THE CHERRY 129 



duce, in other words, the conditions of the second 

 filial generation itself as just analyzed. 



Let me restate all this, using only the letters, 

 to show the convenience of the formula and at the 

 same time fix it in memory: D mated with d 

 in the first generation gives us Dd + Dd + Dd, 

 etc., in the second generation. Dd mated with 

 Dd gives us in the third generation iDD + 

 2Dd + Idd. 



If this is not absolutely clear, you will do well 

 to reread the above paragraphs, and it is quite 

 worth your while to consider the matter some- 

 what attentively. 



If you have only theoretical interest in plant 

 breeding, you should be concerned in the matter 

 no less personally, because the same laws of 

 heredity that are about to be illustrated apply 

 with full force to all life, including human 

 offspring. 



If, on the other hand, you have thought of 

 undertaking some experiments in plant develop- 

 ing, which I hope is the case, it is doubly impor- 

 tant you should get the full significance of these 

 simple formulae. Like other formulae, they are 

 devised solely for convenience in promulgating 

 ideas. As used in the following illustration, they 

 will make it possible to present vividly the case of 

 our black-sheep cherry, and through this to clar- 



Vol. 3 Bur. E 



