BACTERIOLOGY OF THE OYSTER. 81 



strength to pull it out. The writer has noticed that oysters which 

 have been removed from sea water for some time require a great deal 

 of stimulation to make them close again, though after they have been 

 open for a time they react immediately. It may be that the tango- 

 receptors are very much dulled or that the desire for oxygen is stronger 

 than the sense of self-protection. 



The other four oysters were opened with the proper precautions 

 and the mixed shell liquor and the "washings" from the body were 

 inoculated into bile tubes. Two of the oysters were normal in 

 appearance and exceptionally plump. The other two showed slight 

 evidences of decomposition. All the tubes from three of the oysters 

 showed gas and typical B. coli colonies were isolated on litmus-lactose- 

 agar plates. Further identification was not regarded as necessary. 

 The tubes inoculated from the third oyster showed no gas after three 

 days incubation. 



Experiment IL 



Seven oysters were obtained fresh from the water and impregnated 

 with a solution of azolitmin in sea water. They were then washed 

 thoroughly with a stiff brush in running water and immersed in 

 chromic acid for a few seconds and then washed again. All the 

 color was removed in this manner. January 29 they were placed 

 in tumblers and put into cold storage at 34°F. They were left over 

 night to acquire the same temperature as the room and then the 

 tumblers were filled with sea water. The dishes were watched to see 

 if any color had escaped from the oysters. February 2 a slight 

 coloration was found in the bottom of two of the tumblers, but this 

 did not appear to increase for several days. The oysters were not 

 examined again until March 23rd. The color had disappeared from 

 the two tumblers that had previously been discolored. It was 

 observed, however, that the water in the tumblers was not entirely 

 clear. There was a sediment in the bottom of the tumblers that 

 resembled the bits of mucus thrown off by oysters. One of the 

 oysters was taken to the laboratory and placed in sea water. It 

 soon opened, but did not contain any color. It was as active as a 

 normal oyster. Some of the mucus thrown out by the oyster had a 

 purplish color which had been stained with azolitmin. 



April 17 the remaining six oysters were examined. It was found 

 that three of the oysters were open and the other three closed. Covers 



