When these necessary works are completed, advantage is taken of the first spring tide to fill the basin. When the tide begins to ebb, the sluices are closed, so as to retain sufficient water in the basins; and while thus shut up, salt held in solution is deposited, and qualities analogous to those of marine bottoms are produced, purged by cleansing processes of all products offensive to the bivalves. When the basin has been filled with sea-water for the necessary time, and the bottom is sufficiently impregnated, it is emptied and left to dry; and now, the soil being prepared, it only remains to furnish it with oysters of a mellow and ripe age, in order to give them their green hue. Towards the month of September, at low water, the whole sea-side population of Marennes go to gather oysters on the pavement left uncovered by the ebbing tide, or by using a dredger in the deeper parts of the _claires_ where the water still remains. A temporary magazine for the reception of the oysters thus gathered is erected on the banks, which the water revisits twice a day. The young are reserved for cultivation on the parks or _claires_; the fullest are sold for consumption in the neighbourhood; but the quantity of oysters raised at Marennes is insufficient to supply the demand. About a third of the provision intended for the _claires_ comes from the coasts of Brittany, of Normandy, and La Vendée. "These foreign oysters," says M. Coste, "never attain the fine flavour of those bred in the locality. It is necessary to keep them for a long time in the _claires_ before they are sufficiently ameliorated, and, even when they become green, they retain traces of their primitive nature, remaining hard, in spite of the new qualities imparted to them by cultivation; a certain bitterness remains, which is easily distinguished by the true amateur; it is the same with indigenous adult oysters. When they are taken at this stage of their existence the colouring does not succeed with them;--it is only, so to speak, the false brand used to give a speculative value to the merchandise. It is not enough that the mollusc should have a fine flavour; it must have the peculiar taste. It is not enough that it has the green hue; it is necessary that these qualities should pervade it from the earliest age, and that the culture of the _claires_ should continue to the end." It is thus necessary that the oysters for the _claires_ of Marennes should be selected when from twelve to eighteen months old, that the shells should be well-formed, and free from all foreign bodies adhering to the surface. Being thus carefully picked out, the oysters are distributed over the bottom of the _claires_ with a shovel, and afterwards so arranged by the hand that they may not touch each other when they increase in size; that they do not embarrass each other by the movements of their valves; and that nothing should interfere with the regularity of their forms. The young colony reposes