EFFECTS OF PULP MILL POLLUTION ON OYSTERS 
141 
open an average of 22.9 hours per day and specimen No. 4 remained open 21.78 hours 
per day on the average. At the end of the experiment these oysters showed new 
shell growth and had thrown out considerable quantities of debris, neither of which 
was true of the experimental specimens save that they left very small amounts of 
debris. 
Experiments No. 22 ( 1.0 part per thousand ). — The rate of water flow was 120 
cubic centimeters per minute and that of liquor solution (1 : 9) was 1.2 cubic centi- 
meters per minute 
The pH of the solution 
in the experiment 
chamber was 6.8 to 7.3. 
The results ob- 
tained from these two 
specimens (fig. 20) are 
very different from one 
another. Specimen 
No. 5 remained open 
an average of 23.66 
hours per day from 
and 23. Compare with Figures 18 and 20 
March 14 until the 24th, when it showed marked signs of gaping and cessation 
of activity. The last movement occurred on the 28th, 15 days after treatment had 
started. Specimen No. 6, however, remained closed most of the time, averaging 
only 6.74 hours per day open from March 14 to April 11, when the series ended. This 
behavior is definitely abnormal, as will be seen by comparing this record with those 
of the controls. (Fig. 19.) 
Experiments Nos. 8 and 9 ( December 13, 1929 to January 1, 1930 ). — Stock liquor 
for this series consisted 
of 1 part pure liquor to 
9 parts sea water. 
During only part of 
the time was the water 
heated. Because of 
an apparent change of 
behavior due to tem- 
perature variation a 
graph (fig. 24) is pre- 
sented giving average 
daily temperatures of 
the water, calculated 
from hourly thermo- 
graph readings. This will be referred to below. The pH of the water was 7.8. 
One kymograph sheet of the series was unfortunately destroyed. 
Experiment No. 9 ( 0.7 part per thousand ). — This solution was made by water 
flowing into the mixing chamber at the rate of 3.48 cubic centimeters per minute, and 
liquor solution (1 : 9) at 2.5 cubic centimeters per minute. Both specimens reacted 
normally in pure water before liquor was started on December 14 at 9 p. m. Soon 
thereafter both began to stay open less hours per day. The graph (fig. 21) shows the 
behavior up until the experiment was ended. Specimen No. 1 averaged during the 
APRIL 
Figure 20.— Showing a graph of the records of the two specimens in experiment No. 22 
(1 part per 1,000). One specimen remained open most of the time and died, while the 
other one was still living when the experiment was discontinued. Compare with the 
controls (fig. 19) 
