Abstract
A means for altering the ionic composition of perilymph utilizing the cochlear aqueduct and cerebro-spinal fluid in chinchillas is introduced. A decrease in sodium and an increase in potassium concentration in perilymph was observed after ouabain was injected into cerebrospinal fluid. The time course of changes in the perilymph paralleled the CSF change but with a time lag which had not reached equilibrium within 60 minutes.