Boerhaave, HERMANN, the most celebrated physician of the 18th century, was born at Voorhout, near Leyden, December 31, 1668. In 1682 he went to Leyden, where he studied theology and oriental languages, and took his degree in philosophy in 1689. In 1690 he began the study of medicine, and took his doctor's degree in 1693. In 1701 he was appointed lecturer on the Theory of Medicine at Leyden, and in his inaugural lecture recommended to the students the ancient method of Hippocrates in medicine; but in 1703 his views had become greatly enlarged. In 1709 he was elected professor of Medicine and Botany. About this time he published the two works on which his great fame chiefly rests, Institutiones Medicæ (1708), and Aphorismi de Cognoscendis et Curandis Morbis (1709), both of which were translated into various European languages, and even into Arabic. In the first work—a model of comprehensive and methodical learning—he gives a complete outline of the theory of medicine; in the second, a classification of diseases with their causes and modes of treatment. Boerhaave also rendered important services to botany. His best lectures include those delivered on his resignation of the office of rector of the university, De Comparando Certo in Physicis (1714), and De Honore Medici, Servitute (1736); in the latter of which he declares that to be the servant of nature is the highest aim of medicine. To combine practice with theory, he caused a hospital to be opened, where he gave clinical instructions to his pupils. Though so industrious in his own profession, he undertook in 1718 the professorship of Chemistry, and published in 1724 his Elementa Chemicæ, a work which did much to render this science clear and intelligible, and one that will always occupy a high place in the history of chemistry. His fame had meanwhile rapidly increased. Patients from all parts of Europe came to consult him. Peter the Great of Russia visited him; and it is even said that a Chinese mandarin sent him a letter, addressed 'BOERHAAVE, celebrated physician, Europe.' His character was amiable and unassuming, and tinged with a deep but cheerful piety. He died September 23, 1738, having realised from his profession a fortune of two millions of florins. See Burton, Account of the Life and Writings of Boerhaave (2 vols. Lond. 1743); Johnson, Life of Boerhaave (Lond. 1834).