Man 169 



that mental ability in man rose in the same 

 way that trotting ability rose in trotters,— 

 by the performance of corresponding work 

 before reproduction. Union with inferior 

 mental development doubtless caused much 

 of the decline in the sons of these great men, 

 but that is only a partial explanation. A 

 more complete explanation may be found in 

 the fact that these great men, when they had 

 sons at all, had them in early life and not in 

 late life. The following men, sons of old men, 

 became fathers only when young: Ark- 

 wright, Bulwer-Lytton, Coleridge, Cromwell, 

 Franklin, Jay, Peter the Great, Solomon. 



The decline of mental ability and moral 

 characteristics coming from early reproduc- 

 tion is well shown in the case of the "Jukes," 

 investigated by Dugdale. This is a family 

 famous for the production of criminals, pau- 

 pers, and prostitutes. An analysis of the gen- 

 erations given shows that the lowest grade of 

 intelligence and criminality came from the 

 most rapidly moving generations, and that 

 several branches of respectable citizens came 



