[17] 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.
[18] Of the cases usually ascribed to accidents, as falls, blows and the like, the probabilities are that a large part are really to be attributed to some other cause. Deafness is not often likely to result from such occurrences.
[19] See Proceedings of International Otological Congress, ix., 1913, p. 49; _Volta Review_, xiv., 1912, p. 348.
[20] Special Reports, pp. 110, 122, 124. See also _Annals_, xxxiii., 1888, p. 199; lii., 1907, p. 168. In the table are given only the specified causes that represent at least 0.7 per cent of the total amount of deafness. In respect to external ear trouble, impacted cerumen is usually found to result from water in the ear, or wax in the ear. Other diseases of the middle ear of suppurative character are diphtheria, pneumonia, erysipelas, smallpox, tonsilitis, teething, bronchitis, and consumption. Other non-suppurative diseases of the middle ear are whooping cough, scrofula, exposure and cold, disease of the throat, thickening of eardrum, croup, etc. Of the internal ear, other causes affecting the labyrinth are malformation, noise and concussion, mumps, and syphilis; affecting the nerve, paralysis, convulsions, sunstroke, congestion of brain, and disease of nervous system; and affecting brain center, hydrocephalus and epilepsy. Among unclassified causes are also adduced neuralgia, childbirth, accident, medicine, heat, rheumatism, head-ache, fright or shock, overwork, lightning, diarrhea, chicken-pox, operation, and other causes.
[21] Proceedings of National Conference of Charities and Corrections, 1906, p. 250; Ceremonies of Laying of Corner Stone of Rhode Island School, 1907, p. 27.
[22] There are no general or organized movements on foot for the prevention of deafness as there are for the prevention of blindness. This is perhaps chiefly because there are believed to be nothing like so many preventable cases of the one as of the other, so much of blindness being due to diseases that might have been avoided without great difficulty, and to accidents and other injuries to the eye.