Hitherto we have considered Linnaeus principally as a naturalist; but his merits in another department of science were such as to entitle him to rank among its more eminent cultivators. It will be recollected, that he practised medicine with success at Stockholm; that he was appointed physician to the Admiralty; that on the resignation of Roberg he obtained the professorship of anatomy, which in the following year he exchanged with Rosen, and became, with the consent of the chancellor of the university, professor of botany. As the latter chair, however, was essentially a medical one, he was bound to direct his attention to the sanative powers of plants, as well as to their uses as articles of food, and was moreover obliged to deliver lectures on materia medica and dietetics. He may even be said to have been the founder of the first-mentioned of these branches of medical science. As a text-book for his lectures, he published an account of the medicinal substances derived from the vegetable kingdom. This treatise, which appeared at Stockholm in 1749, bears the title of Materia Medica, Liber I. de Plantis digestis secundum Genera, Loca, Nomina, Qualitates, Vires, &c. The author seems to have regarded it as one of his most successful performances; for in his private memoirs he remarks of it, that "it is undoubtedly the best work that has appeared in this department of medical science." In treating of each plant, he first gives its specific character, then a synonyme from Caspar Bauhin, or its discoverer,--thirdly, the country of which it is a native,--fourthly, the Swedish officinal name, the part used, the preparations made of it, and the doses. Its qualities and uses, its effects, the diseases in which it is employed, and the compound medicines of which it forms an ingredient, are then mentioned. At the end of the volume is an index of diseases, with the plants proper for each. Haller's opinion of this work confirms that of Linnaeus himself; for, in his Bibliotheca Botanica, he says of it,--"He has referred to their proper genera very many plants which were highly celebrated for their use in medicine, although their true genus was unknown. He also praises various plants, unknown in the shops, for their healing powers. But it is necessary to read the whole work, which is among the best that its author has produced." Two other parts were published afterwards, one on the animal, the other on the mineral kingdom. The subject of dietetics also engaged his attention in an eminent degree. In this department, however, he did not write any specific volume, but confined himself to his lectures, which were copious and highly interesting.