cially as the Sap is the liquid of the earth, not the blood of the Tree, as is easily proved by adding nurture to the ground, when the Sap fails, which soon restores it? Besides, how is the circulation to be effected in the eternally increasing branches of a Tree, whose every additional twig must make a variation in the quantity of juices wanted ?"

"Whereas it is naturally decreased as it mounts, by throwing out new shoots and branches, which expend the liquor as it rises."

After a variety of further argument, she proceeds:

"And I believe I may say, that I am now so well acquainted with all the different vessels of a Tree, that I can no longer fail from ignorance; but here, except the inner-bark vessels, all proceed in a different direction, either round the Tree, or from the centre to the circumference: how is it possible that such large and powerful parts should be invisible?

"The use of dissection is to correct the use of imagination, or those experiments which have that effect, forcing the juices into channels foreign to that which Nature has appointed for them. I have before said, that I have ever found Nature disposed to such resources, in case of any unnatural impediment. I have myself proved it."

Here I must again remark, that I do not doubt this lady's powers of investigation, or the justness of her description of what she has seen; but her argument, that the Sap is not the blood of the Tree,

but the liquid of the earth, because, by adding moisture to the earth when the Sap fails, it is thereby replenished, is rather singular. Does not the moisture added constitute, or extract, dissolve, and carry with it into the roots the food of the plant? And when blood is taken from an animal, is it not restored again by food and moisture taken in by the stomach? But if blood is not to circulate, I do not see why it should be supposed to exist in a plant.

The effect of grafting, shows that the Sap does not circulate, or at any rate, if it does circulate, that it undergoes no change by the ascending and descending motion; and this also establishes the fact, that every part of a Tree possesses the power of selecting and transforming the portion of fluid destined to its use, as it passes up.

A graft or bud is united by the Sap alone, which is formed into the different substances, as it passes through the various parts of the Tree, and the two parts are joined, like two metals, such as iron and steel, by welding, and like them, although adhering together as one, retain each their peculiar properties. If a graft or a bud of a coarse-grained spongy wood be engrafted on a fine close-grained stock, and both have grown on one stem or trunk, supporting a head for any length of time, even for a century, each will maintain its original and peculiar properties, as well as habits, in the wood; and the junction is always visible, the graft generally projecting to a larger size than the stock, immediately

at the point of junction, which may be seen in most old orchards. And if any number of grafts of different sorts be placed one above another, each will retain its proportion of Sap, and appropriate the same to its own peculiar nature.

If the Sap is passed through the body of the Tree to its leaves, and there prepared and returned back, that part which is uppermost, and producing one variety of wood and fruit, must possess the power of preparing the fluids, for the production of every other sort below it, unless the Sap be supposed to pass up, and return in the same state, which amounts to a superfluity of motion, and an excess of exertion, seldom found in nature.

This subject has always been one of controversy; but notwithstanding the great variety of ingenious and elaborate experiments that have been made, none seem to have been sufficiently conclusive, to produce unanimity of opinion. The subtle and prolix arguments that have been adduced on both sides of the question, have not only failed to contribute much to the benefit of the practical gardener, but the principle, as explained by Mr. Knight, must operate as an obstacle to knowledge, and a bar to perfect practice, which will be seen by a reference to the description of his own method of training; and also by the manner they have been acted upon by Mr. Maher, and explained by the secretary of the Horticultural Society, hereinafter noticed; and also by Sir Humphrey Davy. As to many of Mr. Knight's experiments, I agree

agree with

Mrs. Ibbotson, they may have been conducted with ingenuity and accuracy, but the results, as explained by him, cannot be generally conclusive.

To show the powers of Nature in continuing her functions, even after the apparently complete destruction of her apparatus or systematic arrangement, I state the following facts. A person* having a green bergamot pear tree, that seldom produced any fruit, removed the bark three-fourths of the circumference, which was about twenty-seven inches, and the width of half an inch. A neighbour, for a joke, removed the remaining fourth part of the bark in the same manner, so that a circle of bark, of half an inch, was removed completely round the trunk: the tree, in consequence, was expected to die; but, to the astonishment of many who examined it, the tree lived, and produced fruit, and is now alive, although the operation was performed five or six years since. Supposing that in this case the bark had not been completely severed, and that a small part might have escaped observation, I made the experiment accurately, by removing the bark, quite round the branch of a pear tree, and with it the last annual layer of wood; a shoot was thrown out above the incision, which produced and ripened a pear, before the bark had formed a junction, which it did not accomplish until the third year.

* Mr. William Whitmarsh, of Wilton, in Wiltshire.

61

ON

THE OFFICE AND USE

OF

THE LEAVES OF PLANTS.

THE office and use of the Leaves of Plants are nearly connected with that of the sap, and has also been a subject of much intricate argument, but, like that, discussed with very little practical effect; and as it is an object of much more importance than is generally considered by gardeners, I shall, as before, give the opinions of the several authors upon it.

Miller, speaking of the peach tree, says, "In pruning of those trees, you should always observe to cut them behind a wood bud, (which may easily be distinguished from the blossom buds, that are shorter, rounder, and more turgid than the wood buds,) for if the shoot have not a leading bud where it is cut, it is certain to die down to the next leading bud, so that what fruit may be produced above that will come to nothing, there being always a necessity of a leading bud to attract the nourishment; for it is not sufficient that they have a leaf