EFFECTS OF PULP MILL POLLUTION ON OYSTERS 165 
Table 6. — Effect of neutral red liquor ( specific gravity 1.046) on the rate of feeding of Ostrea lurida 
(size: 4.2Y.3.2 centimeters). Salinity of water, 88.64 parts per thousand 
[October 18, 1929, Pacific Grove, Calif.] 
Figure 40. — Effect of neutral sulphite liquor on the rate of feeding of Ostrea lurida. 
Temperature, 16.0-17.8° C.; pH, 7.9-8.0 
The rate of feeding of the Japanese oyster (Table 7, fig. 41) is also affected by 
the addition of red liquor, the decrease being noticeable at the concentration of 
two parts per thousand. The rate of flow continues to fall with the increase in amount 
of red liquor added. There is, however, a distinct difference between the two species 
of oysters: The Japanese oyster can sustain higher concentrations much better than 
can the small Olympia oyster. At the concentration of 15 parts per thousand, the 
rate of feeding of the Japanese oyster is still about 25 per cent of its normal rate. 
