MOTION OF THE SAP. QQ$ 



will ever be found in the works of (hat excellent naturalift, I Experiments 



rouft requeft permiffion to fend you foroe of the fubjeas of my and obfervationt 



1 ' J J J on the motion of 



experiments, as vouchers for my own accuracy. the fap in trees.- 



Of the inverted cuttings employed by Du Hamel, a fmall 

 portion only appears to have remained above the ground; and 

 under fuch circumftances, the different forms of thofe growing 

 in their natural, or inverted, pofition would be fcarcely ob- 

 fervable. It appears alfo, from his experiments, that fuch in- 

 verted cuttings, in fublequeni years, grow with as much vigour 

 as others that are not inverted; whence we muft conclude, that 

 the organization of the internal bark becomes again inverted, 

 and adapted to the pofition of the branch. The growth of fome 

 inverted plants of the goofeberry-tree, which I obtained, many 

 years ago, from layers, gave me reafon to draw a different con- 

 clufion ; for thefe always continued weak and dwarfifh. I do 

 not, however, entertain the {lighten 1 degree of doubt, but that 

 the affertion of Du Hamel is perfectly correct. 



I intended to have added fome obfervations on the repro- 

 duction of buds and roots of trees; but thefe would necetfarily 

 extend the prefent Paper to an immoderate length ; I fhall 

 therefore referve them for a future communication, and con- 

 clude with an account of an experiment which more properly 

 belongs to the Paper I had the honour to addrefs to you lafi; 

 year, but which had not then fucceeded. 



I have ftated, in that Paper, that the leaf-ftalk, the fruit- 

 ftalk, and the tendril, of the vine, had been fuccefsfully fubfti- 

 tuted, in many inftances, for each other; but that I had failed 

 in my efforts to engraft a bunch of grapes, by approach, on the 

 leaf-ftalk; owing, I conceived, to the operation having been 

 improperly performed. In thofe experiments, I cut the leaf-ftalk 

 into the form of a wedge, and made an incifion in the fruit- 

 ftalk, adapted to receive it; but, undw fuch circumftances, the 

 leaf-ftalk (as I had proved by many experiments) has no power 

 to generate new matter; and the wounds of the fruit-fh.lk heal 

 fo flowly, that I readily anticipated the iil-fuccefs of the opera- 

 tion. In the laft (bring, I pared off' fimilar portions of the leaf- 

 ftalk and fruit-ftalk; and, bringing the wounded parts into 

 contact, I fecured them clofely together, by means of a bandage, 

 letting the leaf remain. Under thefe circumftances, an union 

 took place; and the fruit-fialk being then taken off below the 

 point of junction, and the leaf-ftalk above it, the grapes drew 



their 



