262 MENTAL AND PHYSICAL RESULTS. 



In the case of Shakespeare we have both parents between the ages 

 of thirty and forty and both grandfathers probably (almost cer- 

 tainly) over 45. 



STERILITY. 



Sterility is of two kinds, natural and acquired. Natural ster- 

 ility may be divided into two classes, that which is congenital and 

 consequently arises from causes at present unknown, and that 

 which arises from the circumstances or surroundings of life. Ac- 

 quired sterility may also be divided into two classes, that which 

 has its origin in a vicious or unnatural life, and that which is 

 deliberately produced by the individuals themselves. 



Congenital sterility I shall not discuss because I can throw no 

 new light on the subject. I may remark, however, that it is prob- 

 ably the rarest of all kinds. Although "inherited sterility" is a 

 contradiction of terms, and consequently an absurdity, there is such 

 a thing as inheriting a tendency toward sterility, which tendency 

 may become, or develop into, actual sterility, and thus become con- 

 genital sterility. That this semi-sterility is hereditary is well shown 

 by Mr. Day in his excellent work "The Horse." He mentions the 

 cases of many mares who would slip or be sterile through many 

 seasons, and shows that the few progeny that they did have were 

 afflicted with the same trouble. Mr. Galton, in his "Hereditary 

 Genius," show that heiresses are more frequently sterile than other 

 women, and as a consequence have caused the extinction of a great 

 many English families. The fact that sterility causes such extinc- 

 tion makes it its own remedy, and whatever may be its cause, I 

 assume that it is about as desirable as leprosy. 



CIVILIZATION AND STERILITY. 



That' other form of natural sterility finds its cause in the ad- 

 vancing stages of civilized society, and perhaps may be best illus- 



