Hearing is a much more necessary sense to man than to any other animal. In the latter it is only a warning against danger, or an encouragement to mutual assistance. In man, it is the source of most of his pleasures, and without it the rest of his senses would be of little benefit. A man born deaf must necessarily be dumb, and his whole sphere of knowledge must be bounded by sensual objects. We shall here notice a singular instance of a young man, who, born deaf, at the age of 24 suddenly acquired the faculty of hearing. The account, which is given in the Memoirs of the Academy of Sciences, 1703, page 18, is in substance as follows: "A young man, of the town of Chartres, aged about 24, the son of a tradesman, who had been deaf and dumb from his birth, began to speak of a sudden, to the utter astonishment of the whole town. He gave his friends to understand, that for three or four months before, he had heard the sound of the bells, and was greatly surprised at this new and unknown sensation. After some time a kind of water issued from his left ear, and he then heard perfectly well with both. During these three months he listened attentively to all he heard, and accustomed himself to speak softly the words pronounced by others. He laboured hard in perfecting himself in the pronunciation, and in the ideas attached to every sound. At length, supposing himself qualified to break silence, he declared that he could speak, though as yet but imperfectly. Soon after some able divines questioned him concerning his ideas of his past state, and principally with respect to God, his soul, the moral beauty of virtue and deformity of vice. Of these, however, he did not appear to have the slightest conception. He had gone to mass indeed with his parents, had learned to sign himself with the cross, to kneel down, and to assume all the external signs of devotion; but he did all this without comprehending the intention or the cause. He had no idea even of death, but led a life of pure animal instinct, and though entirely taken up with sensual objects, and such as were present, he yet did not seem to have made any reflections upon them. The young man was not, however, in want of understanding, but the understanding of a man deprived of all intercourse with society is so very confined, that the mind is, in some measure, totally under the control of its immediate sensations." It is possible, nevertheless, to communicate ideas to deaf men, and even to give them precise notions of general subjects, by means of signs, and by writing. A person born deaf, may be taught to read, to write, and even by the motion of the lips to understand what is said to him; a plain proof how much the senses resemble, and may supply the defects of each other.