INFLUENCE OF THE SOIL AND STOCK. 55 



ry, in proportion to the constitutional difference between the 

 stock and the scion, is the effect of the former important. 

 Thus, when pears are grafted or budded on the wild species, 

 apples upon crabs, plums upon plums, and peaches upon 

 peaches or almonds, the scion is, in regard to fertility, exact- 

 ly in the same state as if it had not been grafted at all ; 

 while on the other hand, a great increase of fertility is the 

 result of grafting pears upon quinces, peaches upon plums, 

 apples upon white thorn, and the like. In these latter cases, 

 the food absorbed from the earth by the root of the stock, is 

 communicated slowly and unwillingly to the scion ; under 

 no circumstances is the communication between the one and 

 the other as free and perfect as if their natures had been 

 more nearly the same ; the sap is impeded in its ascent, and 

 the proper juices are impeded in their descent, whence ari- 

 ses that accumulation of secretion which is sure to be at- 

 tended with increased fertility." This view is strongly cor- 

 roborated by the striking similarity between the swollen 

 portion of a grafted limb on a dissimilar stock, as a plum on 

 the peach, immediately above the place of union, and the 

 swollen portion of an ungrafted tree bound with a ligature. 

 From the preceding remarks, we may arrive at the fol- 

 lowing conclusions : 



1. That the difference in the soluble matter contained in 

 the sap of dissimilar stocks, may exert a modifying influence 

 in the fruit ; and that soluble matters in the soil, or their 

 absence, may in a slight degree do the same. 



2. That a further change is at the same time effected by 

 increasing or lessening the supply of sap from the stock to 

 the graft ; and that a similar change may result from a fer- 

 tile or sterile soil. 



3. That both early productiveness and early maturity may 

 be produced by a stock or a soil which lessens the luxuri- 

 ance of the tree ; dwarf trees and those of old or diminished 

 growth maturing their crops perceptibly earlier than those 

 possessing great thriftiness and vigor. 



As a general rule, the influence of the stock is not to be 

 taken into account in ordinary practice, except with kinds of 

 very different natures. Cultivation and fertility of soil are 

 of incalculably greater importance. And while the effects 

 of climate are to be attentively observed in making a selec- 



3* 



