456 THE EVOLUTION OF LIFE. 



6 ted in the struggle for life, by the slight decrease in 

 these comparatively- small bones ? jSTo functional superiority 

 possessed by a small jaw over a large jaw, in civilized life, 

 can be named as having caused the more frequent survival 

 of small-jawed individuals. The only advantage which 

 smallness of jaw might be supposed to give, is the advantage 

 of economized nutrition ; and this could not be great enough 

 to further the preservation of men possessing it. The de- 

 crease of weight in the jaw and co-operative parts, that has 

 arisen in the course of many thousands of years, does not 

 amount to more than a few ounces. This decrease has to be 

 divided among the many generations that have lived and 

 died in- the interval. Let us admit that the weight of these 

 parts diminished to the extent of an ounce in a single gener- 

 ation (which is a large admission) ; it still cannot be con- 

 tended that the having to carry an ounce less in weight, or 

 the having to keep in repair an ounce less of tissue, could 

 sensibly affect any man^s fate. And if it never did this — 

 nay, if it did not cause di frequent survival of small-jawed in- 

 dividuals where large-jawed individuals died ; natural selec- 

 tion could neither cause nor aid diminution of the jaw and 



fortunately the absence, in most cases, of some or many teeth, prevented me 

 from arriving at that specific result which vv^ould have been given by weighing a 

 number of the under jaws in each race. Simple inspection, however, disclosed 

 a sufficiently-conspicuous difference. The under jaws of Australians and Negroes, 

 when placed side by side with those of Englishmen, were visibly larger, not only 

 relatively but absolutely. One Australian jaw onl}-, did I observe, that was about 

 of the same actual size as an average English jaw ; and this (probably the jaw of 

 a woman) belonging as it did to a much smaller skull, bore a much greater ratio 

 to the whole body of which it formed part, than did an English jaw of the same 

 actual size. In all the other cases, the under jaws of these inferior races (con- 

 taining larger teeth than our own) were absolutely more massive than our own— 

 cften exceeding them in all dimensions ; and relatively to the smaller skeletons 

 of these inferior races, they were very much more massive. Let me add that the 

 Austialian and I^egro jaws are thus strongly contrasted, not with all British jaws, 

 but only with the jaws of the civilized British. An ancient British skull in the 

 collection, possesses a jaw almost or quite as massive as those of the Australian 

 skulls. And this is in harmony with the alleged relation between greater size of 

 jaws and greater action of jaws, involved by the habits of savages. 



