Providence, Rhotle Island
SEVEN FIGURES
INTRODUCTIOK
The literature on the functioning of the teleostean physoclistous swimbladder reveals a controversy as to whether or not one or more gases are secreted into the bladder cavity against diffusion gradients by means of a physiological energy mechanism. Of the comparatively recent workers, Ledebur ( '28, '29, '36, and '37) is inclined to believe that active secretion does occur. Jacobs ( '30, '32, '34, and '35)' on the contrary, believes that the "secretion" of the gases can be accounted f o r on the basis of ordinary laws of gas dissociation and diffusion from the blood. Both agree in their concluding review articles that the exact method of gas release is undetermined. Since their time, contributions have been made by Saupc ( '40), Black ( '40, '42, and '48) and Fange ( 'ZO), again without a definitive theory of gas release being developed.
By intensive study of one form of fish with a variety of techniques, it was hoped that a more conclusive theory could be developed. Fundulus heterockitus was chosen because previous work (Copeland, '48 and '50) proves it to be a hardy fish easily studied under laboratory conditions. It has a physoclistous bladder that is quite active physiologically, ' Preliminary report submitted at the Cleveland Federation Meetings (Copeland, *NOW 011 leave of absence to the Surgeon General's Ofiiee, Air Force Head-'51).
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