250 MARINE BIOLOGICAL LALORATORY. 



action of the tides in that body of water do not carry 

 any substance placed in it out to sea, but keep it moving 

 back and forth until it is decomposed. This fact sug- 

 gested the idea that possibly the oxygen in the water 

 could not take care of any such excessive charge of 

 poisonous nitrates and nitrites as would be developed 

 by these decomposing substances. 



The waters of the Sound are therefore being investi- 

 gated this season with reference to their chemical con- 

 dition at various depths. The currents are at the same 

 time being carefully studied by a member of the Coast 

 Survey, and it is hoped in this way to obtain a complete 

 view of the physical conditions under which the oyster 

 has been evidently forced to live. 



