26 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS. 
TaBLE 8.—Bacteriological results on unfloated and floated oysters and on water over 
jloats—Continued. 
WATER. 
~ ~ | | { 
Bacteria per cubic | 
centimeter ‘plain! B eoli ! 
agar, three days). | “ubi 3 : 
s : east Salt. Remarks. 
i = ter 
ETE On 37° C | 
| Per cent. 
29.000 400 1 0.59 | Lower float, low tide. 
2.100 600. | 1 .24 | Middle fioat, low tide. 
13.000 2.000 0 -14 Do. 
2.000 600 10 -10 | Upper float, beginning flood. 
9,000 1,200 | 1 .10 | Upper float. 
i 420 110 | 0 .84 | Mouth of river near oyster beds. 
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 fioats 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 “‘cleansing” and shipped in the shell, 
presumably to be consumed raw. 
