160 Dynamic Evolution 



comparatively young sire, provided there is 

 back of that sire and the dam an accumula- 

 tion of energy enough to more than com- 

 pensate for any lack of accumulation by the 

 son himself. In all of those cases in which 

 information was obtainable this same charac- 

 teristic was found in the pedigrees of the intel- 

 lectual giants. The father was comparatively 

 young in a number of cases, but the factor 

 time for two generations was never small in 

 anything really eminent. In many cases the 

 mother of the eminent man was found to be 

 the daughter of an old and mentally active 

 man. If the quantity of mental work per- 

 formed by the father before getting the son 

 affects the mental status of that son, then he 

 should also be affected in like manner by 

 mental labor performed by the maternal 

 grandfather before the mother was conceived. 

 But such things do not appear in general 

 tables showing the average ages of fathers. 

 They can be reached only by detailed ex- 

 aminations of individual cases. 



The average age at which people marry and 



