THE BACTERIOLOGY OF THE CLOACAL AND GILLS 

 CHAMBERS OF THE OYSTER. 



In describing the anatomy of the gills of the oyster, Kellogg in his 

 book on "Shellfish Industries" makes the following statement: 

 "Behind the body the four gills unite so as to separate a space above 

 the cloacal chamber, from the large mantle chamber below." From 

 this statement it has been assumed at times that the two chambers 

 were entirely distinct and so constructed that bacteria could not pass 

 from one chamber to the other, and that for this reason the bacterial 

 content of the two chambers would differ. Anyone familar with the 

 anatomy of the oyster knows that every day several gallons of water 

 are filtered through the gills into the cloacal chamber. While it is 

 probable that most of the protozoa and algae are caught in the mucus 

 which the gills secrete, it is also probable that a great many of the 

 l^acteria escape, being entrapped by the mucus and pass on into the 

 cloacal chamber. But even though the gill-filter were proven to be 

 bacteria-proof no one has demonstrated that bacteria cannot pass along 

 the space between the mantle and the shell, or around the edge of the 

 shell, between the flaps of the mantle and so pass from one chamber 

 to the other. While it seems very probable from the structure of the 

 oyster that bacteria can pass fron one chamber to the other without 

 difficulty, properly conducted experiments are necessary to prove it. 

 In order thus to prove that bacteria can and do pass, from one 

 chamber to. ^the* other, the following experiments were tried. 



Sepibs'J. ; c'.^ ' '; 



Exp. 1. A well shaped mature oyster about four inches long and 

 two broad was selected. Care was taken to obtain an oyster with a 

 flat right valve. The oyster was placed in a frame with the left 

 valve down so that the right valve was level and was then clamped 

 firmly to the table. A hole was bored through the right valve into 

 the gill chamber quite close to the edge and another into the cloacal 



