REACTIONS OF FISHES TO ATMOSPHERIC GASES 



211 



TABLE 2 



Showing the effect of bubbling gas through a square vessel 30 cm. in depth, holding 

 four and one-half liters of water, and with 150 sq. cm. exposed to the air. The 

 gas was introduced at the bottom. Where not given, average flow was about 50 cc. 

 per min. 



shown in table 2. The flows of gas as given are averages as the 

 tanks were not suppHed with valves giving constant flows and 

 it was necessary to adjust the flows every few hours. 



The second test given in the table shows that exposure to the 

 atmosphere, necessitated by filling the boiler with sufficient water 

 to allow it to run through only once, made accurate determi- 

 nation impracticable, with the apparatus at hand. We note that 

 when oxygen is bubbled through water, the oxygen supply is 

 not only increased but carbon dioxide and nitrogen are decreased. 

 When distilled water is used the carbon dioxide is lowered, but 

 when tap water is used, if the tap water contains bicarbonates, 

 the bicarbonates are largely changed to carbonates (McCoy and 

 Smith '11, McCoy and Test '11), the water becomes alkahne 

 and a slight cloud sometimes appears. This indicates that some 

 carbonates are precipitated and free and half-bound carbon 

 dioxide are both removed just as in boiling. This changes the 

 number of alkaline metal ions in solution. The general results 

 of bubbling nitrogen through tap and distilled water are respec- 

 tively similar except that nitrogen is increased instead of oxygen. 

 When carbon dioxide is bubbled through, it may reach 662 cc. 

 or more if the flow is rapid. All carbonates are kept in solution; 

 oxygen is greatly reduced. Loeb ('04, p. 7), Mast ('11, p. 179) 

 and Wodsedalek ('11, p. 270) bubbled carbon dioxide through 



