136 
BULLETIN OF THE BUREAU OF FISHERIES 
day open. At the end of the experiment the control specimens were as normally 
active as at the beginning. They both showed a delicate new shell growth at the 
edge of the valves, which was not the case of the treated oysters. Further, the con- 
trols showed that they were feeding for they threw out large quantities of fecal 
matter, rejected silt, etc., while the experimental oysters did not. 
Experiment No. 16 (5 parts per 
thousand). — Water flowed into the 
mixing chamber at the rate of 124 
cubic centimeters per minute, and 
liquor (1 : 4) at the rate of 3 cubic 
centimeters per minute. The con- 
centration of pure liquor to water 
was 4.84 parts per thousand, which 
is stated roughly as 5 parts per 
thousand. The pH of the solution 
in the experimental chamber varied 
from 6 . 1 to 6 . 5 . Liquor was started 
February 3, at 2.30 p. m. and con- 
tinued until the end of the experi- 
mental series. Specimens 5 and 6 
(fig. 10) showed a difference in behavior similar to that of the specimens in ex- 
periment No. 17. From February 4 until just before death on the 18th, specimen 
No. 5 was open an average of 10.4 hours per day. On the 19th this oyster was 
gaping wide and motionless, having died after 15 days in the solution. Specimen 
No. 6, from the 4th until the 16th, averaged 22.54 hours per day open, and was 
dead on the 17th, 13 days after 
the liquor was introduced. These 
specimens showed no indication of 
shell growth and threw out no waste 
matter to indicate that feeding was 
going on. 
Experiments Nos. 18 and 19 
( February 1 to March 3, 1930).— 
Records were started on February 
1 at 1.45 p. m., the specimens in 
sea water alone. The pH of the 
sea water was always about 7.8. 
The temperature of the water 
from the 1st to the 3d, inclusive, 
varied from 4° to 8° C., after which 
the water was heated and fluctuated from 12° to 18° C., being usually from 14° 
to 17° C. The stock liquor consisted of 1 part pure liquor to 4 parts sea water. 
Experiment No. 19 (3.4 parts per thousand). — Water entered the mixing chamber 
at the rate of 139 cubic centimeters per minute and liquor (1 : 4) at the rate of 1.67 
cubic centimeters per minute. The pH of the solution in the experimental chamber 
varied from 6.6 to 7.1. 
The results with specimens Nos. 1 and 2 (fig. 11) are closely parallel. Specimen 
No. 1 was open, from February 4 to 27, when it started gaping wide and making a 
Figure 10.— Graph showing the records of two specimens in experiment 
No. 16 (5 parts per 1,000). The oyster which remained closed most 
lived longer than the other specimen. Compare with Figure 9 showing 
the record of controls 
Figure 9.— Graph of the daily number of hours open of the control 
specimens for experiments Nos. 16 and 17. These oysters remained 
open and active a very high proportion of the time. Compare with 
Figures 8 and 10 
