Whilst Boerhaave presided in the chair, in chemistry, medicine, and botany, the city of Leyden was considered the school of Europe in these sciences. In 1715, when Peter the Great went to Holland to study maritime affairs, he regularly attended the lectures of Boerhaave. So widely diffused was his fame, that a mandarine in China wrote to him a letter thus superscribed; “_To the illustrious Boerhaave, physician in Europe_,” and it was regularly received. It was the daily practice of this eminent physician, through his whole life, as soon as he rose in the morning, which was generally very early, to retire for an hour to private prayer, and meditation on some part of the Scriptures. He often told his friends, when they asked him how it was possible to go through so much fatigue, that it was _this_ which gave him spirit and vigour in the business of the day. This he therefore recommended as _the best rule_ he could give; for nothing, he said, could tend more to the health of the body than the tranquillity of the mind, and that he knew nothing which could support himself and his fellow-creatures, amidst the various distresses of human life but a well-grounded confidence in the Supreme Being, upon the principles of christianity: the truth of his doctrine he finely illustrated in his severe illness in 1722, when the course of his lectures and his practice were long interrupted. Of his sagacity and wonderful penetration in the discovery and description of such distempers as betray themselves by no symptoms to common eyes, such surprising accounts have been given, as scarcely can be credited, though attested beyond all doubt. Yet this great master of medical knowledge was so far from feeling a presumptuous confidence in his mighty talents, or from being inflated by his prodigious wealth, that his condescension to the humblest being who approached him, and his unceasing professional application were ever the theme of admiration and astonishment.