10 CHAKLES F. W. MC CLUIIE 



Having considered the osmotic reactions which result when 

 a normal desiccated frog is placed in water, we may now 

 compare these reactions with those obtained when the same 

 frog has again been desiccated and, before being put into 

 water, has had injected into its subcutaneous lymph sinuses 

 a hypertonic saline solution. 



After injecting a hypertonic saline solution into the sub- 

 cutaneous lymph sinuses of a normal desiccated frog and 

 then placing the frog in water, we should expect to obtain 

 a desiccation recovery curve of the same general character 

 as that obtained on a desiccated frog that had not been in- 

 jected. The only difference we should expect to find would 

 be that in the case of the injected frog the curve would have 

 a greater maximum height, owing to an increase in the os- 

 motic pressure of the body fluids beyond that resulting from 

 desiccation. Such a curve (4) is shown in figure 1, which 

 illustrates the behavior of this frog, which had been desic- 

 cated by remaining twelve hours out of water, and into the 

 subcutaneous lymph sinuses of which, before it was placed 

 in water, 1 cc. of a 2.97 per cent solution of NaCl had been 

 injected. The maximum height obtained by this NaCl curve 

 (4, fig. 1) is observed to be much greater than that of any 

 one of the three control curves (1, 2, and 3, fig. 1) obtained 

 when, before being placed in water, the desiccated frog had 

 not been injected with a hypertonic solution. 



This increase in height of the NaCl curve (4, fig. 1) over 

 that of the controls (1,2, and 3, fig. 1), in which the desiccated 

 frog had not been injected with the hypertonic saline solution, 

 indicates that an increased amount of water is driven through 

 the integument by the increased osmotic pressure of the 

 lymph in the subcutaneous lymph sinuses of the injected frog. 

 ( )n this same frog was made another experiment differing 

 from the former only by the fact that the frog was not desic- 

 cated before 1 cc. of a 2.1)7 per cent NaCl solution was injected, 

 and the frog put into water. In this experiment the behavior 

 of the frog is illustrated by curve 5 in figure 1, which shows 

 that for the body fluids to regain their average normal osmotic 



