Note 17 — Chapter II

Deafness has also been divided into three classes: adventitious deafness, congenital or hereditary deafness, and infantile or sporadic congenital deafness, the last class including many cases where there are other antecedent defects, mental or physical, or where the deafness occurred shortly after birth with the exact cause not definitely determined. See Proceedings of International Otological Congress, ix., 1913, p. 49; Volta Review, xiv., 1912, p. 348; xv., 1913, p. 209.