CH. v.] THE SAP. 161 



Many believe, also, that a peach-tree, when 

 grafted upon its native stock, veiy soon perishes, 

 but my experience does not further support this 

 conclusion, than that it proves seedling peach-trees, 

 when growing in a veiy rich soil, to be greatly 

 injured, and often killed, by the excessive use of 

 the pmning-knife upon their branches, when these 

 are confined to too narrow limits. I think the 

 stock, in tliis instance, can only act injuriously by 

 supplying more nutriment than can be expended ; 

 for the root which nature gives to each seedling 

 plant must be well, if not best, calculated for its 

 support ; and the chief general conclusions which 

 my experience has enabled me to draw safely, ai'e, 

 that a stock of a species or genus, different from 

 that of the fniit to be grafted upon it, can be used 

 rarely with advantage, unless where the object of 

 the planter is to restrain and debilitate ; and that 

 where stocks of the same species ^rith the bud, or 

 graft, are used, it will be found advantageous, gene- 

 rally, to select such as approximate in their habits 

 and state of change, or improvement, from cultiva- 

 tion, those of the variety of fmit which they are 

 intended to support^. 



The only situation in which I can believe that the 

 stock of another species can be advantageously em- 

 ployed, is where the soil happens to be unfriendly 

 ^ Trans. Hort. Soc. of London for 1816. 



M 



