——“Have we eaten of the insane root, That takes the reason prisoner?” MACBETH. EV. The contrasts to these phantoms of blind superstition, are those of the _overstrained_ condition of the mind. The Creator has ordained the brain to be the soil in which the mind is implanted or developed. This brain, like the corn-field, must have its fallow, or it is exhausted and reduced in the degree of its high qualities. In our intellectual government, therefore, we should ever adopt that happy medium, equally remote from the bigotry of the untutored, and the ultra refinement of the too highly cultivated mind. It is not essential that I should now offer you more than a hint, that the essence of the gloomy ghosts of deep study, like the melancholy phantoms and oppressive demons of the night-mare, consists in the accumulation of black blood about the brain and the heart; and a glance at phrenology would explain to you how the influence of that blood on the various divisions of the brain will call up in the mind these “Hydras and Gorgons, and Chimeras dire.” The learned Pascal constantly saw a gulph yawning at his side, but he was _aware_ of his illusion. He was, however, always strapped in his chair, lest he should fall into this gulph, especially while he was working the celebrated problem of the cycloidal curve. A distinguished nobleman, who but lately guided the helm of state in England, was often annoyed by the spectre of a bloody head;—a strange coincidence with the phantom of the Count Duke d’Olivarez, the minister of Philip of Spain. From Dr. Conolly we learn the curious illusion of a student of anatomy, who, during his ardent devotion to his study, confidently believed that there was a town in his _deltoid_ muscle. And, from Dr. Abercrombie, the case of a gentleman of high literary attainments, who, when closely reading in his study, was repeatedly annoyed by the intrusive visits of a little old woman in a black bonnet and mantle, with a basket on her arm. So _filmy_, however, was this phantom, that the door-lock was seen through her. Supposing she had mistaken her way, he politely showed her the door, and she instantly vanished. It was the change of posture which effected this disappearance, by altering the circulation of the brain-blood, then in a state of partial stagnation. My friend, Dr. Johnson, has told me of a gentleman of great science, who conceived that he was honoured by the frequent visits of spectres. They were at first refined and elegant both in manners and in conversation, which, on one occasion, assumed a witty turn, and quips, and puns, and satire, were the order of the evening; so that he was charmed with his ghostly visitors, and sought no relief. On a sudden, however, they changed into demoniac fiends, uttering expressions of the most degraded and unholy nature. He became alarmed, and depletion soon cured him of his phantasy.