146 
BULLETIN OF THE BUREAU OF FISHERIES 
Figure 29.— Records of the control specimens in experiments Nos. 24 
and 25. Compare with the experimental oysters (figs. 28 and 30) 
was started on April 18, at 2.20 p. m., and thereafter both specimens showed marked 
reactions. 
Specimen No. 1, from April 19 to 22, after which it began to gape wide and move- 
ments became less frequent, was open an average of only 5.55 hours per day. The 
last movement occurred on the 24th, after 6 days of treatment. From the 19th until 
specimen No. 2 began to gape at 
the end of the 21st, this oyster was 
open an average of 13.57 hours per 
day. 
During the same period of 
time both controls were open and 
normally active about 23 hours per 
day. (Fig. 29.) 
Experiment No. 24 ( 5 parts 
per thousand ). — The rate of flow 
of water was 111 cubic centimeters 
per minute and that of liquor so- 
lution (1:4) was 2.8 cubic centi- 
meters per minute. Both specimens tended to remain closed after the liquor was 
started. During the time of treatment, from April 19 until it started gaping after 
May 7, specimen No. 5 (fig. 30) averaged only 4.41 hours per day open. Similarly, 
specimen No. 6 remained open an average of 5.86 hours per day up until gaping 
started on May 6. Specimen No. 5 was considered dead after 20 days of treatment 
and specimen No. 6 after 18 
days. Compare these re- 
sults with the records of the 
controls. (Fig. 29.) 
From these results, ob- 
tained with neutralized 
liquor, it is clear that it is 
not the acid content of the 
liquor which exerts the 
major unfavorable influence 
upon oysters. The time re- 
quired for the specimens to 
die is easily within that 
which would be expected 
from a comparison of the 
death periods of specimens treated with acid liquor. In Figure 33 and Table 3 it is 
shown that when the length of time that specimens remain open is taken into con- 
sideration the results of these specimens agree substantially with those of other 
experimental oysters. 
In the tests with unneutralized liquor it was noted that the pH of the solutions 
in the experimental chambers was not highly acid, as compared to the freshly mixed 
solutions used in the sensory stimulation experiments. This is due partially to the 
fact that stock liquor was mixed with sea water and during the few days that a bottle 
of this lasted was slowly partially neutralized. But it is chiefly duetto Jthe*exposure 
of the liquor to air in the dripping apparatus. This allowed mostjof the sulphur 
dioxide gas to escape, so that the relatively slight acidity of the final solution could 
hardly be expected to produce any unfavorable results. 
Figure 30. — Records of specimens in experiment No. 24 (5 parts per 1 
tralized sulphite liquor). Compare with the controls (fig. 29) 
