ABSTRACT OF PAPERS OF HORTICULTURAL SOCIETY. 
47 
How to economise these fluids for the ad- 
vantage of the tfee is next to be considered. 
It is obvious, then, that when the upper 
lateral branches are shortened to half the length 
of the leading stem, and the others propor- 
tional, the sap has lesser superficies to cover 
than when they are allowed to extend to an 
improper length and thickness; in consequence 
there is a greater supply for every part of the 
tree, and as other fluids, such as water moving 
in a channel, acquire additional momentum 
when augmented, greater vigour and velocity 
of movement is imparted to the sap by the 
abundance of quantity; and so great is the 
beneficial effect resulting therefrom to the 
tree, that from the extraordinary size, and 
healthy and brighter green foliage which 
clothes the branches, it attracts more than three 
times the nourishment ordinarily imbibed from 
the atmosphere, under different management. 
The branches which are shortened always 
remain slender; by reason of the small super- 
ficies of the branch, and the rapidity with 
which the sap moves, very little of it is re- 
tained by the branch, and of course nearly the 
whole is deposited in the body of the tree, 
and the foliage remains nearly a month longer 
on the tree, which accounts for the wonderful 
rapidity of growth effected by this method of 
pruning. 
The smallness of the branches is of advan- 
tage likewise, when it is necessary to prune 
close to the body of the tree, as the wound 
made by that operation is proportionally small, 
and may be expected to cicatrize in the course 
of three years. It may be worth remarking, 
that if the branches are properly shortened, 
the trees never become what is improperly 
termed hidebound. 
It has been found that trees will advance 
in height and circumference as much, taken 
averagely in six years, if the branches are 
shortened, till a tree is 18 feet in height, and 
15 inches in circumference, as they will in 15 
years, if they are not shortened; and the more 
a tree is pruned up close to the stem before 
it is 18 feet in height, so much is it retarded 
in height, that trees in many cases of consider- 
able age that are in an unhealthy state will be 
brought round by the shortening the 
branches. 
Mr. Gavin Cree has been in practice very 
successfully for many years ; and it is some- 
thing in favour of his system that it has 
always answered well with him. Others have 
published their notions as to the proper way 
of managing fruit trees : Mr. Thurtell, of 
Norwich, has on two or three occasions lec- 
tured on the subject ; once before the Royal 
Botanical Society ; and, on some future occa- 
sion, we shall give the substance of his plan. 
It is quite clear that there are many ways of 
accomplishing the same end : the mischief is, 
that many people attend to part of the in- 
structions, and do not carry out the whole — 
they adopt parts of two systems, and spoil 
everything. 
An Abstract of Reports, Papers, and 
Proceedings of the Horticultural 
Society of London, with notes by a 
Practical Gardener. 
Food of Plants. — The first point of science 
to be known by gardeners is, what constitutes 
the food of a plant. This is ascertained by 
examining its chemical condition. What it 
contains is what it feeds on. Plants have 
many kinds of food, the first of which in im- 
portance is charcoal. Charcoal varies greatly 
in its appearance, according to circumstances. 
The diamond is charcoal in its purest state, 
and charcoal is often combined with other 
bodies, whose appearance would least indicate 
its presence. Loaf sugar is composed of char- 
coal and water. Starch consists of a consi- 
siderable quantity of solid charcoal. Oil of 
turpentine (carbon and hydrogen) contains 
charcoal. Charcoal may also exist in the form 
of air or gaseous matter ; the most important 
of which is carbonic acid, or a combination of 
charcoal and oxygen. But although these 
substances contain more or less charcoal, they 
do not all possess it in a fit state for entering 
into the composition of plants. Those sub- 
stances only can be beneficially applied as 
food which contain charcoal in a form capable 
of being taken up through the skin and leaves 
of plants. Oil of turpentine is not food for 
plants, although it contains charcoal. Sugar 
and starch are, when internal, but not when 
external, partly because solids cannot he taken 
up. It is necessary that they should be dis- 
solved, which readily takes place in the tissue 
of plants. Sugar, however, might be used as 
external food, in minute quantity, if it were 
worth while. Charcoal itself is not fit food 
for plants until it becomes gaseous. This is 
the form in which nature herself provides it. 
From three to eight per thousand parts of the 
air we breathe is carbonic acid gas. It is the 
heavy gas so destructive to animal life, often 
found at the bottom of wells and mines. It 
is supplied in considerable abundance from 
decaying animal or vegetable matter ; but the 
great source of supply is the animal kingdom. 
Indeed there is, perhaps, no arrangement in 
the whole economy of nature more beautiful 
than that observed in relation to this gas. It 
maintains the equilibrium or balance of the 
animal and vegetable world. "What is thrown 
off from the lungs of the animal kingdom as 
poison to it is food in its best form for the 
vegetable world. But notwithstanding the 
