820 OYSTERS, AND ALL ABOUT THEM. 



poor, of small size and dark colour, but of the ordinary 

 flavour. The remaining six oysters were placed in per- 

 fectly fresh water for twenty-four hours, the water being 

 changed several times during that interval. They were 

 then opened and inspected. They were alive and in good 

 order, very fat, or apparently so, and of a creamy white 

 colour and much swoollen, but of very insipid taste. As the 

 oysters were alive at the end of a day's immersion in fresh 

 water, they cannot well be destroyed by the brackish water 

 of low spring ebbs, to which they would not be exposed for 

 more than six hours, though a continuance of heavy freshets 

 might very seriously affect them. 



The evil effects of sudden jars and concussions are 

 probably due to the breakage of the delicate pedal muscle, 

 which after the spawning season, in common with all other 

 parts of the animal, is in a more or less weakened condition. 



In explaining the fact that the oysters in deep water 

 are more affected by cold water and ice than those on the 

 shoals, it is necessary to remember that the lower the tem- 

 perature of sea water the greater its density, and thus, as the 

 surface water becomes cooler, it would sink. The freezing 

 point of salt water is below that of fresh. Therefore the 

 oysters in the deep water, or, generally speaking, those 

 remote from the mouths of the streams, may have surround- 

 ing them water of a slightly lower temperature, depending 

 upon the amount of salinity, than those oysters near the 

 creeks and rivers that are surrounded by ice. Again, the 

 deep water would be much slower to lose or acquire heat 

 than that on the surface or in less depths, which would 

 necessarily be affected quickly by all changes of weather. 



The statement that the oysters recover and reappear 

 after the " sanding " process must be received with great 

 caution, opposed as it is to most experience. That some 



