Raffaelle says, alluding to his celebrated picture, the Transfiguration—“When I have stood looking at that picture, from figure to figure, the eagerness, the spirit, the close unaffected attention of each figure to the principal action, my thoughts have carried me away, that I have forgot myself, and for that time might be looked upon as an enthusiastic madman; for I could really fancy the whole action was passing before my eyes.” Malbranche was seized with violent palpitations of the heart when reading Descartes’s Treatise on Man:— “With curious art, the brain too finely wrought Preys on itself, and is destroyed by thought; Constant attention wears the active mind, Blots out her powers, and leaves a blank behind.” Intense occupation of mind to any particular branch of study, often brings the mind on the verge of madness. “Since the ‘Essay on Truth’ was printed in quarto,” says Dr. Beattie, “I have never _dared_ to read it over. I durst not even read the sheets to see whether there were any errors in the print, and was obliged to get a friend to do that office for me. These studies came, in time, to have dreadful effects upon my nervous system; and I cannot read what I then wrote without some degree of horror, because it recalls to my mind the horrors that I have sometimes felt after passing a long evening in these severe studies.” Boerrhave has related of himself that, having imprudently indulged in intense thought on a particular subject, he did not close his eyes for six weeks afterwards. Spinello, having painted the fall of the rebellious angels, had so strongly imagined the illusion, and more particularly the terrible features of Lucifer, that he was himself struck with such horror as to have been long afflicted with the presence of the demon to which his genius had given birth. Swedenburg saw a terrestrial heaven in the glittering streets of his New Jerusalem. Malbranche declared he heard the voice of God distinctly within him. Pascal often was seen to rush suddenly from his chair at the appearance of a fiery gulf by his side. Luther maintained that during his confinement the devil used to visit him. Hudibras says— “Did not the devil appear to Martin Luther, in Germany, for certain?” He declares that he had many a contest with his satanic majesty, and that he had always the best of the argument. At one time, the devil so enraged Luther that he threw the ink-stand at him, an action which the German commentators greatly applaud, from a conviction that there is nothing which the devil abhors more than ink. Descartes, after long confinement, was followed by an invisible person, calling upon him to pursue the search of truth.