ON THE QUICK GROWING WALNUT 



still matter for change and adaptation; still in the 

 experimental stage, as it were. And precisely be- 

 cause such is their status, these are the things 

 that are subjected to the Mendelian test when they 

 are brought in juxtaposition, through hybridizing, 

 with forms that differ as to these details. 



And as only the relatively new structures 

 Mendelize, so it is the newer member of any pair 

 that assumes prepotency or dominance. Contrari- 

 wise, the older member is recessive. 



Students of different examples of Mendelian 

 heredity, as applied to animals and plants, have 

 puzzled long to discover the underlying principle 

 that determines which character shall be dominant 

 and which recessive. But this simple principle 

 appears to furnish the explanation. 



The new trait or characteristic is dominant over 

 the older one precisely because it is new. 



By making it dominant, nature gives it the best 

 possible chance. It will reproduce itself in all the 

 immediate progeny of the individual that possesses 

 it. Thus nature shows anew that she is progress- 

 ing. She accepts the new characteristic and gives 

 it more than an even chance. 



But at the same time she is not so foolish as to 

 renounce the old character without full testing. 

 She allows it to be subordinated for a generation, 

 but in the next generation it reappears, isolated, to 



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