3

In order to attain this end it is necessary, in the first place, to explain, however briefly, the nature of those vital actions which have a direct reference to cultivation; and further to show how those facts bear upon the routine of practice of the horticulturist, by making them explain the reason of the practical methods employed in various branches of the gardener's art.

The first part of this work therefore embraces the principal laws and facts in vegetable physiology, as deduced from the investigations of the botanist; and the second an application of those laws to practices established by the experience of the horticulturist.

If the laws comprehended in the first book are correctly explained, and the facts connected with them rightly interpreted, they must necessarily afford, in all cases, the reasons why one kind of cultivation is better than another; and all kinds of practice at variance with those laws must be bad. from the very nature of things, this cannot be

Seeing that, otherwise, it follows that, by a careful consideration and due understanding of such laws, the intelligent cultivator will acquire the most certain means of improving his practice.

BOOK I.

OF THE PRINCIPAL CIRCUMSTANCES CONNECTED WITH VEGETABLE LIFE WHICH ILLUSTRATE THE OPERATIONS OF

GARDENING.

A PLANT is a living body composed of an irritable, elastic, hygrometrical matter, called tissue. It is fixed to the earth by roots, and it elevates into the air a stem bearing leaves, flowers, and fruit. It has no power of shifting its place except when it is acted upon by wind or other external forces; it is therefore peculiarly susceptible of injury or benefit from the accidental circumstances that may surround it; and, having no free agency, it is above all other created beings suited to acknowledge the power of man.

In order to turn this power to account, it is necessary to study the manner of life which is peculiar to the vegetable kingdom, and to ascertain what the laws are by which the numerous actions essential to the existence of a plant are regulated. It is, moreover, requisite that the causes which modify those actions, either by increasing or diminishing their force, should be understood.

The vital actions of plants have so little apparent resemblance to those of animals, that we are unable to appreciate their nature in even the smallest degree by a reference to our own sensations, or to any knowledge we may possess of animal functions. Nevertheless, when we carefully reflect upon the phenomena of vegetation, we discover certain unquestionable analogies of a general nature, between the animal and vegetable kingdoms. And although it is necessary that plants should be

studied by themselves, as an abstract branch of investigation, without attempting to reason as to their habits from what we know of other organised beings; still it must never be forgotten that they are living things, possessed, like animals, of vitality, that mysterious force which modifies all chemical and mechanical phenomena, and which so essentially distinguishes the organic world from the brute materials of which it is composed.

In discussing this subject, it will be most convenient to divide the matter into the heads of, 1. Vital force; 2. Germination; 3. Growth by the Root; 4. Growth by the Stem; 5. Action of the Leaves; 6. Action of the Flowers; and, 7. Maturation of the Fruit. By this means the life of a plant is traced through all its principal changes, and an opportunity is afforded of introducing under one or other of these heads every point of information that can be interesting to the cultivator; who will be most likely to seek it in connection with those phenomena he is best acquainted with by their effects.

CHAPTER I.

VITAL FORCE.

MR. ANDREW KNIGHT asserted that, in the course of his numerous experiments, he had never been able to trace the existence of anything like sensation or intellect in plants, but that they always appeared to be influenced by the action of surrounding bodies, and not by any degrees of sensation and passion analogous to those of animal life. This seems to have led to the belief that they do not even possess a vital principle, but are mere chemical laboratories.

One writer ventures to call a plant a porous system-endowed with no vitality other than the power of forming Cytoblasts,* and arranging cellules after a definite type (Gardner in Phil. Mag. xxviii. 432). Even here it is admitted that some vitality exists; for the arrangement of cells, or in other words the construction of plants, each after its kind, out of cells, implies vitality of a high order, although the writer seems to have meant that a plant is little more than a bag of quaternary compounds, and to have overlooked the fact that a plant when dead is a porous system as much as when alive. Nec deus intersit is however a favourite maxim with a certain class of modern writers, although nec absit would appear to be more consistent with all we know of the living world.

But many discoveries have been made since the days of Knight, and a body of facts, showing the existence of high vitality, if not sensation, among plants, has been collected, with which he was wholly unacquainted. So that it is not too much to say, that the vegetable kingdom is now known to stand at least as high in the scale of life as the inferior orders of the animal kingdom.

* A Cytoblast is the vital centre round which the cell and all its contents is eventually formed.