246 On the Economical Uses of some species of Testacea. 



in dredging, those which are too small are thrown back again. The 

 season begins on the first of September, and lasts till April. The 

 dredgers make use of a peculiar kind of net, which is very strong, 

 and fastened to three spikes of iron ; this they drag along the bottom 

 of the sea, and thus force the oysters into it ; each boat requires five 

 men, and they dredge in water from four to fifteen fathoms deep. 

 The green oysters are all procured at or in the neighborhood of 

 Colchester. When they wish to give them this color, they throw 

 ihem into pits dug about three feet deep in the salt marshes, which 

 are overflooded only at spring tides, and to which they have sluices 

 to let out the salt water till it be about one and a half feet deep. 

 These pits become green, and communicate their color to the fish in 

 four or five days, although they commonly let them continue there 

 six weeks or two months, in which time they will become a dark 

 green. The color has recently been ascertained to arise from con- 

 ■fervae, and other marine vegetable matter, decayed by the heat of 

 the sun, on which the animal feeds. A very common and very mis- 

 taken opinion exists, especially among foreigners, that not only those, 

 but all English oysters are impregnated with copper, 'which they get 

 from feeding off copper hanks ;'' such we believe would be quite as 

 injurious to the animal itself as it could be to us, and the fancy can 

 only have arisen from the strong flavor peculiar to this fish. Green 

 oysters are comparatively little esteemed in the present day. 



Use. — The great value of this animal is for diet. The shell was 

 at one time supposed to possess peculiar medicinal properties, but 

 analysis has shown that the only advantage animal carbonates have 

 over those of the mineral kingdom, arises from their containing no 

 metallic or foreign substance.* The inhabitants of the shores of 

 Hindoostan did, two centuries since, and perhaps still may, use it in 

 the same manner. The fish is recommended by the doctors where 

 great nourishment and easy digestion are required, the valuable qual- 

 ity being the quantity of gluten it contains. In the northeastern parts 

 of England, old houses may be seen with their tops and gable ends 

 ornamented with these shells, only the inside being exposed ; a cus- 

 tom which is said, we know not with what truth, to have been intro- 

 duced from Holland. In some parts of Scotland the shells are used 

 as manure, and found very excellent and stimulating ; in other places 

 they are burned as lime. 



* Iodine is found in some of them. — Ed. 



