84 
COURSE OF THE SAP. 
[Part II. 
Candolle states that, in the chestnut, the ash, 
and the vine, “ the pith is interrupted at each 
node, or annual shoot, by a kind of woody par¬ 
tition.” Here, I think, this very great physiolo¬ 
gist makes a very great mistake. It is true 
that, in the ash and horse-chestnut, at the junc¬ 
tion of one year’s shoot with the next, the texture 
of the pith may be described as cheesey , instead 
of spongy . And in the vine, this cheesey pith 
separates the spongy pith, not only at the junc¬ 
tion of each annual shoot with the next, but at 
each knot or side-bud. But there is nothing in 
the least resembling wood in this cheesey pith; 
and when it is scooped out, the pith-channel of 
the vine is of the same size through the knots 
as at any other part, and the pith-channel of the 
horse-chestnut, and ash, is of the same size be¬ 
tween any two shoots as the pith-channel of the 
top of the lower shoot. In these two trees, the 
pith of every shoot and twig is surmounted with 
cheesey pith; so that every bud is placed on 
cheesey pith, and is as much divided from a spongy 
pith by a “ woody partition,” as the pith is in¬ 
terrupted at each node or annual shoot by a 
“ woody partition.” 
If De Candolle’s fact is true, that, in the chest¬ 
nut, the ash, and the vine, “ the pith is inter- 
