The Deaf And Dumb, persons who have not the sense of hearing, and in consequence want the faculty of speech. The primary defect is deafness; dumbness follows from the resulting inability to control the vocal organs. Dumbness without deafness is very rare, and when not due to malformation is almost invariably a sign of idiocy. A person may be born deaf, or may lose his hearing by disease or accident; deafness is thus medically classed as congenital or adventitious. For educational purposes a different distinction is made. Those who become deaf at so early an age that they have not learned articulate language, or speedily lose all impress of it upon the mind, share the mental characteristics of the congenitally deaf, and are classed with them as true deaf mutes. Those who retain some knowledge of articulate language, acquired through the ear, are called semi.mutes. The distinction lies not in the power or practice of speech, but in the habit of thinking in words. - Deafness is more prevalent than is generally supposed. By the deaf and dumb are usually understood only those so deaf that the ordinary means of vocal communication are unavailable with them.

The number of these in a country has invariably proved to have been greatly under.estimated prior to careful enumerations; probably because deafness, unlike blindness, has no outward indication to attract notice. But affections of the ear producing a lower degree of deafness have received comparatively little attention; their extent is not appreciated even by physicians, except the few who make aural surgery a specialty. When noticed they are too often regarded as merely symptoms of more general disorders, and neglected until too late. The demands made upon the ear in ordinary life do not require such acuteness of perception as to render immediately sensible a diminution of its power; imperfect apprehension is often ascribed to mental rather than physical defects; and the decay of hearing in old age is regarded as natural and inevitable. Yet Von Troltsch says that in childhood earache and discharges are very common, and in middle life fully one third no longer hear perfectly and normally with one ear.

It is not known to what extent the "hard of hearing" have been enumerated with the "deaf and dumb" in censuses; but very few who lose their hearing after the age of ten come to the institutions for the deaf and dumb, whose registers are almost the only sources whence statistics of the causes and ages of deafness are derived. - Enumerations of the deaf and dumb are made in the decennial censuses of the United States and Great Britain, and have been taken in most of the countries of continental Europe at different dates. From the rest of the world no statistics have yet been procured. The data thus obtained in Europe and America give ground for the surmise that deafness is more prevalent in cold than in hot countries, and among the Caucasian than among other races. The following will serve as instances of the differences in the proportion of deaf mutes- to the total population:

The true proportion, in the United States and Great Britain, is probably 1 in 2,000; the older estimates made it 1 in 1,600; and 1 in 1,500 may be taken as the average of the United States and Europe. Some of these discrepancies are doubtless due to the errors and omissions which have been detected in even the latest and most carefully taken censuses. Thus in 1870, out of 294 pupils in the Illinois institution, only 97 were enumerated. The two following tables show the numbers recorded in the United States census of 1870, and the proportions deduced thence; to which, for comparison, is added the number of pupils reported by the various institutions during the same year:

1870 Number Of The Deaf And Dumb In The United States And Territories

1870 Ages Of The Deaf And Dumb In The United States And Territories

The numbers for England, the only ones yet received from the census of 1871, were kindly furnished by the registrar general through Dr. Buxton of Liverpool, in advance of publication, and are liable to slight changes. The decrease in 10 years, on the whole, and in every district but three, is remarkable; it amounts to 6.23 per cent., while the total population increased 13.15 per cent.

Number Of The Deaf And Dumb In Great Britain And Ireland

In Europe congenital cases preponderate, in America adventitious cases, as is shown in the following comparison:

The following table shows the ages at which deafness occurred in 2,472 cases in the United States; and in 1,458 cases in Europe: