mer, other shoots, perhaps three or four, will push from the lateral buds below the lead. These shoots seldom extend more. than a foot; but they are likewise furnished with buds similar to those of the parent shoot. Besides these, there are small embryo buds, just above the exsertion of the shoots, which would remain dormant were the true buds permitted to expand.

The gardener endeavours to excite these embryos, and thus to obtain a number of fruitful germs in lieu of those leaf-buds which garnish the shoot. He therefore cuts back those laterals to within one or two inches of the shoot upon which they grow, at some period of June or July, when their wood has become somewhat mature and firm. It will be recollected that there are two seasons of vigorous growth: the one in May, earlier or later, and this is termed the spring-shooting; the other about July. Now, if the laterals be cut back at or before the season of the July shoot, the embryo or lower buds will be stimulated, and produce, in most instances, a multitude of weak woodshoots, all of which must be cut out, or if one be left, as some recommend, it has to undergo the same sort of treatment, and with a similar result; thus time is wasted, the powers of the tree are taxed to no purpose, and no fruitful buds are obtained. The critical period appears to me to be that which is not remote. from, but posterior to, the July shoot, then the wood will be firm, and almost ripe at the lower extremity of the shoots, and the fluids of the tree, though not inactive, in a state of comparative quietude. But even in this situation, the shoots should not be cut entirely off, but broken, or snapped by the hand, at the third of its length below the point of each, leaving the fractured extremities suspended by the bark, and not wholly detached. By this cautious (though, I must confess, not elegant) mode of foreshortening, the fluids of every shoot are kept in perpendicular, but greatly diminished action, and are constrained to enter into the lateral buds throughout the whole of the unwounded part of the shoots, and also into the embryos at their base. These buds and embryos enlarge, but do not push into shoots, and of many of them, situated low on the shoots, one or more will, at the period of the following early-spring pruning, be found swollen into fruitful buds. Then, and not till then, every shoot should be cut back, either to within an inch of the fruit- bd

(now a spur), or, if none such be yet formed, to a point just above a bud situated at an inch or two above the origin of the shoot. The foreshortening above described is to be repeated, year after year, till every lateral produce a fruit-bearing spur. But, independent of these artificial spurs, numbers of others are naturally protruded along the branches of apple and pear trees, and these are always preferable to the others produced by the interference of man; nevertheless, as in these dwarfs, it is indispensably required that every main shoot support a series of fruit-spurs, art must be excited to check the luxuriance of the trees, and constrain them to become prolific.

The foregoing remarks apply chiefly to the trees of the orchard, especially in what respects the dimensions of the trees; but the dwarf trees of the garden are not intended to attain to half the size of the others, they therefore must be pruned very rigorously for spurs. They are intended to bear great quantities of the finest fruit in small compass, and can be made to do so; exhibiting garlands of flowers in the spring of surpassing beauty. Once formed, a dwarf tree, scarcely four feet high, having six regular branches, may be kept within the same limits during many years, and be at all times renewable by shoots, which, rising near the fork of the old ones, may be gradually substituted for those that have become unsightly.

In the routine regulation at the period of winter-pruning, as Lindley justly remarks, "care must be taken to keep the spurs short and close, none of which should exceed three inches; cutting clean all the blank spurs which have produced fruit the previous summer, to the perfect bud below." By the term winter-pruning, I always presume a period just preceding the enlargement of the buds in March or April, because the fluids, excited by the springy influences, are ready, at their first flow, to heal the wounds, and produce the deposition of new vegetable matter.

I believe that it is the torpid condition of a wound which causes disease, under the action of cold frosty winds, snow, and protracted wet, during the winter. Some object that a tree will bleed," if the knife be used in the spring, but facts do not bear out the assertion; and I never yet perceived any injurious results from the bleeding of the vine, although the watery sap has

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oozed from the point of the leading stem for days, and fallen in rapid drops, which might be collected in quantity sufficient to be chemically analyzed.

Tall open standards, for large orchards, do not become the subjects of present inquiry; but it may be stated, in few words, that the ground should be prepared equally well for them as for dwarfs, that, being trained and pruned, during three or four seasons, with judgment, they should then be left to form the figure which the nature of the variety inclines it to assume.

Great trees bear large quantities of fruit; but they require much time to come into full bearing; they then occupy much space, and the gathering of the fruit is at all times troublesome, and is attended with very considerable risk of injury to the fruitful spurs. Nine dwarfs may be brought into a state of vigorous fertility on the same extent of ground occupied by one large standard tree, and in less than one-third of the time. The other comparative advantages are obvious, and I think confer the palm on the dwarf system of culture.

ON THE DISEASES INCIDENT TO THE MOST USUALLY CULTIVATED

PLANTS. NO. I.

By GEORGE W. JOHNSON, Esq., Corresponding Member of the Maryland Horticultural Society, &c.

THE smut, which occasionally ravages our corn crops; the mildew that destroys our peas; the curl which is yearly spreading more widely over the potato districts; the anbury, or clubroot, to which our turnips and other species of brassica are liable, are only a few of the most commonly observed diseases to which the plants we cultivate are liable. Mr Good, the distinguished medical writer, many years since remarked, that the morbid affections to which the vegetable part of the creation is liable, are almost as numerous as those which render decrepid and destroy the animal tribes. It would perhaps be difficult, whatever system of nosology is followed, to lay the finger upon a class of animal physical diseases, of which a parallel example could not be pointed out among plants.

Numerous as are the vegetable diseases, and destructive as

they are to the interests of the cultivator, yet no subject connected with his art has obtained so little attention, and never was even trivial attention followed by benefit less important. The reason of the deficiency of benefit is not difficult to explain. Common experience teaches us that diligence and perseverance, directed by judgment, are the essential preliminaries to success. In examining-in searching for the causes of the diseases and decay of vegetables, we have fewer guides, less assistance from the individuals affected, than we have from a diseased animal; fewer symptoms marking the commencement, or seat of the evil; yet where is the cultivator who ever took a fraction of the care exercised or decimal of the attention to discover the cause, the progress, or the cure of one disease that sometimes brings ruin by the destruction of his hoped for harvests, as he does to detect the disorder of, and the panacea for, some miserable pig? Diligence, perseverance, and judgment, then, have never for any length of time been directed to the diseases of plants; they are yet without their Esculapius.

The subject is one of difficulty, but it is commensurately important; difficulty is very far distinct from impossibility; and the importance of the research is a stimulus to exertion. I shall in this and some following papers endeavour to throw some light upon the path upon which I strenuously seek to persuade practical men to proceed. I would ask of such men to think upon the subject; to observe; "to ask questions of Nature," as the philosophic Bacon expressed his just idea of experiments. Human knowledge is acquired by observation and experience; that is, by conversing with the things about us, by noticing them attentively, and subsequent reflection. Every cultivator is capable of doing this; and if when he found his crops diseased, he would reflect and record from what soil he obtained his seed; how and in what weather it was committed to the ground; its subsequent culture; the crops that preceded; the treatment of the soil; the seasons, whether wet or dry, or severe, through which it has vegetated; with any miscellaneous observations that his own common sense might dictate, vegetable medicine would soon advance more in one year towards that state of reasoned knowledge that deserves the name of science, than it has done during the last century. As observations multiply, the adjutant sciences, Chemistry and Botany,

will contribute and apply their improved stores of information ; and if few specifics for the diseases of plants are discovered, I am quite sure the causes of disease will be better ascertained, and every one is aware that to know the cause of an evil is the most important step towards its prevention.

It is a very important preliminary to the study for which I would gain the attention of practical men, that they understand the nature of plants; of those organic creatures whose diseases they would obviate; for an ignorance of, or an inattention to this, is one of the causes that so little progress has been made in this branch of natural philosophy. It is absolutely necessary and important for them to understand fully that this part of the creation, the very grass they trample upon, is so highly organized, so exhibiting intimations of the functions more highly developed in the superior animals, that it is not possible to point out where animal life terminates, and where vgetable life begins: the zoophyte connects the two kingdoms. It is absolutely necessary, I think, for this to be understood and felt by those who enter upon the investigation of vegetable diseases, because I have a strong opinion that these in many, very many instances, are caused by the plants which they infect being treated as if they were totally insensible, inorganic matters, scarcely more susceptible of injury at some periods of their growth than the soil from whence they partly derive their sustenance.

To determine the question whether plants possess a degree of sensation is not so easy as many persons may believe. "It is as difficult," says Mr Tupper, who has written ably upon the subject, "to ascertain the nature of vegetable existence, as to determine what constitutes the living principle in animals." Darwin, by the aid of imaginary beings similar to the Dryads and Harmadryads of the classic mythology, has raised plants to a position in the order of nature superior to that to which animals are entitled. Other philosophers taking a totally antagonist opinion estimate vegetables as bodies, only somewhat more organized than crystals, but like these entirely and exclusively subject to chemical and mechanical changes.

The above opinions are equally erroneous, as will appear from the facts arranged in the following pages. It might easily be made to appear that the gradation from reason to instinct, from