CHEMICAL CONDITIONS 50 
TABLE II 
SHOWING THE DISTRIBUTION AND SOLUBILITY OF ATMOSPHERIC GASES 
Gas VALUES IN CuBIC CENTIMETERS PER LITER 
AT 0° C AND 760 MM. MERCURY 
KIND OF WATER 
Composition HAvinG Gas 
Gas OF AIR IN At Temperature 20° C. 760 mm. Maximum ConTENT GIVEN 
PERCENTAGES Amounts Found| In PRECEDING 
in Natural Fish CoLUMN 
Water Absorbs | Water Absorbs |Waters, Springs 
from Air Pure Gas Excepted 
Nitrogen, 
argon, etc.. 79.02 D203 21C.Cs 15.00 C.C. 19.00 c.c. | Lakes (74, 
p. 152) 
Oxygen... 20.95 6.28 c.c. 28.38 C.c. 24.00 C.c. | Streams, 
lakes, win- 
ter, with 
green 
algae 
Carbon 
dioxide. ... 0.03 0.27 €.c. | 901.00 C.C. 30.00 ¢c.c. | Ponds 
Ammonia....| Small traces) .....:.. Very large 14.00 ¢.c. | Sewage con- 
locally quantities taminated 
Methane.....| Small traces) ........ 34.00 C.C. 10.00 ¢.c. | Bottom of 
locally lake in 
September 
(74,P. 101) 
Nitrogen has little effect upon animals except when present in excess. 
Under these conditions in the laboratory, bubbles of the gas accumulate 
in the tissues and blood-vessels of fishes and cause death. It is not 
certain that such conditions exist in nature (Fig. 9). 
Oxygen is usually necessary to the life of animals. Most animals 
that have been studied select water with a rather high oxygen content 
instead of water with little or no oxygen. The resistance of animals to 
lack of oxygen varies in different groups. It has been found that water 
with about 6 c.c. of oxygen and 14 c.c. of nitrogen per liter is suitable 
for brook trout. Mackinaw trout have been taken in water containing 
but 1 c.c. of oxygen per liter (6). 
In general, carbon dioxide is a narcotic in its action upon animals. 
In small quantities it is a stimulant, especially to respiratory action. 
In large quantities it produces anesthesia and death. Several workers 
have shown that carbon dioxide is very toxic to fishes. Most aquatic 
animals that have been studied turn back when they encounter water 
containing large amounts of the gas. This turning away from carbon 
dioxide is-much more decided than it is in the case of corresponding 
differences (24 c.c. per liter) in oxygen content. Fishes, for example, 
