4.2 Natural History of Molluscous Animals : — 
Oysters abound on various parts of the British coast, and 
are consumed, under one form or another, in such numbers, 
as to have become a valuable article of commerce. To give 
you some idea of its extent, and of the number of hands to 
which it gives employment, it may be sufficient to mention the 
oyster-fisheries of Essex alone. In the rivers of this county, 
more particularly in the Crouch, the Blackwater, and Colne, a 
great variety of excellent oysters are bred. ‘The boats employed 
in dredging them are from 14 to 30 or 40 tons ; the fitting out 
one of 20 tons will require 1507. Of these vessels there are 
upwards of 200 now employed, and above 500 men and boys. 
The quantity of oysters taken in a season is supposed to be 
above 20,000 bushels, which are chiefly disposed of in Lon- 
don; but they are also sent to Hamburgh, Bremen, Holland, 
France, and Flanders, * So important, indeed, are the oyster- 
fisheries of Britain, that they have long been an object of 
attention to the legislature ; and they are regulated by a Court 
of Admiralty. In the month of May, the fishermen are al- 
lowed to take the oysters, in order to separate the spawn from 
the cultch +, the latter of which is thrown back, to preserve the 
bed for the future. After this month it is felony to carry away 
the cultch, and punishable to take any oyster, unless, when 
closed, a shilling will rattle between its valves. The spawn is 
then deposited in beds or layers formed for the purpose, and 
furnished with sluices, through which, at the springtides, the 
water is suffered to flow. ‘This water, being stagnant, soon 
becomes green in warm weathers and, in a short time, the 
oysters acquire the same tinge, which renders them of greater 
value in the market. Three years, at least, are required to 
bring them to a marketable state; and the longer they remain, 
the more fat and delicate they become.{ Those artificial 
beds, as Pliny informs us, were invented by one Sergius 
Arata, and first established on the Lucrine Lake, a. v. 660; 
and, from some circumstances mentioned by the naturalist, we 
may infer that the said Sergius was no loser by the specula- 
tion. In Scotland we have none of them, but eat our oysters 
just as they are brought from their native rocks ; and though 
* Edin. Encyclopeedia, art. Essex. 
+ By this term are meant the stones, gravel, old shells, &c., to which the 
spawn adheres ; and the reason for punishing its destruction is, that, when 
taken away, the ooze increases, and muscles and cockles breed on the bed, 
and destroy the oysters, gradually occupying all the places on which the 
spawn should be cast. 
{ See Pennant’s Brit. Zoology, vol. iv. p. 227., &c.; Bingley’s Animal 
Biography, art. Oyster; and Thomson’s Annals of Philosophy for January, 
1818, p. 70. 
