in advance of the 

 animal and feels its way as it climbs through life." 

 It was a great advance when the hand began to 

 be habitually used to corroborate or check the 

 impressions gained by smell and by sight. 



There is not much of its own body that a cat 

 cannot see and cannot reach with its tongue, but 

 this is far from being usual among mammals, and 

 Professor Wood Jones is probably right in attaching 

 considerable importance to the way in which the 

 evolving Primate could feel with its hand over most 

 of its body and could also picture itself. Theory 

 apart, it is certain that the various stages of brain- 

 organization seen among the different types of 

 monkeys, show a decreasing importance of the 

 cerebral area for receiving olfactory impressions and 

 a predominance of the neopallial area where sensory 

 impulses from hand and eye and ear stream in 

 an area towards which, moreover, the originative 

 seats of the outgoing motor impulses tend in some 

 mysterious way to become approximated. It is 

 granted, of course, that cerebral organization 

 continued to make progress on terra firma as well as 

 among the branches, but the point is that arboreal 

 life was peculiarly favorable to the evolution of 

 brains. We mean that the arboreal environment 

 afforded peculiarly subtle sieves for the cerebral 

 new departures which were always cropping up. 



