72 BACTERIOLOGY OF THE OYSTER, 



Unfortunately the experiments could not be continued and so we 

 cannot say whether the apparent cleansing, which appeared on the 

 last two days, especially on the last day, was due to a fortunate 

 selection of oysters or was the indication of a real elimination of the 

 intestinal bacteria. The writer is led to believe that the oysters 

 had just begun to open and so allowed the bacteria to be washed out. 

 The low temperature of the water slowed the metabolic processes of 

 the oyster and so, as food and oxygen were not needed in so great 

 quantities, an oyster could maintain itself for sometime without 

 renewing its supply. As soon as the supply was exhausted, however, 

 the oyster opened its shell. 



This investigation shows that under the conditions of the experi- 

 ment with a temperature between 7.2°C. and 5°C. a period of twelve 

 days is not sufficient to allow oysters to free themselves from intestinal 

 bacteria. 



Experiment II. 



May 13, 1913, about a bushel of polluted oysters were taken 

 from Providence River and transferred to the same location in 

 Wickford Harbor as in the previous experiment. 



The water of Wickford Harbor at the place where the oysters were 

 put down was tested by the lactose-peptone-bile presumptive test and 

 no sewage organisms were found. The methods and conditions of 

 the experiment were the same as in the previous experiment except 

 that ten oysters w^ere used instead of fifteen. The sanitary condition 

 of the oysters at the time of transplantation and on two subsequent 

 occasions is shown in the following table: 



