64 PRIMEVAL MAN. 



found to exist between the lowest and the 

 highest human brain, because the fact with 

 which we have to deal is this, that a certain 

 minimum quantity of that mysterious sub- 

 stance is constantly and uniformly associated 

 with all the other anatomical peculiarities 

 of Man. Below that minimum the whole 

 accompanying structure undergoes far more 

 than a corresponding change, — even the whole 

 change between the lowest Savage and the 

 highest Ape. Above that minimum, all 

 subsequent variations in quantity are accom- 

 panied by no changes whatever in physical 

 structure. In placing, therefore, a high value 

 — a value in classification of Order, or even 

 of Class — upon the eleven cubic inches of 

 brain-space which lie between the Hindu and 



