GLINTS, TRIBES AND CLASSES 



by class, cline and tribe are all made to contribute to a local cultural 

 and national adaptation. Finally we may notice that, to slow-moving 

 observers on the earth, compelled to examine human variation at 

 close quarters, the broad clinal slopes have naturally been obscured 

 in the past by the narrow tribal ridges and ravines. 



Clearly to reap the full harvest in the field of human heredity 

 we shall have long to wait. But it is necessary for the student of 

 genetics to recognize the possibilities of his method. Mendelian 

 interpretation of a few physical defects provides their foundation. 

 But on this foundation can be built a structure which will unite 

 in a coherent system of analysis the most varied aspects of the study 

 of man, medical and social, cultural and political. 



The methods of Mendel and Darwin have to be used and com- 

 bined. The tecliniques of chromosome study and statistical analysis 

 have to be fully exploited. And it would be as foolish to deny these 

 enquiries their proper scope as it would be to admit their con- 

 clusions without continued trial. 



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