22 CHARLES F. W. McCLUEE 



colloids rather than to osmotic pressure. The same is ob- 

 served in other cases (fig. 4) where the outside of the skin is 

 turned outward. 



Although the behavior just mentioned (exper. 457 A, fig. 7) 

 has frequently been observed, it is by no means uniformly 

 met with. As in the case of skin gloves with the outside of 

 the skin turned outward (fig. 2), cases are found in which 

 fluid is transported through the skin in a continuous manner 

 when gloves filled with Ringer's solution approximately iso- 

 tonic with frog's blood, with the inside of the skin turned 

 outward, are alternately suspended in the same solution at 

 different temperatures. This behavior is shown in the follow- 

 ing experiment. 



Experiment 458 (fig. 8) was made on a skin glove removed 

 from the right hind leg of a frog (R. pipiens). The glove, 

 with the inside of the glove turned outward, was filled with 

 6 cc. of Ringer's solution isotonic with frog's blood, and then 

 was alternately suspended for definite periods of time in this 

 same solution at temperatures of 16 C. and 26 C. After the 

 usual initial gain in weight obtained during the first hour's 

 suspension, the glove lost weight continuously at both low 

 and high temperatures, and in this respect its behavior dif- 

 fered from that observed in experiment 457 A (fig. 7). The 

 loss in weight of the glove was continuous ; but it will be noted 

 that during certain hourly periods the loss was greater at 

 26 C. than at 16 C. This may be accounted for as follows: 

 at 16 C. and at 26 C. water was transported from the glove 

 through the skin outward. At 16 C., however, the skin itself 

 absorbed, and at 26 C. it lost water. In this way it may be 

 possible to explain the greater loss at the higher temperature. 



After twenty- three hours' suspension in Ringer with the 

 inside of the skin turned outward, the glove was removed 

 from the glass cylinder, and both surfaces of the skin were 

 carefully dried between sheets of filter-paper. The same 

 glove was then again fastened to a glass tube with the outside 

 of the skin turned outward, instead of inward, was filled with 

 6 cc. of Ringer's solution isotonic with frog's blood, and was 



