40 



cleaned; and the same applies also to the sea water two 

 days after change (10,580 B. typhosus per 1 c.c.), i.e., the 

 second lot of originally sterile sea water. It will presently 

 appear that the oysters of this lot still contained at this 

 period an enormous number of B. typhosus in the interior, 

 and therefore the conclusion is obvious, viz., that the above 

 B. typhosus in the sea water after change had been passed 

 out by the infected oysters. This is confirmed by the further 

 fact that as soon as the number of B. typhosus in the oysters 

 markedly decreased (see below), no B. typhosus could be 

 discovered in -^ c.c. of the surrounding sea water. 

 The analysis of the wet oysters showed : 



Oyster 1 (very small) after 1 day in infected water contained 



95,800 B. typhosus per oyster ; 900 B. coli com. 

 3 (small) after 2 days in clean water, 752,800 B. typhosus 



per oyster ; no B. coli com. 

 5 (very small) after 4 days in clean water, 1200 B. 



typhosus per oyster ; no B. coli com. 

 ,, 7 (very small) after 6 days in clean water, 200 B. typhosus 



per oyster ; no B. coli com. 

 9 (medium sized) after 7 days in clean water, 378 B. 



typhosus per oyster ; no B. coli com. 

 11 (full sized) after 8 days in clean water, 56 B. typhosus 



per oyster ; no B. coli com. 

 13 (small size) after 9 days in clean water, 390 B. typhosus 



per oyster ; no B. coli com. 

 15 (full sized) after 11 days in clean water, B. typhosus 



per part of oyster. 



It appears, therefore, from these analyses that the oysters 

 cleared themselves of the B. typhosus decidedly less rapidly 

 than previously clean oysters (Experiments I, II, and III), 

 which under similar conditions in the course of four to six 

 days had practically cleaned themselves of this microbe. 

 It will be, however, noticed that the polluted oysters cleaned 

 themselves very rapidly of the B. coli communis, for thus 

 must be interpreted the fact that the very small oysters, con- 

 taining originally at least 900 B. coli communis, were free of 



