Handbook of Physiology Volume 2 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1885 Excerpt: ...of displacement of their particles; and it is not impaired whtu, like the membrane of the fenestra rotunda, they are not impregnated with moisture. Sonorous vibrations are also communicated without any perceptible loss of intensity from the air to the water, when to the membrane forming the medium of communication, there is attached a short, solid body, which occupies the greater part of its surface, and is alone in contact with the water. This fact elucidates the action of the fenestra ovalis, and of the plate of the stapes which occupies it, and, with the preceding fact, shows that both fenestrae--that closed by membrane only, and that with which the movable stapes is connected--transmit very freely the sonorous vibrations from the air to the fluid of the labyrinth. A small, solid body, fixed in an opening by means of a border of membrane, so as to be movable, communicates sonorous vibrations from air on the one side, to water, or the fluid of the labyrinth, on the other side, much better than solid media not so constructed. But the propagation of sound to the fluid is rendered much more perfect if the solid conductor thus occupying the opening, or fenestra ovalis, is by its other end fixed to the middle of a tense membrane, which has atmospheric air on both sides. A tense membrane is a much better conductor of the vibrations of air than any other solid body bounded by definite surfaces: and the vibrations are also communicated very readily by tense membranes to solid bodies in contact with them. Thus, then, the membrana tympani serves for the transmission of sound from the air to the chain of auditory bones. Stretched tightly in its osseous ring, it vibrates with the air in the auditory passage, as any thin tense membrane will, when the air near it is th...