tion, was "filled with enthusiasm, and discovered the foundations of a marvelous science"; and, it may be that, during his profound meditations, in which he "turned the eye of reason inward upon itself, and tried to measure the value of his own beliefs," an idea became so dominant that the sense of hearing responded to its impression, as if a voice from without had called him "to pursue the truth." In no way, however, did this simple and momentary hallucination interrupt the great work of his life, and in no lawful way can it be interpreted as an expression of a morbid mind.
That Goethe once saw his own counterpart approach him I doubt not, but that this false perception, this passing incongruity—a mere incident of poetic revery when the mind, self-absorbed, wandered in its fancy—should be classed as evidence of a pathological condition, and made to bear witness against the healthfulness of Goethe's mind, is an assumption extravagant and absurd.
That Newton was once "decidedly insane," as some allege, is doubtful; and that he ever suffered from any mental disturbance which justifies the inference that his genius was allied to madness, I hesitate not to deny. Mr. Sully says, "The story of Newton's madness, which is given by a French biographer, and which is ably refuted by Sir David Brewster, may owe much of its piquancy to what may be called the unconscious inventiveness of prejudice."
The facts, as I gather them, point to a congestion of the brain which culminated in a brain-fever—the result of overwork under unfavorable hygienic conditions. Newton himself refers to his illness in a letter to Mr. Pepys, and again in a letter to Locke, wherein he mentions his loss of memory, and his sleepless nights. It is not strange that his illness should excite the fears of his friends, not only for his physical but for his future mental health. Mr. Pepys expressed his anxiety to Mr. Millington, who replied that he had recently seen Newton, who was then well, and that, although his illness had caused "some small degree of melancholy, there is no reason to suspect it hath at all touched his understanding." Huygens, a contemporary scientist, says, in a letter to Leibnitz in 1694, that Newton was ill for about eighteen months with phrenitis or brain-fever, from which he recovered by the use of medicines. With these data before us, it is a misconception of physiological and pathological facts to assert that Newton was insane; and that there was a kinship between his mighty genius and madness, is contradicted by the intellectual work which has given immortality to his name.
The star seen by Napoleon, which was to him an omen of success; the vision which came to Cromwell, and spoke the words prophetic of his greatness; the apparition which uttered the ominous words to Brutus—"I am thy evil genius, thou wilt meet me at Phillipi!" the dreams and visions of Benvenuto Cellini; the "trees like men walking," as seen by Sir Joshua Reynolds, and the appearance of the devil
