Oken, Lorenz, a celebrated Swiss naturalist, was born at Offenberg Aug. 2, 1779. He studied medicine and natural history at Gottingen, and held the position of privat-docent in that university. In 1807 he became extraordinary professor of medicine in the University of Jena; thence he removed to Zurich, where he held the post of professor of natural history till his death, which occurred in August, 1847. At the time when Oken .began to study natural science, the writings of Kant, Fichte, and, Schelling were producing a deep impression on the minds of the students of natural history. Schelling,s who had studied medicine, had applied the principles of the transcendental philosophy to the facts of the natural World, and had by a process of thought endeavored to give an explanation of the phenomena of nature. It was in this school that Oken studied, and the principles of the transcendental philosophy more or less guided his researches as a naturalist throughout his long life. His first work was published in 1802, and was entitled Elemente der Natur-Plilosophie. This was followed in 1805 by a work on Die Zeugung. In these books he endeavored to apply a general theory of nature to the facts presented by the forms and the development of animals. In his classification he took for his basis the presence of the senses, making each class of animals to represent an organ of sense. In his work on Generation he first suggested that all animals are built up of vesicles or cells. The formation of seminal matter is described as taking place by the decomposition of the organism into infusoria, and propagation is described as the flight of the occupant from his falling house. In 1806 he published his Contributions to Comparative Anatomy and Physiology, and pointed out the origin of the intestines in the umbilical vesicle. In this year he made an excursion to the Harz Mountains, which resulted in an important thought. — This may be described in his own language: "In- Auggst, 1806," he says, "I made a journey over the Harz. I slid down through the wood on the south side; and straight before me, at my feet, lay a most beautiful bleached skull of a hind. I picked it up, turned it round, regarded it intensely: the thing was done. "It is a vertebral column!' struck me as a flash of lightning to the marrow and bone; and since that time the skull has been regarded as a vertebral column." This discovery was published in an essay on the "Signification of the Bones of the Skull." The essay, although it attracted little attention at first, laid the foundation of those inquiries which, in the hands of Carus, Geoffroy St. Hilaire, and Owen, have led to the establishment of those laws of homology in the vertebrate skeleton that are now a universally received branch of anatomical science. It was by the persevering use of the idea that flashed across his mind in the Harz that Oken has earned for himself the title of "the father of morphological science." While still a young man, and deeply convinced of the importance of an ideal philosophy in explaining the phenomena of the external world, he wrote his Lehrbuch der Natur-Philosophie (Jenla, 1809; 3d ed. Zurich, 1843), translated into English by Mr. Fulke, and published in 1847 by the Ray Society, entitled Elements of Physio-Philosophy. In this work the author takes the widest possible view of natural science, and classifies the mineral, vegetable, and animal kingdoms according to his philosophical views. "The animal kingdom," says Oken, "is man resolved into his constituent elements; what in the lower stages of animal life are independent antagonisms reappear in the higher as attributes." In 1817 Oken started a natural-history journal entitled his, which he conducted for thirty years. See English Cyclop. s.v.; Ueberweg, Hist. of Philos. 2:227; Tinnemann, Manual of Philos. (see Index); Morell, Hist. of Philos. in the 19th Century (see Index).