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OX TILE HABITS ACQUIRED BY PLANTS. 
not been confirmed ; and if not true, there remains only one mode of excretion, namely, the deposition 
in the leaves which fall off annually ; and this -will be of course applicable only to perennial plants. 
It must be remembered, iu considering the phenomenon of absorption, that, in the majoritv of 
plants, we do not find a simple and direct endosmotic apparatus ; for this there must exist two fluids 
of different densities, separated by a membranous partition. Perhaps this is only met with in an inde- 
pendent state in the few plants which grow- wholly under water. In all others many circumstances 
concur to influence the simple endosmotic process. The large surface of the leaves exposed to the air 
evaporates great quantities of liquid, which must have very great effect upon the absorption of fluids 
bv the cells of the roots which supply the leaves with moisture ; for the evaporation of the water 
from the cells of the leaves must render the remaining fluid contents much more dense, and this will 
excite a much more active endosmotic action here, drawing the thinner fluids from the cells of the 
stem, and the process will be continued froni cell to cell throughout the whole tissue of the plant 
down to the root-cells. This statement, which is deduced from anatomical facts, is borne out by the 
observation of the course of events in nature ; for Hales found that the quantity of water absorbed by 
a plant stands in direct relation to the number of its leaves, and that when one half the leaves of a 
plant were cut off the amount of water absorbed sunk to one half. It is well known, also, that when 
shoots of Vines are led into a hot-house, and caused to unfold their buds during winter, the roots, 
situated outside the house, will begin to absorb moisture from the earth. 
Liebig has shown also, by artificial contrivances, that evaporation may be made to act in opposition 
to the force of endosmosc, and cause fluids to pass out through membranes into thinner media ; and 
this process is so active in plants that it not only suffices to increase the absorption very greatly, and 
even under certain circumstances to cause it to commence when not previously in operation, but is 
even powerful enough when plants have been poisoned to cause them to draw up the poisonous fluids 
In great abundance through the dead parts of the plant, as has been shown in young trees cut off near 
the root, and plunged into a solution of pyrolignite of iron, for the purpose of imbuing them with it 
as a preservative fluid. The leaves, which remain uninjured for some time, go on evaporating their 
fluids actively, and the exhaustion resulting causes the solution to be drawn up into every ramification 
of the stem, although it is clear that it must destroy life in every spot it reaches. 
On the whole we may say, from the foregoing considerations, that, although we are unable to 
explain all the details of absorption by the laws of endosmose, yet it is probable that they arc all 
referriblc to them, and that in time the chain of relations may be clearly made out. 
ON THE HABITS ACQUIRED BY PLANTS. 
By Mb. J. TOWERS, C.M.H.S. &c. &c. 
(HONSIDEIIABLE interest attaches to this subject, on which I propose to offer a few remarks. The 
^J practised gardener in the forcing department of an establishment, if ho be a man of observation, 
and prone to inquiry, must know that if a branch of a Vine, for instance, trained against a wall, be led 
into a frame or glazed pit, where heat can be applied early in the year, its buds will enlarge, and its 
foliage, &c., expand long before the other branches in the open air begin to swell; and thus fruit of 
larger size and finer quality may be obtained two or three months iu advance of the usual season, lint 
it is equally true that more time will be required to excite the introduced branch (although the 
temperature of the pit, &c, be raised to sixty or more degrees) than if the tree had. from its first 
planting, occupied that warmer situation; or, in other words, had been, year after year, subjected 
to heat at a certain definite period. As a converse to this rule, if a Vine in a pot, or otherwise, 
so habituated to heat, he exposed throughout one winter to the open air, it will begin to stir 
considerably earlier than any other Vine growing in the same aspect, which has never'been excited by 
artificial stimulus. These facts being admitted as firsl principles, we may refer to the circumstances 
that were detailed in an article in the Gardeners' Chronicle, and to the elucidatory remark of the 
editor, who instructs bis readers that a branch, or portion of a branch, peculiarly situated, product a 
its own developcnients under a stimulus and nutritive power locally, and to a certain extent, inherent 
in itself. Thus, for example, a branch or shoot of any fruit-bearing tree affixed to a warm Hue. shall 
produce leaves, blossoms, and well-set fruit, even before every other number of the tree shall have 
made any corresponding advances. 1 hope that 1 have correctly expressed the writer's meaning. 
When 1 resided in Berkshire I sometimes visited the gardens at Missenden Abbey, thru, and 
perhaps now, under the management of Mr. John Begbie: on one oi ' ii i early in the Bpring of 1888, 
