"the finger be applied to the foot of the animal, or to the spot on which it rested, the finger will be held there by a very sensible resistance, although no glue is perceptible. And it is remarkable, that if the spot be now moistened with a little water, or if the base of the animal be cut, and the water contained in it allowed to flow over the spot, no further adhesion will occur on the application of the finger,—the glue has been dissolved. It is nature's solvent, by which the animal loosens its own connexion to the rock. When the storm rages, or when an enemy is abroad, it glues itself firmly to its rest; but when the danger has passed, to free itself from this forced constraint, a little water is pressed from the foot, the cement is weakened, and it is at liberty to raise itself and be at large. The fluid of cementation, as well as the watery solvent, are secreted in an infinity of miliary glands, with which the foot is, as it were, shagreened; and as the limpet cannot supply the secretion as fast as this can be exhausted, you may destroy the animal's capacity of fixation, by detaching it forcibly two or three times in succession."
This common limpet, though hard, coarse, and unsavoury, is largely eaten by the poorer classes on our rocky shores. It is easily procured in almost any quantity, between tides, and therefore is a good deal resorted to by those who have little or nothing better. The wretched inhabitants of the isles of Scotland, and of the Atlantic shores of Ireland, in particular, have often been preserved from actual famine by this miserable food. The quantity eaten as a regular part of diet is immense.
- Introd. to Conch, p. 147.