90 Appendix II 



half upon their offspring, it is to be expected 

 that the sum of the father's and mother's 

 influence would equal unity. If exceptional 

 parents married at random this would be the 

 case, but in practice it is not so, for since 

 there is a tendency for like to mate with like, 

 some of the characters undergo reduction. 

 A convenient formula for expressing the 

 actual extent of inheritance is the following : 



Length of son's stature 

 = *4" + TTHF of father's stature -f T W of mother's stature. 



Length of daughter's stature 

 = n"-f fV<r of father's stature -fy 4 ^ of mother's stature. 



(This is, of course, not absolute for indi- 

 viduals, but holds only for averages.) Thus, 

 two parents who have an exceptional stature 

 give their offspring 80 to 83 per cent, of their 

 stature. 



Exceptional grand-parents bring this up to 95%. 



great-grand-parents bring this up to 97%. 



The offspring of the individual who has 

 thus been pulled up, provided his mate is up 

 to the like standard, do not regress. In 

 other words, a stock may be formed in two 

 generations, and, once formed, the respon- 

 sibility of maintaining the stock afterwards 

 lies with the individual. Here, then, begins 

 legitimate pride in ancestry. Similar rela- 

 tions were shown to hold between mother 



