The temporal bones of 24 aged cadavers were examined histologically during the last five years. In 18 cases there was a history of "vertigo". The Distension of Reissner's membrane was present in 26 of the 29 cochleae examined from those with "vertigo" and in 5 of the 9 cochleae of the controls. The degree of hydrops in the cochleae of those with a history of "vertigo" was severer than that in the cochleae of the controls. The temporal bones of two SHR rats with a kind of "vertigo" were also examined histologically. The cochlear structure of the affected side was destroyed and replaced by fibrotic cells in one rat. In one turn of the cochlea on this side, a mass of coagulated blood and fibrosis was observed in the same region, presumably caused by intracochlear bleeding due to hypertension. Ultrastructural studies are needed to clarify those pathological findings.
