The study of aging in individual cells is complicated by the fact that the cellular population of the body changes during life; furthermore, it may be difficult to distinguish the normal changes of aging from alterations caused by injury and disease. The highly differentiated cells of the organ of Corti and auditory neural pathways do not undergo mitosis. Once a specialized function has been established for them, there is no turning back; they age and die. For them the length of individual cell life is conditioned not by stimulation or inhibition of mitotic activities but by ability to maintain characteristic structural organization in the continual adaptation they must make to changes of the tissue environment. It is known that certain families display hereditary patterns of premature cellular decay in certain cell systems; the deafness of aging is a good example.
New light microscopic findings in human temporal bones have prompted