MENDEL'S LAW 19 



In the experiment in which the hybrids were mated 

 with the other pure parent, the following diagram 

 should represent the materials offered by the pure kind 

 having round seeds with yellow albumen on the one 

 hand and by the hybrids on the other : 



By the pure kind By the hybrid 

 R R 



R w 



Y Y 



Y g 



If the hybrids contain equal numbers of each of these 

 two pairs of materials, then equal numbers of the 

 combinations RR and Rw on the one hand, and YY and 

 Yg on the other should be formed. But, as the two 

 sets of materials are distributed independently and 

 simultaneously, the combinations made by one pair 

 should be distributed equally among those made by the 

 other, and equal numbers of the four following com- 

 binations should be formed : 



As, in this case, the pure parent which was crossed 

 with the hybrid carried dominant characters, the 

 progeny carried the dominant characters only and had 

 to be bred on to another generation to determine which 



