The conchologist's companion,
Book format: An electronic version of a printed book that can be read on a computer or handheld device designed specifically for this purpose.
Publisher: Date:8/5/2009 - General Books LLC
By: Mary Roberts
Excerpt from book: days, the acid became pale yellow, and was changed to an orange colour by the addition of pure ammonia. A greater or less degree of softness and transparency then succeeded, and in this state, when touched with ammonia, the part thus touched assumed a deep orange colour inclining to a brownish red: and when much softened by the acid (if afterwards immersed in ammonia), the whole fabric immediately dissolved, and formed a deep orange-coloured solution. These sponges, when digested with boiling distilled water, afforded a portion of animal jelly, or gelation, which was precipitated by infusion of oak bark, in consequence of which the sponges became less flexible, and more rigid: and the remaining part crumbled, when dry, between the fingers: or when moist, was easily torn, like wetted paper. In this state we should naturally conclude that they were entirely useless: but no: the operations of chemistry resemble the moving of a magic wand, the sponges are boiled with lixivium of caustic potash, their latent qualities are called forth, and, behold, a deposition of animal soap. Sponges, when heated in a close vessel, give out an ammoniacal fetid smoke, and are reduced to a black charcoal, which, being burnt to ashes,leaves a small quantity of common salt and some carbonate of lime. Thus it appears that the principal constituents, according to Mr. Hatchett's experiments, are animal gelly, albumen, a small portion of common salt, and carbonate of lime. Fifty different species are assigned by naturalists to this interesting genus, of which a considerable number belong to the British coasts. These curious marine productions vary both in form and colour. The S. oculata, or branched sponge, is delicately soft, and branched with rows of small projecting cells on the edges, through which ...