LUTHER BURBANK 



pulpy fruits, to be sure, develop a certain amount 

 of sugar, but the percentage is relatively small 

 with most fruits of temperate climates. The con- 

 trast in this regard between the average wild plum 

 and such a fruit as the fig or the date is very 

 striking. 



But we have seen illustrated over and over that 

 a habit once ingrained in a race is with very great 

 difficulty shaken off altogether, so it is not strange 

 that, under exceptional circumstances or condi- 

 tions of soil and climate, an individual plum tree 

 might show reversion to the state of its tropical 

 ancestor and produce a fruit much sweeter than 

 other plums. 



Such an individual, if its fruit came to the 

 attention of the orchardist, would be likely to be 

 preserved and propagated; and in the course of 

 time, through selection among the seedlings of this 

 tree, a race of sweet plums would be developed. 



But it is only under conditions of artificial 

 cultivation, in all probability, that such a race 

 could be preserved. 



For, of course, the production of a large amount 

 of sugar must draw on the energies of the tree, and 

 if this increased sweetness of fruit did not prove 

 beneficial to the tree itself, natural selection would 

 presently weed it out. 



So, as I said, we may fairly assume that it is 



[88] 



