120 THE RELATIONS OF MAN 



the brain of a monkey exhibits a sort of skeleton map of 

 man's, and in the man-like apes the details become more 

 and more filled in, until it is only in minor characters, 

 snch as the greater excavation of the anterior lobes, the 

 constant presence of fissures usually absent in man, and 

 the different disposition and proportions of some convolu- 

 tions, that the Chimpanzee's or the Orang's brain can be 

 structurally distinguished from Man's. 



So far as cerebral structure goes, therefore, it is clear 

 that Man differs less from the Chimpanzee or the Orang, 

 than these do even from the Monkeys, and that the differ- 

 ence between the brains of the Chimpanzee and of Man is 

 almost insignificant, when compared with that between the 

 Chimpanzee brain and that of a Lemur. 



It must not be overlooked, however, that there is a 

 very striking difference in absolute mass and weight be- 

 tween the lowest human brain and that of the highest ape 

 — a difference which is all the more remarkable when we 

 recollect that a full grown Gorilla is probably pretty nearly 

 twice as heavy as a Bosjes man, or as many an European 

 woman. It may be doubted whether a healthy human 

 adult brain ever weighed less than thirty-one or -two 

 ounces, or that the heaviest Gorilla brain has exceeded 

 twenty ounces. 



This is a very noteworthy circumstance, and doubtless 

 will one day help to furnish an explanation of the great 

 gulf which intervenes between the lowest man and the 

 highest ape in intellectual power ; " but it has little sys- 



* I say help to furnish : for I by no means believe that it was any original 

 difference of cerebral quality, or quantity, which caused that divergence be- 

 tween the human and the pithecoid stirpes, which has ended in the present 

 enormous gulf between them. It is no doubt perfectly true, in a certain sense, 

 that all difference of function is a result of difference of structure ; or, in other 

 words, of difference in the combination of the primary molecular forces of 

 living substance ; and, starting from this undeniable axiom, objectors occasion- 



