782 REPORT— 1897. 



into instruments of prehension, and of the lower limbs into columns of support and 

 progression, are not in themselves sufficient to give that distinction to the human 

 body which we know that it possesses. They must have co-ordinated with them 

 the controlling and directing mechanism placed in the head, known as the brain 

 and organs of sense. 



The head, situated at the summit of the spine, holds a commanding position. 

 Owing to the joints for articulation with the atlas vertebra being placed on the 

 under surface of the skull, and not at the back of the head, and to the great reduc- 

 tion in the size of the jaws, as compared with apes and quadrupeds generally, the 

 head is balanced on the top of the spine. The ligaments supporting it and connected 

 with it are comparatively feeble, and do not require for their attachment strong 

 "bony ridges on the skull, or massive projecting processes in the spine, such as one 

 finds in apes and many other mammals. The head with the atlas vertebra can be 

 rotated about the axis vertebra by appropriate muscles. The face looks to the 

 front, the axis of vision is horizontal, and the eyes sweep the horizon with com- 

 paratively slight muscular effort. 



The cranial cavity, with its contained brain, is of absolutely greater volume in 

 man than in any other vertebrate, except in the elephant and in the large whales, 

 in which the huge mass of the body demands the great sensory-motor centres in 

 the brain to be of large size. Relatively also to the mass and weight of the body, 

 the brain in man may be said to be in general heavier than the brains of the lower 

 vertebrates, though it has been stated that some small birds and mammals are 

 exceptions to this rule. 



We have abundant evidence of the weight of the brain in Europeans, in whom 

 several thousand brains have been tested. In the men, the average brain-weight 

 is from 49 to 50 oz. (1,390 to 1,418 grm.). In the women, from 44 to 45 oz. 

 (1,248 to 1,283 grm.). The difference in weight is doubtless in part correlated 

 with differences in the mass, weight, and stature of the body in the two sexes, 

 although it seems questionable if the entire difference is capable of this explana- 

 tion. It is interesting to note that even in new-born children the boys have 

 bigger heads and heavier brains than the girls. Dr. Boyd gives the average for 

 the girl infants as 10 oz., and for boys 11"67 oz. A distinction in the brain 

 weight of the two sexes is obviously established, therefore, before the child is bom, 

 and is not to be accounted for by the training and educational advantages enjoyed 

 "by the male sex being superior to those of the female sex. 



The brains of a number of men of ability and intellectual distinction have been 

 "weighed, and ascertained to be from 55 to 60 oz. In a few exceptional cases, as 

 in the brains of Ouvier and Dr. Abercrombie, the weight has been more than 60 oz. ; 

 but it should also be stated that brains weighing 60 oz. and upwards have occa- 

 sionally been obtained from persons who had shown no sign of intellectual eminence. 



On the other hand, it has been pointed out by M. Broca and Dr. Thurnam, 

 that if the brain falls below a certain weight it cannot properly discharge its 

 functions. They place this minimum weight for civilised people at 37 oz. for the 

 men, and 32 oz. for the women. These weights are, I think, too high for savage 

 men, more especially in the dwarf races. We may, however, safely assume that if 

 the brain-weight in adults does not reach 30 oz. (851 grm.), it is associated with 

 idiocy or imbecility. There would seem, therefore, to be a minimum brain-weight, 

 which is necessary in order that the mental functions may be actively discharged. 



We have unfortunately not much evidence of the weight of the brain in the 

 uncultivated and savage races. The weighings made by Tiedemann, Barkow, 

 Reid, and Peacock give the mean of the brain in the negro as between 44 and 

 45 oz., a weight which corresponds with that of European women ; whilst in 

 the negress the mean weight is less than in the female sex in Europeans. In two 

 Bush girls from South Africa — representatives of a dwarf race — the brain is said 

 to have been 34 and 38 oz. respectively.^ 



From the weighings which have been published of the brains of the Orang and 



' Sir E. Quain in Pathological Transactions, 1850, p. 182, and Messrs. Flower and 

 Murie in Journal of Anatomy and Phyt., vol. i. p. 206. 



