TO CAUSE. FRUITFULNESS. 



but the moment this natural direction is deviated from, the 

 vessels become more or less compressed, their action is im- 

 peded, and finally, if the inversion is perfect, it becomes so 

 slow that an accumulation of the proper juices necessarily 

 takes place through every part of the system. 



One of the objects of training is to produce the same ef- 

 fect. Branches are bent more or less from their naturally 

 erect position ; their motion, in consequence of the ac- 

 tion of winds upon them, which is known to facilitate the 

 movement of the fluids, is totally destroyed ; and hence 

 arises the accumulation of proper juice which is necessary 

 to their fertility. Nor is the influence of the stock of an es- 

 sentially different nature. In proportion as the scion and 

 the stock approach each other closely in constitution, the 

 less effect is produced by the latter ; and on the contrary, 

 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 spe- 

 cies, Apples upon Crabs, Plums upon Plums, and Peaches 

 upon Peaches or Almonds, the scion is, in regard to fertili- 

 ty, exactly 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 Whitethorn,* 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 be- 

 tween the one and the other as free and perfect as if their 

 . natures had been more nearly the same ; the sap is impe- 

 ded in its ascent, and the proper juices are impeded in their 

 descent, whence arises that accumulation of secretion which 

 is sure to be attended by increased fertility. N o other in- 

 fluence than this can be exercised by the scion upon the 

 stock. Those who fancy that the contrary takes place ; 

 that the Quince, for instance, communicates some portion 

 of its austerity to the Pear, can scarcely have considered the 

 question physiologically, or they would have seen that the 

 whole of the food communicated from the albernum of the 

 Quince to that of the Pear ig in nearly the same state as 

 when it entered the roots of the former. Whatever elabora- 

 tion it undergoes must necessarily take place in the foliage 

 of the Pear ; where, far from the influence of the Quince, 



* This is probably a mistake : " Whitethorn" could not have been intended. 

 Bo should have said Paradise or Doucin stock. 



