'TREATISE ON THE CULTURE/ &c. 195 



The ufe of grafting is, to propagate any curious forts of 

 fruits fo as to be certain of the kinds ; which cannot be done 

 by any other method : for, as all the good fruits have been 

 accidentally obtained from feeds, fo, of the feeds of thefe, 

 when fown, many will degenerate, and produce fuch fruit as 

 is not worth the cultivating : but when moots are taken from 

 fuch trees as produce good fruit, thefe will never alter from 

 their kind, whatever be the flock or tree on which they are; 

 grafted. 



The principle or philofophy of grafting is fomewhat ob- 

 fcure ; and, had not accident given the firfl hint, all our 

 knowledge of Nature would never have led us to it. The 

 effect is ordinarily attributed to the diverfity of the pores or 

 duels of the graft from thofe of the flock, which change the 

 figure of the particles, of the juices in parting through them to 

 the reft of the tree- 

 Mr, Bradley, on occafion of 'fome obfervations by Agricola, 

 fuggefls fome thing new on this head. The flock grafted on, 

 he thinks, is only to be confidered as a fund of vegetable 

 matter which is to be filtered through the cion ; and digefled, 

 and brought to maturity, as the time of growth in the veifels 

 of the cion directs/' A cion, therefore, of one kind grafted 

 on a tree of another, may be rather faid to take root in the 

 tree that it is grafted in, than to unite it! elf with it : for it is 

 vifible, that the cion preferves its natural purity and intent, 

 though it be fed and nou rimed by a mere crab; which is, 

 without doubt, occafioned by the difference of the veflels in 

 the cion from thofe of the flock ; fo that grafting may be 

 juftly compared to planting. 



In profecution of this view of that ingenious author, we 

 add, that the natural juices of the earth, by the fecretion and 



C c 2 com- 



