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The resting membrane potential data existing in the literature for the giant axon of the squid, frog muscle and barnacle muscle have been analyzed from the standpoint of the theory of membrane potential due to Kobatake and co-workers. The average values derived for the effective charge density phi chi (where phi is a constant, 0 less than phi less than 1, and represents the fraction of counterions that are free, and chi is the stoichiometric charge density in the membrane) present on the different biomembranes existing in their normal ionic environment are 0.3, 0.325 and 0.17 M for the squid axon, frog and barnacle muscles, respectively. On the assumption that the values of phi are 0.4 and 0.2 for nerve and muscle membranes, respectively, values of 0.75, 1.62 and 0.85 M have been derived for the stoichiometric charge density (chi) present in the respective biological membranes. These correspond to 1 negative charge per 222, 103 and 195 A2 of the membrane area of the squid axon, frog and barnacle muscles, respectively.

SynopsisThe emf's of the system Ag, AgCI/NaCI (mI)/membrane/NaCl(mIr)/AgC1, Ag containing phenol-formaldehyde sulfonate membrane have been measured a t 3OOC.The membrane phase has been analyzed for its electrolyte and water contents and intramembrane activity coefficients have been derived as a function of external electrolyte concentration. Transference numbers of Na + counterion and water have been measured as functions of both current density and external concentration. The data have been used to test the principal theories of membrane potential. The fixed-charge theory of Teorell and Meyer and Sievers did not give satisfactory agreement between observed and calculated emf's of membrane cells, whereas the Scatchard theory did.

Crosslinked phenol sulfonic acid resins in the form of rods have been prepared. Anion uptake by these resins in equilibrium with aqueous solutions of NaCl, NaBr, Na2CO3, and Na3C6H5O7 at 30°C. in the concentration range 0.001–3.0N, their density, water content, and exchange capacity have been determined. From these data, activity coefficients of small ions in the resin phase have been calculated and compared with the values derived by the existing theories of Mackie and Meares, and Lazare et al. The agreement between the observed and calculated values is not satisfactory.

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