320 VICTOR E. SHELFORD AND EDWIN B. POWERS. 



The absorption of oxygen in connection with the development 

 of the hydrogen sulfide probably prevents any very great excess 

 of CO2 from accumulating (Lederer '12). 



III. The Resistance of Fishes to Contamination and 

 Decomposition Products. 



It was not possible to try the resistance of the fishes (Wells, 

 '13) to the effect of the lack of oxygen either separately or in 

 combination because no means of removing it was at hand. It 

 was possible only to add gases to the water. Hydrogen sulfide 

 and carbon dioxide were used. 



I. Herring {Clupea pallasii Cuvier). 



Hydrogen sulfide is extremely poisonous to the fishes (Weigelt, 

 '03). In the first attempted gradient experiments where the 

 water at one end contained only a little of the gas the fishes 

 turned on their backs in two or three minutes when the one 

 inflow was showing 8.3 c.c. per liter and the other was pure sea 

 water. This happened in spite of the fact that more than half 

 of the time was spent in the end with least H2S. The experiments 

 were performed in the manner described by Wells. When placed 

 in a solution of 7.6 c.c. per 1. the herring gasped after i minute 

 and 45 seconds, turned over after 5 minutes, and were apparently 

 all dead in 6 minutes. In carbon dioxide of about 20 c.c. per 1. 

 the herring showed evidence of loss of equilibrium after three 

 minutes. Some of them sank to the bottom after 12 minutes. 

 After 39 minutes to 62 minutes herrings turned on their sides 

 on the bottom, resting in this position for a time and then 

 swimming more nearly normal for a time again. One died after 

 102 minutes, the others after 159 minutes' exposure. The 

 oxygen was about 5.5 c.c. per 1. and varied directly with the 

 amount of tank CO2 used, indicating that the carbon dioxide 

 contained much oxygen. 



When carbon dioxide and hydrogen sulfide were used together 

 the carbon dioxide was about 30 c.c. per 1. and the hydrogen 

 sulfide 2.9 c.c. per 1. The amounts were controlled with some 

 difficulty and thus the experiments are not alike in the matter of 

 concentration. Herring were much stimulated at the beginning. 



