Title: MECHANISMS OF WATER MOVEMENT INTO AMPHIBIANS WITH SPECIAL REFERENCE TO THE EFFECT OF TEMPERATURE Abstract approved Redacted for Privacy

The rate of osmotic movement of water across the skin of Rana 0pipiens, in vivo and in vitro, was measured at 5 C and 15o C. With 23 mM/1 sucrose bathing the epithelium the osmotic flow into intact animals was 1. 40111/cm2-hr at 5 ° C and 2. 62 µl /cm-hr at 15 C (Q10 = 1. 9). The osmotic flow across isolated skin (23 mM/1 sucrose outside, Ringer's solution inside) was 1.3 and 2. 0 ii.1/cm 2-hr at 5 ° C and 15 ° C respectively (Q10 5). The osmotic movement of water, JOS, in both in vivo and Din vitro skin consists of two components, diffusive flow, JF, and Hhydrodynamic flow JF. Tritiated water (THO) was used to measure D H H OS DJF and JF was calculated, (JF = JF JF), after correcting 5for the gradient. The units are 1.11/cm2-cm H 0 x 10. For in viv