A text-book of the diseases of the ear and adjacent organs . s circumference. At first I had them made of glass, but now of redvulcanite. The instrument is introduced as follows : with the wider opening * See Schvrabachs article, Horrobren, in Eulenbergs Recd-Encykloplidirmdicin. Wissemchaft. HEARING-INSTRUMENTS FOR THE DEAF. 711 pointing upwards, the small end is pushed into the external meatus, andthen it is turned in the auricle so that the large opening looks backwardstowards the concha, and is pushed towards it. With regard to the amount of improvement in the power of understandingspeech
A text-book of the diseases of the ear and adjacent organs . s circumference. At first I had them made of glass, but now of redvulcanite. The instrument is introduced as follows : with the wider opening * See Schvrabachs article, Horrobren, in Eulenbergs Recd-Encykloplidirmdicin. Wissemchaft. HEARING-INSTRUMENTS FOR THE DEAF. 711 pointing upwards, the small end is pushed into the external meatus, andthen it is turned in the auricle so that the large opening looks backwardstowards the concha, and is pushed towards it. With regard to the amount of improvement in the power of understandingspeech caused by the application of this instrument, according to the experi-ments hitherto made, the hearing-distance, on an average, is at least more than one-fourth of the cases it had no influence on the hearing-distance ; in several cases it caused a decrease. For a number of years I have used in persons who were hard ofhearing an instrument I devised, the principle of which dependsupon the vibration of the cartilaginous plate of the auricle being. Fig. 331. transmitted by an elastic sound-conductor to the rnembrana tym-pani. It consisted of rubber tube (drainage tube) 4-5 cm. long, and 2 mm. thick ;its clipped inner end (Fig. 331) being brought into contact with the rnembranatympani (t), while the outer end (c) in the concha is in contact with thecartilage of the auricle. The effect of the instrument is increased by a roundrubber plate placed near its outer end. The improvement in hearing pro-duced by this instrument is occasionally 4-5 times the former is of most benefit in middle-ear catarrh with flaccidity of the rnembranatympani; it is entirely without benefit in rigidity and anchylosis of theossicula. In the last decade different apparatuses have been constructed,which will be shortly described here. Khodess audiphone, the beneficial effect of which depends uponthe intensified sound-conduction through the cranial bones, consistsof a flexible p
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecteardiseases, bookyear
