114 



EDWIN CARLETON MACDOWELL 



periods. The progress of selection must be sought within this 

 period and within the earher period. 



With these facts in mind the curves showing the means of the 

 sons and daughters in the high selected race are to be examined 

 (fig. 3). The means for generations 2 to 11 differ somewhat 

 from those given previously. In order to increase the rigidity 

 of selection, families with certain lower grade parents were 



2 4 6 8 10 12 14 16 IB 20 22 24 26 28 30 32 34 36 38 40 42 44 46 4E 



Fig. 3 Means of the parents, sons and daughters in the total generations of 

 the high selected race. The means of the parents have been weighted according 

 to the numbers of their offspring. The curves of the sons and daughters are 

 much alike in their fluctuations; except in the early generations the curves of 

 the parents and offspring do not show parallel fluctuations. 



excluded together with all their descendants. As here given, 

 the means include all such families. The resulting changes in 

 the means are insignificant from the standpoint of a general 

 conclusion, since they do not modify the general form of the 

 curve. 



In the earlier report, the initial rise in the means was 

 emphasized. It would be a difficult matter to determine just 

 where this initial advance was stopped. Were certain striking 



