340 I»RIN CIPLES OF VEGETATION. 



the int^rcourfc of the former fliould be moft frequent and certain feerns 

 natural ; but the diftances which often intervene between plants of the 

 latter kind is confiderable, and indeed furnilhes no trifling objeflion to 

 the fuppofition of their intercourfe. As we have feen fonne animals felf- 

 impregnated, uniting in one individual the parts necelTary to this effcft, 

 what fhould prevent the fame in plants ? Again, if what is related of the 

 delcent of impregnation in the inftance of the gnat be true, why may 

 |j,not this principle alfo obtain among vegetables? So that if a plant be 

 this year impregnated, it fhail not need a repetition of this circum- 

 ftance the next ieafon (or next generation) : and fince there maybe va- 

 rious other departures from what is, notwithflanding, a general rule; and 

 fince indeed among the moft gentral rules Nature often furprifes us with 

 very extraordinary exceptions, I fee no reafon to deny ekher the affirmed 

 fexual fyftem of plants, or the force or fadt of thole inftances which, in 

 the opinion of many, militate againft it. 



Vegetables are capable no doubt of propagation by flips and cuttings, 

 and 1 (hould fuppofe tar beyond what is related of any animal whatever, 

 wonderful as are the fad:s admiitted of the polypus : but whether there be 

 any vegetable capable of propagation only by this method is not that I 

 know of affirmed j or whether there be any vegetable entirely precluded 

 from this m.ethod : for not only plants may, by trailing, be made to fhoot 

 from the knots, &c. in their items, but branches of trees, if judicioufly 

 managed, will become complete trees, not inferior in magnitude to their 

 parents; nor are lefs remarkable the fubdivifions of vitality in the fruit 

 of a potato, every iye of which is capable of producing a pcrfedt plant. 

 There is however one remarkable fingularity attending vegetables, in that, 

 as the branches are capable of thus becoming roots, fo the roots are ca- 

 pable of becoming branches. Should we incline to change the lituation 

 of thefe parts of a tree, the undertaking isfeafible, and has actually been 

 accomplifhed in fmallcr fobjeds, by lurrounding the branches with earth 

 in a garden-pot; and, when they have drawn nutriment from the earth, 

 gradually withdrawing the root from its bed, and accuftoming it to de- 

 pend for fupply on its former branches; then judicioufly choofing the 

 tim^ for its cxpoiure to tlie air, and its production of leaves. 



Grafting is a kind of planting a brancn from one tree in the body of 

 another ; to this it unites, and with this it lives and profpers, or withers 

 and det ays : but it does not here unite by (hooting out roots as it would 

 were it in the earth, tor its nutritive juices are not tofeek; the tree lup- 

 plies thtiij, partly dicrclUd too, and fie for immediate ufe. This is clearly 



the 



