33G STUDIES, SCIENTIFIC AND SOCIAL chap. 



in the Australian and smaller in the European, even when 

 the actual size is identical. Why should the jaw be mea- 

 sured by the brain as a standard, any more than the foot, 

 the hand, or the stature ? On the same principle the 

 Australians might be proved to have very large hands, and 

 to be much taller that Englishmen, whereas, like most 

 savages, they have rather small hands, and are hardly our 

 equals in stature. The only reasonable way of comparing 

 the jaws of two races so nearly equal in stature as Austra- 

 lians and Englishmen, is to compare them directly. The 

 jaw is really a limb, used in the mastication of food to supply 

 the whole body with nourishment, not the brain only ; and 

 its true organic relation is with the body, not with the 

 brain case to which it is attached, still less with the brain 

 itself By the illogical process he uses, of first increasing 

 the linear dimension of the Australian's jaw in the same 

 proportion as the English skull is larger than the Australian 

 skull, without attempting to ascertain whether the depth 

 and thickness increase in the same proportion, and tihen 

 cubing this dimension, he arrives at the amazing result that 

 the Australian's jaw is very nearly double the bulk of the 

 modern English jaw ! Mr. Piatt Ball, on the other hand, 

 finds the weight of the latter to be only 5 per cent, less, 

 when reduced in proportion to the lighter skull, the actual 

 difference being 17 percent. ; but both results are founded 

 on far too small a number of specimens to be in any way 

 trustworthy. Mr. Collins then replies, and I think forcibly, 

 to two of Mr. Ball's suggested causes of the decrease — 

 lightness of structure facilitating agility, and sexual selec- 

 tion — but he passes over the two which have most weight, 

 the one as a " tentative suggestion," the other altogether 

 unnoticed ; namely, cessation of selection, and increase or 

 decrease caused by use and disuse in the individual. The 

 first, Mr. Collins says, with a strange misapprehension of 

 the point, would only affect the weight and thickness of the 

 jaw, not the peripheral measurement which he has used. 

 But why should not the size — the length and depth — of 

 the jaw be quite as important as the thickness and strength ? 

 The greater length and depth of the jaw would be effective 

 in giving more room for the attachment of the muscles on 

 which the whole efficiency of the masticating organ depends 



