The Sponge is a natural production, which has been known from times of the highest antiquity. Aristotle, Pliny, and all other writers who occupied themselves with natural history in ancient times, are agreed in according to it a sensitive life. They recognize the curious fact that the sponge evades the hand which tries to seize it, and clings to the rocks on which it is rooted, as if it would resist the efforts made to detach it. Pliny, Dioscorides, and their commentators, even formed the idea that sponges were capable of feeling, that they adhered to their native rock by special force, and that they shrunk from the hand which tried to seize them. They even distinguished males from females. Erasmus, however, criticising Pliny, concludes that he may pass over all he has written upon the sponge. The sponge, in short, was to the ancients something between a plant and an animal. Rondelet, the friend of the celebrated Rabelais, whom the merry curate of Meudon designated under the name of _Rondibilis_, who was himself a physician and naturalist of Montpellier, denied at first the existence of sensibility in sponges. He originated the idea that these productions belonged to the vegetable world--an idea which Tournefort, Gaspard Bauhin, Rey, and even Linnæus, in the first editions of his "Systema Naturæ," supported by the great authority of their names. Afterwards, influenced by the convincing labours of Trembley and some other observers, Linnæus withdrew the sponges from the vegetable world. He satisfied himself, in short, that certain polypiers much resembled sponges in the nature of their parenchyma, and that, on the other hand, the assimilation of sponges with plants was not such as could be maintained. Neuremberg, Peyssonnel, and Trembley maintain the animal nature of sponges, and their views are adopted by Linnæus, Guettard, Donati, Lamouroux, and Ehrenberg on the Continent, and by Ellis, Fleming, and Grant in England. They live at the bottom of the seas in five to twenty-five fathoms of water, among the clefts and crevices of the rocks, always adhering and attaching themselves, not only to inorganic bodies, but even growing on vegetables and animals, spreading, erect, or pendent, according to the body which supports them and their natural habit. The power of fixing themselves to other objects, which certain animals possess, is very singular. Nevertheless, it is certain that whole tribes exist consisting of innumerable strictly adherent species, which live and die attached to some rock or other object; and among these are all polypiers, such as the sponges and corallines. It follows that they are wholly dependent on external agencies for their means of existence. "The poor little creatures," says Alfred Frédol, "receive their nourishment from the wave which washes past them; they inhale and respire the bitter water all their lives; they are insensible to that which is only the hundredth part of an inch from their mouth."