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revealed by nature, from those which are to be found only in the conventional systems of man, and upon a final scrutiny, to abide by the doctrine which seems to afford the greatest degree of probability, without blinking the weak and hypothetical parts which may belong to it. We shall review in succession the Salvinia, Equisetacea, Musci, Hepatica, Lycopodiacea, Filices, Alga, Lichenes, Hypoxyleæ, and Fungi. In proceeding in this order, we pass by gradually changing shades of difference from the species which approach the nearest to phænogamous vegetation, to those which recede the farthest from it.

Before we enter into the detail of our subject, let us premise a few words concerning the texture of the substance of plants of this nature.

A membranous and cellular texture belongs to the substance of all plants, but subject to a vast variety of modifications, all which modifications are not found to exist in every species. We are acquainted, for instance, with certain phænogamous species in which neither trachea, false tracheæ, nor moniliform vessels are to be found. None of these modifications of texture belong to the mushrooms, liverworts, hypoxyleæ or alga, which are most probably all of them of the agamous class. The substance of these consists of a mass of continuous cells of various elongations, with membranous walls of various thickness; and their outer skin or epidermis, which can seldom be detached from the rest of the texture, is without miliary glands. Excepting the algae, the plants of this class have no parts of an herbaceous nature.

The other groups, viz. the Ferns, Lycopodiaceæ, Hepaticæ, Mosses, Horse-tails, and Salviniæ, do not appear to differ from those of the phænogamous class in the nature of their texture; leaves, or else herbaceous processes that serve the turn ofleaves, and vessels, have been observed in the greatest part of them. Struck by this analogy to the phænogamous plants, some authors have concluded from thence, that the plants of these groups could not be without sex; not a very consequential way of reasoning at all events, since it is not yet proved that the presence of tracheæ, false trachea, miliary glands, leaves, &c. &c., necessarily imply that of stamens and pistils. Let us lay

aside all such groundless conclusions, and keep close to the detail of facts.

SALVINIE.

This group consists of the genera PILLULARIA (Pill-wort,) MARSILEA, SALVINIA, and ISOETES (Quill-wort,) all aquatic plants, which are to be found in France. We place it at the head of the ranks of the cryptogamous class, as other botanists have done before us.

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PILLULALIA grows in wet places. Its creeping stem puts out small branches at different points; these produce slender cylindrical leaves, at first like a sheep-crook; at the foot of each branch arises a globular involucre, as large as a pea, without any opening this involucre parts itself into four pieces, which then constitute four distinct cells, each containing from sixteen to twenty pistils, and from thirty to two-and-thirty anthers; the pistils are situated in the lower part of the cell, and have an obtuse stigma, the anthers are collected in a round tuft, and are suspended from the top of the same cell; these last are conical, and open transversely at the top; their pollen consists of globular grains, which do not burst when they come in contact with water; each pistil is provided with a seed that germinates by a leaf.

Linnæus, who had taken but a very superficial view of PILLULARIA, but was determined to find sexual organs in that as well as all other plants, supposed the involucre to be one entire pistil, containing several ovula, and that the pollen was disseminated over the leaves. But Bernard de Jussieu, by explaining the true structure of the sexual organs of this genus, has completely refuted the opinion of Linnæus. Nor can it be said that it was one founded upon observations of the least weight, or supported by any evident analogy; but stands a proof with how little circumspection even the most skilful authors make assertions in aid of any favourite system they have to build up. A reflection that will often obtrude itself into our minds, as we proceed.

MARSILEA has a stem which creeps along the ground, the same as in PILLULARIA; but here there are long petioles which

bear at their top four leaflets, disposed in the form of a cross, and near their base eggshaped involucres that do not open. The cavity of the involucres is divided lengthwise into two cells, which are subdivided into several compartments, containing pistils and anthers mingled together. The anthers are very numerous and very small, do not open, have but one cell, and are filled with a pollen consisting of opaque grains; the pistils are not numerous; they are provided with a style, and contain within a double membrane, a granular transparent matter. This is the sum of what we collect from the observations of Bernard de Jussieu and Mr. Robert Brown; but in admitting that the facts stated by these skilful botanists are correct, yet the appellations of pistils, stamens, and pollen, may after all be misapplied, for experience has not yet taught the real uses of any of the organs of this genus.

SALVINIA floats on and extends itself over the surface of stagnant waters, in the form of a lively verdant carpet. Its branches are furnished with small opposite oval leaves,sprinkled with minute glands surmounted by four spirally curled hairs; from under the pairs of leaves, and among the roots, are produced in groups several close globular involucres of about two centimetres in diameter. There is only one female involucre in each group; the rest are males, and contain from one to two hundred whitish globular anthers, each with a small filament of its own, by means of which the whole are collected in bunches upon a common shaft. The female involucre encloses from ten to twelve white oblong chagreened pedicled pistils, which become as many small capsular fruits, with one small seed (seminulum) in each. All these involucres separate from the parent plant towards the end of summer, and sink to the bottom of the water. In the following month of April, the capsules having rid themselves of the involucre, rise again to the surface of the water, and germination takes place. At first the capsule opens at the top by three teeth; then two radicles, like two little horns, are evolved; then a petioled leaf makes its appearance in the form of an inverted crescent; when the stem at last issues from the sinus in the leaf.

Linnæus had taken a false view of the sexual organs of SALVOL. V.

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VINIA. Like Micheli, he took the male involucres for germens, the anthers for seeds, and the hairs on the leaves for stamens ; but since his time, the organs of generation have been very carefully described in this genus by Guettard; and M. Vaucher has explained its mode of germination. But after all, the manner in which impregnation takes place in it, is still a problem; and until this is solved, it behooves us to suspend our opinion concerning the stamens, and not to take for granted facts which have not been duly demonstrated.

ISOETES, Quill-wort, represents a fascicle of narrow elongated leaves. The base of the exterior one swells out and becomes an involucre, in which are enclosed one hundred pistils. Adanson asserts, that these pistils are accompanied by stamens; but Linnæus puts the stamens at the base of the interior leaves, and pretends that they consist of a scale surmounted by an onecelled anther. But all this is very obscure; and we can decide nothing concerning either the opinions of Linnæus or Adanson, without a fresh investigation of the parts of this genus.

We already find in this, the very foremost group, that the customary forms of the sexual organs of phænogamous plants have disappeared; and in fact, many botanists are of opinion, that all the plants that rank in it have neither pistils, stamens, or seeds. Necker, for instance, maintains that the involucres of PILLULARIA, MARSILEA, and SALVINIA, contain nothing but what he calls Bésimences, which he defines to be reproductive bodies, originally of a mucilaginous consistence, that become solid, and form themselves into a germen without the co-operatica of impregnation. But still it is right that we should keep in our minds, that the involucres in PILLULARIA, MARSILEA, and SALVINIA, inclose bodies of two distinct kinds, and that Bernard de Jussieu has witnessed the transverse dehiscence of those which he considers as anthers.

To be continued.

ART. VIII. Case of a Child aged six months, who swallowed a double-bladed Knife without Injury.

FEW subjects are more interesting, than the contemplation of

the wonderful manner in which the human frame accommodates itself to the various violences to which it is subject: compression upon the brain; the effusion of fluids into the pericardium, thorax, and abdomen; a musquet ball or other extraneous body in the midst of muscle, &c.; all may remain a considerable length of time, without necessarily proving destructive: the human stomach is daily exposed to severe trials by the glutton and the drunkard, and daily it evinces its power of contending against such attacks, although it ultimately falls a sacrifice to their repetition or continuance.

If we are surprised at the efforts it is capable of in such instances, how much more must we wonder at those remarkable powers of adaptation by which it is sometimes enabled to remain uninjured when such substances as nails, pins, knives, &c. are swallowed by accident.

The painful and ridiculous feat of the Indian jugglers in passing a blunt piece of iron, under the name of a sword, into their stomach, which certainly contributes to render them short lived; and the instances we have of men actually swallowing knives to the number of 12 or 13, for a reward of spirits or wine, do not come within the intention of these observations : they are meant chiefly to apply to those cases where foreign substances have been inadvertently swallowed.

In the Transactions of the Royal Society, cases are recorded, of knives being swallowed by adults, which forced their way through the coats of the stomach by producing inflammation, &c. or were removed by incision: we have also many histories of nails, padlocks, knives, &c. being swallowed without producing fatal consequences; but I am not aware of any case being recorded where a knife remained so long in the stomach of so young a child, as in that of which I now give the particulars, and which, on that account, deserves to be

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