IN AN EARLIER contribution to the study of deafness in 581 cases, in which 461 biochemical examinations of the blood were undertaken, there were a large number of cases with the criteria to warrant a diagnosis of otosclerosis.1 Among these otosclerotic patients were groups of deafened sisters and deafened mothers with deafened children.
In the familial groups, the biochemical findings in the blood were so significantly similar, irrespective of the differences in age of the blood relatives, that a specific study of the heritage of deafness in otosclerosis was begun, particularly so because of the pertinent biochemical abnormality in the blood, which was demonstrated by the first study of the blood of both parents and of the deafened child, of which I have knowledge. These parents, although totally unconscious of having any loss in hearing acuity, nevertheless showed in the pathologic picture of their blood that they carried a metabolic