Vegetable Stanch. 147 
Another argument for the circulation of 
the fap, is, that fome forts of graffs will 
infed and canker the flocks they are grafted 
on : But by Exper. 12, and 3 7, where mer- 
curial gages were fixed to frcfli cut ftems of 
trees, it is evident that thofe ftems were 
in a ftrongly imbibing flare,* and confe- 
quently the cankered flocks might very like- 
ly draw fap from the graff, as well as the 
graff alternately from the flock j juft in the 
fame manner as leaves and branches do 
from each other, in the viciffitudes of day 
and night. And this imbibing power of 
the flock is fo great, where only fome of 
the branches of a tree are grafted, that the 
remaining branches of the flock will, by 
their ftrong attradion, ftarve thofe graffs 5 
for which reafon it is ufual to cut off the 
greateft part of the branches of the flock, 
leaving only a few fmall ones to draw up 
the fap. 
The inftance of the Ilex grafted upon the 
Englijh Oak, feems to afford a very confh 
derable argument againft a circulation. For 
if there were a free uniform circulation of 
the fap thro' the Oak and Ilex, why fliould 
the leaves of the Oak fall in winter, and not 
thofe of the Ilex > 
L z 
Another 
