Licence: Public Domain Mark
Credit: Address to the Anthropological Section / William Turner. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
16/25 page 15
![into instruments of preliension, and of the lower limh.s into columns of support and progression, are not iu themselves siiRicient 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 I'idges on the skuti, or massive projecting processes in the spine, such as one tinds in apes and many other mammals. The head with the a.tlas 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 sliglit muscular etfort. The cranial cavity, with its contained brain, is of absolutely greater volume 'u man than in any other vertebrate, except in the elephant and in the large whales, in which the huge mass of the bodv demands the great sensory-motor centres in the brain to be of large size. Relatively also to the mass and weight of the body, tlie 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 te.sted. In the men, the average brain-weight i.s from 4‘J to 50 oz. (1,390 to 1,418 grm.). In the women, from 44 to 45 oz. (1,248 to ],28.'-i grm.). The ditference in weight is doubtless in part correlated with dlli'erences iu 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 beads and heavier brains than the girls. Dr. Boyd gives the average for the girl infants as 10 oz., and for boys 1TG7 oz. A distinction in the brain W'eight of the two sexes is obviously established, therefore, before the child is born, and is not to be accounted for by tlie 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 ascertaired to be from 55 to 60 oz. In a few exceptional cases, as in tlie brains of Cuvier 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 shovvn 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 tlie 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 I'eacnck give the mean ot the brain in the negro as between 44 and 45 oz., a weight which corresponds with that of European women; whilst in the Degress the mean weight is less than in the female sex in Europeans. In two Bush girls Irom South Alrica—representatives of a dwarf race—the brain is said to have been 34 and 38 oz. respectively.^ Eroin the weighings which have been published of the brains of the Orang and ‘ Sir B.. Quain in Patholnr/ieal Tramactions, 1850, p. 182, and Messrs. Flower and Miirie iu Journal of Anatomy and Phya., vol. i. p. 20(1.](https://iiif.wellcomecollection.org/image/b22473385_0017.jp2/full/800%2C/0/default.jpg)
