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Shells.

THERE is a philosophy in oyster shells, a noble and wondrous philosophy revealing to us glimpses of the workings of creative power among the dim and distant abysses of the incalculable past; speaking to us of the Genesis of oystercreatures, ere the idea of man occupied the creative mind; giving us a scale by which to measure the building up of the world in which we live, such as the mathematician, and the natural philosopher, and the astronomer, all combining, could not furnish; unfolding for us the pages of the volume in which the history of our planet, its convulsions and tranquillities, its revolutions, and gradualities, are inscribed in unmistakable characters. The letters of that book are shaped in the likenesses of extinct and existing beings; planets and animals; not written slovenly and shapelessly, but drawn by a firm and sure hand. The sentences of that book are all consistent and inseparable verses of one eternal and symmetrical psalm; of a grave and harmonious hymn, plenarily inspired. There can be no question about the plenary inspiration of the Book of Nature. Yet the letters of those sublime sentences are in great part despised oyster shells and similar relics. The alphabet that we use ourselves, could we read what passes in the mind of an infant, would seem bizarre, fantastic, and incomprehensible, if looked upon without understanding its meaning and purpose. The great majority of grown men, educated and uneducated alike, are to the alphabet of nature in the position of children. To them the oyster shell is a mere rude and sportive device. But teach them to read and spell, to peruse and study the great Bible of nature, and that device becomes a sign pregnant with meaning.

Unobserved even of what passes in its immediate vicinity, its whole soul is concentrated in itself; yet not sluggishly and apathetically, for its body is throbbing with life and enjoyment,

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The mighty ocean is subservient to its pleasures. The rolling waves waft fresh and choice food within its reach, and the flow of the current feeds it without requiring an effort. Each atom of water that comes in contact with its delicate gills, evolves its imprisoned air to freshen and invigorate the creature's pellucid blood. Invisible to human eye, unless aided by the wonderful, inventions of human science, countless millions of vibrating cilia are moving incessantly with synchronic beat on every fibre of each fringing leaflet. Well might old Leuvenhock exclaim, when he looked through his microscope at the beard of a shell fish, "The motion I saw in the small component parts of it was so incredibly great, that I could not be satisfied with the spectacle; and it is not in the mind of man to conceive all the motions which I beheld within the compass of a grain of sand." And yet the Dutch naturalist, unaided by the finer instruments of our time, beheld but a dim and misty indication of the exquisite ciliary apparatus by which these motions are affected. How strange to reflect that all this elaborate and inimitable contrivance has been devised for the well being of a despised shell fish! Nor is it merely in the working members of the creature that we find its wonders comprised. There are portions of its frame which seem to serve no essential purpose in its economy; which might be omitted without disturbing the course of its daily duties, and yet so constant in their presence and position, that we cannot doubt their having had their places in the original plan, according to which the organization of the mollusk was first put together.

A collection of shells is a beautiful and surprising sight; beautiful, since more exquisite samples of elegance of form and brilliancy of colour cannot be found through the wide range of natural objects, whether organized or unorganized; surprising, when we consider that all these durable relics were constructed by soft and fragile animals, among the most perishable of living creatures. Still more surprising is such an

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assemblage, when we reflect upon the endless variation of pattern and sculpture which it displays, for there are known to naturalists more than fifteen thousand perfectly distinet kinds of shells, each presenting some peculiarity of contour or ornament, distinguishing it from every other sort. Then, again, whilst multitudes of species present constant and invariable features, others, as numerous, are capable of changing their dress so capriciously that scarcely two individuals can be found exactly alike. Some, too, obey in the coiling of their whorls the most exact geometrical rules, whilst others are twisted and twirled into fantastic likenesses of cornucopiæ and trumpets, without regard to symmetry or direction. Yet every one of the fifteen thousand and more kinds has a rule of its own, a law which every individual of each kind through all its generations implicitly obeys. Thus there is a liberty to vary given to some, whilst others are rigidly bound by immutable rules of the utmost simplicity; but to none is allowed the license to depart, unless in the exceptional case of useless and abnormal monstrosities, from the law of its specific organization. The researches of the naturalist have made him conversant not merely with the fact of these myriads of modifications of the type of the molluscous shell, but also with the laws obeyed by whole groups of forms, and the principles which may be evoked from the careful and minute study of species and genus. Thus a science arises out of the knowledge of conchological details, and truths are elicited which bear importantly upon the elucidation of the laws of life and being, throughout organized nature. The formation of the shell itself is but an example of a process at work equally in the animal and vegetable kingdoms. A shell, whether simple or complicated in contour or colour, is the aggregate result of the functional operations of numberless minute membranous cells, the largest of which does not exceed one-hundredth of an inch in diameter, and in the majority of instances is less than one two-thousandth of an inch. In the

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cavities of these microscopic chambers is deposited the crystalline carbonate of lime, which gives compactness to the beautiful dwelling house, or rather coat of mail, that protects the tender mollusk. How astonishing is the reflection that myriads of exactly similar and exceedingly minute organs should so work in combination that the result of their labours should present an edifice rivalling, nay exceeding, in complexity yet order of details and perfection of elaborate finish, the finest palaces ever constructed by man! Throughout nature we find the same complicated results attained by the same simple mechanism. The flower of the field, the shell of the sea, the bird of the air, the beasts of the forest, and man himself, are all so many cellconstructions, wings of the one wonderful animated edifice, whose masons we may behold through the aid of instruments of human construction, but whose architect is beyond the power of mortal science to comprehend. Every where the naturalist discovers the hand-prints of an Omniscient Designer, but must humbly content himself with endeavouring to develope the unity and benevolence of the design.

The mollusk in building up its house does not always labour for itself alone. The brilliant lustre and gleaming iridescence of its shelly envelope are not always destined to remain hidden in the depths of ocean, or immured within mountains of rock. The painted savage appreciates its pearly charms, and plunges beneath the waves to seek the living joints of his simple necklaces and armlets, or to supply his civilized brother with highly prized materials for more elaborate ornaments. Mother-of-pearl, as it is called, is the nacreous portion of the shells of certain mollusks belonging to very different orders. Its charming colouring is not due to pigments, but caused by the arrangements of the layers of membrane and solid matter of which it is composed. The nacreous shells which furnish it are now sought for greedily wherever they can be obtained in sufficient quantity, and form articles of considerable import. From our

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