ON PRUNING. 



149 



pruning Vines is at the time of the leaves falling ; 

 because when the pruning is deferred till the spring, 

 the Vines are liable to bleed on the rising of the 

 sap, and especially at large incisions, where strong 

 wood has been cut away ; but when Vines are 

 pruned in the autumn, there will be time, during 

 the winter, for the wounded parts to heal, and for 

 the pores to close, before the rising of the sap in 

 the spring. As Vines are sometimes greatly inj ured 

 by their bleeding, it may not be deemed improper 

 here to say a few words on that subject. 



Vines, pruned even in the winter months, will 

 sometimes bleed a little, on the rising of the sap in 

 the spring ; but if a Vine gets wounded at that 

 season, it will, like the birch, bleed copiously from 

 the wounded part. " It is astonishing/' says Mr. 

 Evelyn, " that some trees should, in a few hours, 

 " weep more than they will weigh." 



The discharge from the wounded part is, in a 

 great measure, regulated by the state of the at- 

 mosphere/ 



a u In order that we may have a distinct view of the motion of 

 the sap, it will be necessary to reflect, that the root, stem, 

 branches, and leaves, are constructed in the same manner. 

 Sallows, Willows, Vines, and most shrubs, will grow in an in- 

 verted state, with their tops downward in the earth. Dr. 

 Bradly describes the manner of inverting a young cherry-tree, 

 the roots of which will put forth leaves, and the branches become 

 roots. Hence it is obvious that the nutritive matter may be 

 conveyed as well by the leaves as the roots, their vascular struc- 

 ture being the very same. 



" During the heat of a summer's day, all plants perspire freely 



L 8 



