35 



brushed and steamed before use. This would indicate that 

 of the eight oysters a number of living B. typhosus had 

 actually passed out of their interior. 



Oyster 17, "previously wet/' opened 24 hours after 

 change into sterile sea water total amount of fluid, 2 75 c.c. ; 

 with Jo c - c - f tn i s ^d made one Drigalski plate; this 

 yielded 17 colonies of B. typhosus (no other colonies) this 

 amounts to 935 B. typhosus per whole oyster. 



Oyster 18, " previously dry," 24 hours after change into 

 sterile sea water total amount of fluid, 2 75 c.c. ; ^ c.c. of 

 this fluid was added to 0'9 c.c. of sterile sea water; of 

 this took T \y c.c. for one Drigalski plate. Plate yielded a 

 number of B. typhosus amounting for the whole oyster to 

 1900. 



Assuming all the previously wet oysters and all the 

 previously dry oysters contained at the same date the same 

 number of B. typhosus respectively, we had before the change 

 into the sterile sea water a total stock of B. typhosus in the 

 eight oysters of 4,374,000 B. typhosus. At the end of 24 

 hours in sterile water they would represent a stock of 10,375 

 B. typhosus only, so that a large margin is here offered for 

 discharge of B. typhosus by the oysters into the sea water. 

 The presence of the 500,000 B. typhosus in this sea water 

 (2000 c.c.) as above found at that stage would, therefore, be 

 readily explained, although it must be evident that the 

 difference between 4,374,000 and 10,375 is too large to 

 permit of ascribing to the discharge of the half-million in the 

 2000 c.c. of the sea water, the entire cause of this great 

 reduction of the B. typhosus in the oysters, and we are 

 justified in concluding that besides a comparatively small 

 discharge of living B. typhosus from the infected oysters into 

 the surrounding sea water even accepting the destruction of 

 B. typhosus going on in the water the chief cause of the 

 great reduction in the number of B. typhosus within the 

 oysters is due to inimical action by the oysters themselves. 

 This would be in harmony with what we found in the " dry " 

 oysters of Experiment II. 



Sea water after second change was analysed, -^ c.c. direct 



D 2 



