LUTHER BURBANK 



case of a single pair of species, often using differ- 

 ent individuals and varieties of the species. 



Instances in which a hybridizing experiment 

 at last proved successful after many years of fail- 

 ure as for example in the case of the sunberry 

 will be recalled by the reader. 

 PRACTICAL AND SCIENTIFIC INTERESTS COMBINED 



In general, practical results were sought, rather 

 than the establishment of theories; yet for the most 

 part, in such a line of experiment, theory and 

 practice necessarily go hand in hand. 



The only sharp distinction between our method 

 and that of an experimenter who is looking only 

 to the investigation of the laws of heredity is that 

 we were obliged to select for preservation a few 

 only among large companies of hybrid seedlings, 

 destroying the rest, and to that extent making the 

 record incomplete. 



It would be of great scientific interest to trace 

 the entire company of a hybrid stock as to all its 

 individual members through successive genera- 

 tions. 



But when the members of a fraternity number 

 ten thousand or a hundred thousand or a million, 

 as was often the case in our experiments, the at- 

 tempt to preserve all and to investigate their prog- 

 eny through several generations would necessitate 

 the expansion of our experiment farm until it com- 



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