AN EXPERIMENTAL ANALYSIS OF OEDEMA if 



behavior of the frog, may be spoken of as desiccation recov- 

 ery curves (D.R.C. in figure), and represent in a typical 

 manner the general behavior of normal frogs observed under 

 similar experimental conditions. 



The three desiccation recovery curves (1, 2, and 5 in fig. 1) 

 show that, immediately following the suspension of the desic- 

 cated frog in water, it gains weight continuously for a period 

 varying between two and four hours. This signifies that 

 during this time more water enters the subcutaneous lymph 

 sinuses through the integument than is simultaneously ex- 

 creted by the kidneys. On the other hand, when the body 

 fluids have regained their normal osmotic pressure, the loss 

 in body weight which follows (curve 1, fig. 1) signifies that 

 more water is then being excreted by the kidneys than simul- 

 taneously enters the subcutaneous lymph sinuses — a circum- 

 stance which may possibly be explained on the grounds that 

 free water has been released from the tissue colloids and has 

 become available for excretion by the kidneys. As shown 

 by the desiccation recovery curve 2 in figure 1, the amount 

 of water driven through the integument into the subcutaneous 

 lymph sinuses may, in course of time, be equibalanced by that 

 excreted by the kidneys. At such a time, slight fluctuations 

 in body weight can be temporarily produced by raising or 

 lowering the temperature of the water. As thus far observed 

 by the writer, frogs usually gain slightly in weight when 

 transferred from water at a high to water at a lower tem- 

 perature, and lose in weight when transferred from water 

 at a low to water at a higher temperature. Such fluctuations 

 in body weight would appear to be due to a temporary gain 

 or loss of water by the tissue colloids rather than to fluctua- 

 tions in kidney function, since it can be demonstrated that 

 in the normal frog the kidneys serve as passive agents, and 

 are more than capable of excreting any excess of free water 

 in the body made available to them, when the frog is in 

 water at any temperature within the range of that of its 

 natural environment. 



