24 
PROPAGATION. 
that it may not make too large a demand on the root for a sup 
ply of food. 
Budding may be done in the spring as well as at the latter 
end of summer, and is frequently so performed upon roses, and 
other ornamental shrubs, by French gardeners, but is only in 
occasional use upon fruit trees. 
Influence of the stock and graft. 
The well known fact that we may have a hundred different 
varieties of pear on the same tree, each of which produces its 
fruit of the proper form, colour, and quality ; and that we may 
have, at least for a time, several distinct, though nearly related 
species upon one stock, as the Peach, Apricot, Nectarine, and 
Plum, prove very conclusively the power of every grafted or 
budded branch, however small, in preserving its identity. To 
explain this, it is only necessary to recall to mind that the as- 
cending sap, which is furnished by the root or stock, is nearly a 
simple fluid ; that the leaves digest and modify this sap, forming 
a proper juice, which re-descends in the inner bark, and that 
thus every bud and leaf upon a branch maintains its individu- 
ality by preparing its own proper nourishment, or organizing 
matter, out of that general aliment, the sap. Indeed, according 
to De Candolle,* each separate cellule of the inner bark has this 
power of preparing its food according to its nature ; in proof of 
which, a striking experiment has been tried by grafting rings of 
bark, of different allied species, one above another on the same 
tree without allowing any buds to grow upon them. On cutting 
down and examining this tree, it was found that under each 
ring of bark was deposited the proper wood of its species, thus 
clearly proving the power of the bark in preserving its identity, 
even without leaves. 
On the other hand, though the stock increases in size by the 
woody matter received in the descending sap from the graft, yet 
as this descends through the inner bark of the stock, it is elabo- 
rated by, and receives its character from the latter ; so that, 
after a tree has been grafted fifty years, a shoot which springs 
out from its trunk below the place of union, will always be found 
to bear the original wild fruit, and not to have been in the least 
affected by the graft. 
But, whilst grafting never effects any alteration in the 
identity of the variety or species of fruit, still it is not to be de- 
nied that the stock does exert certain influences over the habits 
of the graft. The most important of these are dwarfing, indu- 
cing fruitfulness, and adapting the graft to the soil or climate. 
Thus every one knows that the slower habit of growth in the 
* Physiologie Vegciabte. 
