114 Dynamic Evolution 



ber several hundred, but the larger part of 

 the 1292 performers were got by those par- 

 ticular sons which were raced. Thus, of the 

 several hundred, fifteen which went to the 

 track and were raced sired more than one- 

 third of the entire 1292. 



We can get a little more light on this by 

 taking the record sons of record brothers, 

 and the non-record sons of non-record 

 brothers. 



Two Generations with and without Records 

 Performers Produced 



By record Sons of 27 record Brothers. . 685 . .Average, 25.3 

 By non-record Sons of 28 non-record 



Brothers 50. .Average, 1.8 



Performers by Half-Brothers from Same Dams 



22 record Half-Brothers 666. .Average, 30. 



25 non-record Half-Brothers 100. .Average, 4. 



Performers by Half-Brothers Having Same Sires 



747 Half-Brothers with records 6941 . .Average, 9.29 



1262 Half-Brothers without records. .6341 . .Average, 5.02 



An investigation was made of the effect of 

 two generations of brood mares not required 

 to do work other than produce foals. To 

 do this Volume VI. of the Trotting Register 



