Section IV., 1915 [5i] Trans. R.S.C. 



On an Accumulation of Gas in the Tissues of the Frog as a result of 

 Prolonged Submersion in Water. 



By A. T. Cameron and T. I. Brownlee. 



(From the Department of Physiology and Physiological Chemistry, 

 University of Manitoba, Winnipeg.) 



Presented by Professor Swale Vincent, F.R.S.C. 



(Read May Meeting, 1915). 



In some previous work directed in part to ascertain how frogs 

 survive the winter in such climates as those of Manitoba, we were led 

 to the conclusion.'^ "Frogs surviving degrees of cold such as those 

 occurring during a Manitoban winter do so below the surface, near 

 the margin of springs, and are themselves not subjected to temper- 

 atures below the freezing-point of water." 



Since this conclusion indicated a possible prolonged submersion 

 in water, and since we have been unable to find any definite state- 

 ment as to whether frogs can survive such prolonged immersion, we 

 have carried out a series of experiments to test this specifically. 



Observations on such a point as this, if they have been made, 

 are not improbably hidden amidst other data. Our library facilities 

 have not permitted an exhaustive search, and the general textbooks 

 have afforded us no assistance. Gadow^ makes no statement on the 

 matter, and Miss Dickerson^ makes only the general statement "the 

 frog can live under water for months at a time " 



Our earlier experiments showed us that frogs survive immersion 

 in water for very varying periods, and that, under the particular 

 conditions, in most cases, previous to death, they became distinctly 

 swollen and buoyant, being no longer able to dive below the surface. 

 This buoyancy was due to the presence beneath the skin, and through- 

 out the tissues, of a gas which analysis showed to be almost pure 

 nitrogen. There also occurred varying absorption of water, up to 

 about 30 or 40 per cent, of the original weight of the animal. Since 



^ A. T. Cameron, "Further experiments on the effect of low temperatures on the 

 frog," Trans., 1914, vol. viii, Sect. IV, p. 265 (p. 266, line 1, should read as in the text 

 above) . 



2 Gadow, "Amphibia and Reptiles" (Cambridge Natural History), 1901. 



3 Miss M. C. Dickerson, "The Frog Book," (New York, Doubleday, Page & Co., 

 1908), p. 231. 



