REACTIONS OF FISHES TO ATMOSPHERIC GASES 



237 



Exoeriment 72X 



Control 72 

 3 Notropis 



3 Nolropis 

 ^ Q Boi!ed Tap Tap 



Experiment 75 



3 Lepomis 



Boiled „ , ^ 

 ^ Qj Boiled 



Control 75 



3 Lepomis 



Tap Tap 



h-^ L J '*-^ ' * '_Jr-^. 



Experiment 80 



3 Lepomis 

 B6iied -r 



3 Lepomis 



Boned Tap 



Chart 2 Showing the reactions of fishes to an oxygen gradient in boiled water 

 and to the effect of boiling. For oxygen concentration, see table 9; for experiment 

 80, table 15. For a description of the method of charting, et cetera, see chart 1, 

 p. 233. 



(table 9) were in general very indefinite, but the activity was 

 greater in the experiment, due to the stimulating effect of the 

 change in character of the water in passing from one end of the 

 tank to the other. Time preference was not strongly in favor 

 of the high oxygen end except in experiment 72x (chart 2). In 

 72 fright appeared to enter into the behavior and there 

 was a time preference for the low oxygen end. In all cases, 

 turnings in the gradient were more numerous from the low than 

 the high, though the differences from the control were not so 

 great as in the case of carbon dioxide. Chart 2, experiment 72x, 



