182 INJURY, RECOVERY, AND DEATH 



Spaeth (1916) to account for variations in permeability 

 under the influence of salts. 



The great variations in the electrical resistance pro- 

 duced in living protoplasm by the action of salts seem 

 to the writer to depend on the fact that living protoplasm 

 is in a state of dynamic equilibrium so that the 

 material of which it is composed is constantly chang- 

 ing. This constant change is due to a succession of 

 chemical processes which may be easily influenced so 

 as to produce great changes in electrical resistance 

 which appear to become irreversible if carried beyond 

 a certain point.^^ 



In dead protoplasm, as in gelatin, such processes do 

 not occur, or at least they go on much more slowly. As 

 a result we cannot expect such great variations in electri- 

 cal conductivity. If we wish to imitate these it would 

 seem advisable to work with systems, which, like living 

 protoplasm, are in dynamic equilibrium. 



Clowes (1918), states that he has prepared emulsions 

 of oil in soap, which change their electrical resistance 

 under the influence of NaCl and CaClj, in a manner 

 similar to that observed in Laminaria. It remains to be 

 seen whether this parallel extends to the effect of 

 other substances. 



The writer obtained similar results some years ago,'* 

 with the shells, of the Horse Chestnut (Aesculus) which 

 had been killed by boiling or by soaking for 24 hours in 5% 

 formaldehyde. He was not able to convince himself, how- 

 ever, that the factors involved here are the same as in 

 living protoplasm. 



"'This apparent reversibility finds a ready explanation on the theory 

 of successive reactions. See page 121. 



"A brief account of these was given at the Boston meeting of the 

 American Physiological Society, in 1915. 



