CHAP, viii.] THE GREEX OYSTERS. 359 



One of the most lucrative branches of foreign oyster-farm- 

 ing may be now described i.e. the manufacture of the cele- 

 brated green oysters. The greening of oysters, many of which 

 are brought from the He de Ee parks, is extensively carried dn 

 at Marennes, on the banks of the river Seudre, and this par- 

 ticular branch of oyster industry, which extends for leagues 

 along the river, and is also sanctioned by free grants from 

 the state, has some features that are quite distinct from 

 those we have been considering, as the green oyster is of 

 considerably more value than the common white oyster. The 

 peculiar colour and taste of the green oyster are imparted to 

 it by the vegetable substances which grow in the beds where 

 it is manipulated. This statement, however, is scarcely an 

 answer to the question of " why," or rather " how/' do the 

 oysters become green? Some people maintain that the oyster 

 green is a disease of the liver-complaint kind, whilst there 

 are others who attribute the green colour to a parasite that 

 overgrows the mollusc. But the mode of culture adopted 

 is in itself a sufficient answer to the question. The in- 

 dustry carried on at Marennes consists chiefly of the fatten- 

 ing in claires, and the oysters operated upon are at one 

 period of their lives as white as those which are grown at 

 any other place ; indeed it is only after being steeped for 

 a year or two in the muddy ponds of the river Seudre that 

 they attain their much-prized green hue. The enclosed ponds 

 for the manufacture of these oysters and, according to all 

 epicurean authority, the green oyster becomes " the oyster 

 par excellence" require to be water-tight, for they are not 

 submerged by the sea, except during very high tides. Each 

 claire is about one. hundred feet square. The walls for re- 

 taining the waters require therefore to be very strong ; they 

 are composed of low but broad banks of earth, five or six feet 

 thick at the base and about three feet in height. These walls 

 are also useful as forming a promenade on which the watchers 



