encounter, in the argument, that the degree of perfection at which our analyses have lately arrived, rather encourages than precludes the hopes of their further improvement. It must be confessed, that the modern and elaborate analyses of Professors Berzelius, Brandis, Steinmann, and Dr. Struve, afford a certain degree of plausibility to this objection. On, however, comparing their labours with those of experienced chemists, who preceded them, we find them to correspond in all the essential points, and the additions of the former to regard alone the detection of a few ingredients in very minute portions, and whose presence in mineral waters was never before suspected. According to the present accurate mode of instituting analyses, large quantities of water are submitted to the process at once. The weight of every single ingredient is thus ascertained by the direct method, and no longer by merely subtracting the remainder from the entire mass; and the amount of the single ingredients is yet required to agree with the sum total. Nor are the precipitates in the drain that carries off the waste water from the spring, or the fossils occurring in the vicinity of the latter, overlooked-both being submitted to a chemical examination. It is scarcely to be apprehended, that analytical research, thus conducted, and facilitated by all the resources of modern chemistry, will leave much to future detection, that can be deserving of medical regard. Thus, reasons, both chemical and philosophical, compel us to admit, that mineral waters, prepared on scientific principles, and with the observance of an undeviating accuracy of imitation, will present us remedies, to the full as valuable as the original springs;-and recent medical experience tends amply to support such a conclusion. We might add, that they promise even a more uniform efficacy than can be looked for in many of their originals, whose constituent proportions are known, owing to atmospherical influences, to fluctuate at times. Thus, variations of this kind have even been experienced in the springs of Carlsbad and of Ems; and the baths of Töplitz, in Bohemia, have, within a period of five-and-twenty years, gradually been deprived of one-half their solid contents. Dr. Scudamore's "Chemical and Medical Report" contains observations of the same nature, relative to the waters of Tunbridge-wells, Harrow gate, and Cheltenham; and we may remark, that those of Seidschutz and Püllna are not considered fit for medicinal use, until they have stood long enough in their basins to become adequately impregnated with saline particles, which their taste then indicates. The method practised in bottling artificial mineral waters, whereby decomposition is entirely obviated, is an advantage which the natural springs do not possess. With regard to a pump-room, at which mineral waters of many various kinds are dispensed, the facility of relinquishing the use of one spring in favour of another, without sacrifice either of time or expense, must be equally appreciated by the physician and the patient. A gradual transition from a weaker to a more powerful springeven a mixture of two remote ones, a mode of treatment often attended with benefit-is thus alone rendered feasible; and where experiment is the object of the practitioner, the convenience afforded by such an establishment is too obvious to need any further remark. Natural History of the Earwig. INSECTS.-Class 5.-Order 1. Coleoptera.-Wings 2, covered by two shells, divided by a longitudinal suture. Genus Forficula.-Antennæ tapering; shells abbreviated; wings folded and depressed; shells tipt with white; length when full grown, eight lines. THE Earwig is common and well known; it is rather an ugly and hostile looking insect: its very name has given it a character of dread, and, consequently, is an object for destruction, whenever or wherever met with. This insect changes from its chrysalis state in the spring and early summer months. From heaps of garden or field rubbish, dunghills, or hot beds, they may be seen on fine warm evenings issuing forth in great numbers, immediately taking flight, rising to a considerable height in the air, where they disport themselves on wing till darkness sets in, when they descend and retire to hiding-places till the next evening. At this stage of their life they are of a pale yellow colour, about four lines in length, and remarkably active and quick in their motions. Their appearance at this time, in size and colour, as well as in quickness of movement, both on wing and on foot, has induced some naturalists to consider them as a distinct species, under the designation of Forficula minor; and though further distinguished by two joints less of the antennæ, yet it is probable they are only different semblances of the same insect. It cannot be observed how often the same individuals take their evening's flight; but as they congregate apparently from the instinctive impulse of sexual association, it is likely they only continue their flight till that important act of their being is consummated. Throughout the summer and beginning of autumn, they are usually seen lurking in holes of walls, joints, and in crevices of wood-work, or among any dry materials. As they are the natural prey of many kinds of birds, particularly the Picæ, Gallinæ, and several of Passeres tribes, they shun the light, pass the day, if not disturbed, in their retreats, and issue forth to assemble together or feed during the night. They are one of the greatest plagues of the gardener, for as soon as the earliest (and which is also the choicest) fruits begin to be scented, the earwigs begin their depredations, generally eating a hole either close to the stalk of pomeous, or at the apex of drupeous fruits, disfiguring, if not destroying them. Apricots are their favourite repast, and from which the spoiler abstracts almost all their value. Many guests at the dessert, and particularly ladies, have hardly courage to take a Moor park apricot on their plate, lest they should be disgusted with the sight of earwigs having possession of the cavity round the Hence the gardener is ever at war with them, and especially in defending his wall fruit, for there the insects have not only safe retreats, but also "the first-fruits" to invite their voracity; and as they are midnight plunderers, he can only place reeds, and other hollow stalks of plants, to allure their entrance, and where they may be daily caught and destroyed. Though the richest fruits seem to be preferred by them, there are many other vegetable substances which serve them for food. The florist often has to regret the loss or laceration of some of his favourites: they eat the epidermis of stalks and leaves, sometimes the petals and stamina of the flower, and occasionally devour young plants, as those of the French marigold (tagetus patula), and others. Throughout the summer and autumn they continue to in crease in size, and in the latter season become unwieldy, and cease using their wings. The abdomen becomes much enlarged, from which circumstance they all appear to be females; this cannot, however, be ascertained, as there are no visible sexual marks in any stage of their existence; but from the habitudes of other genera in this class of insects, it is probable the males die soon after the purposes of their life is completed; and as we see the full grown ones skulking about the places where the young are resuscitated in the spring, it is likely the eggs are laid in the course of the autumn, and pass the maggot and chrysalis states during the winter. From the weapon-like appendices at the end of the abdomen, they appear to be intended for offence, and though used for the purpose of defence, this is not the sole use of those threatening instruments, but they are the organs, without which, they could neither fold nor unfold their wings. When these are unfolded for flight, they are at least half an inch in length, and when folded lie under the protection of a shell not one-fifth of this length! The membranous and transparent wing has no tendinous or muscular motion in itself, but by the assistance and form of the forceps, they are quickly folded, like a large map in an octavo volume, with the greatest adroitness. Such provision has nature made for the disposal of appendages so necessary to the animal at one time, and for the defence of the same at another, when the pioneering habits of the insect endangers the safety of those delicate organs. Another circumstance in the structure of this loathed insect deserves remark; its safety depends on its power of secreting itself from its natural enemies, by creeping into sinuous holes and cavities; but this it could not do without such flexuosity of body, as its short shells allows; for if it had shells or elytra, covering the whole length of the abdomen, like the greater number of the tribe, it could not enter with facility into winding holes necessary for its safety. The name of this insect, in almost all European languages, has given it a character which causes a feeling of alarm even at the sight of it. Whether or not they ever did enter the human ear is doubtful,—that they might endeavour to do so, under the influence of fear, is more than probable; and this, perhaps, has been the origin of their name, and the universal prejudice against them. As it is said that anatomists deny the possibility of their deep or dangerous entrance into the ear, it is a pity that this is not generally known, as it might defend the constitutionally timid from unnecessary alarm, and give a more favourable idea of a part of animal creation, which forms a most necessary link in the chain of being. While the naturalist contemplates the economy of the earwig, he cannot avoid noticing the wonderful power of instinct with which this despicable animal is endowed. In starting into active life from its dreary abode in the earth, and fitted at once to become a temporary inhabitant of the air, what but instinct. opposes its not venturing forth until the evening, when the swallow and martin, and other muscivorous birds have fled the sky and retired to rest. The same unerring substitute for want of reason, directs them to shun the light of day, lest they should be exposed to view of their enemies, and they always prefer the most secret recesses of quiet and darkness, for the preservation of their existence, till the important work of securing a succession of their species is accomplished. J. M. The Characters of Achatinella, a new group of terrestrial Shells, with Descriptions of six Species.-By William Swainson, Esq., F.R.S., L.S. &c. THE study of the Molluscæ is attended with difficulties not to be found in any other class of animated nature. Their shells or habitations, indeed, are easily procured, and are generally the first objects with which the young naturalist begins his collection but the living animals to which they served but as a protection, and whose structure alone can decide their place in JAN.-MARCH, 1828. G |