In the year 1858 Herr von Hartmann entered the crack artillery regiment of Berlin as volunteer. He then passed three years at the artillery school, intermingling the scientific studies of his profession with artistic and philosophic researches, and frequenting meanwhile the refined society to which his family belonged. About this time a rheumatic affection, which had first declared itself toward the close of his school-days, became complicated with a fracture of some of the delicate machinery of the knee. The injury was both painful and incurable, and in 1864 he was obliged to resign his position, and thereupon left the army with the grade of first lieutenant. These latter details are given by way of counterbalance to the calumnies of his enemies, who, in explaining his pessimism by the state of his health,--which they insinuate was brought about by excessive and unusual debauchery,--have in one way and another managed to vituperate his chief work into nine editions. On leaving the army he sought a career first as painter and then as musician; it did not take him long, however, to discover that his vocation was not such as is found in purely artistic pursuits; "the bankruptcy of all my ambitions," he says, "was complete; there remained to me but one thing, and that was thought." It was from thought, then, that he demanded a consolation and an employment, and turning to metaphysics he began at once to plan his "Philosophy of the Unconscious." Meanwhile, for his own distraction and instruction he had written a few essays, of which but one was destined to see the light of day. This monograph, "Die dialektische Methode," was so favorably viewed at Rostock, that he received therefrom the degree and title of Doctor of Philosophy. "The Philosophy of the Unconscious," when completed, remained a year in his closet, and was only published in 1868, owing to an accidental meeting with an intelligent publisher. Before, as since, the appearance and success of this work, which is very generally considered as the chief philosophical event of the last two decades, Dr. von Hartmann has lived at Berlin, where he endeavors in every-day life to prove the practical value of evolutionary pessimism, which it is his wish to substitute for the indifferentism and quietist doctrines of Schopenhauer.