of fine fibres, some radiating from the central part to the circumference, and others arranged in concentric rings. It is kept gently on the stretch by two small muscles, one of which draws it tighter, and the other loosens it, by acting upon a chain of small bones. We shall not undertake to describe the curious and complicated anatomy of the inner ear—the drum, containing air, the curious chain-work of minute vibrating bones, the labyrinth filled with water containing little crystalline particles and fine elastic bristles, and where the delicate fibres of the auditory nerve commence. "There is also," says Tyndall, "in the labyrinth a wonderful organ discovered by the Marchese Corti, which is, to all appearance, a musical instrument, with its chords so stretched as to accept vibrations of different periods, and transmit them to the nerve-filaments which traverse the organ. Within the ears of men, and without their knowledge or contrivance, this lute of 3,000 strings (as Kölliker estimates) has existed for ages, accepting the music of the outer world, and rendering it fit for reception by the brain. Each musical tremor which falls upon this organ selects from its tensioned fibres the one appropriate to its own pitch, and throws that fibre into unisonant vibration. And thus, no matter how complicated the motion of the external air may be, those microscopic strings can analyze it, and reveal the constituents of which it is composed." By this wonderful apparatus are all the tremulous movements of the outer world translated to the world within. How the auditory nerve transmits its impressions is not a matter of demonstration, but the probability is great that it transmits them as it receives them as impulses of motion waves of force that are conveyed to the brain and expended in the production of those physical motions which are the material conditions and accompaniments of consciousness. That the organ of feeling and thought is itself a sphere of vibrations and wave-actions traversing in all directions the millions of microscopic fibres which pervade the encephalon, will be thought absurd by many: but we know that wave-action is a part of the method of Nature; that it produces the most wonderful effects in all the common forms of matter; that the brain is a material instrument in the closest physical relation with the outward order; and that material changes of some kind within it are the concomitants of its exalted functions. That there should be unity in the whole scheme does not appear irrational.
Be this as it may, the marvels of what is known are inexhaustible. Could we see what takes place in a room when a tuning-fork is in vibration, giving out a single note, we should behold all the particles of the air agitated in tremulous sympathy, and filling the space with swiftly-expanding spheres of spectral beauty. Or, were the effect produced by several instruments concurrently played, we should see the forms in countless variety carving the air into ever-changing figures of geometrical harmony, and creating the perfect music of geometrical form. Such a revelation is impossible, from the swiftness of movement,
