the acute is quick or the grave slow; but that such is the motion of the one from the celerity, and such the motion of the other from the tardiness of its operation upon the sense. And there does seem to be an analogy between those sounds and the sharp and blunt, as perceived by the Touch; for the sharp pricks, and the blunt pushes, as it were, because the motion exerted by the one is rapid, by the other tardy; and it is in this manner that the terms in question have originated. Let us here, however, close our observations upon the nature of sound.
The voice is a sound produced by a living creature; for nothing inanimate speaks, although there are objects, such as the flute, lyre, and others, which, having range of note, harmony, and expression, are said, from a resemblance between their tones and the voice, to do so; and the voice does seem to have all the variations of note possessed by those instruments. Many creatures have no voice (as all the insanguineous, for instance, and some of the sanguineous, as fishes), which is very understandable, seeing that sound is a certain motion of the air; and with respect to those fishes which are found in the Achelous and said to speak, they produce sound by their gills, or other such part. But although the voice is a sound emanating from a living creature, it does not imply any kind of sound, or a sound produced by any kind of part; and as all sound is produced by the
