DEAF AND DUMB, or DEAF MUTES, persons both deaf and dumb, the dumbness resulting from the deaf ness which has either existed from birth or from a very early period of life. Such persons are unable to speak because they have not the guidance of the sense of hearing to enable them to imitate sounds. Among the causes assigned for congeni tal deafness are consanguineous mar riages, hereditary transmission, scrofula, certain local or climatic conditions, ill health of the mother during pregnancy, etc. Acquired or accidental deafness, which occurs at all ages, is frequently due to such diseases as smallpox, measles, typhus, paralysis, hydrocephalus and other cerebral affections, but more pax ticularly to scarlet fever, which is some what apt to leave the patient deaf, ow ing to the inflammatory state of the throat extending to the internal ear, and thus causing suppuration and destruction of the extremely delicate parts of the auditory apparatus. In the greater pro portion of deaf-mutes no defect is visible or can be detected by anatomical exami nation, and no applications yet discovered appear to be useful.
In ancient times Aristotle and others, and also in the Christian ages, Augus tinus and his contemporaries considered that deaf-mutes were incapable of edu cation. In ancient days and also in the Middle Ages there were a few cases known in which spiritual culture was at tained by the deaf and dumb. In ancient Rome two dumb painters attracted at tention. The most famous of the more ancient instructors of deaf-mutes was the Spanish monk Pedro de Ponce at Sahagun, in Leon, who taught four deaf and dumb people to speak. In Germany about the same time the court preacher of Brandenburg, Joachim Pascha, suc ceeded in teaching his deaf and dumb daughter to speak.
In 1648 John Bulwer published the earliest work in England on the instruc tion of the deaf and dumb. This was followed by Dalgarno's "Ars Signorum" (Art of Signs) in 1661 and Dr. W. D.
19—Vol. III—Cyc Holder's "Elements of Speech." Dr. John Wallis, Savilian Professor of Mathematics at Oxford, is generally sup posed to have been the first Englishman to instruct deaf-mutes. In 1743 Pereira, a Spaniard, publicly demonstrated this new art before the French Academy of was established at Leipzig, for the edu cation of deaf-mutes, a public institution which is still retained at Vienna and throughout Germany. About 20 years previously Thomas Braidwood. had es tablished near Edinburgh, in 1760, a deaf and dumb school on the articulat Sciences, which gave its testimony to the success of the method. About the
same time the Abbe de l' pee, introduced a system for the instruction of the deaf and dumb, which was taught with great success in the Royal Parisian Institu tion. In 1779, through the labors of Samuel Heinicke, the great upholder of the vocal or articulatory system, there ing system. This was visited by Dr. Johnson during his tour in Scotland. The first public institution in Great Britain for the gratuitous education of the deaf and dumb was founded at Ber mondsey in 1792 by the Rev. Messrs. Townsend and Macon. In 1817, the first American asylum for the deaf-mute was founded at Hartford under the su perintendence of Mr. Gallaudet, who was the promotor of a system of teaching styled the "American System," which widely differs from those followed in Eu ropean schools. From this sprung up, in 1818, the New York Asylum, now known as the New York Institution for the In struction of the Deaf and Dumb, one of the largest in the world; in 1820, the Asylum of Philadelphia; and, since that time, many others in most of the States, which, throughout the country, make easily accessible to the deaf-mute the inestimable blessings of education.
The two chief methods of conveying instruction to the deaf and dumb are by the means of the manual alphabet, and by training them to watch the lips of the teacher during articulation. There are two kinds of manual alphabet, the double-handed alphabet, where the letters are expressed by the disposition of the fingers of both hands; and the single handed, in which the letters are formed with the fingers of one hand. The meth od of teaching by articulation, the pupil learning to recognize words and in time to utter them, by closely watching the motions of the lips and tongue in speech, and by being instructed through dia grams as to the different positions of the vocal organs, has given excellent re sults. A new method of teaching ar ticulation, was devised by Prof. Melville Bell called "visible speech." The char acters of the alphabet on which this system is founded are intended to re veal to the eye the position of the vocal organs in the formation of any sound which the human mouth can utter. The proportion of deaf-mutes in the popula tion varies with relation to economic and social conditions. It varies from 1 to 760 in India, 1 to 1,200 in France, 1 to 1,970 in England, to 1 in 2,400 in the United States.