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.
These artificial Mussel beds are termed 'bouchots.' The fishermen who engage in this branch of industry are known as 'boucholeurs.'
'The little Mussels,' continues M. Quatrefage, 'that appear in the spring are known as seeds. They are scarcely larger than lentils, till towards the end of May, but at this time they rapidly increase, and in July they attain the size of a haricot bean. They then take the name of renouvelains, and are fit for transplanting. For this purpose they are detached from those bouchots, which are situated at the lowest tide mark, and are then introduced into the pockets or bags made of old nets, which are placed upon the fences that are not quite so far advanced into the sea. The young Mussels spread themselves all round the pockets, fixing themselves by means of those filaments which naturalists designate by the name of byssus. In proportion as they grow and become crowded together within the pockets, they are cleared out and distributed over other poles lying somewhat nearer to the shore, whilst the full-grown Mussels which are fit for sale are planted on the bouchots nearest the shore. It is from this part of the Mussel bed that the fishermen reap their harvest, and every day enormous quantities of freshly gathered Mussels are transported in carts or on the backs of horses to La Rochelle and other places, from whence they are sent as far as Tours, Limoges, and Bordeaux.... The following data, which were collected by M. D. Orbigny more than twenty years ago, will show how important this branch of industry must be to the district in which it is cultivated. In 1834 the three communes of Esnandes, Charron, and Marsilly, representing a population of 3000 souls, possessed 340 bouchots, the original cost of which was valued by M. D. Orbigny at 696,660 francs; the annual expenses of maintaining them amounted to 386,240 francs, including the interest of the capital employed, and the cost of labour, which, however, is spared to the proprietor who works on his own account. The nett revenue is estimated at 364 francs for each bouchot, or 123,760 francs for the three communes. Finally, the expense of the carts, horses, and boats, employed in transporting the Mussels, then amounted annually to 510,000 francs; but these numbers are far from representing the expenses or profits at the present day. At the time M. D. Orbigny lived at Esnandes, the bouchots were only arranged in four rows; now however, there are no less than seven rows, and some of them measure more than 1000 yards from the base to the summit. The whole of these bouchots, which were at first limited to the immediate neighbourhood of the three villages, of which I have already spoken, extend at the present day uninterruptedly from Marsilly far beyond Charron, and form a gigantic stockade for two miles and a half in breadth, and six miles in length.'
A curious circumstance connected with the Mytilus remains to be described. Let the reader, who may be so fortunate as to possess a good microscope, cut away a portion of the fleshy part of the Mussel, then place it in a watch glass, and examine it through that 'portal to things invisible,' and, unless I am much mistaken, he will own the sight to be supremely wonderful. Some water being deposited in the glass the fleshy object will be seen to swim about in a most singular and mysterious manner, while a close inspection shows every portion of it to be in active motion.