THE OYSTER. 89 



A wharf was built from high-tide mark across the 

 flat out to the edge of the channel, and the shells of all 

 the oysters which were consumed in the house were 

 thrown on to the mud alongside the wharf. In the 

 third summer the flat in the vicinity of the wharf 

 had become converted into an oyster-bed, with a few 

 medium-sized oysters and very great numbers of 

 young, and the bottom, which had been rather soft, 

 had become quite hard ; in fact, the spot presented all 

 the characteristics of a natural bed. Changes of this 

 sort are a matter of familiar experience, and it is plain 

 that something else besides the absence in the oyster 

 of locomotor power determines the size and position 

 of a bed. 



Xow what is this something else? 



If the planting of dead shells will build up a new 

 bed, may we not conclude that a natural bed tends" to 

 retain its position and size because the shells are there? 



This conclusion may not seem to be very important, 

 but I hope to show that it is really of fundamental 

 importance, and is essential to a correct conception of 

 the oyster problem. 



Why should the presence of shells, which are dead 

 and have no power to multiply, have anything to do 

 with the perpetuation of a bed? 



We have already called attention to the fact that 

 oysters are found on the hard bottom on each side of 

 the channel, while they are not found in the soft mud 

 of the channel itself, and it may at first seem as if there 

 were some direct connection between a hard bottom 

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