28 CHARLES F. W. MCCLUEE 



tion only in the amount of NaCl present. As compared with 

 the isotonic solution, these three solutions are hypotonic and 

 contain, respectively, 6.5, 6.25, and 6 grams of NaCl, added 

 to 1000 cc. of H 2 instead of 7 grams, as in the isotonic 

 solution. 



The following three sets of experiments (figs. 11, 12, and 

 13) illustrate the behavior of gloves of frog's skin, with the 

 outside of the skin turned outward, when filled with a hypo- 

 tonic Ringer's solution and suspended in a hypertonic 

 Ringer's solution. The crosses (x) in the figures represent 

 the behavior of the controls; that is, the behavior of the 

 gloves filled with Ringer's solution approximately isotonic 

 with frog's blood and suspended in the same solution. The 

 circles represent the behavior of skin gloves filled with a 

 hypotonic Ringer's solution and suspended in a hypertonic 

 Ringer's solution which is approximately isotonic with frog's 

 blood. In each case the gloves for the control and for the 

 experiment were taken from the hind legs of the same frog. 



1. The behavior of gloves of frog's skin filled with a Ringer's 

 solution containing 6.5 grams of NaCl to 1000 cc. of HJO, 

 tvhen suspended in a Ringer's solution containing 7 grams 

 of NaCl to 1000 cc. of H 2 



Controls: The behavior of skin gloves filled with a Ringer's 

 solution containing 7 grams of NaCl to 1000 cc. of H, 2 0, ivhen 

 suspended in the same solution. 



The important feature illustrated by this set of experi- 

 ments is that, as in the case of the controls, the skin gloves 

 filled with hypotonic Ringer immediately gained in weight 

 when placed in a hypertonic Ringer's solution. At the end 

 of twelve hours' suspension in the solution, however, the 

 amount gained by the gloves containing the hypotonic solu- 

 tion (experiments 506, 507, and 508, fig. 11) was less than 

 that gained by the controls (experiments 506 A, 507 A, and 

 508 A, fig. 11), in which the gloves containing Ringer's solu- 

 tion approximately isotonic with frog's blood were suspended 

 in the same solution. The fact that the rate at which water 



