THE PAST EVOLUTION OF MAX 15 



likely to be associated with high intelligence. The 

 chief characteristic of the human as distinguished 

 from the simian brain, and of the brain of higher 

 races of men as distinguished from savages, is the 

 exceptional development of the frontal region. The 

 relation of this region to the intelligence may now 

 be fairly regarded as indisputable. 



Here I may be permitted parenthetically to meet 

 a possible objection. It may be said that I con- 

 trast the relatively vertical human forehead with 

 the receding forehead of the ape. But how comes 

 it that woman, who is, on the average, intellectually 1 

 the inferior of man, has a forehead more vertical 

 than his ? Does not this directly contravene the 

 theory ? This objection may be very easily answered. 

 It involves the cardinal error of the old phrenology 

 that the external contour of the skull may uncriti- 

 cally be accepted as indicative of the contour of the 

 brain. In consequence probably of sexual selection, 

 man has developed a more resonant voice than 

 woman. Its resonance is largely due to the presence 

 of actual resonating chambers connected with the 

 air-passages. Amongst such air-chambers — formed 

 by the separation of the two dense layers which 

 form the inner and outer surfaces of the cranial 

 bones — are the frontal sinuses, which appear pro- 

 minently above the nose and eyes of most men. It 

 is their presence which renders the frontal outline 

 of man less vertical than that of woman ; and not 

 any greater development in woman of the frontal 

 iobes of the subjacent brain. 



In another volume I must deal with the im- 



1 I beseech the reader to observe that I do not say morally. 



