286 Heredity and Eugenics 



Criminality in its worst forms is similarly due to a lack of 

 appreciation of or receptivity to moral ideas. 



If we seek to know what is the origin of these defects, 

 we must admit that it is very ancient. They are probably 

 derived from our apelike ancestors in which they were 

 normal traits. There occurs in man a strain that has not 

 yet acquired those traits of inhibition that characterized 

 the more highly developed civilized persons. The evidence 

 for this is that, as far back as we go, we still trace back the 

 black thread of defective heredity. 



We have now to answer the question as to the eugenical 

 application of the laws of inheritance of defects. First, 

 it may be pointed out that traits due to the absence of a 

 determiner are characterized by their usual sparseness in 

 the pedigree, especially when the parents are normal; by 

 the fact that they frequently appear where cousin marriages 

 abound, because cousins tend to carry the same defects 

 in their germ plasm though normal themselves; by the 

 fact that two affected parents have exclusively normal 

 children, while two normal parents who belong to the same 

 strain, or who both belong to strains containing the same 

 defect, have some (about 25 per cent) defective children. 

 But a defective married to a pure normal will have no 

 defective offspring. 



The clear eugenical rule is then this: Let abnormals 

 marry normals without trace of the defect, and let their 

 normal offspring marry in turn into strong strains; thus 

 the defect may never appear again. Normals from the 

 defective strain may marry normals of normal ancestry; 

 but must particularly avoid consanguineous marriages. 



The sociological conclusion is: Prevent the feeble- 

 minded, drunkards, paupers, sex-offenders, and criminalistic 

 from marrying their like or cousins or any person belonging 



