1677-1761

English Physiologist and Clergyman

Although trained as a clergyman with no formal education in physiology, chemistry, or medicine, Stephen Hales became one of the most important British scientists of the eighteenth century. He can be considered the father of plant physiology, and his studies of circulation in animals were the most important after William Harvey's (1578-1657) over a century earlier. Hales conducted experiments on gases with equipment of his own design that influenced the later work of Joseph Black (1728-1799), Henry Cavendish (1731-1810), Joseph Priestley (1733-1804), and Antoine Lavoisier (1743-1794). He also did important research on respiration and in public health involving ventilation and fresh air.

Stephen Hales was born in Bekesbourne, county of Kent, England, on September 17, 1677, into an established, influential family. In 1696 he entered Benet College at Cambridge University, where he received a bachelor's degree and then a master's in 1703. In 1709 he was...