The brain of BLAISE PASCHAL was so vitiated by passing his life in the laborious exercises of study, thought, and imagination, that certain fibres, agitated by incessant motion, made him perpetually feel a sensation, which seem’d to be excited by a globe of fire being plac’d on one side of him; and his reason being overpower’d by the disorder of his nerves, he could scarce banish the idea of the fiery globe being actually present. SPINELLO painted the devils thrown from Heaven by the Almighty, and gave so fierce a countenance to Lucifer, that he was struck with horror himself; and during the remainder of his life, his imagination was continually haunted with the figure of that demon, upbraiding him with having made so shocking a portrait of him. There are many others, whom the force of genius too much rous’d, has for ever hurried beyond the boundaries of truth. GASPAR BARLÆUS, who was at once an orator, a poet, and a physician, was not ignorant of this danger, concerning which he admonish’d his friend CONSTANTIUS HUYGENS[18]; but being blind with regard to himself, he by immoderate studies so broke the force of his sensorium, that he thought his body was made of butter, and carefully shun’d the fire, lest it should melt him, till being at last tir’d of his excruciating fears, he leapt into a well. I must still grieve for a friend of a penetrating genius, an excellent understanding, of strict morals, and one that seem’d born for a better fate; who being animated with too great a love of learning, and in particular of the medical science, by reading night and day, observing, making experiments, and meditating, at first became sleepless; then began to talk, sometimes incoherently, and sometimes rationally; at last run mad, and having scarcely escap’d with life, never recover’d his reason. I have known many others, who by study alone were first rendered phrantic, or crazy, and at length became idiots. I love, esteem, and honour an illustrious man, and a man of extraordinary abilities, who being twelve hours intent upon settling a difficult memorial, after having finish’d his work, became delirious till a soft sleep quieted the state of his nerves. Observers give us accounts of many similar cases, and I was inform’d by a witness who may be confided in, that PETER JURIEU was formerly famous for his talent at disputing, by his labours in writing books of controversy, and expounding the apocalypse, so disorder’d his brain, that though he thought like a man of sense in other respects, he was firmly persuaded that the seven fits of the cholic, with which he was tormented, had been occasion’d by a constant fight between seven horsemen that were shut up in his bowels. There have been many instances of persons, who thought themselves metamorphos’d into lanterns, and who complain’d of having lost their thighs.