Electrophysiological and histological observations in guinea pig's cochleas after amikacin treatment (14 X 450 mg/kg) confirm the results obtained in a former experiment: clear, short-latency, click-evoked responses were recorded in cochleas with only very few hair cells remaining at the extreme apex. Detailed analysis of these responses strongly indicates a neural origin and confirms their low-frequency sensitivity. Careful histological observations confirm the extensive hair cell loss and the preservation of nerve fibers in the remnants of the organ of Corti and of the vestibular sense organs. These results suggest that the acoustical vibrations either stimulate the vestibular receptors or act directly or through some kind of mechano-electrical transduction on the remaining cochlear nerve fibers.