Despite various modes of destruction, a “standard pattern of degeneration” occurred in the organ of Corti. Degeneration of the neural elements closely followed the degeneration of the supporting elements of the organ of Corti. The stria vascularis atrophied only following rupture of Reissner's membrane. Debris from the “standard pattern of degeneration” accumulated in lysosomes of Claudius cells and Heissner's membrane. Exogenous tracers passed into scala media through Reissner's membrane. They were also found in lysosomes of Claudius cells and Reissner's membrane. Debris within scala media never passed into scala vestibuli. The cochlear duct is surrounded by selective barriers which suggest both active and passive transport. © 1969, SAGE Publications. All rights reserved.