=Hermann Boerhaave=, the son of a minister, was born near Leyden, in 1668. He occupied himself in turn with theology, classics, mathematics, chemistry, and botany, when he turned to physic, and, after a course of study at the University of Harderwyk, in Gelderland, began to practise. In 1702 he was appointed to a lectureship, and eventually to the Chair of Medicine, in the University of Leyden, of which he became Rector in 1714. His reputation as a teacher spread throughout Europe, and steadily increased until his death. [Illustration: HERMANNUS BOERHAAVE Medicinæ, Botanices, Chemiæ & Collegii practici, in ACAD. LUGD. BAT. PROFESSOR ORDINARIUS. After a painting by T. Wandelaar] Boerhaave was one of the most learned men of his age, and singularly well cultured, not only in science but in history, poetry, and polite literature. He conversed in English, French, and German, and read Italian and Spanish with facility. “The Latin he spoke extempore in lectures or conversation was so clear that, with his action, method, and the aptness of his similes, he could level the most abstruse points to the meanest capacities.”[2] He was fond of music, and a good performer on several instruments, particularly the lute. He delighted to welcome musicians to his house. His profession as a physician brought him wealth, much of which he spent in horticulture; and the garden of his country seat, nearly eight acres in extent, was enriched with all the exotic trees he could procure and induce to flourish in the climate of Holland. [2] Burton, _Life of Boerhaave_, p. 58 _et seq._ Boerhaave was of a robust frame and healthy constitution, early inured to constant exercise and the inclemencies of weather. His stature was rather tall, and his habit corpulent. He had a large head, short neck, florid complexion, light brown curled hair (for he did not wear a wig), an open countenance, and resembled Socrates in the flatness of his nose and his natural urbanity. He died at Leyden on September 23rd, 1738, in the seventieth year of his age. As a chemist Boerhaave is chiefly known by his _Elementa Chemia_, published in 1732—the most complete and most luminous chemical treatise of its time, translations of which appeared in the chief European languages. The work is divided into three main parts. The first is concerned with the origin and progress of the art, and with the personal history of its most distinguished cultivators. The second and largest part deals with the attempt to form a system of chemistry based on such observational matter as seemed well established. The third consists of a collection of chemical processes relating to the analysis or decomposition of bodies, grouped under the heads of “vegetables,” “animals,” and “fossils”—the beginnings, in fact, of subdivision of the science into organic and inorganic chemistry.