How to keep well : a text-book of physiology and hygiene for the lower grades of schools / by Albert F. Blaisdell.

  • Albert F. Blaisdell
Date:
[1921]
Catalogue details

Licence: Public Domain Mark

Credit: How to keep well : a text-book of physiology and hygiene for the lower grades of schools / by Albert F. Blaisdell. Source: Wellcome Collection.

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    279. Hearing. —We have ears which help us to keep in touch with the outside world. Next to sight, hearing is the most important of the senses. We could get along without being able to taste; but without seeing and hear- ing life would be almost a blank. Animals that have a backbone always have the organ of hearing in the head. Birds have no out- ward ears, but they are very sharp at catching the call of their own kind, or the cry of a hawk. The cricket has ears, but they are on its legs. Our own ears have their delicate parts securely lodged in the bones on either side of the head. 280. The Outer Ear. — The outer ear is a piece of gristle covered with skin. It is curiously molded and serves as a sort of wind sail to catch sounds. In some animals it is quite large and movable; hence the timid rabbit and the intelligent horse “ prick up their ears ” to listen. The tube in the ear is about an inch long, and guides the sound inward just as an ear trumpet does. At the lower end of this passage we find a delicate membrane stretched tightly across, which serves as a partition between the outer and the middle ear. It is Fig. 120 The Outer Ear
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