62 THE ROYAL SOCIETY OF CANADA 



The experiment was commenced on March 29th. Four frogs 

 were immersed in the solution, and kept continuously below the sur- 

 face. The solution was changed on the second day. One frog died 

 during the third day. It was very swollen, weighed 82 grams, and over 

 20 c.c. of liquid were removed, indicating an absorption of over thirty 

 per cent of the original body weight. At the end of the third day 

 the other frogs were removed (all were apparently dead). Two, 

 dead, gave the following figures: The first weighed 95 grams; 30 c.c. 

 of liquid were removed from it (46 per cent of the original weight). 

 The second weighed 65 grams; 20 c.c. of liquid were removed, amount- 

 ing to 44 per cent of the original weight. The remaining frog con- 

 menced to breathe 3 or 4 minutes after removal. It weighed 65 

 grams. It lost weight steadily, and after 6 days weighed 45 grams, 

 and had attained approximately constant weight. Accepting this 

 as approximately the original weight, in this case also the absorption 

 of liquid was over 40 per cent of the original weight of the frog. In 

 no one of these frogs was any trace of buoyancy exhibited so that 

 osmotic absorption is not in itself the mechanism causing retention 

 of gas. 



The following experiments were carried out in a similar apparatus 

 and under similar conditions to those of experiment 7, different solu- 

 tions being employed. 



Experiment 8. Commenced April 24th, 1915. Four frogs 

 were placed in distilled water. The water was changed on the third, 

 tenth, and fourteenth days. Frogs died on the first, second, four- 

 teenth and nineteenth days. They were only slightly swollen ; none 

 showed any trace of buoyancy. 



This experiment indicated that the solid constituents of the 

 Winnipeg tap-water are probably connected with the causation of 

 gas retention, since in their absence this does not take place. We 

 had hoped to show much longer average life in distilled water than 

 in tap-water. The shorter life observed is probably due — as are the 

 results in experiment 6 — to the period of year when the experiment 

 was performed, the frogs, which should normally have been feeding, 

 being weakened after their winter fast. The higher average temper- 

 ature may be an additional cause. 



Experiment 9. Commenced April 19th, 1915. About four 

 grams of calcium chloride (anhydrous) were dissolved in 5 litres of 

 distilled water, the solution containing about three times the number 

 of calcium ions as the tap-water. Four frogs were immersed. The 

 water was changed on the third, and on the eighth day. Frogs died 

 on the first, second, and eighth days. They were not markedly 

 swollen, and showed no trace of buoyancy. The remaining frog was 



