158 HUMAN BIOLOGY 



were distinct races already among the human precursors, 

 and that more or less different races were present throughout 

 the existence of man. It is not impossible, even, that more 

 than one race of precursors were evolving simultaneously 

 towards man, though only the most successful of such 

 possible separate developments appears to have survived. 



It may therefore legitimately be said that from the earhest 

 times of its existence humankind was tending to differentiate 

 into races; and that racial differentiation in man is a con- 

 tinuous, general hfe process, without sharply demarkable 

 beginnings or end. Its causes are organic variability, adapt- 

 abiHty to changed conditions, eventual heredity of the 

 newly developed and sustained characters, and prolonged 

 segregation of the new groups. 



Nascent Races 



Whenever a human group of some magnitude and geo- 

 graphical extent begins to assume lasting somatological 

 characters that tend to differentiate it plainly from other 

 groups of man, it may justly be regarded as a nascent race. 

 Whether such a race becomes successful, i.e. prevails and 

 becomes established, will depend on conditions. 



The tendency towards the development of new human 

 races may be observed in many parts of the world today. 

 Its chief present factors are, on one hand, the basic human 

 qualities or functions of variability and blending; and on the 

 other hand intermixture, with unification of activities. 



Wherever two or more racial elements come into such 

 contact as will bring on free intermarriage, there will before 

 long begin to form an intermediary type or progressive 

 blend. In most cases such a blend, through circumstances, 

 becomes dissolved into one or more of the parent bodies, 

 or is so influenced by the predominance of one or another of 

 these that it fails to reach any distinct status of its own. 

 But in favorable cases, which are those of mixtures within 

 large political units, there will be formed a "nation," which 

 with time advances towards uniformity of language and 

 habits. And such a unit, if immigration is not great, will 

 show ever more of physical resemblances. 



