The mechanism of the diffusion of electrolytes through the membranes of living cells

Abstract

When eggs of Fundulus are transferred from sea water directly into a solution of a potassium salt a number of embryos will be poisoned during the first hours so that their hearts stop beating. When the eggs are washed for twenty-four hours in H₂O (or any solution of a non-electrolyte) before being put into the same solution of potassium salt they have acquired a remarkable immunity 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 H₂O 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 KCl solutions made up in H₂O and different concentrations of sea water or NaCl + CaCl₂ 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 m/4. If a slightly higher concentration, e. g., m/1, 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 mentioned, is due to a difference in the rate of the diffusion of the potassium salts through the membrane.