The Anatomy and physiology of the organ of hearing : with remarks on congenital deafness, the diseases of the ear, some imperfections of the organ of speech, and the proper treatment of these several affections / By David Tod.

  • Tod, David.
Date:
1832
Catalogue details

Licence: Public Domain Mark

Credit: The Anatomy and physiology of the organ of hearing : with remarks on congenital deafness, the diseases of the ear, some imperfections of the organ of speech, and the proper treatment of these several affections / By David Tod. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    60/174 (page 38)
    Meatus Auditorius, and closely connected by a process of its superficial covering with the Membrana Tympani. This appendage, from being of an elastic nature,—from having muscles to act upon its various eminences and de- pressions, and a great number of nerves, blood-vessels, and glands, dispersed over its surface,—from being covered with a very thin membrane, and having an irregular con- cave and convex surface, must not only have the power of moving in different directions, and to certain degrees, but also be susceptible of some particular excitement*. From its forming the External portion of the Meatus Externus, it must have the power of dilating and contracting the orifice to a certain extent. Its connexion with the Mem- brana Tympani must also give it the power of producing a certain action in that membrane. And from its nerves, which are very large and numerous, being derived from the Portio Dura, it must have the power of exciting, through their connexion with the Chorda Tympani, certain effects in the Apparatus of the Tympanum, and, through their union with the Pes Anserinus, certain sympathies with the surface of the Head, Face, and Neck. From all these con- siderations, then, have we not reason to assign to the Au- ricle, notwithstanding all that has been said to the con- trary, an office of some importance ? We believe that we have : and in this opinion we are strengthened when we refer to the Inferior Animals. Do!we not there find that the Auricle t is provided, of especial size &c., to those whose * Some writers dispute the utility of the Auricle, and consider it as a mere ornamental appendage. And in support of their ideas, they affirm that horses which have their Ears cropt hear quite as well as those which have not. But how can they prove this ? That horses which have their Ears cropt hear very well, no one can deny; but how can they prove that their hearing is not in the smallest degree dete- riorated by this operation ? f In worms, insects, fishes, and reptiles, there is no Auricle or Me- atus Externus. In birds there is a Meatus, which is chiefly cartilaginous. In the Cete quadrupeds the Meatus is long and winding, and in every other quadruped it is very large.— Vide Scarpa de Aiiditu et Olfactu, fol. Pav. 1760. 4