Studies from the psychological laboratory of the University of Chicago: The role of the tympanic mechanism in audition
This paper reports a case of a person who enjoys good hearing in spite of the destruction of the ' sound-conducting' mechanism of both ears. When she first came under our observation, in the summer of 1906, her auditory acuity was such that a group of acquaintances who had been her constant associates for several weeks had not suspected any auditory impairment; and at the present time, although the condition of her hearing is not as good as it was then, it is still acute enough to enable her to
... gh to enable her to carry efficiently forward her work as a teacher. The statement that efficient hearing is still possible after both drum membranes have been destroyed and the larger ossicles removed comes as a surprise to those whose attention has not been previously directed to the pathology of the ear. It means that the account which Helmholtz gave of the mechanism of sound-conduction is untenable, at least as regards his theory of the sound-intensifying function of the tympanic membrane. Dissatisfaction with this theory has been rife in otological circles for some years, owing to its inadequacy when confronted by the facts of aural pathology. Beckmann* in 1 The MS. of this article was received April 8, 1907. *'Znr Theorie des HBrens,' Verhandl. der deutsche otol. Ges., 1898. See Treitel, 'Recent Theories of Sonnd-conduction,' Archives of Otology, 1903, p. 385. Treitel gives an admirable summary of the literature up to 1902, and concludes that the problem of the middle ear has not yet been solved. 229 1 In addition to the articles summarized by Treitel, cf.' Der physiologische Werth der Labyrinthfenster/ 1904, Arch.f. Physiol., Suppl. Bd., S. 193. Also S. 409 and S. 488. * Arch.f. Ohrenheilk., LV., Heft. 3-4. Cf. Treitel, /. c. »Arch.f. 'Physiol., 1904, Suppl. Bd., S. 490. '"Weitere Untersuchungen uber 'Knochenleitnng' nnd Schallleitnngsapparat im Ohr.," Zeits.f. Ohrenheilk., XLVIII., 107. 1 Since the above was placed in type the writer has learned that K. S. Schaefer has found in Berlin several cases of patients who hear without drum membranes, and some who lack the larger ossicles; and all are able to hear difference-tones. A full description of these interesting cases with a discussion of their bearing upon theories of difference-tones may be expected soon from Dr. Schaefer's pen. *' Des diverses modalites des monvements de la chaine des osselets.'/oar. Physiol. Pathol., 1905, VII., 665.