HEREDITY. 17 



cretin, it is evident to the world that Nature has put 

 down her foot and refused to go further ; but in many 

 others, although the necessarily fatal type has been 

 attained, it is not discoverable, and it is not until, 

 after one or more marriage, we find them childless, or 

 have seen their wretched children, one after another, 

 succumb long before reaching the procreative period, 

 that we recognise the fact that the end has been 

 reached. "When men wilfully frustrate the noble 

 purposes of their being, and selfishly ignore the laws 

 of hereditary transmission, Nature takes the matter 

 out of their hands, and puts a stop to the propagation 

 of degeneracy." 



I will give a case in point. It is the history of the 

 family of a patient of my own, and shows how, when 

 a certain low- water mark of vitality is reached, Nature 

 rids herself of the useless : 



