194 ARBOREAL MAN 



description of human mentality. That it knows what 

 it is doing presupposes the existence of consciousness. 

 That it remembers what it has done argues the dawning 

 of a conscience. That it can estimate what it might 

 do implies the laying of the foundation stone for building 

 ideals of cojidnct. Here is at least the basis for the 

 formation of that grade of moral social behaviour that 

 results from the lessons taught by experience. If ideals 

 of conduct be the answers to an ever-insistent series of 

 problems comprised in the question, " What shall I 

 do ?" then the area in which ideals of conduct are lodged 

 is, very probably, the prefrontal silent area. It must 

 be pointed out that in thus approaching the question of 

 the function of this area we are proceeding by more or 

 less logical steps; we are not merely localizing vague 

 functions, of which we can obtain no physical signs, in 

 an area from which no response can be elicited b}' experi- 

 ment. We are not forced by the extremities which 

 urged Descartes to assign the habitation of the soul to 

 the pineal body, but we are attempting to determine 

 the functions of this association area, just as we should 

 determine the function of any such area, by ascertaining 

 the probable characters of its neighbours. 



But this finding brings us face to face with the diffi- 

 culty, that in imagining the intellect to be represented 

 anatomically in the summation of all the neopallial areas, 

 and ideals of conduct to be lodged in the prefrontal areas, 

 we are supposing a rather definite separation of these 

 two factors in cortical representation. I believe that 

 this is, as a matter of fact, no difficulty at all, but is in 

 many ways a clue to understanding some normal and 

 abnormal conditions displayed in human mentality. It 

 should be possible to have a very definite separation of 

 these qualities displayed by their very unequal develop- 

 ment in different individuals. There are certainly 

 persons in whom no very special qualities of the intel- 

 lectual mind are present, but to A\hom the problems of 

 conscience and conduct bulk so large as to be a definitely 



