NURTURE VERSUS NATURE 



that may be urged with a fair measure of assur- 

 ance. 



EESTKICTING THE FECUNDITY OF THE UNFIT 



First and foremost among these is the belief 

 that the notoriously unfit members of the com- 

 munity, as represented by criminals, the insane, 

 and the mentally defective, should on no account 

 be permitted to have progeny. 



These defectives represent a recessive element 

 in the human germ-plasm. And all our modern 

 studies make it increasingly clear how difficult it 

 is to eliminate a recessive trait from the strains 

 of any race of organisms. To be sure, a recessive 

 quality disappears altogether in the first filial 

 generation when mingled in the germ-plasm with 

 the antagonistic and dominant quality. But it not 

 only reappears tangibly in a certain proportion 

 of the offspring of the second generation, but it 

 also remains as a latent factor in the germ-plasm 

 of two out of three of the progeny of that genera- 

 tion who give no outward evidence of its presence. 



Such, it will be recalled, is the characteristic 

 feature of Mendelian inheritance, and when we 

 consider the facts from the present point of view, 

 it might fairly be questioned whether the terms 

 dominant and recessive might not better have 

 been reversed. It is far easier to fix a recessive 

 quality, because its tangible manifestation proves 

 the absence of the corresponding dominant fac- 

 tors. But we have no way of telling that any or- 



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