PRUNING. 



165 



object of their care is exposed to the blast, in a 

 state of almost perfect nakedness. 



This mode of pruning, though at first sight it 

 may seem to answer completely the end intended, 

 serves, in tact, for no purpose but that of ruining 

 the tree. This will appear by attending to the 

 economy of the sap, according to the most probable 

 account of it that has yet been given. The roots, 

 in the first place, extract this fluid from the earth, 

 and it ascends through the stem and branches, till 

 it reach the leaves^. By the latter it is elaborated 

 and rendered fit for nourishment, which, without 

 their agency, it would never become, any more 

 than the food of animals would contribute to their 

 support, if it remained in its original state, without 



* Pontey's theory is, that the use of the leaves is for at- 

 tracting the sap from the roots, and that they are absolutely- 

 necessary for this purpose. But that this is altogether vision- 

 ary, appears from the following considerations, or any one of 

 them : — First, The sap ascends in spring before the leaves 

 make their appearance ; secondly, When the top of a tree is 

 cut off, provided it be in a healthy state, and belong to any of 

 the deciduous species, the sap, nevertheless, still ascends, and 

 new shoots spring forth ; thirdly. The same effects are conse- 

 quent on the common practice of heading down plants when 

 young. Were the leaves necessary to attract the sap upwards, 

 it would rise in none of these cases. 



