20 CHARLES F. W. MCCLUEE 



skin in the opposite direction, the gain in weight of the glove 

 must have been due to the presence of fluid which had been 

 absorbed by the skin and held by the latter. "We have reason 

 to suppose that if this same skin had been filled with Ringer's 

 solution, its behavior would not have differed essentially 

 from that of the glove which had been obtained from the 

 same frog, but which had been filled with Ringer's solution 

 (exper. 409). 



When a living frog remains out of water, we know that as 

 the result of loss of water from the body the osmotic pressure 

 of its body fluid may be raised. The same may be said of 

 skin gloves, which undoubtedly lose some water during the 

 handling in preparation for the experiments. While osmosis 

 may play some role in accounting for the fact that skin 

 gloves, with the inside of the skin turned outward, almost 

 invariably gain weight when first placed in Ringer 's solution, 

 the following experiments seem still further to bear out the 

 view that this gain is due chiefly to the absorption of fluid 

 by the skin until its tissue colloids have reached their hydra- 

 tion capacity. 



Experiment 457 A (fig. 7) is one of interest for the reason 

 .that it shows a form of behavior indicating that a gain or 

 a loss in weight of the glove is influenced by temperature, but 

 cannot be explained on the grounds of osmotic pressure. 



In this experiment a skin glove, with the inside of the skin 

 turned outward, which had been removed from the right hind 

 leg of a frog (R. pipiens) kept in the laboratory for several 

 months prior to the experiment, was filled with Ringer's 

 solution approximately isotonic with frog's blood and was 

 alternately suspended in the same solution at 17 C. and at 

 27 C. During the first hour of its suspension at 17 C. the 

 glove gained about 30 per cent, because the skin itself had 

 a marked capacity to absorb and hold water. During a period 

 of eight hours' suspension following this initial gain, the 

 glove uniformly lost weight when transferred to Ringer's 

 solution at the high temperature (27C.) and gained weight 

 when transferred from this solution to one at the low tern- 



