242 READINGS IN BIOLOGICAL SCIENCE 



"Age of Man," yet it has produced this revolution, this amazing upheaval 

 in numbers and in attainments, which is in vivid contrast with the long 

 previous span of man's existence during which culture had plodded ahead 

 at a barely perceptible pace. Very few Bushmen remain in South Africa, 

 or blackfellows in Australia, and these have probably survived by grace 

 of living in a desert and a remote island respectively; but in those days 

 of the end of the Paleolithic the races we distinguish to-day must have 

 been more equal in numbers. The point of this effort to ignore the present 

 scene, and instead to restore that of 10 millenniums ago, is to give these 

 now negligible races their proper significance. When they and possible 

 others stood on more equal terms with those which dominate to-day, the 

 whole species would have presented an appearance of even greater di- 

 versity than at present, and this very diversity is an index of the age of 

 the species itself, because races can not have appeared overnight. 



Races seem to have formed almost entirely as the result of random evolu- 

 tion. It is conceivable that the tropical sun was an influence in establishing 

 dark skin in the possessors of that feature, and woolly hair as well. If so, 

 it was certainly a long process, too gradual a one to have affected the 

 Indians of tropical America over many thousand years. But geographic 

 isolation, the simple separation of groups descended from the original 

 Ho?no sapiens, was probably the most important factor. Such groups 

 changed slightly but continuously, by nature's laws, and being separated 

 geographically, they tended to drift aimlessly apart in physical form as 

 well, becoming racially diverse. Bagehot, the economist, once suggested 

 that when man was new his meager culture allowed natural selection to 

 act powerfully upon him, leading to the rapid development of races. This 

 is a poor hypothesis all around; natural selection would affect the func- 

 tional development of his legs, etc., but selection would actually tend to 

 prevent racial differentiation. There is no real reason to think that there 

 was irregularity in the speed of racial development, or anything except 

 an even increase in diversification, which reached a maximum about ten 

 thousand years ago. 



The process probably took a long time. The only sighting point by 

 which we can judge its pace is the beginning of the Upper Paleolithic. The 

 first unquestioned Homo sapieris, the Cro Alagnons, demonstrate; (i) that 

 there has been no progressive racial development, as far as can be seen, in 

 some 30 millenniums, and (2) that the men of that time were hardly more 

 primitive in an evolutionary sense. In Europe, the Cro Magnons and re- 

 lated types were purely "white" in character, showing that this racial 

 stock, at least, was fully developed and by no means in any embryonic 

 stage. And there is some evidence from other skeletons of comparable 

 age that the Negro and Mongoloid stocks were equally well established. 

 Furthermore, the native AustraUan of to-day is definitely more backward 



