Lectures on aural catarrh Author:Peter Allen Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: LECTURE III. METHOD OF EXAMINATION—(continued). Gentlemen,—You have seen, in the out-patient's room, what very valuable assistance to our means of diagnosi... more »s is afforded by the use of the vibrating tuning-fork placed on the vertex of the patient's head; in fact, you never witness a thorough examination of a new comer without this test being applied. It is only within a short period that a knowledge of the fact of sound-conduction by the bones of the head has been rendered so practically valuable in the diagnosis and prognosis of aural disease, and we are chiefly indebted to Lucse, Politzer, and Mach for their scientific investigations in this direction. The tuning-fork is employed principally in distinguishing affections of the conducting apparatus (the external and middle divisions of the ear) from those of the auditory nerve. It had been known for years thatthe watch or tuning-fork, placed on the forehead or between the teeth, was better heard if the auditory meatus was stopped with the fingers; but no very satisfactory conclusions were drawn, nor any material aid in diagnosis derived from this fact. It must always be remembered that any sonorous vibrations which once get into the tympanum become intensified by resonance. The common speaking-tube is a familiar example of sounds being strengthened thus when confined in cavities of any sort. That this is the case with regard to the tympanum and its continuous tube, the osseous meatus, may be proved by closing the external passage with the fingers, when, if a tuning-fork be set vibrating on the head, or a humming sound or reading be kept up, the sounds, being conveyed through the cranial bones to the cavities of the ear, will become considerably intensified. This fact is made still more evident by placing a vibrating tun...« less