Cullen, WILLIAM, M.D., physician, was born at Hamilton, Lanarkshire, on 15th April 1710, his father being factor to the Duke of Hamilton. After learning his profession, first as apprentice to a surgeon-apothecary in Glasgow, next as surgeon on board a West Indian trading ship, and then as assistant to an apothecary in London, he returned to Scotland in 1731, and commenced practice in his native county. Feeling the necessity of more systematic study, he spent two winters at Edinburgh University under Munro primus, and then removed to Hamilton, where he soon secured a good practice. One of his articulated pupils was William Hunter (q.v.), to whom he became extremely attached; and it was agreed that one of them should be alternately allowed to study during the winter, while the other carried on the practice. Cullen spent the first winter at Edinburgh, and it is at this time that he appears to have taken an important part in founding what is now known as the Royal Medical Society. It being Hunter's turn next year he went to London, and having attracted attention there, did not return, Cullen generously cancelling the articles. In 1740 Cullen graduated M.D. at Glasgow University, gave up surgical work, and soon after established himself in Glasgow as a physician. At that time there was not in Glasgow any regular course of medical study, and Cullen occupied himself much in the foundation of a medical school, himself lecturing on various subjects. One of his pupils was the famous Dr Joseph Black (q.v.). Cullen's labours resulted in his appointment to the chair of Medicine in the university, which he occupied four years. In 1755 he was persuaded to leave Glasgow for Edinburgh, and for the next thirty-five years was one of the mainstays of the Edinburgh medical school. During this long period he occupied successively the chairs of Chemistry, Institutes of Medicine, and Medicine, besides teaching clinically in the Royal Infirmary all the time.
Living as he did in what might be termed the renaissance period of the history of medicine, Cullen was essentially a man of his time, and did much to advance the science. For many centuries all disease had been referred to disorders of the fluids of the body. Just before Cullen's time, Boerhaave had added to this a pathology of the 'fibres' still strongly tinctured with the old fluid or humoral pathology. To Cullen is largely due the recognition of the important part played by the nervous system both in health and disease. He denied the theory supported even by Boerhaave, that the brain was an excretory organ and the nervous influence a fluid. Many of his speculations as to reflex nervous action, the possible presence in a single nerve of both sensory and motor fibres, and the connection of sensory and motor nerves with the anterior and posterior nerve roots, have now been proved to be facts. He had a singularly open and candid mind, and while himself introducing the use of several new drugs, as oxide of antimony and tartar emetic, was careful to distinguish between the action of drugs and the curative operations of nature. It may be said of him in his own words when speaking of Sydenham, 'that he rather sought for theory to connect his facts, than for facts to support his theory.'
In the later years of his life arose the controversy on the Brunonian system (see BROWN, JOHN, M.D.), which system Cullen bitterly opposed. Brown's specious division of diseases into sthenic and asthenic was obviously a deduction from Cullen's theories of nerve influence, and was only one instance out of many where a reputation was built on ideas borrowed from Cullen.
Cullen died on 5th February 1790 at his small estate of Ormiston Hill, having nearly completed his seventy-ninth year, and having been actively engaged in teaching and consulting practice till within a few months of his death. Cullen's most important works are First Lines of the Practice of Physic (Edin. 1777), Synopsis Nosologiae Methodicae (1785), Institutions of Medicine (1777), A Treatise on the Materia Medica (1789). See Biography, vol. i. by Dr John Thomson (1832), vol. ii. by Cullen's son and Dr David Craigie (1859), also an article by Sir W. Hamilton in the Edinburgh Review (1831).