706 OYSTERS, AND ALL ABOUT THEM. 



which was deposited in the same enclosure. Such experi- 

 ments have in our country at least always led to negative 

 results. However, we are not certain that they were taken 

 with the necessary precautions, the water being only very 

 rarely and partially changed. The consequence of this 

 must have been extensive mortality of the spat by the 

 water becoming de-oxygenated, and loss of spat at those 

 whenever so few occasions on which the water was 

 partially renewed. 



In our experiments we wish by all means to eliminate 

 such sources of error. We have had the free disposition 

 given to us, during the whole time of the experiment, of one 

 of the largest oyster pares. It is represented in this figure. 

 At these points there are inlets for the sea- water that can 

 be opened and shut, and the volume of water forming the 

 oyster park is divided by smaller dykes and by wooden 

 enclosures into several compartments. 



One of these has been entirely separated from the 

 rest, and is specially devoted to the purpose of our experi- 

 ments. In this separated portion, here indicated by dark 

 blue, and which has a superficial extent of about a quarter 

 of an acre, about 10,000 mature oysters are about to be 

 deposited, the floor of the compartment having been 

 covered by apparatus for collecting the spat. As long as 

 the breeding season has not yet so far advanced that the 

 spat is set free, the water is changed with every tide. In 

 the meantime we have here put up a steam engine, and by 

 this we intend to bring about artificial oxygenating of the 

 sea-water the moment the spat makes its appearance. We 

 then shut all the exterior inlets of water once for all, and 

 continue our experiments during the rest of the summer 

 with the water at that moment contained in the park. In 

 this way there is ist, no possibility of the spat escaping. 



