HUXLEY ON THE RELATIONS OF MAN TO THE LOWER ANIMALS. 81 



Chimpanzee, 38 : 101 mm. = 1 : 2-66. 



Orang, 35 : 96 = 1 : 2'74. 



Human child, 22 : 96 = 1 : 4.36. 



Adult man, 50 : 157 = 1 : 3-1. 



Hence, it is clear 1°, that the cerebellum in the Chimpanzee and in the Orang are 

 proportionally larger than in man; 2°, that the Orang in this respect approaches man 

 more closely than does the Chimpanzee." — " Anatomical Investigation," &c., 1. c. pp. 

 265-7. 



The authors go on to remark that the same large proportion of the 

 cerebellum to the cerebrum is characteristic of the lower Mammalia, as 

 Soemmering had already observed, and that, consequently, the uncovered- 

 ness of the cerebellum arises as much from the disproportionately large 

 size of the latter, as from the defect of the posterior lobe of the cere- 

 brum. They further show that the human cerebellum is proportionally 

 still smaller in a six-months' foetus (1 : 4*7) ; and that, while in the adult 

 the cerebellum has more than double the size it had in the new-born 

 child (50 : 22), the cerebrum of the adult is only 1-J times as large 

 in the adult as in the new-born child (157 : 96). At the same time the 

 cerebellum attains its full size by the end of the third year — a fact which 

 indicates very interestingly the relations of the cerebellum with the lo- 

 comotive power. 



M. Gratiolet commences his description of the cerebral convolutions 

 of man thus : — 



" The form of the human brain is well known. Its singular height, the width of the 

 frontal lobe, whose anterior extremity, instead of narrowing to an acute point, is termi- 

 nated by a surface whose extent corresponds to that of the frontal bone ; the large angle 

 which the two orbital fossae form, the depression of the fissure of Sylvius, the richness and 

 complications of the secondary convolutions, at once distinguish this brain from that of all 

 the Primates. But these differences, great and characteristic as they may be, yet consist 

 with the existence of such analogies between the brain of man and that of apes, that the 

 same general description serves both equally well. There are the same principal divi- 

 sions, the same lobes, the same convolutions ; all the parts are not the same, but they are 

 homologous." — L. c, pp. 57, 58. 



M. Gratiolet then goes on to point out what the differences of these 

 homologous parts are ; but I cannot give them in detail here, without 

 entering upon a full explanation of his terminology, which would occupy 

 too much space. 



There is no lack, then, of real differences enough between the brain 

 of man and those of the highest Quadrumana, though they are not those 

 which have been asserted to exist. The question, what is the value of 

 these differences ? could only be satisfactorily answered, if the extent 

 of variation exhibited by the brain among the different races of man- 

 kind had been carefully determined. We are greatly in want of know- 

 ledge on this important subject ; but what little is known tends distinctly 

 to the conviction, that no very great value can be set upon these dis- 

 tinctions, inasmuch as the differences between the brains of the highest 

 races and those of the lowest, though less in degree, are of the same 

 order as those which separate the human from the simian brain. I am 



vol. i. — N. H. E. M 



