THE ROYAL WALNUT 85 



been able to make their traits manifest, but which 

 have always transmitted these potentialities as 

 submerged and subordinated tendencies. The 

 admixture of the divergent racial strains — one 

 from Europe, the other from California, or in the 

 case of the Royal, from origins separated by the 

 breadth of a continent — sufficed to bring together 

 factors of growth that for all these generations 

 had been separated, and the atavistic phenom- 

 enon of a giant walnut came into being. 



Thus interpreted, the case of the big walnut 

 is not dissimilar to the case of our white black- 

 berries or to that of the fragrant calla. 



In each of these instances, as in that of num- 

 berless others that we shall have occasion to ex- 

 amhie, a mixture of racial strains brings about a 

 reversion to the structure or quality of a remote 

 ancestor. 



In the case of the walnuts we have had occasion 

 to go back a few thousand generations farther 

 than in the other cases, but there is ample warrant 

 for believing that nature sets no limit on the 

 length of time throughout which a submerged 

 character may be transmitted, with full possi- 

 bilities of ultimate restoration. 



We shall have occasion to examine further evi- 

 dence of the truth of this proposition, drawn 

 from a quite different field, in a later chapter. 



