80 BACTERIOLOGY OF THE OYSTER. 



room for several days was poured into the dishes until it covered the 

 oysters. Immediately after the oysters were covered five samples 

 of two cubic centimeters each were taken from each dish and inocu- 

 lated into bile tubes and incubated at 37°C. for 18 hours. Every tube 

 showed gas. January 22, the oysters were examined in the dishes 

 and it was found that four were closed tightly, five were open widely 

 enough to be seen as they lay in the dishes and the other seven were 

 found to be slightly open. The opening of these last seven was not 

 perceptible to the eye, but upon taking them out and squeezing them 

 one could hear a "squashy" sound, showing that they were not firmly 

 closed. Apparently the five oysters that were open had lost their 

 sensitiveness, for they would not remain closed when the valves were 

 pressed together. The mechanical stimulation of the gills and mantle 

 was not tried. The oysters were observed on several days until 

 February 2nd and it was found that some of the oysters that had been 

 firmly closed at first had opened and vice versa. 



The oysters were not observed again until March 23. It was found 

 that two of the oysters in one dish were open and dead. Two others 

 were wide open but closed immediately when touched. These two 

 oysters were brought to the laboratory and put into a dish of sterile 

 sea water and observed for several days. They were just as active 

 as oysters freshly brought from the beds. They were then tested for 

 B. coli. Both oysters showed gas in 1-100 c.c. of shell liquor. These 

 tubes were plated in litmus-lactose-agar and typical colon colonies 

 were found in the plates from one oyster, but not from the other. 

 This showed that B. coli can live under such condition for at least 

 sixty-nine days. 



The remaining oysters were again examined April 24, one hundred 

 days after they were put into storage. Five of the oysters were 

 apparently living, while the others were dead. These five were 

 brought to the laboratory and examined. It was found that three were 

 closed tightly, while the other two appeared a little "weak." One 

 of the tightly closed oysters was put into a dish of sea water and it 

 soon opened like an oyster removed only recently from its natural 

 element. When the shell was touched it would close immediately, 

 though its movements were not so vigorous as those of an oyster 

 taken directly from the water. When the gills and mantle were 

 touched with a wire it did not respond readily. Apparently its 

 tactile sensations were not very acute, although after repeated 

 stimulations it closed and gripped the wire so that it took considerable 



