26 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS. 



TABLE 8. Bacteriological results on unfloated and floated oysters and on water over 



floats Continued . 



WATER. 



DISCUSSION. 



The experiments were conducted on the lower float. The results 

 of these analyses show the unfloated oysters to be moderately free 

 from pollution, but when oysters from this same lot were floated over- 

 night in water proved to be polluted they became dangerously 



FIG. 7. Dumping city refuse to fill a depression within 50 yards of oyster floats. Washings from this 

 material as well as drainage from piles of manure on fertilized land drain directly into the cove where 

 oysters are floated. 



contaminated. The water taken from the mouth of the river con- 

 tains less salt than the water over the oyster beds farther out in the 

 channel, where they grow to maturity. The experiments were made 

 in a locality where about 500 oyster boats and floats operate at a 

 distance of one-half to 1 mile above the mouth of the river (figs. 9 

 and 10). About 60 carloads of shell oysters are shipped daily from 

 this point during active season. They are all passed through water 

 of the above character for ll cleansing" and shipped in the shell, 

 presumably to be consumed raw. 



