Swelling of Erythrocytes in Solutions of Ammonium Salts

Abstract

Besides the hydrogen ion, as is well known, the ammonium ion is the only cation capable of passing through the membrane of erythrocytes. Possibly the mechanism of this is a simple diffusion; possibly, as assumed by Jacobs (1926-27), it consists in a diffusion of N-H, into the erythrocyte, followed by an exchange of hydroxyl ions from the corpuscle for the anion with which the ammonium ion was combined in the surrounding fluid.If the former possibility holds good, the rate of diffusion of ammonium salts into the red corpuscles may be estimated by means of the coefficient of diffusion of a single salt through the membrane: 2UV U+V"If the diffusion of the salt is based exclusively upon an exchange of anions, the question becomes more complicated, as there is a definable coefficient of diffusion only when there is the same fall in the concentration of the two anions.Taking the simple diffusion of the ammonium ion for a working hypothesis, I have tried to work out an equation from which the rate of the swelling of erythrocytes in solutions of ammonium salts may be expressed by a single numerical quantity, which is to be regarded as a relative diffusion constant for the salt in question. Thus it becomes practicable to compare directly the rates of diffusion of various salts and to study the influence of different factors upon the diffusion rates of individual salts.