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. 
