This paper is a report on the histopathological changes of the inner ear following artificial rupture of the left round window membrane observed in 19 experimental guinea pigs.

We found that the artificially perforated round window membrane could heal spontaneously, that no noticeable morphological changes took place in Corti’s organ within 2 weeks postoperatively and that if the round window membrane rupture failed to heal 2.5 months postoperatively, the Corti’s organ in the basic turn would be the chief part to be damaged, as a result of which the high frequency hearing ability might be impaired. These findings call the clinicians’ attention to the fact that if the hearing of patients who are suspected of labyrinthine window membrane rupture does not improve distinctly 2 weeks after the appearance of the symptoms, operations must be performed immediately for exploration and repair.