52 CHARLES F. W. McCLURE 



If a large glove of frog's skin (A, fig. 24), with the outside 

 of the skin turned outward, is filled with Ringer's solution 

 isotonic with frog's blood and is then suspended in a con- 

 tainer (B) filled with the same solution, we have seen that 

 fluid can be transported continuously from the container 

 through the skin (D) into the glove (A). If a smaller glove 

 (C, fig. 24), with the outside of the skin turned outward, is 

 now filled with isotonic Ringer, and is placed inside the larger 

 glove (A, fig. 24), water will be transported continuously 

 from the large glove (A) through the skin into the smaller 

 glove (C). Now, with both surfaces of both skin gloves 

 bathed by solutions having the same osmotic pressure, we 

 may expect to establish a continuous flow of fluid passing 

 from the container (B) through both skins (D and E) into the 

 smaller glove (C). Any excess of fluid in the smaller glove 

 (C) would flow from the latter into the capillary tube (F). 



If, in either of the two gloves, we should substitute for the 

 Ringer 's solution isotonic with frog 's blood a Ringer solution 

 having a slightly lower osmotic pressure, we know that water 

 will continue to be transported through the skin in the same 

 manner and direction. If a Ringer's solution containing 6.5 

 grams of Nad to 1000 cc. of water, instead of 7 grams as in 

 the so-called isotonic solution, were placed in the smaller 

 glove (C), water would still continue to be transported 

 through the skin from the large into the smaller glove, in the 

 opposite direction to osmotic pressure. (See experiments 

 506, 507, and 508, fig. 11.) Also, if this same hypotonic 

 Ringer solution were substituted for the isotonic solution in 

 the larger glove (A), w r ater in container B would still con- 

 tinue to be transported in a continuous manner through the 

 skin into the larger glove and through the skin into the 

 smaller one (C), even though the latter contained a Ringer 

 solution of the same or of a slightly higher concentration than 

 that in the larger glove. Also, it is evident that the rate at 

 which fluid would be transported through the skin might be 

 modified by the presence or absence of K in the solutions. 

 (See experiments illustrated by figs. 15 to 23, inclusive.) 



