382 
Tas_e I 
Showing the effect of hydrogen ion concentration on the survival of rock 
bass in low-oxygen water, August, 1918. 
Number of Weight Survival O. in ¢. ¢. Temp., deg. 
fish gm. | in min. she | per liter (ok 
a 10 43 6.0 42 16 
b 10 55 6 25 16 
c ish 50 6.2 &8 16 
d 14.5 1500+ 6.5 79 16 
e 16 71 | 6.1 70 16 
f 18 350 6.5 Su) 16 
g 18 60 6.2 68 16 
h 21 55 6.5 -42 16 
i 28 45 6.3 APES 16 
j 138 124 6.0 72 16 
Taste II : 
Showing the effect of hydrogen ion concentration on the survival of large- 
mouthed black bass in low-oxygen water, January, 1921. 
Number of | Av. weight Survival Temp., deg. 
fish em. in min. oe IEG. C. 
6 346 84 8.6 .18 13.5 
a 
6 287 62 Smo .18 135 
7 215 64 8.5 -055 BIB) 
b ‘ 
6 285 47 6.2 06 Bhs) 
2 255 70 825 .06 13.5 
12 328 63 Te .06 13.5 
10 320 50 6.2 .06 U5 
Comparing individuals a, b, and c (Table I) it is evident that a de- 
crease of .5 on the pH scale is more important than one of .20 c.c. in O, 
and that a decrease of .3 on the pH scale equals in effect a difference 
of .46 c.c. in oxygen. Furthermore, fish c was heavier than a or 0, and 
the larger fish usually live longest. Fishes f and g show a striking differ- 
