540 HEREDITY 



and this he regarded as extremely essential. Instead of following 

 a number of characters at a time, he thought it best at first to 

 follow only two characters and these should be contrasting 

 characters, such as red and white flower, long and short stem, 

 etc. His idea was to follow two contrasting characters throughout 

 a number of successive generations, to see how they appear in 

 the successive offspring. With respect to the contrasting char- 

 acters chosen for study, the individuals of each generation should 

 be carefully compared with each other and with their parents. 





FIG. 475. Gregor Mendel, the Austrian monk, who from his study of 

 heredity, chiefly in Garden Peas, discovered the laws of heredity bearing his 

 name and thereby made an invaluable contribution to science. 



(Taken by permission from " Recent Progress in the Study of Variation, Heredity and 

 Evolution," by R. H. Lock, published by E. P. Button & Co.) 



Mendel experimented with a number of kinds of plants, but 

 did most with the Common Garden Pea which he found to fulfill 

 the requirements better than the other plants tried in his experi- 

 ments. Like most other plants of the Bean Family, the stamens 

 and pistils of Peas occur in the same flower and are so well 



