F. G. HALL. 



TABLE V. 



ANALYSES OF THE GASES FROM THE SWIMBLADDERS OF PERCH SUBJECTED TO 

 WATER OF Low OXGYEN CONTENT. 



Experiments were performed in a laboratory aquarium. Water made oxygen- 

 free by boiling and fishes were left in it for varying periods of time. N indicates 

 normality, i.e., no free carbon dioxide. 



approximately ten cubic centimeters. The average percentage 

 of oxygen was found to be 19.9 per cent. In other words the 

 actual amount of oxygen would be about two cubic centimeters. 

 From work on the rate of respiratory exchange in perch (to be 

 reported in a later paper) the oxygen consumption was found to 

 be 61.8 cubic centimeters per kilogram of weight per hour at 

 3 C. The average perch weighs somewhat less than 100 grams. 

 Thus the amount of oxygen required would be about six cubic 

 centimeters of oxygen per hour. The amount that the swimblad- 

 der could furnish is only a fraction of that amount. We must 

 conclude, therefore, that although the perch may draw on the 

 swimbladder for oxygen when in regions of low oxygen, the 

 amount that can be furnished to the blood by re-absorption is 



