Ee a ee i 
383 
ence in survival when both pH and O, are moved in the unfavorable direc- 
tion. Fishes ) andi are similar to f and g, but the 28-gram fish (7) should 
have lived longer considering its larger size. 
Turning to Table II, group a shows that the average time-survival 
is greater at pH 8.6 than at 6.5, but the difference in weight would oper- 
ate to exaggerate this. However, the same result is shown in group b, 
where both oxygen and size of fish would operate to reverse the result. 
Furthermore, group c, with fish-weight standing on the whole so as to 
reverse the result, shows a progressive decrease in survival-time with 
increase of hydrogen ion concentration. 
Taste III 
Showing the effect of hydrogen ion concentration on the survival of bluegills 
in low-oxygen water. December, 1920, and January, 1921. 
Number of | Av. weight | Av. survival H ORCic: Temp., deg. 
fish gm. in min. p per 1 C: 
4 A= *21+ 7.25 12 13 
a 
4 1i+ 721+ 8.85 12 13 
4 =e +60 8.9 12 13 
b 
4 tise §47 8.8 12 13 
5 14.5 Sy ee 6.4 12 13 
c 
6 16 30 8.8 12 13 
6 11 31 8.8 .12 13 
di4 11 23 6.5 12 13 
4 11.5 18 6.2 -12 13 
13 12.3 8 8.5 .06 13.5 
e 
15 11.8 27 6.5 .06 13.5 
*O. K. at 21 minutes. + Anaesthetized at 21 minutes. 
t All anaesthetized at 21 minutes. § Two anaesthetized at 21 minutes. 
Table III shows results with bluegills. Groups a and 6 are self- 
explanatory. Group c shows survival one-half as long at the low pH 
as at the high. Group d shows a progressive shortening of life as pH 
is lowered. Group e suggests that with very low oxygen, pH 6.5 is more 
favorable than 8.5. The work of Wells and Hall (Table IV) shows 
similar results with different species. 
