A practical treatise on the diseases of the ear including the anatomy of the organ . ed with an apparatus forconducting the undulations of sound to the ear, which is at thesame time efficient and unconspicuous. This is the great de-sideratum of most patients who are affected with incurable 554 HEABENG TRUMPETS. impairment of hearing, for nearly all deaf persons would liketo conceal their infirmity. It is possible that the developmentof the science of acoustics will yet furnish us with a sound lens,that will refract and focus rays of sound upon the drum-headand assist the hearing power; but in
A practical treatise on the diseases of the ear including the anatomy of the organ . ed with an apparatus forconducting the undulations of sound to the ear, which is at thesame time efficient and unconspicuous. This is the great de-sideratum of most patients who are affected with incurable 554 HEABENG TRUMPETS. impairment of hearing, for nearly all deaf persons would liketo conceal their infirmity. It is possible that the developmentof the science of acoustics will yet furnish us with a sound lens,that will refract and focus rays of sound upon the drum-headand assist the hearing power; but in the very nature of thingsit is not likely that we shall ever have an apparatus so welladapted to the pathological changes in a diseased ear, as areconvex lenses to the physiological process of thickening of thecrystalline lens and rigidity of the ciliary muscle, which we termpresbyopia. The physician can only therefore advise hispatients to use one of the simple conductors of sound that arehere delineated, as being all that science, as yet, offers to thehopelessly deaf. Fig. Hearing Trumpets. It will be seen that the first is a flexible speaking tube,which is very convenient for conversation, and is in fact calleda conversation tube. The second and third figures representthe ordinary metallic trumpets which aid many persons withimpaired hearing to hear addresses, sermons, and so many churches long flexible tubes run from beneath thepulpit to the seats of those whose hearing is impaired, and areused as is the conversation tube. I am very much in doubtas to the value of the so-called auricles, represented in thefourth figure. The most different accounts are given as to HEARING TRUMPETS. 555 their value as assistance to the hearing power. They are, ofcourse, worn over the head and fit into the meatus. The simpler apparatus are usually the best. It is some-times of advantage to use little clamps which hold up theauricle, as deaf people do with their hands, in order t
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