Chapter V 



MENDEL'S TWO LAWS OF 

 HEREDITY 



Gregoe Mendel studied the heredity of certain 

 characters of the common edible pea, in the garden 

 of the monastery at Briinn. In the account of his 

 work pubhshed in 1865, he said: 



It requires indeed some courage to undertake a 

 labor of such a far-reaching extent ; it apj^ears, how- 

 ever, to be the only right way by which we can finally 

 reach the solution of a question the importance of 

 which cannot be over-estimated in connection with 

 the history of the evolution of organic forms. 



He tells us also why he selected peas for his work : 



The selection of the plant group which shall serve 

 for experiments of this kind must be made with all 

 possible care if it be desired to avoid from the outset 

 every risk of questionable results. 



The exjDerimental plants must necessarily 



1. Possess constant differentiating characters. 



2. The Iwbrids of such plants must, during the 

 flowering period, be protected from the influence 

 of all foreign pollen, or be easily capable qf such 

 protection. 



Mendel succeeded not only because of his fore- 

 sight in planning the experiments, and in keeping 



