568 STRUCTURE AND LIFE HISTORIES 



gence with which we may order our own conduct and lives. 

 If the study of plants had rendered no other service to 

 mankind than this contribution of an effective method of 

 ascertaining the laws of heredity, it would have amply 

 justified all the arduous labor that men have devoted to 

 it for 2,000 years.-' 



1 Only one of the simplest cases worked out by Mendel is summarized 

 in this chapter. A more thorough study of his experimental results and 

 theories must be reserved for a more advanced course. 



