Natural History promises to become, ere long, a favorite study in America; and the encouragement afforded to the Boston Journal of Science, to the New-Haven Journal, to the Journal of the Academy of Sciences of Philadelphia, strengthens this opinion. Independent of the charms which it holds out as a pleasing relaxation from the graver duties of life, its study may be urged on higher grounds: through it, we become acquainted with the laws and operations of nature, the great variety and beauty of her forms; and the classification of these numerous objects forms a most excellent exercise and discipline of the mind. We say nothing of the actual benefit the country derives from all researches into its botanical and mineralogical treasures, as these must be obvious to the most unlearned of our readers.

In a short and modest advertisement prefixed to this volume, the following are stated to be the reasons which led to its publication.

"The object of the Lyceum in publishing its annals, is to record new and valuable facts in Natural History; and to advance the public good by the diffusion of useful knowledge. The importance of this science is, at present, every where acknowledged; and the attention bestowed on it in our own country, has already been amply repaid. A great variety of new, useful and elegant productions have been discovered; and important facts connected with the agricultural, commercial and manufacturing interests, have been elucidated. In our attempts to bring to light the hidden riches of our country, we solicit the assistance of the public; we ask no emolument, we expect no gain; we cherish the hope that our exertions will be encouraged, that we shall be enabled to proceed in the course which we have now commenced."

The contents of the volume are obviously of a multifarious nature, and are illustrated by thirteen plates highly creditable to the art of engraving in this city.

But we wish our readers themselves to become acquainted with the book; our own pages are too limited to make extracts. To those who feel an honest pride in the literary and scientific character of the city, we hope that enough has been said to secure their patronage. To the members of the Lyceum, we tender our warmest wishes that they may continue to display the same industry and zeal in the study of these noble and ennobling sciences, and earn the high reputation of "accurate observers of nature." May they be encouraged to proceed in their career of usefulness by the reflection that their pursuits are intimately connected with the best interests of their country!

1. Lectures on the Elements of Botany. Part I. By Anthony Tod Thom son, F. L. S. 8vo.

2. Elements of Physiological and Systematic Botany. By T. B. Stroud. 8vo. London. 1824.

To the mere observer, who regards only the beauty and fragrance of nature, who finds in these alone sufficient sources of enjoyment, and who cares not to inquire into the exquisite organization by which Providence has.chosen to produce the wonders he admires, the physiology of botany will always appear an unnecessary and uninviting branch of study. Regaled with the odors of fruits and flowers, or pleased with the richness of natural colors, he is satisfied with the grateful sensations which these qualities afford to his senses, and the pleasures which their skilful arrange

ment imparts to his taste. Indeed, a great part of the world go no farther than this, and stop short in the pursuits connected with natural history, when their general effect only is perceived. They suppose it unnecessary, if not presumptuous, to proceed beyond the limits of our senses; and from them proceed the ridicule and opposition which have so much retarded the progress of the natural sciences.

On the other hand, however, botany has had its enthusiastic admirers, and generally captivates, even on the slightest acquaintance. The dangers of unknown seas have been incurred, the inhospitality of distant shores, and the cruelty of ferocious savages have been braved, to make new acquisitions in her cause. Indeed, the biography of most botanists is but a repetition of misfortune, and a narrative of continual exposure to poverty, disease, disaster and death. We should therefore regard, with especial favor, a science for which so much has already been done, but for which there remains so much to do; and if any of us should not immediately perceive the tendency or utility of preliminary pursuits, we should remember that it is only by a laborious collection and compilation of facts, that the foundation is laid upon which the sublime truths of natural philosophy repose.

Botany is ordinarily divided into the three following branches: 1. The description and arrangement of plants.

2. The anatomy and physiology of plants.

3. Their agricultural, economical, and we may add, their medicinal uses. This arrangement has been found the most convenient, and is, therefore, for practical purposes, decidedly the best. The system at present observed in the description and arrangement of plants, is synthetic in its method, for it proceeds from general principles to their widely spread results; and in a concise and comprehensive classification it embraces the whole of the vegetable world. The artificial arrangement has happily superseded the necessity of a tedious and analytical process of investigation. Yet this method must necessarily have been adopted in the infancy of the science. Man, in his uncivilized state of being, goaded by hunger, eats the natural food which surrounds his habitation. Chilled by the inclemency of the weather, he converts to his use the skins of animals, or unites the leaves of plants by their fibres into temporary covering. Overtaken by disease, he seeks restoratives among the spontaneous productions of the earth, and learns from experience their peculiar properties and uses. The child of nature relieved from want, then tears them in pieces to find their hidden qualities, and wonders at the singularity of their interior structure. In new searches after food and medicine, he classes insensibly, what is nourishing and what injurious, what is beautiful and what deformed, and learns gradually to distinguish, by similarity of external appearance, the different families of plants.

But art beginning where nature left off, retraces her steps at ease through all her modifications. First she seeks and examines the individuals, embracing all their numerous varieties; next collects them into groupes; then investigates their internal structure and cause of life; examines their hidden springs of action, and stops at last where the child of nature commenced, in applying them to the necessities and comforts of life

The collection and classification of plants have as yet occupied the principal attention of botanists. Ray, Townefort and Linnæus have successively been engaged in this pursuit, and their chief care was so to arrange them, naturally and artificially, that order should be maintained, in their respective ranks, and that that each individual should be known by the definite characteristics. In short it was a system, which they aimed at,

not the intimate knowledge of what they were systematizing. It would at this time be useless and irrelevant to discuss the peculiarities of the different systems of these distinguished men, as their works can be easily referred to, and are within the reach of every one. The system of the Swedish naturalist has been generally adopted; and even in France, where all the passion of originality and love of invention which distinguishes that nation, have been exercised in the formation of a natural arrangement, it has now very recently been acknowledged, that their methods are only productive of confusion and disorder.

While, therefore, the industrious collector has every facility in the classification of his plants, and while we must, with unfeigned pleasure, admire his zeal, his perseverance and his success, we fear that there is too general a disposition to stop at the confines of the vegetable kingdom, without attempting to pass its boundaries, penetrate into its interior, and explore the wonders of that almost undiscovered region.

The second head of the arrangement before mentioned will therefore, for the present, receive our more particular attention. According to Mr. Thompson, the recent historian of the Royal Society, and the author of one of the works before us, most if not all the discoveries by which the physiology of botany has been advanced, have been made since the year 1800; and indeed, the silence of the elder botanists corroborates, if it does not establish, the assertion. Grew, Hale and Malpighi, scarcely advanced the general principles of the science. The physiology of plants implies the knowledge of their nature, their habits, their health, and their anatomy. To make this apparent and palpable, it has been common to compare plants with animals, as far as their functions are similar, and if the comparison will hold between them, their physiology is not more amusing than important to the botanist.

Thus the bark of plants is like the skin of animals; it clothes and defends them, discharges moisture, and absorbs it. The medullary substance of pith, like that in the human body, may perform the offices of exhalation and absorption, and may be a part of a nervous system of plants. The wood of plants in their trunk and branches, gives, like bones, figure, stability and permanence. The sap is the vital fluid, the blood of plants. They have also proper juices, which are their necessary diluents and solvents, varying in strength with the constitutional habits of the individual. The pores of the wood and bark, so apparent when subjected to a magnifying power, are of different sizes and formation, each having respective duties in facilitating the passage of the fluids, conveying the nutriment of the earth, and assisting the rise of the sap to the remotest branches of the the plant. These are the veins and arteriesof the tree; and without these both fruit and flowers would die upon "the parent stem." The leaves are compared to the lungs of animals; they expectorate, imbibe moisture, and decompose air.

Thus far the comparison is pretty obvious, and the general resemblance is readily acknowledged; but a wide field of inquiry is here offered to investigation. The offices of the constituent parts already named are scarcely understood, and their action is still a secret which is almost entirely unknown.

We shall now briefly mention the different topics for consideration, which fall within the limits of the physiology of botany, and state what yet remains to be done with regard to them.

I. The propagation of plants is one of the first importance. This is effected by buds, seeds, bulbs, and cuttings, which are variant with the nature, climate and locality of plants. It has also been found that by the

interchange of the pollen of plants, varieties may be, and actually have been produced in fruits and flowers.

The former well-known methods are familiar to gardners and nursery men; and some of the finest of the stone-fruits have been obtained by experiments dependent on this branch of the physiology of botany. This is, then, truly important, and the reward which it promises is fully adequate to the labor required for the research. The whole world is interested in the result.

II. The culture of Plants.-This must depend upon a knowledge of their habits. their structure, and their modes of action.

Among the desiderata necessary to acquire this knowledge, is an acquaintance with physiological botany, as far as it respects, 1. The office of leaves. 2. The flowing of the sap. 3. The food of plants. 4. The decay of plants. Mr. Thos. Knight, an able and indefatigable physiologist, has demonstrated, that the office of leaves, is to decompose the sap, and the result is by them sent back to the bark, and there deposited, giving it the character of gummy, resinous, astringent, &c. If we add to this ingenious theory, the well-known power of leaves to absorb carbonic acid gas and emit pure oxygen, the subject must be acknowledged to abound with interest. The purity of the atmosphere, the advantages of trees and shrubberies in cities, the clearing away of forests, have all an intimate connection with the subject. Priestley, Henry, and Saussure, jun., have indulged in some interesting speculations with regard to this subject; but much remains to be learned, and many investigations must be made, before any one certainty shall be established.

2d. The cause of the flowing of the sap is still a mystery. Grew accounts for it by its levity; but what particular levity exists in this fluid, which is unusually consistent, and by what law would its specific gravity be overcome? Malpighi supposed it was owing to the dilation of the air vessels ; but why should not the flow of the sap be lateral as well as perpendicular, if it be owing to the air vessels, which exist in every part of the wood? Capillary attraction has been also mentioned as the cause; but by the law of capillary attraction, the fluid would remain suspended between the two contiguous rings, which, at some given and permanent height, attracted the column. Another writer speaks of suction in the most unphilosophical manner, but does not particularize how it is to be produced, or how it is to affect the rise of sap.

Mr. Knight supposes an expansion of the internal air, and the operation of valves upon the sap vessels; but no valves have yet been discovered; and, indeed, if they were, they could not be of any service, as they would be obliged continually to open both up and down for the rise and fall of the sap, and be equally fixed whether moving up or down. We know of no such kind of valves.

The former part of the theory, however, seems plausible and satisfactory, although the royal academicians have chosen to condemn it. Call Mr. Knight's expansion rarefaction, and the remaining difficulty disappears. Mr. Hales asserts, however, that the sap ascends with a force sufficient to balance a column of mercury of 38 inches, and that to produce such a velocity, 608 degrees of Fahrenheit would be necessary.

To this may it not be answered-first, that the velocity alluded to must rest in assertion only, which no experiment has yet confirmed? But is it not certain that wood contains air, and that it often remains in confinement, even after it is dried, until rarefied, and exploded by a still greater accession of caloric? May not the following fact accord, at least generally, with the supposition of Mr. Knight?

In the spring, when the weather becomes mild and genial, (and the flow of the sap is surely dependent upon the weather.) the tops of the trees and their different branches present a large surface to the action of the sun and warm air. The natural effect must be a rarefaction of what air and juice remained in the tree. By the laws of pneumatics the fluid within must rise from the roots in order to replace in the partial vacuum the loss of the former moisture driven to the bark, or evaporated in the sun. The pressure of the atmosphere will not be felt in this atmosphere, where the expansion of the air has already overcome its weight, and where a direct pressure cannot possibly be felt or ascertained. The sap must rise to the extremities, and will continue to ries until the opening of the leaves in the maturity of the season. This must necessarily prevent the farther operation of direct heat upon their own trunk and branches, and will, of course check the former perceptible rapidity of the circulation. In autumn and in winter, when the evaporation necessarily ceases, the sap descends again to the earth, where, if the reservoir of the plant be sufficiently deep, it is sheltered until once more called into action as above.

Upon a correct knowledge of this department of Botany, the cutting and seasoning of wood depend; and to this alone must we look for the remedy against the rot in timber, so important in commercial and domestic uses, in the building of ships, and construction of frame houses-and so essential to the beauty and durability of household furniture Botany seems in this light almost indispensable to our ease, safety, and enjoyment.

3d. The food of plants. It is well known that many plants which are absolutely poisonous in their native state, have become very nutritious under the influence of cultivation. This must depend upon the change of food alone. The power of plants to take up in solution their proper nutriment is almost incredible. In some plants, silex is found, and iron is a common constituent of the colored plants. This branch of physiology is almost totally unknown, and yet eminently deserves the most assiduous cultivation. It is the basis of the whole system of manures-vegetable, animal and mineral; and our grains, grasses, fruits, flowers and vegetables can never be materially improved until this part of the physiology of botany be better understood. Experience alone will not do; and it is a fact well known, that foreign gardners do not succeed in their management of American plants, because they depend solely on an experience, not fully applicable to our peculiarity of climate and soil. When this subject receives the attention it deserves, we may expect to see plants, now strangers to our soil, and only artificially produced, springing up with all the beauty and verdure and luxuriance of indigenous productions.

4th. The decay of plants.-This branch is almost wholly uninvestigated. Mr. Knight has assigned as the proximate cause of the decay of trees, their inability to produce leaves. He has established the singular fact (18 Rep. 238.) that their appearance differs essentially at different periods of the tree which produces them. It is very certain that there are many phenomena attending the decline of fruit-trees in this country, which have never been explained. If these can be remedied, it is only by a series of close investigations that the remedy can be discovered.

Having briefly discussed those parts of the physiology of botany, which are yet open to critical observation, we trust we have not pointed them out in vain. May we not hope that some of those gentlemen who have so distinguished themselves as terminologists and collectors, will ere long apply their learning to these far more important inquiries. The mysteries of science may delight the profound and curious student, but we are of that school which only regards learning and science and philosophy as subser,