W. J. V. OSTERHOUT 413 



duce injury increase permeability. The amount of increase may be 

 regarded as a measure of the amount of injury. A quantitative 

 basis is thereby furnished for such conceptions as death, injury, re- 

 covery, and vitality. 



The striking agreement between the behavior of frog skin and that 

 of Laminaria, as well as of other plants previously studied,^ strongly 

 confirms the idea that the ideas which have been developed from 

 the study of Laminaria are of general application. These ideas have 

 been tested by the use of diverse methods.^^ 



The general outcome of these studies reveals a marked amount of 

 agreement, and it would seem that the physiological characteristics 

 which they bring to Hght belong to the fundamental properties of 

 protoplasm. 



SUMMARY. 



Quantitative studies show a striking agreement between frog skin 

 and plant tissues in respect to certain important aspects of permea- 

 bility, antagonism, injury, recovery, and death. 



17 Osterhout, W. J. V., Science, 1917, xlv, 97; /. Biol. Chem., 1918, xxxvi, 485. 



