by the root of the stock is communicated slowly and unwillingly to the scion; under no circumstances is the communication between the one and the other as free and perfect as if their natures had been more nearly the same; the sap is impeded in its ascent, and the proper juices are impeded in their descent, whence arises that accumulation of secretion which is sure to be attended by increased fertility. No other influence than this can be exercised by the scion upon the stock. Those who fancy that the contrary takes place; that the Quince, for instance, communicates some portion of its austerity to the Pear, can scarcely have considered the question physiologically, or they would have seen that the whole of the food communicated from the alburnum of the Quince to that of the Pear is in nearly the same state as when it entered the roots of the forWhatever elaboration it undergoes must necessarily take place in the foliage of the Pear; where, far from the influence of the Quince, secretions natural to the variety go on with no more interruption than if the Quince formed no part of the system of the individual.

mer.

If we consider upon what principle the flavour of particular fruits may be improved, we shall find that it is entirely due to the increased action of the vital functions of leaves. When the sap is first communicated by the stem to the leaves, it has experienced but few chemical changes since it first entered the roots. Such changes as it has undergone have been due rather to the solution of some of the pre-existing peculiar secretions of the individual by the sap in its way upwards through the alburnum, than to any other cause. As soon, however, as it enters the leaves, it becomes altered in a variety of ways, by the combined action of air, and light, and evaporation; for which purposes the leaf is admirably adapted by its anatomical structure.

Thus altered in the leaves, it ceases to be what we call sap, but becomes the proper juice; or, in other words, acquires the peculiar character of the final secretions of the individual from which it is formed. Discharged by the leaves into the bark, it is thence conveyed by myriads of channels of cellular substance throughout the whole system. From these secretions, of whatever nature they may be, the fruit has the power of attracting such portions as are necessary for its maturation. Hence it follows, that the more we can increase the peculiar secretions of a plant, the higher will become the quality of its fruit; and that, on the other hand, the less the plant is in condition to form those secretions, the less will be the quality of the fruit. It is for the purpose of producing the former effect that pruning and training trees are more especially destined. In pruning, we remove all those superfluous branches which overshadowed the remainder, and we endeavour to expose every part to the freest action of light and air. In training, the same thing takes place, but is increased; there is not a branch that is not fully exposed to the most direct rays of light, and to the freest circulation of air, and even to the unimpeded action of the sun in aspects exposed to the south, east, or west. This action is obviously most powerful on the south, and hence the higher quality of fruits matured upon that exposure than on any other; while, on the other hand, fruits raised upon a northern aspect are well known to be less highly flavoured than those from even an open standard. For a similar reason, forced fruits, which are obtained at a period when there is little light, cannot be compared with those which are matured in the full blaze of a summer sun; and hence melons grown in frames covered with mats, and carefully excluded from the influence of that solar light which is indispensable to them, have, whatever may be their ex

a

ternal beauty, none of that luscious flavour which the melon, when well cultivated, possesses in so eminent a degree.

of

The next subject of consideration is the mode of multiplying improved varieties of fruit, so as to continue in the progeny exactly the same qualities as existed in the parent. Unless we have the power doing this readily, the advantages of procuring improved races would be very much circumscribed; and the art of horticulture, in this respect, would be one of the greatest uncertainty. The usual mode of increasing plants, that mode which has been more especially provided by nature, is by seeds; but, while seeds increase the species without error, the peculiarities of varieties In can rarely be perpetuated in the same manner. order to secure the multiplication of a variety, with all its qualities unaltered, it is necessary that portions should be detached from the original individual, and converted into new individuals, each to undergo a similar dismemberment, with similar consequences. It happens that while in animals this is impracticable, except in the case of polypes, the system of life in a plant is, of all others, the best adapted to such a purpose. We are accustomed to consider individual plants of exactly the same nature as individual animals: this is, however, a vulgar error, which is dissipated by the slightest enquiry into the nature of a plant. A plant is really an animated body, composed of infinite multitudes of systems of life; all, indeed, united in a whole, but each having an independent existence. When, therefore, any number of these systems of life is removed, those which remain, as well as those which are separated, will, under fitting circumstances, continue to perform their natural functions as well as if no union between them had ever existed. These systems of life are buds, each having a power of emitting descending fibres in the form of roots,

and also of ascending in the form of stem. The first of these buds is the embryo; the others are subsequently formed on the stem emitted by the embryo. As these secondary buds develope, their descending roots combine and form the wood, their ascending stems give rise again to new buds. These buds are all exactly like each other they have the same constitution, the same organic structure, and the individuals they are capable of producing are, consequently, all identically the same; allowance, of course, being made for such accidental injuries or alterations as they may sustain during their subsequent growth. It is upon the existence of such a remarkable physiological peculiarity in plants, that propagation entirely depends; an evident proof of which may be seen in this circumstance. Take a cutting of a vine consisting only of the space which lies between two buds, or an internodium, as botanists would call such a piece, and no art will succeed in ever making it become a new plant, no matter how considerable the size of the internodium may be.* But, on the other hand, take the bud of a vine without any portion of the stem adhering to it, and it will throw out stem and root, and become a new plant immediately. If we examine the various modes employed in horticulture for propagating plants, we shall find that, however different they may be in appearance, they all consist in the application of these principles under various forms. It will be most convenient to consider these methods separately.

Propagation is effected by the arts of Increasing by Eyes, Striking from Cuttings, Laying, Budding, and Grafting.

Increasing by Eyes is the simplest of all these methods it consists in nothing but extracting a single

This is, of course, said without reference to the power which some plants possess of developing latent buds, a subject which is foreign to the present enquiry.

system of life, or a bud, from a given plant, placing it in due heat and moisture, and surrounding it with fitting food, and thus causing it to grow as a solitary individual, instead of as one of the community to which it originally belonged.

Striking from Cuttings is a slight modification of the last method. Instead of taking a single bud, a stem containing two, three, or more buds, is placed in circumstances fitted for the maintenance of its life. In this case, the chances of success are increased by the additional number of buds which are the subject of experiment. That bud which is the nearest the bottom of the cutting emits its roots at once into the earth, and so establishes a communication between the general system of the cutting and the medium from which its food is to be derived. The other buds, by pushing their stems upwards into light, attract the nutriment absorbed by the roots, and so stimulate the latter to increased action. Ultimately, the roots of all the buds descend between the bark and the wood until they reach the earth, into which they finally pass, like those of the first bud. There is another circumstance which renders the operation of striking plants from cuttings less precarious than from eyes. In both cases, the buds have, at the outset, to feed upon matter in their vicinity, until they shall have formed roots which are capable of absorbing food from the earth; but in eyes, the nutritive matter can exist only in such portions of the stem as may have been cut away with themselves; while, on the other hand, in cuttings, the stem itself forms an important reservoir of nutriment. This is a consideration, the practical importance of which will be obvious to every cultivator. cultivator. As it is from the buds alone of cuttings that roots proceed, it follows, that in cases of difficulty, when plants strike unwillingly, any thing which may facilitate the immediate introduction of roots