SOME INTKRESTINC, FAILURES 



ciently divtrticnl to inliuducc a gtcaU'r diversity 

 of conflicting tendencies than is consonant with 

 racial progress when tlie strains are brought 

 together. 



But it will be recalled that when the California 

 black walnut was hybridized with the English 

 walnut — producing the "Paradox" — the results in 

 this regard were quite different. While the indi- 

 vidual offspring showed great vitality, they were 

 almost sterile, producing only a few stray nuts in 

 contrast with the profusion of the Royal liybrids. 



And we may infer from this result that the 

 California walnut and its remote English cousin 

 have diverged to a point lying just on the border 

 line of the limits of desirable racial mingling. 



These limits have not quite been crossed as 

 they have been in the case of the dewberry and 

 apple tree, and the strawberry and raspberry, but 

 they are being approximated; and there is no 

 probability that the hybrid offspring of the black 

 walnut and the English walnut could maintain 

 itself through successive generations as a new race 

 in a state of nature. At all events, its fight would 

 be a doubtful one. 



The Application to the Human Species 



It is more than likely, then, that the lessons 

 taught by the unsuccessful experiments recorded 

 in this chapter are quite as important as if they 



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