others that of the common holly, were observed at Claremont, where the bark was split and rent asunder from the wood below it; and Sir Oswald Mosley has given me the following instance, which occurred under his own observation. An oak tree, growing upon the south side of a hill, in a sheltered situation, in Knightly Park, near Burton-uponTrent, in the county of Stafford, was rent in the severe frost of last winter in two different places, to the height of thirteen feet three inches. There was an interval of eleven inches between the two shakes, which were each of them one-quarter of an inch wide, and extended in depth to the heart of the tree. The girth of the tree is six feet ten inches, and as soon as the frost went the openings closed again, and the tree is now as flourishing as ever.' To these cases many more might be added.

"The organization of woody tissue appears to be affected, but not by laceration. If a frozen and unfrozen transverse slice of the stem of Hibiscus Rosa Sinensis be placed, side by side, upon the field of the microscope, it is obvious that the diameter of the tubes of the wood and liber, is considerably less in the former than in the latter; this appears to be owing to an increase in the thickness of the sides of the tubes, which has the effect of diminishing their calibre.

"The expulsion of air from æriferous organs, and the introduction of it into parts not intended to contain it, is a striking phenomenon. Every one must have remarked that when a leaf has been frozen to death, it changes color as soon as thawed, acquiring a deeper green, and being of nearly the same depth of color on both sides; the same appearance is produced by placing a leaf under the exhausted receiver of an air-pump, and in both cases is owing to the abstraction of air from the myriads of little air-chambers contained in the substance of this organ. If the leaf of Hibiscus Rosa Sinensis in its natural state is examined, by tearing off the parenchyma from the epidermis with violence, it will be found that the sphincter of its stomates, the cells of the epidermis, and the chambers immediately below the latter, are all distended with air; but in the frozen leaf of this plant, the air has entirely disappeared; the sphincter of the stomates is empty; the upper and under sides of the cells of the epidermis have collapsed, and touch each other, and all the cavernous parenchyma below the epidermis is transparent, as if filled with fluid. Whither the air is conveyed is not apparent; but as the stomates have evidently lost their excitability, and are in many cases open, it may be supposed that a part of the air at least has been expelled from the leaf; and as the pith of this plant, in its natural state, contains very little air, and in the frozen state is found to be distended with air, it is also probable that a part of the gaseous matter expelled from the leaf when frozen is driven through the petiole into the pith. In the petiole of this plant are numerous annular and reticulated vessels, which, under ordinary circumstances, are filled with air, but after freezing are found filled with fluid; is it not possible that their functions may have been disturbed, by the violent forcing of air through them into the pith, and that when that action ceased, they were incapable of recovering from the overstrain; and filled with fluid filtering through their sides? That annular ducts are in some way affected by frost, was shown by their state in a thawed branch of Euphorbia Tirucalli, when they were found in a collapsed state, empty of both air and fluid, with their sides shrivelled, and with the fibre itself, which forms the rings, also wrinkled transversely. Facts of an analogous kind were remarked by me in Erica sulphurea. The minute long-haired leaves of this species are in their natural state firm, bright green, with a rigid petiole, and upon being exposed to pressure in a compressorium, at first offer perceptible resistance to its action, and afterwards, as the pressure increases, discharge, chiefly through their petiole, a great quantity of air. But leaves of this plant, which have been frozen by exposure to the tem

perature of 27o are very different; they are softer, dull olive green, with a flaccid petiole, and offer but little resistance to pressure: yet, although they give way freely, the quantity of air which the compressorium expels is comparatively small, and readily driven out. Moreover, the long hairs of this plant, which in the natural state are occupied by fluid, were always found filled with air after freezing, and this without pressure having been exercised upon them.

"I am inclined to refer to this cause the well-known fact, of which many cases occurred this winter, that the sudden exposure of frozen plants to warmth will kill them; though they may not suffer if warmed gradually. In such cases, it may be supposed that the air, forced into parts not intended to contain it, is expanded violently, and thus increases the disturbance already produced its by expulsion from the proper air cavities; while, on the other hand, when the thaw is gradual, the air may retreat by degrees from its new situation without producing additional derangement of the tissue. It is also possible that leaves, from which their natural air has been expelled by the act of freezing, may, from that circumstance, have their tissue too little protected from the evaporating force of the solar rays, which we know produce a specific stimulus of a powerful kind upon those organs.

"These circumstances are, in themselves alone, sufficient to account for death being produced in plants by frost; and it is chiefly to such as these, that Professor Morren has directed his attention. It however appears to me that there are some other points of im portance to which observers have not applied themselves.

"The green coloring matter of leaves, or chlorophyll, is certainly affected by so little as only two or three degrees of frost. In Stapelia, when thawed, it is found collected into clusters, and apparently half dissolved. In Euphorbia Tirucalli, when the plant is alive, it is extremely abundant, and consists of distinct spheroidal transparent particles, but, after a slight freezing, a considerable part of it disappears, and the remainder loses its transparency, becomes fusiform, is sometimes surrounded by coagulated gelatinous colorless matter, and many of the particles appear as if burst. In the green subcutaneous parenchyma of the leaf of Hibiscus Rosa Sinensis, the vesicles forming the sides of the air chambers are filled with distinct, angular, deep green particles, which, after freezing, become amorphous, and seem as if partially dissolved. It is possibly to the decomposition, of which these appearances are the incipient signs, that the extremely offensive odor of some frost-bitten plants, especially the Laurustinus, when thawed, is to be ascribed.

"The amylaceous matter, which is so abundant in many plants, also undergoes alteration. This has been remarked by Professor Morren, who found that when potatoes are frozen, a part of their starch disappears, leaving the deformed integuments behind it, and he suspected that the starch thus lost had furnished the sugar formed in the process of freezing this tuber. I believe it will be found a general fact, that starch is materially altered by frost, for I have always found that the amylaceous particles seem less abundant in a plant after freezing than before, and of those which remain, a part is generally becoming amorphous, clustered together, and certainly diminished in size. This is particularly striking in Hibiscus militaris. In that plant the cells of the pith abound in amylaceous granules, and are often quite filled with them; and they also occur abundantly inside the cells of the bark, of the medullary rays, and even of the tubes of the wood, and, in short, every where except inside the woody tubes of the liber; so that a thin slice of the stem of this plant, treated with iodine, forms a most beautiful microscopical object. But after being frozen, a great part of the starch disappears, and the particles which remain are not more than a half or a quarter of their former size. I have not, however, remarked among them any appearance of dissolving; neither have I been able to observe

any change in the curious double-headed bodies, in form resembling dumb-bells, found in the vessels of Euphorbias, and supposed to be a state of amylaceous matter, because iodine colors them violet; they appeared to me to be in precisely the same state before and after the plant was frozen to death. M. Payen, however, denies that any starch whatever is lost in frozen potatoes (Comptes rendus, vi. 345;) but as only a small part of his important treatise on amylaceous matter has reached this country, I am unable to state in what way he explains the action of cold upon this substance.

Finally, it appears that frost exercises a specific action upon the latex, destroying its power of motion. If, as Prof. Schultz supposes, this is the vital fluid of plants, such a fact would alone account for the fatal effects of low temperature. In all the cases I have observed frost coagulates this fluid, collecting it into amorphous masses. In Stapelia, where the laticiferous vessels are easily found, the latex itself is so transparent, that it is difficult to perceive it in a living state, even with the best glasses; but after freezing it is distinctly visible, resembling half coagulated water. In the Hibiscus above mentioned, the stem is covered with long, rigid, simple hairs, filled with a plexus of capillary laticiferous vessels of extreme tenuity, but in which the motion of the latex may be seen beautifully with the one-eighth of an inch object glass of an achromatic microscope. Upon being thawed, after freezing, all this apparatus is found reduced to some misshapen separate sacs of fine grumous matter, in which no motion can be detected. That these vessels lose their vitality after freezing, may indeed be seen withont the aid of a microscope; for if a stem of a Ficus elastica, or a Euphorbia, or any such plant, which discharges an abundance of milk when wounded, be first frozen, and then thawed, no milk will follow the incision.

"From these facts, I think we must draw the conclusion, that the fatal effect of frost upon plants is a more complicated action than has been supposed; of which the following are the more important phenomena:

"1. A distention of the cellular succulent parts, often attended by laceration, and always by a destruction of their irritability.

"2. An expulsion of air from the æriferous passages and cells.

"3. An introduction of air, either expelled from the air passages, or disengaged by the decomposition of water, into parts intended exclusively to contain fluid.

"4. A chemical decomposition of the tissue and its contents, especially of the chlorophyll.

"5. A destruction of the vitality of the latex, and a stoppage of the action of its vessels.

"6. An obstruction of the interior of the tubes of pleurenchyma, by the distension of their sides.

"These phenomena may be considered in part mechanical, in part chemical, and in part vital. The two latter are beyond our control, and probably depend, in part, upon the quality of fluid and organic matter, which may resist the action of the cold in different degrees, according to their various modifications; and, in part, upon specific vitality. Salt and water freeze at various temperatures, according to the density of the mixture, from 4° to 27°; oil of turpentine at 14°; oil of bergamot at 23°; vinegar at 28°; milk at 30° water at 32°; olive oil at 36°; oil of anise at 50°; and it is not to be doubted, that in like manner, the fluid contents of plants, which we know are indefinitely modified, will resist the action of cold in very different degrees.

"The mechanical action of frost may, however, undoubtedly be guarded against to a great extent. It is well known, that the same plant growing in a dry climate, or in a dry

soil, or in a situation thoroughly drained from water during winter, will resist much more cold, than if cultivated in a damp climate, or in wet soil, or in a place affected by water in winter. Whatever tends to render tissue moist, will increase its power of conducting heat, and consequently augment the susceptibility of plants to the influence of frost; and whatever tends to diminish their humidity, will also diminish their conducting power, and with it their susceptibility; this is an invariable law, and must consequently be regarded as a fundamental principle in horticulture, upon attention to which all success in the adaptation of plants to a climate less warm than their own, will essentially depend. The destructive effects of frost upon the succulent parts of plants, or upon their tissue, when in a succulent condition, may be thus accounted for, independently of the mechanical expansion of their parts; indeed, it is chiefly to that circumstance, that Dr. Neuffer ascribes the evil influence of cold in the spring; for he found that at Tubingen, nearly all the trees contain eight per cent more of aqueous parts in March, than at the end of January: and the experience of the past winter shows, that the cultivation of plants in situations too much sheltered, where they are liable to be stimulated into growth, and consequently to be filled with fluid, by the warmth and brightness of a mild protracted autumn, exposes them to the same bad consequences as growing them in damp places, or where their wood is not ripened, that is to say, exhausted of superfluous moisture, and strengthened by the deposition of solid matter, resulting from such exhaustion."

HOW TO MAKE AN AMATEUR.

BY N. Y. H.

THE history of trees in the United States, has been too much after the following fashion; much of the land had the reputation, if it had not the reality, of abounding in chills and fevers, or fevers alone; whether the trees by causing dampness, or the unwonted exposure of the settler caused disease, the native forests were considered in fault. To some extent this was true, for till the country in many places, was cleared, and the sun, that vivifier and sweetener, was let in, miasmatic influences were more or less rife. Tree followed tree, and when they were all down, and the house built, the settler had what he believed he wanted—a clearing; he too often did not reflect that a belt at the north of his dwelling would keep the wintry blasts from roaming down his chimney, or protect his sheep and poultry. His wife wanted sun to dry the clothes, never thinking of thermometers at 90°, and a clearing both parties had. The settler, however, either moved further to swing his indiscriminating axe in the same manner, or, as many a sad history would tell, if it had a LAURIE TODD to commemorate it, he and his wife fell victims to over exertion and exposure.

The next owner is probably a man of more means; a little cultivated himself, he would like to see cultivation around him; he looks about for trees to fill the gaps so ruthlessly made, but sees or hears of none for sale in the vicinity, except it may be very small ones; so he either moves a few from the remaining "woods," without knowing what precautions to use, or adopts the small ones from the distant nursery. In either case, two owners must live under the influence of cold winter winds, and hot summer suns. What is to be done in the matter?

It is somewhat difficult to find an answer that will at once remedy the evil, but we will

quote CICERO on the subject, as our best refuge for a reply. "If," says he, a man would build, he should reflect a great while, and perhaps not build at all; but if to plant is the question, he should not reflect, but plant immediately." Wise CICERO! no better advice could be given by the best modern editor.

What shall we plant, inquires the new owner of the clearing. We answer, take a little pains to plant trees for shade, that will produce something either in the shape of timber or fruit. What more ornamental trees than our true shellbark hickory, or the white oak; we have one of the latter now in our eye, not fifty years old, which is a model of strength and beauty; very sure, we are, that the owner, who planted it himself, would decline five hundred dollars for it; and certainly, in the estimation of every person of taste, it adds

more than that sum to the sale value of his estate.

It is a curious circumstance which we have often remarked, that the generality of persons, whose attention has not been particularly drawn to the cultivation of trees, &c., are not aware what it is that produces their pleasure, when suddenly introduced into a properly planted and cultivated pleasure garden; they are surrounded by beauties, but they do not define, because they do not know the plants before them; yet something teaches them that they are in the presence of beauty and novelty; the whole effect is good, and they involuntarily exclaim, "how delightful! how we should like to live here!" Here is the intuitive love of nature. Let the same individual learn to know each particular plant, its history, origin, home, what length of time it has been introduced into gardens, its rarity, its uses, the height it attains, whether of rapid or slow growth, to say nothing of its botanical distinctions, and the enjoyment is increased a thousand fold; every plant so studied is an old friend, recognised and greeted wherever we go. There is no real knowledge acquired, that is not valuable and agreeable; botany, geology, astronomy, are continual sources of pleasure, whatever country we visit; let a person but thoroughly know the varieties of the rose by name and peculiarities of habit, and ever after a garden is visited with vastly increased delight; suppose that amount of knowledge multiplied by reading, observation, practice, and study, till we know in addition most of the new trees and plants, as well as those of older introduction; with what gusto and vivacity one searches for and sees a novelty of which he has only read. But we are straying from our clearing, for whose adornment this periodical has already given, and will continue to give, lists of the most valuable and easily procured trees, for shade and product.

After the planter has made up his mind what to plant for immediate effect, and what for posterity-for we hold the axiom, so often in the mouths of the unreflecting, that because posterity has done nothing for us we will do nothing for posterity, in utter abhorance- -he will ask his life companion, she is entitled to be consulted in all such cases, what fruits she most values; he will be glad to learn that by planting the Spanish Chestnut he can have a companion tree to his white oak, which, like it, will throw out its lateral branches, and spread over the lawn, producing in a very few years not only fine shade, but bushels of its large and delicious nuts to astonish and gratify himself and his visitors. So far he has cultivated himself, and bids fair to become an amateur; the clearing in his minds eye has assumed a new shape and value, and he takes to studying during the winter evenings, some further particulars; these acquire intense interest as he proceeds; books are consulted, but unfortunately books do not tell him all that he wants to know, for he has yet to learn his a, b, c, in horticulture. One great object of periodicals, like this, is to inform him. He does not know, perhaps, that yearling fruit trees can be had at Rochester, Flushing, Philadelphia, and other places, for a very small sum; that yearling pears, cherries, apples, plums, apricots, and so forth, of the finest sorts, grafted