Diffusion of Electrolytes through Living Cells. ii 



solution of potassium salt they have acquired a remarkable im- 

 munity against potassium salts. When eggs are put directly 

 from sea water into an m/8 KC1 solution in one and one-half hours 

 the heart beat stops in two thirds of the eggs; the same effect 

 requires in eggs previously washed for twenty-four hours in H 2 0 

 four days, i. e., an m/8 KC1 solution poisons the embryos of 

 unwashed eggs sixty times as rapidly as the washed eggs. 



It can be shown that this difference between the washed and 

 unwashed eggs is due to the fact that the unwashed eggs have 

 some of the salts of the sea water at their surface. If we put 

 washed eggs into m/8 KC1 solutions made up in H 2 0 and different 

 concentrations of sea water or NaCl + CaCl 2 or NaCl or any 

 other Na salt, the eggs are poisoned the more rapidly the higher 

 the concentration of the sea water or the sodium salt, up to a 

 concentration of about w/4. If a slightly higher concentration, 

 e. g., m/i, is used, the opposite result is observed; namely, a 

 retardation of the rate of diffusion of KC1 into the egg and hence 

 a protection of the eggs. This is the antagonistic salt action 

 which has hitherto exclusively occupied the attention of biologists. 



Experiments, which lack of space forbids to enumerate, show 

 that the difference in the rate of poisoning of the embryos men- 

 tioned, is due to a difference in the rate of the diffusion of the 

 potassium salts through the membrane. It follows then that 

 for the diffusion of potassium salts through the membrane of the 

 egg of Fundulus, aside from the osmotic pressure of the solution a 

 second factor is required, which we will call the general salt effect, 

 and which consists in a reaction between the electrolyte and a certain 

 constituent of the membrane (possibly the proteins) whereby the 

 membrane becomes diffusible for the potassium salt. If the potas- 

 sium salt is alone in solution it cannot diffuse into the egg until it 

 has produced the salt effect upon the membrane. This requires 

 considerable time if the concentration of the KC1 solution is low 

 and this explains why it takes so much more time for the KC1 

 solution to poison washed eggs than eggs transferred directly 

 from sea water into the KC1 solution. 



A further proof for the correctness of this view is found in the 

 fact that if eggs are poisoned in a potassium salt they cannot 

 recover when put into a solution of a non-electrolyte, while they 



