Variability of the hereditary deafness in the white cat. II. Histology.

Cochlear degeneration in white cats was investigated by light- and electron-microscopic examinations. A great variety of histological damage was encountered both in completely and partially deaf animals. These variable features are discussed mainly with regard to the rate of degeneration and the site of the first damage. Atypical findings, such as primary degeneration of spiral ganglion neurons, are presented. The possibility for some damaged cochleas to work without hair cells is described. These results clearly demonstrate that hereditary degeneration in the cochlea of white cats is not a unique and regular process.