Paracelsus, Philippus Aureolus (1493–1541)

Swiss physician, alchemist, and scientist who developed the idea that minerals and chemicals might have medical uses (iatrochemistry). He introduced the use of laudanum (which he named) for pain-killing purposes.

Overturning the contemporary view of illness as an imbalance of the four humours (see humours, theory of), Paracelsus sought an external agency as the source of disease. This encouraged new modes of treatment, supplanting, for example, bloodletting, and opened the way for new ideas on the source of infection.

Paracelsus was extremely successful as a doctor. His descriptions of miners' diseases first identified silicosis and tuberculosis as occupational hazards. He recognized goitre as endemic and related to minerals in drinking water, and originated a medical account of chorea, rather than believing this nervous disease to be caused by possession by spirits. Paracelsus was the first to distinguish the congenital from the infectious form of syphilis, and showed that it could be treated with carefully controlled doses of a mercury compound.

Paracelsus was born in Einsiedeln, Schwyz canton. Like many of his contemporaries, he became a wandering scholar, studying at Vienna, Basel, and several universities in Italy. He was a military surgeon in Venice and the Netherlands and is said to have visited England, Scotland, Russia, Egypt, and Constantinople. Having practised as a physician in Austria, he became professor of medicine at Basel in 1527, but scandalized other academics by lecturing in German rather than Latin and by his savage attacks on the classical medical texts – he burned the works of Galen and Avicenna in public – and was forced to leave Basel in 1528. In 1541 he was appointed physician to Duke Ernst of Bavaria.

Paracelsus was the disseminator in Europe of the medieval Islamic alchemists' theory that matter is composed of only three elements: salt, sulphur, and mercury. His study of alchemy helped to develop it into chemistry and produced new, nontoxic compounds for medicinal use; he discovered new substances arising from the reaction of metals and described various organic compounds, including ether. He was the first to devise such advanced laboratory techniques as the concentration of alcohol by freezing. Paracelsus also devised a specific nomenclature for substances already known but not precisely defined, and his attempt to construct a system of grouping chemicals according to their susceptibility to similar processes was the first of its kind.