With regard to wall trees, they cannot so well be beat, but they can be easily swept. It is not my object to take notice of different kinds of walls, but I believe the best will have crevices, where the vermin deposit their ava; it will therefore be necessary to sweep the wall carefully and completely before the blossom opens; which will in a great measure prevent their depredations. If, notwithstanding, they attack the blossom, it likewise must be swept off. The use of sweeping, so far as relates to the vermin, will in a great measure be superseded by the practice of peeling.

The next cause is constriction of the bark. This appears to be a more frequent disease, and more dangerous than is commonly imagined. It is indicated by the unequal growth of the tree, in all parts, and

most commonly between the stock and graft; by the tree swelling more where the bark has been cut, or torn off by accident; by the canker, indurations, contractions, and rotting of the bark appearing in different parts of the tree; by the barending of its own accord; by the inner bark rending after the outer bark has been taken off, frequently in the very instant, and often not stopping at the peeled part, but running a great way above, bursting both inner and outer bark. This completely shows that the disease rests in the outer bark.

In this case a longitudinal incision, or a partial peeling, may prove a cure; but it is more certain and complete to peel all round, from the surface of the earth, or rather a little below it, where the bark is soft and yielding, the whole trunk and larger

branches, as far as the bark will admit of division.

If the bark bound the tree like a hoop or cord, by being fixed only at the two ends a longitudinal incision would be a complete cure; but as the bark is fixed all round, such a cure must be very incomplete. It may, however, be useful on the branches of wall trees, where the flower buds are thick, and cannot be easily peeled, with out destroying these. It may likewise be of considerable service on cherry trees, where the stricture depends chiefly on the transverse bark, which, being more lightly attached to the longitudinal than that of pear and apple trees, when cut, sometimes separates itself all round. This disease, or rather cause of diseases, is of the most serious nature, because it always increases it

self. The bark, losing its health along with that of the tree, becomes tougher, which makes the stricture still stronger.

It may perhaps be thought necessary I should inform at what age, that the earliest period, the trees should be peeled. It is difficult to fix a particular date for different species, varieties, soils, and situations; some species and varieties growing faster than others, and all growing faster or slower, according to the soil and situation. It must therefore be regulated by the symptoms of constriction before mentioned, or as soon as the bark will admit of division. As the tree advances in age, the bark thickens and hardens; the peeling therefore must be carried further up every year.

The practice of grafting shews that a

stricture takes place very early; for I believe it will seldom succeed where the graft is more than one year old; and as it is better preventing diseases than curing them, it may be proper to remove the outer bark before an of these symptoms appear; I have accordingly done so to a number of trees, (pear and apple,) of two years old, which have both produced fruit, and grown well to the wood.

A little time, and further observation, may however determine this question with mathematical accuracy, as far as relates to the different kinds of trees *, but whatever the exact proportion may be, it will be in an in

* I see no impossibility but soil may be applied to this rule.