In addition to the preceding, there are still some singular circumstances that deserve to be mentioned with reference to the voice. If saw-dust or sand is thrown down in the orchestra of a theatre, or if the walls around are left in a rough state, or empty casks are placed there, the voice is absorbed; while, on the other hand, if the wall is quite straight, or if built in a concave form, the voice will move along it, and will convey words spoken in the slightest whisper from one end[361] to the other, if there is no inequality in the surface to impede its progress. The voice, in man, contributes in a great degree to form his physiognomy, for we form a knowledge of a man before we see him by hearing his voice, just as well[362] as if we had seen him with our eyes. There are as many kinds of voices, too, as there are individuals in existence, and each man has his own peculiar voice, just as much as his own peculiar physiognomy. Hence it is, that arises that vast diversity of nations and languages throughout the whole earth: in this, too, originate the many tunes, measures, and inflexions that exist. But, before all other things, it is the voice that serves to express our sentiments,[363] a power that distinguishes us from the beasts; just as, in the same way, the various shades and differences in language that exist among men have created an equally marked difference between us and the brutes. CHAP. 113. (52.)—SUPERFLUOUS LIMBS. Supernumerary limbs, when they grow on animals, are of no use, which is the case also with the sixth finger, when it grows on man. It was thought proper in Egypt to rear a human monster, that had two additional eyes in the back part of the head; it could not see with them, however. CHAP. 114.—SIGNS OF VITALITY AND OF THE MORAL DISPOSITION OF MAN, FROM THE LIMBS.