Cytochemical staining of demyelinated peripheral axons revealed two types of axon membrane organization, one of which suggests that the demyelinated axolemma acquires a high density of sodium channels. Ferric ion-ferrocyanide stain was confined to a restricted region of axon membrane at the beginning of a demyelinated segment or was distributed throughout the demyelinated segment of axon. The latter pattern represents one possible morphological correlate of continuous conduction through a demyelinated segment and suggests a reorganization of the axolemma after demyelination.