62 
COURSE OF THE SAP. 
[Part II. 
in the year previous to their bursting. They are 
the offspring of no second chemical cause, but of 
the First Cause. They are fairly conceived by 
the Creator, and borne in the womb of the bud 
for perhaps nine months. The generation of a 
new leaf is about as much an affair of chemistry 
as the generation of an animal is. And it is in 
consequence of each bud giving rise to a family 
of leaves that all nature’s growth is symmetrical , 
and not made up of Liebig’s patchwork. 
In the case of a second or midsummer shoot*, 
or of an accidental shoot from the bare stem of 
a tree, a regular bud is first formed; and, conse¬ 
quently, even these accidental shoots have sym¬ 
metrical growth. But a leaf is never formed 
by itself; so that, in the case of an accidental 
shoot from a bare stem, it may be said that a 
* I imagine that a second or midsummer-slioot of the plane 
would be impossible without the previous defoliation of the 
tree, since the winter-buds are ensheathed in the footstalks 
of the leaves. The plane, therefore, is essentially and ne¬ 
cessarily deciduous. And I have observed, at Madeira, that 
the plane is for two or three months without leaves, though 
our oak may in those climes almost be called an evergreen. 
The idea in Madeira is, that the old leaves of the oak are 
only displaced by the bursting of the spring-buds. But the 
buds of every tree I know, except the plane, may burst 
without displacing the leaves, as they actually do in the 
second or midsummer-shoot. 
