i82 THE FIRST PRINCIPLES OF HEREDITY 



" That the best general constitutions should be mated 

 is the first rule of good breeding. 



" That a markedly good constitution should not be 

 paired with a markedly bad one is a second rule, a dis- 

 regard of which means wanton wastage. 



" A third rule is that a person exhibiting a bias towards 

 a specific disease should not marry another with the same 

 bias. 



*' In other words, every possible care should be taken of a 

 relatively sound stock. The careless tainting of a good 

 stock is a social crime. Every reasonable precaution 

 should be taken to prevent a badly tainted stock from 

 diffusing itself." 



" What is above aU precious," to quote the same 

 authority, " is the conservation of good stock. No 

 number of veneering modifications — superficial screens of 

 organic defects — can atone for allowing a deterioration of 

 the germinal inheritance to diffuse itself or accumulate. 

 For progress which is really organic — for progress, that is, 

 in our natural inheritance — ^we must wait, or rather work, 

 patiently. The quest after ' Eutopias ' and ' Eutechnics ' 

 must be associated with an enthusiasm for ' Eugenics.' " 



As for moral characteristics, there is no doubt that we 

 cannot but hold them subject to the general biological laws 

 of inheritance. In fact, Pearson has been able to show, 

 as mentioned once before, that mental and moral characters 

 are inherited in the same ratio as physical qualities. It is 

 true, the moral and intellectual powers depend as much 

 as the other physiological functions of the body on the 

 appropriate stimuli supplied by early culture and educa- 

 tion ; it is true, the outward expression of these inherent 

 qualities may be modified by the superimposed weight of 

 social sentiments, habits, and customs — the social heritage 

 bequeathed by society to the individual ; but, after all, 

 how each individual reacts towards these outside forces 

 depends completely on his intrinsic inherited potentialities. 

 And it would be rash to deny that there are no different 



