This account of charge movement in striated muscle membrane must be regarded as essentially tentative. I have tried to present, within a simplified descriptive scheme, one way in which the present confusion of results can be resolved into a self-consistent account. But I am sure that as more complete and more accurate measurements are made, the deficiencies of this account will become even clearer. Nevertheless I believe that any successful description of the dielectric properties of biological membranes will have to take account of slow and nonlinear polarization of numerous membrane constituents and of the improbability of finding within the experimentally available range any finite potential region where polarization is linear.