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 which they have 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 cause 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 apparent 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. Candolie has extended the 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 Yenite, 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 may exist, likë 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 desciptions, 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 researches. 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 only 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, deemed 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 beginning 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

to be classed in a certain order, to aid the memory in recollecting them. Notwithstanding this long and useless list, we every day see some new systems advanced, and our journals filled with defences of their authors. How can men of talents be so discordant, and continue such controversies? The reason is, that if any one of them were right, neither he nor the others could ascertain it. To discover if a fact is owing to a certain cause, it is necessary to know the nature of the cause, and the circumstances of the fact. What, therefore, are the authors of geological systems, but persons who seek the causes of facts before the facts themselves are known? Can we conceive an end more chimerical? Yet we are ignorant, not merely of the interior of the globe, but even of its most exterior crust. Hence, some persons will have millions of years for the formation of secondary mountains, while others pretend that about 5000 years ago they were formed in one."

It appears that there are still above six hundred species of unknown shells in the basin of Paris, and the bones of twelve or fifteen unknown quadrupeds, notwithstanding the smallness of its extent, and its convenience for study. La Marck has been able to ascertain the species of forty or fifty of the shells, but even these have been the labour of many years. Yet ten or twelve theories of the formation of this basin have been published, not one of the authors of which knew its conThe following positions are laid down by the authors, as the proper method of commencing and pursuing the study of geology, divested of visionary speculations, and founded on facts only. These points should be ascertained, and clearly established, before attempting to solve the grand question of "the causes which have reduced our globe to its actual state."

tents.

"1st. To search if the division of great chains in one middle and two laternal banks or dikes, observed by Pallas, and developed by Deluc, is invariable, and examine, as Ramond has done on the Pyrenees, the causes which sometimes conceal them.

"2d. To examine if there is also any thing certain or uniform in the succession of secondary strata, if such a kind of stone is always below such another, and vice versa.

"3d. To proceed in a similar manner with the fossils, determine the species which appear first, and those which are only seen afterwards; discover if these two sorts never accompany each other, if there are any alterations in their appearance, that is, if the first found appear a second time, and if the second have then disappeared.

"4th. To compare the fossil with the living species more minutely than has hitherto been done, and determine if there is. any relation between the antiquity of the beds, and the similarity or dissimilarity of fossils with the living beings.

5th. To determine if there is any uniform relation or cor

respondence of climate between fossils and those living beings, which most resemble them; as for example, if they have migrated from the north to the south, the east to the west, or if there have been mixtures and irradiations.

"6th. To determine what fossils have lived where they are now found, what others have been transported there, and if there are, in this respect, uniform rules with regard to the strata, species, or climate.

"7th. To follow, minutely, their different strata throughout their whole extent, whatever may be their doublings, inclinations, ruptures, and slopings; and, also, to determine what countries belong to one and the same formation, and what others have been formed separately.

"8th. To follow the horizontal beds, and those which are inclined in one or different ways, to determine if there is any relation between the greater or less constancy in their horizontal position, antiquity, or nature.

9th. To determine the valleys in which the re-entering and saliant angles correspond, and those in which they do not; also those in which the strata are the same on both sides, and those in which they differ, in order to discover if there is any relation between these two circumstances, and if each of them taken apart has any analogy with the nature and antiquity of the strata composing the heights which limit the valleys.

"All these points are necessary to its elucidation, if we wish to make geology a body of doctrine or a real science, independent of every desire which we may have to find an explanation of facts. We dare affirm, that there is not one of those points on which any thing, absolutely certain, is yet known, every thing which has hitherto been advanced, being more or less vague. The greatest part of those, who have treated of such subjects, have considered them rather as they answered their system, than according to impartial observations. The fossils alone, singly considered, would furnish matter for the study of 30 years to several industrious philosophers; and their connections with their strata will still require as many more years of travel, of boring and other arduous researches.

M. André, in imitation of Saussure, traversed the Alps, from St. Gothard to St. Bernard, passed the Jura, and examined the Vosges. He describes Mont Blanc, the Vallais, St. Gothard, Jura, and Vosges, with great precision and perspicuity. To his descriptions he has added several others from the best authorities, so that his work is very complete. The following is an abstract of his theory, which his reporters, M. Hauy, Lelievre, and Cuvier, have in part adopted as their

own.

"He thinks that the actual arrangement of the surface of the