256 FATTENING THE MOLLUSCS. 



during the months of May, June, July, and August, when 

 the bivalve is depositing its spawn. 



When first removed from their habitat, oysters, how- 

 ever, do not possess in their highest perfection the proper- 

 ties which are so much esteemed by oyster-eaters; and to 

 render them fatter, more tender, and more savoury, they 

 are deposited, before being sent to market, in " parks " 

 of from three to four feet deep, the bottom of which 

 consists of sand or pebbles, with gently sloping sides, 

 and communicating with the sea by means of a channel 

 or trench which is easily shut or opened. In some 

 " parks " the water is renewed every tide : in others, only 

 once or twice a month. The celebrated oyster-parks at 

 Marennes, Treport, Etretat, Fecamp, and Dunkirk, belong 

 to the former category ; those at Havre and Dieppe to 

 the latter. 



The period during which the bivalves undergo the 

 fattening process varies from a few days to a month. 

 Under certain conditions, they acquire a greenish colour- 

 ing, as well as that piquant flavour to which the epicure 

 is so partial. 



A French authority M. Yalmont de Bomare appar- 

 ently supposing that oysters feed upon grass, enunciated 

 the hypothesis that the colour of the "green oyster" can 

 be produced only in " parks " freely surrounded by vege- 

 tation ; an hypothesis which it is quite unnecessary to 

 examine with any degree of seriousness. Another French 

 writer M. Gaillon attributes it to a microscopic ani- 

 malcule, the Vibrio ostearius, on which the mollusc feeds; 

 but it has been proved that the vibrio is not normally 

 green, and becomes so only under the same conditions as 

 the oyster. Bory de St. Vincent thought it arose from 



