70 OYSTER BEDS. 



thicker and stronger by successive layers. Marine 

 vegetables are the food of oysters. They become 

 green in three or four days, if put into small pits 

 in the salt marshes where the water is about three 

 feet deep. 



Oysters are amazingly fruitful. Poli, styled by 

 Kirby " the great luminary of conchology," states that 

 one of these animals contains 1,200,000 eggs, so that 

 a single oyster might yield enough to fill 12,000 barrels. 

 Here we discover the care of Providence, that the de- 

 mands made upon them to gratify the human appetite, 

 shall not destroy the race. 



The eggs are expelled in the form of spawn, or white 

 fluid, very similar to a drop of grease, in which, aided by 

 the microscope, may be observed innumerable minute 

 oysters. Fishermen give the name of " spats" to this 

 substance. The matter in which they swim, doubtless 

 serves to attach them to the submarine bodies, or to 

 individuals of their own species. Then the new ones, 

 in being developed, smother, as it were, the old ones, 

 not permitting the water to reach them, or hindering 

 them from opening their shell. In this way are formed 

 immense banks of oysters. These beds, as they are 

 called, are kept up principally by collecting the spawn at 

 sea, and in different places along the coasts of England 



