Page:Popular Science Monthly Volume 55.djvu/525

Rh the broad-headed. Prof. Karl Pearson, in his Chances of Death (voL i, page 205), has given the following sexual ratios of the superiority of English, German, and French men over the opposite sex:

In other words, men's skulls contain about eight per cent more and their brains weigh four per cent more than women's, even allowing for the difference in height. So, too, there is a uniform increase of cubic capacity from the skulls of the Australians (75 cubic centimetres) up to the Teutons (93.5 cubic centimetres). The same authority gives the average weight of brain in a number of brachycephalic individuals as 1,314 grammes, as against 1,287 grammes for dolichocephalic cases. Professor Pearson points out that the higher the caste in India the broader the skull, the Brahmans being highest, with an index of 78.86, according to the measurements of Pisley. The same writer gives a long list (page 290) of the indexes of skulls of some thirty-seven races, ranging from Australians at the bottom of the list, with 70.34, and headed by mediæval Jews (only twelve skulls), with an index of 84.74. Every indication seems to point out that in races where progress depends upon brain, rather than muscle the brain-box broadens out as a natural consequence. Little investigation has as yet been made as to the influence of brain development on the form of the skull, but what little has been done all points in the same direction. Dr. Giulio Chiarugi has made some careful measurements of twenty-one brains, and has shown that in every instance there is much greater complexity of the cerebral convolutions in the brachycephalic as compared with the dolichocephalic skulls, in which the brains were contained. From the nature of the sutures of the skull it is tolerably obvious that if brain capacity produces an enlargement of brain, the consequent internal pressure on the skull will be lateral and tend to produce brachycephalism. The application of all this to the case of Jews seems obvious. If they had been forced by persecution to become mainly blacksmiths, one would not have been surprised to find their biceps larger than those of other folk; and similarly, as they have been forced to live by the exercise of their brains, one should not be surprised to find the cubic capacity of their skulls larger than that of their neighbor's. When it is remembered that