[cameron-brownlee] gas in TISSUES OF THE FROG 53 



before death. The last three males were utilized in determining 

 some of the figures shown in table I below. 



Experiment 3. Commenced on March 10th, 1915. Ten frogs 

 were confined under the same conditions. As noted above, a number 

 of the frogs were removed before death had occurred, and the results 

 cannot be used in determining the average period of survival. The 

 data obtained in this experiment are shown in part in the tables 

 below. 



Experiment 4. Commenced on March 29th, 1915. Ten frogs 

 were confined in a larger apparatus containing over ten litres of water. 

 The other conditions were unaltered. In this experiment several 

 frogs died in a swollen but non-buoyant condition. The five female 

 frogs died, one on the third day, one on the seventh, one on the nine- 

 teenth, one on the twenty-fourth, and one on the thirty-sixth day. 

 The first two and the fourth were swollen, but not buoyant. The 

 others were swollen and buoyant. Three male frogs died, one on 

 the thirteenth day, one on the sixteenth, and one on the fifty-second 

 day. AH were swollen and buoyant. The other two, both swollen and 

 buoyant, were removed from water while still living, on the thirteenth 

 day, and it is estimated for reasons given below that they would 

 have died on the fifteenth day. 



The average life of the frog, immersed completely in running 

 Winnipeg tap-water, as deduced from experiments 1, 2, and 4, on a 

 total of twenty-two frogs, is between fifteen and sixteen days. The 

 extremes observed in these experiments were 3 days and 52 days. 

 The experiments, on the whole, seem to show a somewhat shorter 

 period for females. This is not improbably due to the time of year 

 at which the experiments were carried out. 



Numerous measurements on the dead frogs and observations 

 on their condition were made. Many of the data obtained are shown 

 in the following table. The figures for weight (column 5) are correct 

 to 0-5 gram. Those for volume, obtained by displacement in water, 

 are probably correct to 1 c.c. The density of the normal frog has 

 been taken as unity within the limit of error of the methods of measure- 

 ment employed; this figure was given by a number of measurements 

 on normal frogs. The residual weight (column 8) was obtained either 

 by direct weighing after the frog had been cut up under water for 

 removal of gas, when absorbed liquid also escaped (adherence of water 

 giving an error not greater than one gram as determined by actual 

 measurement), or by subtraction of the measured absorbed liquid, 

 (column 10) (in which 1 c.c. has been assumed to weigh 1 gram, since 

 the liquid was in all cases a thin serum). In the former case the 

 liquid absorbed has been determined by the difference between the 



