ANTAGONISM 183 



The writer has experimented with a great variety 

 of materials in order to determine whether it is possible 

 to imitate by means of non-living materials, the change 

 in permeability found in living cells. In some cases 

 membranes have been found which show an increase of 

 conductivity when transferred from sea water to NaCl 

 and a decrease when transferred from sea water to CaCL 

 or LaCl 3 . 55 But in no case was the alteration great enough, 

 nor produced by a, sufficient variety of substances, to 

 justify the author in concluding that the effects were 

 really the same as those found in living material. The 

 relatively small changes found in dead material, 

 in so far as they are due to the cell walls (or intercel- 

 lular substance), must in the living conditions be 

 superimposed on the changes due to the activities of 

 the protoplasm. 



Until we succeed in finding a membrane (or other 

 static system) which imitates qualitatively and quanti- 

 tatively the permeability of the living protoplasm, the 

 author is inclined to regard a dynamic equilibrium 

 as essential. 



55 The solutions of NaCl, CaCL and LaCl 3 had the same conductivity 

 as sea water. When transferring from sea water to another solution a 

 temporary rise or fall may occur which is due to diffusion. See page 28. 



