140 MAN AND THE LOWER ANIMALS n 



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, such 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 

 convolutions, 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 difference 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 between 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 Bosjesman, 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 tho 



