HUMAN PROGRESSION AND RETROGRESSION 223 



367. Popularly, and even by most scientific men, the human 

 race is supposed to be undergoing progression in all sorts of 

 directions. Others suppose that cessation of selection is resulting 

 in general retrogression. But clearly, as in other species, the great 

 majority of human physical characters are merely stationary. 

 They are selected, but only to an extent which maintains an 

 efficiency previously established. They fit the race sufficiently 

 well to the environment, and only marked defect usually results in 

 a failure to rear offspring. Judging from ancient remains and 

 from a comparison with modern savages, civilised man differs 

 little, if at all, from his remote ancestors in hands, feet, blood, bones, 

 heart, lungs, and the like. Doubtless, owing to accidents of 

 survival, to sexual selection, or to migration which brings different 

 sets of selecting agencies into play, all races have undergone 

 some structural changes ; but these are comparatively unimportant. 

 In obvious physical features, the features by which biologists are 

 accustomed to measure physical change, humanity as a whole has 

 undergone little innate alteration during the few thousands of 

 years of civilisation. We are said to be more bulky than our 

 ancestors of six or seven centuries ago, but there is no evidence 

 that during the interval big individuals have been specially 

 selected for survival. Probably, therefore, the increase in size is 

 due merely to environmental changes, such as improved nutrition 

 and treatment of the young, which permits better individual 

 development. An analogous case is that the modern girl of the 

 higher classes is taller on the average than her grandmother, and 

 the modern field labourer than the factory hand. Some modern 

 savages are taller on the average than the members of any 

 civilized race, and some skeletons of the Stone Age are those of 

 large men with well developed crania. 



368. Of retrogression, also, there is little positive evidence. 

 Thus, when suitably trained, civilized men appear to be, on the 

 whole, just as keen of sight and hearing and as capable of enduring 

 fatigue as savages. The Boers and Australian whites are cases 

 in point. It is only when we compare man to the nearest lower 

 animals that we seem to obtain positive evidence. Some of his 

 senses, his hearing and sense of smell, for example, appear 

 weaker. His jaws and teeth certainly, and probably his digestive 

 apparatus, have undergone retrogression. He is less able to 

 masticate and assimilate the raw coarse food on which his 

 ancestors subsisted. But, even here, it is probable that much is 

 attributable to the direct action of the environment on the developing 



