Physiologist. Born in Hamilton (South Lanarkshire), William Cullen was renowned in Glasgow and Edinburgh as a physician and professor of medicine. His beliefs that life was a function of nervous energy and that muscle was an extension of nerve were fundamental to his teachings. He lectured in botany and chemistry, and is known to have demonstrated the refrigeration apparatus in 1748. He was appointed to the Chair of Medicine at the University of Glasgow in 1751 and as joint Professor of Chemistry in the University of Edinburgh in 1756. With an unrivalled reputation as a lecturer, Cullen also gave classes in clinical medicine at the Royal Infirmary of Edinburgh. His publications include A Treatise on Materia Medica (1789) and Synopsis Nosologiae Methodicae (1785). Cullen was a founding fellow of the Royal Society of Edinburgh in 1783.