TRANSACTIONS OF SECTION H. 783 



Chimpanzee, it would seem that the brain-weight in these apes ranges from 11 to 

 15 oz. (312 to 426 grm.),and the brain-weight appears to be much about the same 

 in the Gorilla. These figures are greatly below those of the human brain, 

 even in so degraded a people as the dwarf Bush race of South Africa. Thev 

 closely approximate to the weight of newly born male infants, in whom, as has just 

 been stated, the average weight was 11 '67 oz. For the purposes of ape-life, the 

 low brain-weight is sufficient to enable the animal to perform every function of 

 which it is capable. Its muscular and nervous systems are so accurately co-ordi- 

 nated that it can move freely from tree to tree, and swing itself to and fro ; it can 

 seize and retain objects with great precision, and can search for and procure its 

 food. In aU these respects it presents a striking contrast to the infant, having an 

 almost similar brain-weight, which lies helpless on its mother's knee. 



Another line of evidence, of which we may avail ourselves, in order to test 

 the relative size of the brain in the different races of men and in the large 

 apes is to be obtained by determining the internal capacity of the cranium. 

 Examples of the brains of different races (except Europeans) are few in number in 

 our collections, but the crania are often well represented, the volume of the 

 cavity in which the brain is lodged can be obtained from them, and an approximate 

 conception of the size and weight of the brain can be estimated. In pursuing this 

 line of inquiry, account has of course to be taken of the space occupied by the 

 membranes investing the brain, by the blood vessels and the cerebro-spinal fluid. 

 A small deduction from the total capacity will have to be made on their behalf. 



There is a general consensus of opinion amongst craniologists that the mean 

 internal capacity of the cranium in adult male Europeans is about 1,500 c.c. 

 (91-5 cub. in.). The mean capacity of the cranium of fifty Scotsmen that I have 

 measured by a method, which I described some years ago,^ was 1,493 c.c. 

 (91-1 cub. in.). The most capacious of these skulls was 1,770 c.c, and the one 

 with the smallest capacity was 1,240 c.c. Thus, in a highly civilised and 

 admittedly intellectual people, the range in the volume of the brain-space amongst 

 the men was as much as 530 c.c. in the specimens under examination, none of 

 which was Imown or believed to be the skull of an idiot or imbecile, whilst some 

 were known to be the crania of persons of education and position. In twenty- 

 three Scotswomen the mean capacity was 1,325 c.c, and the range of variation was 

 from a maximum 1,625 to a minimum 1,100 c.c. — viz., 525 c.c. 



Again I have taken the capacity, by the same method, of a number of crania 

 of the Australian aborigines, a race incapable apparently of intellectual improve- 

 ment beyond their present low state of development. In thirty-nine men the 

 mean capacity was only 1,280 c.c. (78'1 cub. in.). The maximum capacity was 

 1,514 c.c, the minimum was 1,044 c.c. The range of variation was 470 c.c. In 

 twenty-four women the mean capacity was 1,115-6 c.c, the maximum being 1,240 

 and the minimum 930, and the range of variation was 310 c.c. It is noticeable 

 that in this series of sixty- three Australian skulls, aU of which are in the 

 Anatomical Museum of the University of Edinburgh, eight men had a smaller 

 capacity than 1,200 c.c, and only four were above 1,400 c.c. Of the women's skulls 

 ten were below 1,100 c.c, four of which were between 900 and 1,000 c.c, and only 

 three were 1,200 c.c and upwards. 



Time does not admit of further detail on the cranial capacities of other races 

 of men. Sufiicient has been said to show the wide range which prevails, from the 

 maximum in the Europeans to the minimum in the Australians, and that amongst 

 persons presumably sane and capable of discharging their duties in their respective 

 spheres of activity; for we must assume that the crania of the Australians, 

 having the small capacities just referred to, were yet sufiiciently large for the 

 lodgment of brains competent to perform the functions demanded by the life of a 

 savage. From a large number of measurements of capacity which I have made of 

 the skulls of the principal races of men, I would draw the following conclusions : 

 First, that the average cranial capacity, and consequently the volume and weight 

 of the brain, are markedly higher in the civilised European than in the savage 

 races ; second, that the range of variation is greater in the former than in the 



> Human Crania, Challenger Reports, Pt. xxix. 1884, p. 9, 



