12 CHARLES F. W. MCCLUEE 



the same solution. It will be observed that, during a period 

 of twenty-four hours' suspension in the solution, these three 

 gloves showed marked differences in the rate at which water 

 was transported through the skin from without inward. In 

 one case the gain in weight of the glove amounted to 272.2 

 per cent; in the two remaining gloves it amounted to 160.7 

 and 68 per cent, respectively. In cases where the rate of 

 passage of water through the skin was relatively rapid, it was 

 found that the glove continued to gain in weight for a period 

 of forty-eight hours or more, although the gain was less on 

 the second than on the first day of suspension. These three 

 experiments showed that, among different frogs of the same 

 species, during the same season of the year, marked differ- 

 ences exist in the rate at which water is transported through 

 the skin into the glove under the conditions above mentioned. 



When skin gloves, with the outside of the skin turned out- 

 ward, are filled with Ringer's solution approximately isotonic 

 with frog's blood and are alternately suspended in the same 

 solution at different temperatures, their behavior may be the 

 same during the first day's suspension as if the temperature 

 of the Ringer's solution had been constant (experiments 431 

 and 442, fig. 2). Also, the rate at which water is transported 

 through the skin into the glove is not invariably influenced 

 by temperature, in the sense that the gain in weight of the 

 glove is greater at a high than at a low^er temperature. As 

 a matter of fact, instances were frequently met with in which 

 the reverse conditions were observed. 



During the second day of their suspension in Ringer's so- 

 lution at different temperatures, the skin gloves usually 

 showed signs of molting, and the rate at which water was 

 then transported through the skin into the glove became 

 greatly diminished. After the loss of the superficial layer 

 of skin (molt skin), a complete reversal was brought about 

 in the direction in which the transport of water through the 

 skin was accomplished. In such cases water was transported 

 through the skin outward instead of inward. The behavior 

 of skin gloves during the second day of their suspension in 



