79 



was used for the plate; this yielded 587 (blue) colonies of B. 

 typhosus. This amounts to 58,700 B. typhosus per oyster. 



Fig. 2. Oyster 4, 24 hours in typhoid-infected water, 

 four days afterwards kept dry ; T J ff part of the oyster was 

 used for the plate; this yielded 174 (blue) colonies of B. 

 typhosus. This amounts to 17,400 B. typhosus per oyster. 



Fig. 3. Oyster 8, 24 hours in typhoid-infected water, 

 seven days afterwards kept dry ; T J D part of the oyster was 

 used for the plate ; this yielded 13 (blue) colonies of B. 

 typhosus. This amounts to 1300 B. typhosus per oyster. 



LONDON : PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, 

 DUKE STREET, STAMFORD STREET, S.E., AND GREAT WINDMILL STREET, W. 



