Effects of Two Generations 109 



geldings. The descent is through both sons 

 and daughters, and there are all combinations 

 of descent except one. Descent from George 

 Wilkes to 2 : 10 stallions is indifferently 

 through sons and daughters, but not so in 

 descent to 2 : 10 mares or 2 : ro geldings. 

 The lines of descent through sons to mares 

 and geldings of 2 : 10 quality are plentiful, 

 but the blood of George Wilkes reaches these 

 animals through a daughter only when there 

 is another male in the line of descent between 

 the daughter and the mare or gelding. It 

 also reaches these mares and geldings only 

 when the son or daughter's son in the line of 

 descent was trained to some extent during 

 his immature stage, and the frequency with 

 which it occurs in any particular line appears 

 to be closely proportional to the extent of 

 this early training. 



Here we have a horse which did more 

 trotting work during his adult stage than 

 any other horse, and this work involved an 

 accumulation of energy in the organs used 

 in trotting. If we assume that this accumu- 



