In general the sure sign of their not being in a healthy condition is when the shell opens; for, while the animal retains any sense whatever, it exercises a strict and judicious 'closeness.' I have found, however, on several occasions, that the shell being contracted is not always a valid proof of its owner's convalescence, for when placed in water the Mussel would float for several days upon the surface like a cork, although it was near death's door. This phenomenon must be caused, I should suppose, by some sudden fright compelling the mollusc to close its shell with such rapidity as to prevent a proper supply of water being taken in. Having only air to exist upon, the animal then lingers on until its branchiæ become dried up, and all moisture exhausted. In this state the Mussel opens its shell with a deep bursting sigh, and sinks to the bottom--dead. Being at the sea-side one fine summer day, I heard a little Scotch girl cry out to her brother who was about to swallow entire, a fine specimen of the _Mytilus edulis_, 'Eh, Willie dear, dinna ye eat that. Dinna eat the _beard_ or ye'll dee!' Many years ago I remember a remark to the same purport as the above being made by a poor child to its playmate, in the neighbourhood of Gravesend. I little thought at that time that the Mussel was so interesting a shell-fish, or that I years after should spend many an anxious hour studying the formation and nature of its despised beard. I need hardly state that the idea of the beard being poisonous is a vulgar error. In general the fish may be eaten entire with impunity. Cases have occurred where persons have been taken ill after eating it, but this result has been satisfactorily explained to have been caused by the Mussels being procured from places such as Leith Docks, where their food consisted chiefly of unwholesome and putrescent matters. This mollusc is not used as food to any very great extent by the poorer classes. It is employed very extensively, however, by the fishermen as bait along all parts of the British coast. But in France it is much esteemed both by rich and poor. The trade in them is successfully cultivated, and affords a means of support to hundreds of industrious and deserving men. From the learned author of the "Rambles of a Naturalist" we learn that at the village of Esnandes, on the coast of France, the Mussel trade, commenced about eight hundred years ago, has assumed a gigantic extent. Both here and at the neighbouring villages of Charron, Marsilly, Mussels are bred in an ingenious and systematic manner. At the level of the lowest tide short piles or stakes are driven into the mud, in a series of rows about a yard apart. This palisade is then roughly fenced in with long branches. On this structure the Mussel spawn is deposited, and it is found that the molluscs thus produced in the open sea are much finer than those which are bred nearer the shore.