submerged leaves have no need of protection from rapid evaporation, nor of any mechanical contrivance by which a too active influence might be exerted upon them by the atmosphere; and besides, the atmospheric air by which they are to be acted upon is itself dissolved in the circumambient water. Hence such leaves have no cuticle.

With regard to the stomata, the author shews, by various observations, that the common opinion, of there being openings through the cuticle into the cavernous parenchyma of the leaf, is just; and consequently, that they are not closed up by a membrane, as is the opinion of Turpin and Raspail, and as has been more recently stated by Mr. Brown. His best proof of this is that which he has drawn from an inspection of very young unexpanded leaves of the Narcissus and Lily, examined near the bulb. In these the stomata are circular evident perforations, surrounded by a circular elevated rim. The paper, which is published in the Annales des Sciences for December last, is accompanied by highly magnified drawings.

3. GERMINATION OF SEEDS AT THE SURFACE OF MERCURY. Some experiments have been instituted by Professor Mulder to determine the force with which roots are developed. He placed seeds of the bean and buckwheat in glasses containing mercury, covered over with water, laying them upon the surface of the mercury, and taking care that they were just about to germinate. The very next day the beans had forced their radicles into the mercury; but those of the buckwheat ran along the surface, forming a sort of net-work by their interlacing, and not making the smallest impression upon the mercury. This experiment was instituted on the 26th of September; on the 26th of October he found many of the bean-roots had ramified beneath the mercury, between it and the sides of the glass; but what was especially worthy of remark, in every instance the root was curved back upon itself in the water at its origin. Hence the author concludes, that there is an internal force which propels the roots, and which, while it sometimes yields to external circumstances, is never wholly destroyed.

4. FERTILIZATION OF PLANTS.

M. Amici has lately indicated a simple mode of witnessing the manner in which the fertilization of vegetables takes place. When M. Adolphe Brongniart published his opinions upon this subject he asserted that, upon the bursting of a grain of pollen, an internal very delicate membrane is protruded, which acts as a boyau, or sheath, to the vivifying particles that are emitted, and which insinuates itself between the cellules of the tissue of the stigma, thus establishing the ingress of the fertilizing matter into the system of the ovarium. It has since been a common opinion, that M. Brongniart was, in that respect, deceived by some optical illusions, and that the sheath or boyau in question has no existence. The object of M. Amici is to

shew how these sheaths may be distinctly seen, so as to leave no doubt of their existence. If,' he says, you take the stigma of Hibiscus Syriacus, or the Althæa frutex, and compress it gently between two plates of glass, it will become transparent; and the observer will perceive not only the sheath introduced into the tissue of the stigma, but may behold the vivifying particles circulating within them. In addition to this fact, M. Amici asserts, that each grain of pollen frequently protrudes from twenty to thirty sheaths, and that each sheath penetrates from the stigma to the foramen of the ovulum, there being always one sheath for each ovulum. If,' he remarks, 'I am asked how such a sheath is to traverse the tissue of these styles, which are very long, my answer is, that perhaps when it has once effected an entrance within the tissue of the stigma, it receives from the tissue itself such nourishment and increase of matter as may be necessary.' We scarcely need add, that it is highly desirable, that these observations should be repeated by others.

5. STRUCTURE OF THE RADISH ROOT.

It is well known to most observers that at the summit of the root of the common radish, at the very base of the stem, or at that place which the French call the collet, the English the neck, is an appendage, at first resembling a membranous sheath, enwrapping the young root, and subsequently, as the root distends, becoming two loose straps hanging down on each side of the root. The nature of this appendage was unknown until the late ingenious L. C. Richard discovered the existence of two modes of germination, called the exorhizal and endorhizal, and suggested that the radish was an example of the latter mode; a notion which has been generally admitted by recent writers, notwithstanding the circumstance, that, if endorhizal, the radish would offer an exception to a very general law that endorhizal germination goes along with endogenous growth. M. Turpin has lately demonstrated that the fleshy supposed root of the radish belongs to the ascending axis, not to the descending one, and that, consequently, it belongs to the system of the stem, and not to that of the root. In the next place, he asserts, that the tumour, which ultimately becomes the radish, is in the beginning cylindrical, and that its cuticle loses, at a very early period, the power of distension; in short, that it dies, and separates from the subjacent living matter, just as dead bark separates from liber and young wood, in old stems. Now, this premature death of the cuticle is connected with the rapid lateral distension of the tumour, the cause of the existence of the two appendages in question, which are nothing more than two straps of dead cuticle, rent asunder by the gradual but rapid distension of the part that they originally ensheathed.

6. RUSSET IN APPLES.

Mr. John Williams, C.M.H.S., in a paper recently published in the

Transactions of the Horticultural Society of London, attributes the cause of apples becoming russet to the alternating temperature, light, shade, dryness, and moisture, which occur many times in the course of a day, when July or August are showery. Continued rain, preceded and followed by a cloudy sky, does not seem to produce the same effect, but the sudden intense light which commonly succeeds a shower at the time the fruit is wet, injures the skin, and occasions small cracks, like the net-work upon a melon.

7. MEDICINAL USE AND EFFECT OF THE AVA ROOT.

The intoxicating property of the Ava root, the cutaneous eruption which succeeds its use, and the renovating effect it has upon the constitution, have been noticed ever since the discovery of the Society Islands. Mr. Collie, late surgeon of H. M. S. Blossom, in her voyage to the Pacific, observes that a course of it is most beneficial in renovating the constitutions which have been worn out by hard living, long residence in warm climates, without, however, affections of the liver, and by protracted chronic diseases; more especially, if the disorder be such as by humoral pathologists would be attributed to an acrid or attenuated state of the blood.' He had an opportunity of seeing a gentleman, a foreigner, who had undergone a course of it, to remove a cutaneous affection, said to have been similar to St. Anthony's fire. It had affected, at different times, almost every part of the body, going from one place to another, but had been particularly obstinate in one leg. He took two doses a day, of half a pint each, one before breakfast, and one before dinner, by which his appetite was sharpened, and by the time he had finished his meal, a most pleasing state of half intoxication had come on, so that he was just able to go to his couch, where he enjoyed a sound and refreshing sleep. About the second or third week the eyes became suffused with blood, and the cuticle around them began to peel; and then the whole surface of the body assumed the appearance above described. The first dose is continued for a week, or so, according to the disease, and then gradually left off. The skin clears at the same time, and the whole system is highly benefited.

Mr. Collie administered the ava, and had an opportunity of seeing its first effects upon a man affected with chronic superficial ulceration, affecting the greater part of the toes, and the anterior part of the soles of the feet; and from what he observed, he had no hesitation in saying, that if he could have procured and applied a suitable dressing for the ulcers, with appropriate support to the oedematous extremities, the plan which he adopted would have succeeded; and even with these disadvantages, he was inclined to think that a cure would be effected if the man abstained from liquor*.

* Beechey's Voyage to the Pacific and Behring's Straits, Part II. p. 434.

8. MEXICAN DOMESTIC BEES. (MELIPONA BEECHEI.)

Captain Beechey, when at Xalisco, obtained two hives constructed by these bees, which he brought to England in H. M. S. Blossom. One of them has been presented to M. Huber, and the other to the Linnean Society. They are formed of hollow trees, a portion of which, of between two and three feet in length, has been cut off, and a hole is bored through the sides into the hollows at about the middle, and the ends of the hives stopped up with clay. These hives are usually suspended on a tree in a horizontal position, with the opening into the cavity directed also horizontally, and are speedily taken possession of by the bees. Their interior arrangement differs materially from that of the European bee, some of the layers of the comb assuming a vertical and some a horizontal position, the cells of the latter being most numerous. All the combs, both vertical and horizontal, are composed of a single series of cells applied laterally to each other, and not, as in the European bee-hive, of two series, the one applied against the extremities of the other. The cells appear destined solely for the habitation of the young bees. The combs are placed together, at some distance from the opening of the hives, and surrounding them are several layers of wax, as thin as paper, irregular in their form, and placed at some little distance from each other: externally to these are placed the sacs for containing the honey, which are generally large and rounded in form. They vary in size, some of them exceeding an inch and a half in diameter. They are supported by processes of wax from the wood of the cavity, or from each other, and are frequently placed side by side; but their disposition is altogether irregular, and bears some resemblance to that of a bunch of grapes. Some of the honey sacs are placed apart from the others, and form a distinct cluster.

From this irregular position of the honey sacs, a most important advantage is gained by the cultivators of the Mexican hive bee, as, in order to possess themselves of the honey, all that is necessary is, to remove the plug from the end of the cavity employed as a hive, and to introduce the hand and withdraw the honey. The store of the laborious bee is thus transferred to the proprietor of the hive, without injuring, and almost without disturbing, its inhabitants. The end of the hive is then again stopped up, and the bees hasten to lay in a fresh store of honey. A hive treated in this way affords, during the summer, at least two harvests.

The bee itself, by which this nest is constructed, is smaller than the European hive bee; its abdomen especially being much shorter. It is distinguished also from the European race of hive bees by the form of the first joint of its hinder tarsi, which is that of a triangle, with its apex applied to the tibia. Its technical characters are intermediate between the two genera melipona and trigona of M. Latreille, one of the mandibles being toothed, and the other nearly

entire. It has a leaning towards the trigona, but its general appearance is entirely that of a melipona, approaching very closely to that of melipona favosa, Latr., apis favosa, Fab.

Some curious anecdotes are related by the possessors as to the manners of these bees; one of which deserves to be recorded. They assert, that at the entrance of each hive a sentinel is placed to watch the outgoings and incomings of his fellows. and that this sentinel is relieved at the expiration of twenty-four hours, when another assumes his post and duties for the same period. Of the duration of this guard some doubts may be reasonably entertained; but of its existence ample evidence has been obtained by repeated observation. At all times a single bee was seen occupying the hole leading to the nest, who, on the approach of another, withdrew himself within a small cavity apparently made for this purpose on the left hand side of the aperture, and thus allowed the passage of the individual entering or quitting the hive, the sentinel constantly resuming his station immediately after the passage had been effected. During how long a time the same individual remained on duty could not be ascertained; for, although many attempts were made to mark him by introducing a pencil tipped with paint, he constantly eluded the aim taken. With the paint thus attempted to be applied to the bee the margin of the opening was soiled, and the sentinel, as soon as he was free from the annoyance he suffered from the thrusts repeatedly made at his body, approached the foreign substance to taste it, and, evidently disliking the material, he withdrew into his hive. A troop of bees was soon observed to advance towards the place, each individual bearing a small particle of wax, or of propolis, in his mandibles, which he deposited in his turn upon the soiled part of the wood. The little labourers then returned to the hive, and repeated the operation until a small pile rose above the blemished part, and consequently relieved the inhabitants from the annoyance*.

9. MEAN METEOROLOGICAL RESULTS.

M. Bouvard, from the examination of more than a hundred thousand observations, made at the Royal Observatory of Paris, and embracing a period of eleven years, deduces the following conclusions: -The mean height of the barometrical variations is (mm.15.

That from nine o'clock in the morning till three in the afternoon, the variation from the mean height is about double of that from three to nine in the afternoon. Hence it is necessary, in determining the mean pressure of the atmosphere, to pay attention to the times of observation. During the months of February, March, and April, the variation from the mean is greater than in the months of November, December, and January; and that during the rest of the year the barometer, between the hours of nine A. M. and three P. M., only suffers slight oscillations about the mean height. The height

Beechey's Voyage, App. p. 613.