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process of chemical action, especially when modified by a vital principle. We shall, however, translate the view which the reporters, MM. Chaptal, Labillardière, and Cuvier, take of the subject.
“ Before entering into the opinions," say they, "of M. Candolle, it is necessary first to establish the facts which lead to the solution of the grand question of vegetable nutrition. These may be dirided into seren, ihree of which are chemical, three anatomical, and one physiological. The three chemical are: “1. What are the elementarý materials wbich compose
vege. table body? 2. What are the foreign materials from which the vegetable draws those which con.pose it? and .3d. What changes ought these foreign materials to undergo, to assume the proportion in which they should constitute the vegetable?
“ The solution of the last question results from that of the preceding two, as it is sufficient to indicate the difference between the constituent and foreign materials. The first question is already solved by chemical analysis, which has shewn, that vegetables are composed of carbon, hydrogen, oxygen, a little nitrogen, some earths and salts. We have, therefore, only to examine what aliments vegetables require, compare the composition of those aliments with that of vegetables, and see if their difference does not consist in what they exhale.
• In desert countries, where wood rots, undisturbed by men.or animals, it forms a thick stratum of earth, which still consists almost entirely of carbon. The same takes place where no carbon pre. viously existed, and earth is formed on naked rocks, and among pure sand, wherever vegetation is allowed to establish itself. The general and definitive effort, therefore, of vegetation must be to develope carbon, and consequently to decompose the carbonic acid in exhaling its oxygen. This is directly the reverse of animalization ; animals are nourished either mediately or immediately on vegetable carbon. But, as their composition requires less carbon and more nitrogen, it is necessary that the superabundant carbon should be continually carried off by respiration. By this process they form carbonic acid, whereas vegetables decompose it. Perhaps the hydrogen has some influence."
The above is a very conjectural reply to these three chemical questions, and amount to no more than saying what the answer should be. The old conceit of the alternate emission of oxygen and carbon by plants is here repeated without any correct knowledge of the subject. The three anatomical questions are not less difficult than the preceding; vegetable anatomy is yet very imperfectly understood.
1. By what route do the aliments enter the vegetable, and apply themselyes to the organs in which they have to undergo trans
formation? 2. What are the organs in which this transformation takes place? 3d. and finally, when transformed, what course do the aliments pursue, in order to become subservient to the parts which they ought to nourish? It is important to know the part at which the transformation takes place. Perhaps it may be asked, if the aliments of vegetables are transformed, that is, if they change their proportion before nourishing the plant, or before that they are incorporated in its fibre? Or, if the aliments do not wait to change their proportion, may they not in some measure constitute a part of the vegetable fibre ?
“ Too much has been attributed to analogy with animals. Zoophytes have evidently no intermediate transformation; when the excrements are separated from the chyle, the latter immediately nourishes the parts, and if any more changes in the proportion are necessary, they must be effected by a sort of cutaneous transpiration. This simplicity iŮ the economy of zoophytes should excite doubts as to the existence of multiplied transformations in vegetables. As 200phytes have no respiration, properly so called, may not vegetables also want digestion? May not the gross excrements be excluded from entering by the absorbent pores? And may not all the changes of proportion take place at their surface, and in the matter already inserted in their fibre? M. Candolle considers the sap of the vegetable as the undigested food of the animal; the aqueous transpirations as the gross excrements; and the gaseous emanations, and absorptions in the green parts, as the respiration.
“ The sap, in some cases, takes a contrary direction to its usual progress, and even retrogrades when the atmosphere is humid. We shall ask, therefore, is it necessary to have a juice prepared different from the sap to nourish and develope the parts? or is it the sap which directly nourishes and developes them? The former proposition is adopted by M. Candolle, who founds his proofs on the growth of dicotyledon plants. Such plants grow above ligatures, because the descending sap cannot descend. But if it 'vere proved that the true sap always ascends, and never retrogrades, or descends, it would also be proved that it could not be the nourishing sap of the wood. It is not surprising, then, that wood has a particular mode of growing ; it forms in plants, like the teeth, shells, and stony bodies of madrepores, except that its successive layers pre-exist and increase by intussception, while the others, perhaps, are simply deposited, without being first in embryo; or that the liber of the preceding year hardens, while the bodies above alluded to are transuded. M. C. contends that the sap' elaborates the buds, these again the leaves, and the leaves the calyres. The proper juice he considers the descending, as the nourishing juice ought to be : it is more abundant at the top of the plant, which induces the belief that it has deposited a part of its substance in descending. The vessels containing this proper juice are in the parts where the bark, sap, and wood, are developed. Such a juice must have an important use.”.
The question in physiology is, perhaps, more difficult than all the others. " What are the degree, direction, and source of the powers, which produce the motion of vegetable fluids?" The author has treated of the materials which nourish plants, the transformations which they undergo, the place where such transformations take place, the exterior agents which produce them, the chemical affinities in virtue of which they exist, and the routes wnich they huve to traverse to be incorporated with different parts of the body. The effect of heat and moisture, as operating on the vegetable powers, is considered; but no satisfactory answer is given to the above question. 'A vital force or action, indeed, is introduced, and also the contractility, called irritability. Those who attribute to irritability every movement produced in the organize;} body, by à calise which the mechanical impulse alone would be incapable of producing, if it had not been seconded by an interior predisposition, may give this name to the movements of the stamina of certain plants. In the opinion of the reporters; however, “this definition might be relaxed, to embrace the spontaneous movements, (without any apparert exterior cause) called the sleep of plants.” Others, it is admitted, who investigate more rigorously the nature of things, think that nerves and fleshy fibre are necessary to irritability. The reporters would define it “a movement in appearance greater than its cause." Vital force is used to express a power unknown.
The only thing peculiar which we have noticed in this very laboured memoir, is a distinction between cellular and vascular vegetables; the former belong to the cryptogamic class, and the latter are so called because their fluids have a marked direction in the interior disposition of the fibre. All that is said about the descending juice and true sap, is very vague and inconclusive, when compared with the researches of Knight into the same substances. Neither do we think that M.Can. dolle has extended thie boundaries of our previous knowledge, on this subject, in the smallest degree ; and we fear that the questions stated by the reporters, although apparently very perspicuous, will not greatly facilitate the discovery of this important desideratum. M. Lelievre describes a Ferruginous (ferrifere) carbonat of
. Manganese, which contains oxyd of manganese, 53; oxyd of iron, 8; lime, 2. 4; insoluble residuum, consisting of silica and arsenical iron, 4; loss by fire, 35.6. The specific gravity of this mineral is 3. 743.
The same mineralogist has discovered a new mineral, a black
silicious oxyd of iron, which, in a memoir, he calls renite, to commemorate the battle of Jena. We gave a description of this mineral in our account of Brogniart's Mineralogy, Appendix to vol. 29, p. 663, to which we refer the 'reader.
The “ Observations on the extravasation of blood into the cavity of the pericardium, and on a collection of pus in this cavity, which was discharged internally by an abscess above the clavicle, by M. Sabatier, » convey no practical advantage. The cases were mortal; the former was a species of aneurism, and the latter an abscess in the neck, which discharged a serous foetid matter, arising from that collected in the pericardium. M. Portal, in a." Memoir on fungus excrescences in the intestinal canal, and other interior parts,” has merely proved, although perhaps not incontrovertibly, that such fungus excrescences inay exist, like those in the nose, vagina, &c. that they may or may not be hydatides, that they can be removed by escharotics, or mercurials, that they emit yellow or red viscous humour, like pus, but should not be treated as such, nor as cancerous matter. This and the preceding paper evince the great inferiority of the French medical writings, when compared with those of the English.
The most valuable article in this volume is the account of M. André's manuscript work, a theory of the actual surface of the earth,” by MM. Haüy, Lelievre, and Cuvier. The authors have developed the true course of proceeding in the study of geology; and divested this sublime and interesting science of its visionary speculations, to establish it on the solid basis of accurate observation. We shall translate some of the leading directions. The authors divide the natural history of unorganized bodies into two classes; the one embracing desca ptions, and chemical properties, and distinctive characters of each individual substance, and called mineralogy; the other unfolding the relative position of species, and component parts of masses, mountains, and divers strata, called geology, geognosy, or physical geography, according to the extent and profundity of the real searches. The latter branch they consider capable of attaining as much accuracy as mineralogy, properly so called.
“ To give it this quality," say they, - it is cnly necessary to treat it
as all the natural sciences ought to be ; that is, to collect with care the particular facts, and to deduce no general conclusions until these facts are collected in sufficient numbers, observing always the most rigid rules of logic. It is also evident that this science constitutes a part of natural history, not less indispensable to the knowledge of the globe than mineralogy itself. It is to the latter what the history of the climate, soil, and situation proper to each plant, is to botany.
Its utility to society, if once completed, would be no less evident. By it we direct our researches for divers minerals, and anticipate the expences and advantages of public works. Thus our engineers could not calculate the expence of a subterraneous conduit to substitute for the water-machine at Marly; geology taught them that at such a place they should expect to find nothing but chalk. By this science miners discover mines, and have determined the characters of mountains with metallic veins. It must, therefore, be evident that a science which furnishes the same data for discovering useful minerals
, as it does to miners for discovering metallic veins, is of great importance to society."
The authors then proceed to notice the abuses of this science, which have hitherto obstructed its progress, and rendered it useless to society. The study of the fossils and petrifactions was so fascinating, and so susceptible of visionary theories, that it soon changed geology “ from a science of facts and observations, into a tissue of hypotheses and conjectures, so vain and so contradictory, that it is become almost impossible to pronounce its name without a smile.". The tradition of the deluge gave birth to numerous theories of the origin of fossil beds ; but their authors forgot that this catastrophe is stated as a miracle, or an immediate act of the Creator's will, and that consequently it is superfluous to look for any secondary causes.
“ At first, fossils and petrifactions were, inconsiderately, deeined Lusus naturæ. But when more extensive study proved their general forms, texture, and, in many cases, their chemical composition, were the same as those of analogous parts in living bodies, it became necessary to admit that these objects had also possessed life, and that, consequently, they had existed at the surface of the earth, or in the waters of the sea. How did they become buried under immense masses of stones and earth ? How were marine bodies transported to the summits of mountains ? But above all, how was the order of the climates reversed, so that we find the productions of the torrid zone near the pole ?"
- A deluge could not account for these changes, and at the begiitning of the last century it was perceived that one inundation, however violent, could not produce such immense effects. It was necessary, then, to admit of a long series of operations, either slow or sudden. This step once taken, and hypotheses were no longer limited; the systematical method of Descartes was again revived, although Newton appeared to have banished it for ever from the physical sciences. Every one conceived a principle, à priori, and endeavoured to accommodate, well or ill, the facts within his knowledge to it. By a fatality hardly conceivable, it was almost entirely neglected to extend our knowledge of facts. In this manner, the number of systems of geology have exceeded eighty, which require