411 



DEAFNESS. 



DEAFNESS. 



443 



more than forty years in America, and are fast extending to all the States 

 of the Union. That at Hartford, Connecticut, was commenced in 1817; 

 New York in 1818 ; Philadelphia, 1821 ; Danville, Kentucky, 1822 ; 

 Columbus, Ohio, 1826; Stauntou, Virginia, 1839; Indianopolis, In- 

 diana, 1843 ; Knoxville, Tennessee, 1844 ; Raleigh, North Carolina, 1845 ; 

 Jacksonville, Illinois, 1849; in South Carolina, 1849 ; Louisiana, 1852; 

 Wisconsin, 1851 ; Michigan, 1854 ; there are also institutions in Iowa 

 and Missouri. We have not space for particulars respecting these 

 institutions ; in the aggregate they educate upwards of 1600 pupils ; 

 they are carried on in a vigorous spirit by zealous and intelligent 

 teachers, and they [are fulfilling their purposes as well as those in 

 our [own country ; though, in some respects, they are carried on 

 under disadvantages which are unknown to the schools in the British 

 Isles. 



The Canadian government established an institution for the deaf 

 and dumb at Montreal a few years ago ; it is understood to be flourish- 

 ing, but we have been unable to obtain any particulars as to its extent 

 and progress. In the year 1856 a small institution was commenced at 

 Halifax, Nova Scotia, which has recently increased in extent, and 

 received much public favour ; according to the Annual Report (1859), 

 it contains twenty-seven pupils, several of whom are adults. 



The advantages which have resulted to the community from the 

 education of deaf-mutes have been large and important. The class 

 itself, as an item of this public good, is brought from the normal con- 

 dition described in the earlier part of this article into that of intelligent 

 moral beings, awakened to the tenure by which human life and citizen- 

 ship are held, and to the hopes which religion inspires. In the every- 

 day business of life we find a fair proportion of deaf-mutes occupied 

 in workshops, counting-houses, studios, and various other offices, who 

 by industry and trained skill support themselves creditably, and whose 

 general good conduct entitles them to respect. Without instruction 

 these persons could not have been producers, but would generally 

 have been a burden on the industrious classes. The art and science 

 of primary education have also been gainers from the experience 

 acquired in simplifying knowledge for the instruction of the deaf and 

 dumb, whose teachers work upon the ignorance of their pupils rather 

 than on any supposed acquirements. Children who have in the first 

 instance to obtain their knowledge of language by single words, by 

 short sentences, by visible objects or their representations, require the 

 aid of black-boards, diagrams, pictures, plans, maps, models, collections 

 of natural and artificial objects, and such other illustrations as the 

 inventive talent of their teachers can suggest. The greater part of 

 these accessories to instruction were employed in our deaf and dumb 

 institutions for many years before they were recognised as legitimate 

 aids by ordinary teachers. The time has arrived when they are gene- 

 rally adopted, and by their means, simplified and improved modes 

 of instruction have arisen in the majority of schools. 



DEAFNESS, the sense of hearing diminished or abolished. Deafness 

 is either congenital or acquired. When congenital, it arises from an 

 original malformation of the ear, and is then always accompanied with 

 dumbness. When acquired, it arises from a variety of diseases affecting 

 different parts of the complex apparatus connected with the sense of 

 hearing. Some parts of this apparatus are placed beyond the reach of 

 examination, and the function of other parts is but imperfectly known : 

 go that it is often difficult to ascertain the exact seat of the disease, 

 still more difficult to ascertain the exact nature of the disease, and 

 even when this is discovered, more difficult than all to apply an effectual 

 remedy. Hence the study and treatment of deafness are attended 

 with peculiar difficulties ; yet the subject has by no means engaged 

 such a share of the attention of the scientific surgeon and physician as 

 its importance deserves. 



Deafness may arise from disease of the organ of hearing, or from 

 disease of the brain. The organ of hearing consists of two parts, that 

 destined to collect and transmit sound to the auditory nerve, and that 

 composed essentially of a peculiar arrangement of the sentient extremity 

 of the auditory nerve destined to receive sound and to transmit the 

 impressions to the brain. 



That part of the apparatus whose office it is to collect sound is 

 termed the auricle, or the external ear the ear commonly so called. 

 [EAR ; NAT. HIST. Div.] From the auricle proceeds a narrow winding 

 passage, termed the external auditory passage (meatu* auditorial ex- 

 tennu), which is closed at its farthest extremity by a membrane called 

 the mtmbrana tympani, or the drum of the ear. Beyond the membrana 

 tympani is the cavity of the tympanum, which is a chamber of air, 

 containing a curious and complex apparatus, put in motion by the 

 vibrations of the air that produce sound. These vibrations are com- 

 municated to the internal apparatus by the membrana tympani, or 

 drum of the ear, and, variously modified by that apparatus, and com- 

 municated to the air in the chamber of the tympanum, are conveyed 

 to the internal organ, or the ear properly so called. Besides all this 

 there is the passage called the Eustachian tube, which leads from the 

 throat to the cavity of the tympanum. All these parts of the ear are 

 subject to various diseases, any one of which is capable of impairing in 

 a greater or less degree the sense of hearing, or of producing deafness. 



Any considerable malformation of the auricle, or external ear, whose 

 office it is to collect the vibrations of the air that produce sound, is 

 found to occasion a greater or less degree of deafness. But the external 

 auditory passage is lined by a vascular and highly sentient membrane, 



studded with organs of secretion, by which are elaborated the cerumen, 

 or wax, with which the passage is kept in a state of moisture, and by 

 which it is defended from the entrance of external bodies. A certain 

 quantity and a certain quality of this secretion are indispensable to a 

 sound condition of the function of hearing. If the secretion be 

 diminished or suppressed, the hearing becomes extremely imperfect ; 

 if it be increased and thickened, the hearing may become altogether 

 abolished. The quantity and quality of this secretion may be changed, 

 in either of these modes, by many diseases ; by inflammation, for 

 example, induced by the application of cold and other causes. Accord- 

 ingly, a vitiated state of the secretion of the wax, which may be accu- 

 mulated in such a degree as completely to block up the passage, and so 

 to prevent the transmission of sound to the internal ear, is among one 

 of the most common causes of deafness. But inflammation may pass 

 into ulceration ; purulent matter may form, collect, and completely 

 obstruct the transmission of sound. Moreover, morbid growths, as 

 polypi, may spring from the lining membrane of the rneatus, and plug 

 up the passage. In these different modes there may be a complete 

 obliteration of the auditory passage. This obliteration of the auditory 

 passage is ordinarily attended with the total abolition of the sense of 

 hearing ; yet cases are on record in which the canal has been reduced 

 to less than a line in diameter, and in which its walls at different points 

 have even touched, without a great degree of deafness having resulted. 

 In these cases, instead of deafness, there has been a constant noise or 

 buzzing in the ear. Occasionally, though very rarely, there is the 

 opposite state of the auditory passage : it is preternaturally enlarged ; 

 in one case it was so much enlarged, that the ring-finger could easily 

 penetrate to the bottom of the canal. Deafness equally resulted from 

 this enlargement of the auditory passage as from its obliteration. 



The diseases of the auditory passage may be communicated to tho 

 membrana tympani, which may be inflamed, thickened, ulcerated, and 

 rendered wholly incapable of performing the office of transmitting 

 sound. It has been observed to acquire a thickness as great as that of 

 the sclerotic coat of the eye, by a successive deposition of adventitious 

 membranous layers. It is then of a yellowish colour, and quite opaque. 

 Deafness often coincides with this altered condition of the membrana 

 tympani ; but it is doubtful whether, if this be the sole affection, it be 

 capable of abolishing the sense of hearing. 



The membrane which lines the chamber of the tympanum may par- 

 take of the diseases of the parts of the auditory apparatus which are 

 external to it, or it may itself be the primary seat of disease. It may 

 become inflamed and thickened, in consequence of which the capacity 

 of the chamber for containing air must be proportionally diminished. 

 The fluid commonly secreted by its membrane may be increased in 

 quantity and vitiated in quality, and this increased and vitiated liquid 

 may occasion deafness by the exclusion of air from the chamber. 

 Such an altered secretion occurs chiefly in children and young persons, 

 whose mucous secretions in general are easily deranged. This accumu- 

 lation may take place without any pain in the ear, without any dis- 

 charge of fluid from the ear, and without any appreciable lesion of the 

 auditory passage. It may be suspected to be the cause of deafness 

 when the sense of hearing varies materially at different periods of the 

 day ; when the deafness is greatest in the morning, and is suddenly 

 and manifestly increased by a (Lamp day, or by exposure to a cold and 

 humid atmosphere. There may also be an accumulation of pus or of 

 blood in the chamber at the tympanum. Pus may be suspected to be 

 accumulated in the tympanum when deafness follows severe pain in 

 the internal ear, attended with other signs of inflammation ; and when 

 inflammation and ulceration of the auditory passage are either absent 

 or exist only in a slight degree. Blood nuiy be suspected to be con- 

 tained in the chamber when deafness follows a severe blow on the 

 head in the neighbourhood of the ear, or a fall, or any cause by which 

 a preternatural quantity of blood is determined to the head. Whether 

 the cavity of the tympanum be obliterated by an increased secretion of 

 the fluid which moistens its walls, or by an accumulation of pus, or of 

 blood, the effused matter is often spontaneously removed by absorption, 

 and the sense of hearing gradually returns as the process of absorption 

 goes on. 



One of the conditions essential to the sense of hearing is a free 

 passage of air to the chamber of the tympanum through the Eustachian 

 tube. But the diameter of this tube may be diminished or wholly 

 obliterated by an accumulation of the mucus which moistens its inter- 

 nal surface, by the thickening of its lining membrane, and by the 

 adhesion of this membrane at different points. The entrance of air 

 into the Eustachian tube may also be obstructed by various diseases of 

 the throat, as inflammation attacking the soft palate and the tonsils, 

 the consequent enlargement of the tonsils, which may cover and com- 

 pletely close the opening of the Eustachian tube. The inflammation 

 may also spread from the throat into the Eustachian tube ; hence the 

 pain in the ear and the deafness which so often accompany severe sore 

 throat. 



The internal ear, or that part of the auditory apparatus in which the 

 impression of sound is received, the true and proper ear is, without 

 doubt, subject to its own diseases ; and it is probable that a very slight 

 change in this delicate structure is sufficient to occasion deafness. But 

 this organ is placed so far beyond the reach of examination, and the 

 function of its different parts is so little understood, that its morbid 

 changes, as the causes of deafness, are alike obscure during life, and 



