500 
BULLETIN OF THE BUREAU OF FISHERIES 
Table 10. — Correlation table showing relation between oxygen consumed and oxygen tension 
The above expresses in mathematical terms what can roughly be seen from the 
correlation table; namely, that the oxygen consumption is independent of oxygen 
tension when the latter is above 2.5 cubic centimeters per liter, and that below that 
point the rate of oxygen consumption diminishes as the 0 2 tension decreases. 
It must be borne in mind that the statistical treatment of a series of observations 
permits the measurement of the relationship between the two variables but can not 
reveal the cause or causes of the phenomena observed. For the latter purpose 
further experimentation is necessary. It was thought that the dependence of oxygen 
consumption on oxygen tension may be due to the inhibition of the ciliary activity of 
the gill epithelium and to the consequent decrease in the rate of flow of water through 
the gills. Using the method developed by the senior author and described in previ- 
ous publication (Galtsoff, 1928), the rate of flow of water through the gills was meas- 
ured at various oxygen tensions. The results of two experiments are presented in 
Table 11. An oyster was first placed in the sea water which for three days was kept 
under vacuo at 37° C. Oxygen determinations and pH readings were made simultane- 
ously with the measurements of the rate of flow. Then the water was aerated for 1 
hour and readings were repeated. The results of the experiments show no significant 
differences in the rate of flow of water at the oxygen tensions of 0.69 and 5.45 cubic 
centimeters per liter. 
Table 11. — Rate of flow of water through the gills at normal and low oxygen tensions 1 
Experiment and date 
Time 
Tempera- 
ture ° C. 
Oj, c. c. 
per liter 
pH 
Rate of flow, 
c. c. per hour 
Average 
Maximum 
Minimum 
Number of 
readings 
A, Sept. 1 
! 11. 20 
20.0 
0.69 
7.9 
972 
1,030 
946 
20 
1. 27 
19.3 
5. 45 
7.8 
900 
1,011 
810 
20 
B, Sept. 4 
! 11. 22 
22.2 
0. 975 
7.9 
2, 657 
2,702 
2,430 
20 
12.55 
22.2 
4. 52 
7.7 
2,683 
2,702 
2,430 
29 
i Size of the oysters: Experiment A, 8.4 by 7.6 cm., wet weight of meat 14.5 g.; experiment B, 9.7 by 7.8 cm., wet weight of meat 
32.7 g. 
a After these readings, air bubbled in. 
