20 LUTHER BURBANK 



their fruit is rather soft and acid. The full pos- 

 sibilities are revealed only in later generations, 

 and in particular after other species and varie- 

 ties of plums have been brought into the com- 

 bination. 



As rapidly as possible the hybridizations were 

 extended, until forty-three races of plums had 

 been used. In successive generations the various 

 strains were intermingled until they were complex 

 far beyond computation or accurate recording. 



The original seedlings were used as stocks for 

 grafting the cions of new seedlings year by year. 

 To this day they stand in the original rows, al- 

 though little is left of the original trees except 

 the trunk and the bases of the branches. Each 

 season, the grafts that have been proved to be of 

 no value are removed and cions from new seed- 

 lings are put in their place. 



Most of the trees have borne from ten to 

 twenty sets of grafts. 



Details given in other chapters will enable the 

 reader to follow in imagination the process of 

 blending and selection through which, on the 

 average, year by year a better and better com- 

 bination of qualities was effected among my 

 plum proteges. 



Almost as a matter of course, there ultimately 

 appeared individuals that far surpassed most of 



