206 INJUBY, RECOVERY, AND DEATH 



In the first of these methods 10 different solutions were 

 placed on opposite sides of a piece of tissue. The appa- 

 ratus used is shown in Fig. 89. The diffusion of salts 

 through the tissue was then measured. In the first 

 , -I experiments, a solution of NaCl 0.52 M 



was placed on one side, NaCl 0.26 M was 



^ J-lu-.-A pi ace d on the other: CaCl 2 0.28 M and 



0.14 M, as well as sea water and sea 

 water diluted with one volume of dis- 

 tilled water were employed in the same 

 way. As the stronger solution diffused 

 into the weaker the increase in the elec- 

 trical conductance of the latter was 

 measured. In Fig. 90, the rate of 

 change of the electrical conductance is 

 plotted against time. It will be observed 

 that NaCl diffuses through the tissue 

 FIG. so Apparatus for more rapidly than sea water, while CaCU 



testing the rate of diff- ^ 



at first diffuses more slowly than sea 

 ?' Voided water and then more rapidly : 



If dead tissue be substituted for 



tissue of Laminaria, ,-> r* -, , -, , ,- /> i /* 



which is sealed to the living, we find that the rate of diffusion 



glass cells by a mixture . , . 



of vaseline and beeswax, is very much more rapid in all cases, 



F. The lower cell is pro- 

 rubber uibhig* cTnd a ml ^ ^at a ^ the solutions pass through 

 pinch cock, 'D. a ^ about the same rate of speed. 



These results are precisely what would be expected in 

 view of the results of the electrical experiments. 



In the second of these methods, 11 tissues of the dande- 

 lion (Taraxacum officinale) were placed for a short time 

 in a salt solution and the rate at which salts subsequently 

 diffused out of the cell was measured by placing the 



10 Cf. Brooks, S. C. (1917, B). 



11 Cf. Brooks, S. C. (1916, A). 



