IOO 



F. G. HALL. 



dissolved gases were detected in the water during the experiments 

 A second gas sample was taken from the swimbladder after a 

 varying interval of time. A comparative record of the results 

 are shown in Table VII. 



The large black bass and the carp were also used and the 

 results are summarized in Table VII. 



TABLE VII. 



RESULTS OF EXPERIMENTS WITH THE SECOND REMOVAL OF GASES FROM THE 

 SWIMBLADDER; THE DISSOLVED GASES IN THE SURROUNDING MEDIUM 



WERE KEPT CONSTANT. 



The results show that the percentage of oxygen increases in 

 the bass and the perch when second sample is taken after an 

 interval of time. In the carp, however, only slight changes could 

 be observed. The carp has an open duct leading from the 

 swimbladder while the bass amd the perch have closed swim- 

 bladders. This is believed to be the explanation for the differ- 

 ence in the response of the two types to withdrawal of air from 

 the swimbladder. 



It is apparent that the question of whether oxygen is trans- 

 ferred to the swimbladder by physical diffusion or secretion rests 

 on a knowledge of the partial pressures of the gases in the blood 

 and in the swimbladder. If one can know the partial pressures 



