on the Motion of the Sap in Trees . 1 89 
duction of buds and roots of trees ; but these would necessarily 
extend the present Paper to an immoderate length; I shall 
therefore reserve 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 address to you last 
year, but which had not then succeeded. 
I have stated, in that Paper, that the leaf-stalk, the fruit- 
stalk, and the tendril, of the vine, had been successfully substi- 
tuted, in many instances, for each other ; but that I had failed 
in my efforts to engraft a bunch of grapes, by approach, on the 
leaf-stalk; owing, I conceived, to the operation having been 
improperly performed. In those experiments, I cut the leaf-stalk 
into the form of a wedge, and made an incision in the fruit- 
stalk, adapted to receive it; but, under such circumstances, the 
leaf-stalk (as I had proved by many experiments) has no power 
to generate new matter; and the .wounds of the fruit-stalk heal 
so slowly, that I readily anticipated the ill success of the opera- 
tion. In the last spring, I pared off similar portions of the leaf- 
stalk and fruit-stalk ; and, bringing the wounded parts into 
contact, I secured them closely together, by means of a bandage, 
letting the leaf remain. Under these circumstances, an union 
took place; and the fruit-stalk being then taken off below the 
point of junction, and the leaf-stalk above it, the grapes drew 
their whole nutriment through the remaining part of the leaf- 
stalk. They did not, however, acquire their full size; and the 
seeds were small, and, I think, incapable of vegetating; but 
this I attribute to the want of nutriment in quantity rather than 
in quality; for the union of the vessels of the leaf-stalk with 
those of the fruit-stalk was very imperfect The grapes, which 
