[Mercury--a major agent in the history of medicine and alchemy]

From ancient time the history of mercury has been connected with that of the medicine and chemistry. Mercury therefore contributes to the history of science throughout times. Knowledge of cinnabar (HgS) is traced back to ancient Assyria and Egypt, but also to China. The Greek philosophers were the initiators of theoretical science. The idea of the four elements, earth, air, water and fire, was introduced mainly by Empedocles and Aristotle in the 5th and 4th century BC. The theory encouraged the hope of transmuting metal to gold. The early development of practical alchemy is obscure, but some hints are given in the encyclopedia compiled by Zosimos about 300 A.D. in Alexandria. It also includes the invention of equipment such as stills, furnaces and heating baths. Medical treatment is described by Pliny and Celsus, e.g. the use of cinnabar in trachoma and venereal diseases. When the Arabs learned Greek alchemy by the Nestorians, they introduced or improved chemical equipments and new chemicals were obtained such as sublimate (HgCl2), different salts, acids, alkaline carbonates and metal oxides. The first recorded account of animal experimentation on the toxicity of mercury comes from Rhazes (al-Razi) in the 9th century and in the 11th century Avicenna (Ibn Sina) had the foresight to recommend the use of mercury only as an external remedy, and quicksilver ointments were used by the Arabs in the treating of skin diseases. In the medieval west scientific experiments were forbidden since the interpretation of the world order should not be changed. Greek and Arabic medicine and alchemy were therefore authoritative and the breakthrough in scientific inventions first appeared after the introduction of the Renaissance. The Renaissance medicine included ancient medicine as well as "modern medicine", based on iatrochemistry, and this chemical approach was introduced by Paracelsus. The medicine included sulphur and salts or oxides of for instance mercury, copper, iron, antimony, bismuth and lead. Most important was mercury when the outbreak of syphilis appeared in Europe at the end of the 15th century. The Arabian quicksilver ointment was remembered and used for the treatment of syphilis, but the treatment also included pills and ointments of sublimate and calomel (Hg2Cl2). The breakthrough in science was the discovery of oxygen by Priestley in the late 18th century. Priestley heated the oxide of mercury and examined the gas and thereafter Lavoisier recognized that combustion involves oxidation. All this led to a new understanding of respiration and furthermore established the basis of modern chemistry. The apothecaries of the 19th and 20th century showed many colourful mercurials as calomel, sublimate, cinnober, oxides of mercury and mercury. Calomel pills were used in acute and chronic diseases and furthermore as a diuretic drug before the organomercurials appeared in the 1920s. Skin diseases were treated with ointments or plasters of the mercurials or quicksilver. Antiseptics were introduced by Semmelweis hand-washing with chlorinated water before deliveries in obstetrics and by Lister's antiseptic ritual with carbolic acid during surgical operations. Also organomercurial "antiseptics" were used but unfortunately these agents were bacteriostatic rather than bacteriocidal and allergic contact dermatitis has been observed. Today the problems are solved by sterilization and aseptic conditions. Penicillin appeared in the 1940s and chlorothiazide in 1957 and new effective agents have taken over in the treatment of diseases with mercurials.