76 THE OYSTER. 



through them in safety without artificial help is very 

 great, and if there were no other dangers or uncertain- 

 ties there would be no need of measures for their pro- 

 tection. As they swim to and fro in the water they 

 are carried to great distances by the tides and currents, 

 and they reach all parts of the region of water within 

 several miles of the parent bed. In a favorable season, 

 any plant, or bush, or piece of driftwood which floats 

 near an oyster-bed becomes covered with small oys- 

 ters, although the nearest bed maybe miles away; and 

 the fact that young oysters may be thus collected in 

 any part of our bay shows that they are distributed 

 everywhere, and we might expect the adults to have an 

 equally general distribution. This is by no means the 

 case, and nothing can be farther from the truth than 

 the idea that the bottom of the oyster area is uniformly 

 covered with oysters or ever has been, although it is 

 quite true that oysters may be reared artificially over 

 nearly the whole of it. The idea that it is only neces- 

 sary to throw a dredge overboard anywhere in the 

 oyster area, and to drag it along the bottom for a short 

 distance in order to bring it up full, is totally errone- 

 ous. Such a condition of things is quite within the 

 reach of the cultivator, but it never exists under 

 natural influences alone. In this country, as well as 

 in Europe, the oysters are restricted to particular spots 

 called "banks," or "beds," or "rocks," which are as 

 well defined and almost as sharply limited as the tracts 

 of woodland in a farming country — they are so well 

 marked that they may be laid down on a chart, or they 

 may be staked out with buoys ; and even in the best 

 dredging grounds they occupy such an inconsiderable 



