14 SOCIAL HEREDITY AND SOCIAL EVOLUTION 



it. In tlie discussion of eugenics in the public 

 press reference is most commonly made to the sad 

 and terrible story of the ravages played upon 

 the race by the sexual diseases which are undoubt- 

 edly transmitted from parent to child. The actual 

 attempts made by certain States to regulate mar- 

 riage by requiring medical certificates of fitness 

 of the contracting parties have reference largely to 

 the question of the presence of the venereal dis- 

 eases. Nothing is more certain than the disasters 

 that follow in the train of these diseases, and no 

 attempt should be spared to eradicate them by con- 

 trolling marriage if this is possible. But to make 

 our discussion clear it must be definitely understood 

 that these diseases are not inherited in the same 

 sense that we inherit the color of our eyes and other 

 features of our bodies. It is true that they are passed 

 from parent to child, but not by organic inheritance. 

 They are contagious diseases, and the child does not 

 inherit them, but, rather, ** catches" them from its 

 parents. They are due to perfectly well-known 

 microorganisms which lodge in the reproductive or- 

 gans and may pass bodily from the parent to the 

 child by simple contact. When one child acquires 

 measles from another we never think of saying that 

 he inherits it from his sick friend. In the same way 

 if the parent has contracted one of these loathsome 

 diseases, the child may be directly infected with the 

 disease organisms at birth, or even before birth, but 

 does not in the true sense inherit the disease. We 

 must clearly recognize that by true organic inherit- 

 ance reference is made only to such characteristics 

 as have been incorporated into the germinal matter 

 in the egg or sperm and not to any extraneous para- 



