OXYGEN REQUIREMENTS OE SHELEFISH. 2ig 
Table: IV. — Oxyge'n Absorbed by Empty Oyster Shells. 
47.8 
47-8 
73-4 
73-4 
73*4 
153 
153 
161 
161 
Temperature of experiment in degrees centigrade. . 
22. 4 
1.9 
25. 8 
2.4 
21. 7 
3-6 
22.3 
4. 1 
26. I 
6-3 
22. 0 
6. 1 
25.8 
8.3 
21. 5 
II -5 
26. 5 
14.4 
Table V. — Oxygen Absorbed by Closed Oysters. 
Weight of 
oyster. 
Temp>era- 
ture of 
experi- 
ment. 
Oxygen 
used per 
hour. 
Description of control experiment. 
45 grams. . . 
“C. 
22. 0 
Mgrlio. 
1. 70 
Control .... 
22. 0 
I. 70 
Empty shells of same oyster with artery clamp. 
50 grams . . . 
22* 0 
1.83 
Control 
22. 0 
1.&3 
Do. 
66. s grams.. 
23. 2 
2.04 
Control 
21. 0 
1. 92 
Do. 
Control 
23. 2 
2 .s8 
Empty shells of oyster weighing 45 grams with clamp. 
66.S grams. . 
20. S 
1.41 
Control 
20. 5 
1.48 
Empty shells of oyster weighing 51 grams with clamp. 
128 grams . . 
20. 5 
1.79 
Control 
20. 5 
I. 92 
Empty shells of same oyster with artery clamp. 
147 grams. . 
20. 5 
1.74 
Control 
20. 5 
I. 62 
Do. 
244 grams. . 
20. 5 
I. 70 
Control 
21. 0 
2*34 
Do. 
262 grams. . 
20. 5 
3-39 
Control 
21. 0 
4-68 
Do. 
244 grams. . 
37-5 
3-47 
1 
128 grams. . 
27. 5 
2.36 
^ontrol experiments not made. 
66.5 grams. . 
27-5 
2.49 
76 grams . . . 
27 * 5 
2. 80 
J 
resistance of oysters to lack op oxygen. 
A series of experiments was undertaken to find out the minimum oxygen supply 
that would maintain an oyster alive. The sea water surrounding an oyster in a vacuum 
desiccator was as far as possible rendered oxygen free by boiling at room temperature 
under diminished pressure for half an hour. It was found in two trials that sea water 
alone when so treated and kept twelve hours in the closed desiccator still had an oxygen 
content less than 0.5 of a part per million. An oyster kept under these circumstances 
four days showed no ill effects. Another was kept thus three days, transferred to a 
second desiccator of exhausted sea water, which was quickly again pumped out, and 
was then kept four days further in the oxygen poor medium. The shells then had some 
black deposits on them indicative of incipient anaerobic putrefaction. The sea water 
on opening the desiccator was found absolutely oxygen free. The oyster, however, 
seemed unimpaired, and after remaining in the aquarium some time was opened and 
found apparently entirely normal. As each desiccator held about 1,200 c. c. and the 
oxygen content of the water in each case was at the most 0.5 of a part per million, the 
oxygen available to the oyster might be estimated as 1.2 milligrams plus the small 
amount obtained during the transfer from one desiccator to the other. If we disregard 
the latter source because the oyster was tight closed at the time, only 1.2 milligrams of 
oxygen were used during seven days. 
