. Human physiology : designed for colleges and the higher classes in schools, and for general reading. ve distributed there, cause the sensationof hearing. Of course, if either of the membranes covering theopenings into these passages be destroyed or broken, the fluidwill run out from the ear, and there can be no more hearing,although the rest of the apparatus is perfect. The drum wilicontinue to vibrate as sounds strike upon it, the little chain ofbones will repeat the vibration, but it will stop at the end ofthe chain, the stirrup-like bone. So too, although the mem-branes may be entire, and
. Human physiology : designed for colleges and the higher classes in schools, and for general reading. ve distributed there, cause the sensationof hearing. Of course, if either of the membranes covering theopenings into these passages be destroyed or broken, the fluidwill run out from the ear, and there can be no more hearing,although the rest of the apparatus is perfect. The drum wilicontinue to vibrate as sounds strike upon it, the little chain ofbones will repeat the vibration, but it will stop at the end ofthe chain, the stirrup-like bone. So too, although the mem-branes may be entire, and the whole apparatus may be perfectas a piece of mechanism, so that the succession of vibrationsfrom the air without through the drum and the chain of bones,to the fluid of the labyrinth, is uninterrupted, if the nerve ofhearing be paralyzed, so that it cannot be impressed with thevibration of the fluid that bathes its branches, there can be nohearing. Partial deafness is undoubtedly often owing to athickening of the fluid in these passages, or to a partial failureof the nerve distributed in THE EAR. 279 Principles of transmission of sound observed in the arrangement. 419. It will be proper to say a word here in relation to thechoice of a fluid, instead of a solid or an aeriform substance, asthe medium through which the impression of the vibration ofsound is communicated to the nerve. It is better than a solidwould be, so far as we can see, because no arrangement of avibrating solid with the minute fibres of the branches of thenerve could bo effectual, and at the same time so little liableto derangement, as the arrangement of nervous fibres immersedin a liquid, and the whole inclosed in solid walls of bone. Itis better than air would be, for at least two reasons. 1st. Thevibrations of sound, as stated in § 409, are communicated withmuch more ease and rapidity through water than through we see to be a consideration of some importance, when welook at the complica
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