. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . hlearbranch of same. such animals as the horse or cow, but little use as a collectingorgan for the vibrations of the air. The meatus or auditorycanal may be regarded both as a conductor of vibrations andas protective to the middle ear, especially the delicate drum-head, since it is provided with hairs externally in particular,and with glands that secrete a bitter substance of an unctuousnature. The Membrana Tympani is concavo-convex in form, andhaving attached to it the chain of bones
. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . hlearbranch of same. such animals as the horse or cow, but little use as a collectingorgan for the vibrations of the air. The meatus or auditorycanal may be regarded both as a conductor of vibrations andas protective to the middle ear, especially the delicate drum-head, since it is provided with hairs externally in particular,and with glands that secrete a bitter substance of an unctuousnature. The Membrana Tympani is concavo-convex in form, andhaving attached to it the chain of bones shortly to be noticed,is well adapted to take up the vibrations communicated to itfrom the air; though it also enters into sympathetic vibrationwhen the bones of the head are the medium, as when a tuning-fork is held between the teeth. Ordinary stretched membraneshave a fundamental (self-tone, proper tone) tone of their own,to which they respond more readily than to others. HEARING. 559 If such held for the membrana tympani, it is evident thatcertain tones would be heard better than others, and that when. Fig. 402.—Photographic representation of right membrana tympani, viewed fromwithin (after Flint and Uiidinger). 1. divided head of malleus; 2. neck; 3. handle,with attachment of tendon of tensor tympani; 4, divided tendon; 5. 6, long handleof malleus; 7, outer radiating and inner circular fibers of tympanic membrane; 8,fibrous ring encircling membrana tympani; 9,14,15, dentated fibers of Gruber; 10,11. posterior pocket connecting with malleus; 12, anterior pocket; 13, chorda tym-pani nerve. the fundamental one was produced the result might be a sensa-tion unpleasant from its intensity. This is partially obviatedby the damping- effect of the auditory ossicles, which also pre-vent after-vibrations. Some suppose that what we denominate shrill or harshsounds are, in part at least, owing- to the auditory meatus hav-ing a corresponding fundamental note of its own. The Auditory Oss
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