Obrazy na stronie

that his parental care is over all his works; they form part of the great world that was called forth from chaos, on which man is placed, to adore his goodness, and to be trained up for the enjoyment of that glorious inheritance, which the Most High has promised to those who love him.

Sponges are, apparently, insignificant; yet they form a number of little worlds, peopled with a numerous tribe of animated beings, and designed to answer some important purpose in the general economy of nature. The creatures which inhabit them, belong to the class Vermes, order Zoophyte; and are described by Linnæus, as fixed, and flexile, composed either of net-like fibres, or small spines, and covered with minute mouths, by which they absorb and reject water.

Examine one of them in a microscope, and you will be delighted with its construction. It looks like a gallery, with compartments that rival in intricacy and number, those of the celebrated labyrinth of Crete—the ramified entrances of a marine pavilion, gradually extending upwards, and sending forth branches in different directions, till they at length unite, and form a compound net-work throughout the inside of the Sponge. Small openings are also discoverable at the ends of the upper shoots; and as we trace these openings downwards, a soft whitish substance is discoverable, filling the internal hollow parts of the ramifications, throughout the whole Sponge; these ramifications are nearly transparent, of an amber colour, and are undoubtedly the habitations of a particular kind of Vermes. For though we cannot distinguish either vesicles or cells, or indeed discover any other kind of organization than that of a variety of hollow tubes inflected, and wrought together into a multitude of agreeable forms—some branched like corals, or expanded like a fungus,many rising like a column, others resembling a hollow, inverted pyramid, with irregular cavities, entrances, or apertures; yet, from many obvious resemblances to different kinds of marine productions, as well as from the chemical analysis of Sponges in general, we are amply justified in referring them to the class of animal productions.

I have often contemplated with astonishment, the formation of these Zoophytes. Nothing could be more appropriate. As the creatures which inhabit them are never designed to remove from their places of abode, they are provided with a dwelling that is capable of close adhesion to the surface of the rocks : and what is still more wonderful, as this peculiarity of construction forbids them to go in quest of prey, innumerable mouths are arranged in all directions, like fishing nets. These are capable of being either opened or closed, as necessity requires. Nor is the general dissimilarity of construction which prevails in different species of this extensive genus, less deserving of attention.

The most able mechanic would find it no easy matter to contrive fifty pieces of mechanism, resembling each other in their internal structure, fitted up with similar cogs and wheels, and adapted in every respect to answer the same purpose; and yet different in their external form, highly ornamented, varying in shape and colour, and embellished with a variety of minute and elegant decorations. This dissimilarity is obvious in the fifty species that form the present genus; and what are these but complicated pieces of machinery, formed of net-like fibres, curiously woven together, and endowed with life? Let us examine a few of the most conspicuous. The Branched Sponge is soft, and branched, with rows of small projecting cells on the edges, through which the inhabitants draw in their food. It is common to the British seas, and grows from five to ten inches high. In the Coronet Sponge, these cells, on the contrary, look like small spines, surmounting a pale yellow tube ; while in the Grape Sponge, they appear at the end of hollow branches, resembling bright yellow grapes. In the Creeping, brittle Sponge, with round, erect, and obtuse branches, they are scattered, like open pores, over the whole surface of the sponge, which during autumn is beautifully diversified with small blue and shining globules, and present a most elegant appearance when seen through the clear waters of the Swedish and English lakes. In the common Sponge, which is porous, tough, elastic, and irregularly formed, growing into lobes of a woolly consistence, and adhering, by a broad base, to marine substances, these tubes appear like open cells or pits.

And now, if you wish to consider the chemistry, , as well as the mechanism of this curious Zoophyte, it will not disappoint your expectations. I refer to its inherent properties. When a Sponge has been immersed for fourteen or sixteen days in nitric acid (diluted with three parts of distilled water), it becomes nearly transparent, and when touched with ammonia, assumes a deep orange colour, inclining to a brownish red. But if much softened by the acid, the whole fabric immediately disappears, on being immersed in ammonia, and forms a deep orangecoloured solution. A Sponge, when boiled, also gives out a considerable portion of animal jelly. The infusion of a small quantity of oak bark, causes this to fall to the bottom of the vessel, as a sediment, and so entirely changes the nature of the Sponge, that, when dry, it crumbles between the fingers ; and, when moist, it may be torn like wetted paper. In this state, we should naturally conclude that it is entirely useless : but no; the operations of chemistry resemble the moving of a magic wand. Boil the same in water, with caustic polish, its latent qualities


will be called forth ; and behold, a deposition of animal soap !

Sponges, when heated in a close vessel, give out an unpleasant smoke, and become reduced to a black charcoal, which, on being burnt to ashes, leaves a small quantity of common salt, jelly, and carbonate of lime.

To this we may add, that each Sponge possesses the property of absorbing rapidly, as much fluid as it can hold, and of yielding it when compressed.

Hence they are useful in medicine and in the fine arts; and also in stopping the effusion of blood. For this purpose, a dry and solid piece, of a conical form, should be pressed on the ruptured vessel, to which it will adhere closely, and thus the bleeding of a large artery has been frequently prevented.

Nor is this remarkable production entirely uninteresting to the historian. - It recals to recollection one of the most eventful periods in the history of Carthage. “Send me," said the unfortunate Gelimer, when driven from his throne, and wandering on the mountains of Numidia, “send me, my dear Pharos, a lyre, a sponge, and a loaf of bread : a lyre, on which to sing the history of my misfortunes; a sponge, that I may soothe with it my eyes, inflamed by weeping; and a loaf of bread, because I have not tasted any for a considerable time.'

* Gibbon's Decline and Fall of the Roman Empire.

« PoprzedniaDalej »