86 



INJURY, RECOVERY, AND DEATH 



and microscopic measurements show most conclusively 

 that this does not occur. The contrary effect would be 

 produced by the addition of salts in solid form, for they 

 would tend to produce plasmolysis and thereby increase 

 the space between the cells. 



As these remarkable changes in permeability seemed 



DAY 1 



DAY 2 



80 



200 



Mm. 



FIG. 36. Extreme alterations of net electrical resistance produced by placing Laminaria 

 agardhii alternately in CaCh 0.278 M (unbroken line) and in NaCl 0.52 M (broken line) 

 and then in sea water (broken line with dots). The experiment was repeated with the same 

 lot of tissue on the second day. All readings were taken at 18 C. or corrected to thie tem- 

 perature. The control in sea water remained constant during the two days. 



to produce no bad effects, it occurred to the writer to 

 see whether the protoplasm could endure still more violent 

 alterations without permanent injury. In order to test 

 this the following experiment was performed. A lot of 

 tissue was found to have in sea water a net resistance 

 of 750 ohms. It was placed in CaCl 2 0.278 M, which had 

 the same conductivity as the sea water. At the end 

 of 10 minutes a reading was taken which showed that the 

 resistance had risen to 168%. The material was 



