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Stephen HalesEnglish physiologist
Date of Birth: 07.09.1677
Country:  Butane |
Content:
Early Life and Education
Stephen Hales, an English physiologist, was born on September 7, 1677, in Beckenham, Kent. In 1696, he enrolled at the University of Cambridge, where he studied theology and natural sciences.
Career and Contributions
In 1703, Hales was ordained as a minister and became a vicar in Teddington, Middlesex in 1709. He conducted quantitative experiments in the field of animal and plant physiology. Hales studied transpiration, the process of water evaporation in plants, and discovered that leaves play a vital role in this process. He calculated the rate of evaporation and used a "hemostatic method" to determine the pressure of plant sap as it moved from the roots to the stem. Hales measured the growth rate of plant shoots and leaves under different conditions. He also investigated plant respiration and demonstrated that plants absorb carbon dioxide from the air.
Hales was the first to measure blood pressure in animals. He inserted a glass tube into a blood vessel and observed the height to which the blood rose. He conducted the first measurements of cardiac output, blood flow velocity, and vascular resistance. In 1718, Hales was elected as a member of the Royal Society of London, and he presented his first paper on the influence of solar heat on the ascent of sap in trees. In 1727, he published his book "Vegetable Staticks," and in 1733, he published "Haemastaticks," which summarized his experiments on animals. That same year, Hales was awarded the Copley Medal for his work on Mrs. Stephens' famous "magical" remedy for treating urinary calculi.
Later Life and Legacy
Hales invented several devices for collecting gases produced during chemical reactions and created an artificial ventilator for supplying fresh air in buildings. These ventilators were installed in prisons, St. George's Hospital, and Royal Navy ships. Hales also wrote pamphlets on the harmful effects of alcohol, which significantly contributed to the passing of restrictive laws in England in 1757. He passed away on January 4, 1761, in Teddington. Hales' contributions to the fields of physiology and medicine continue to be celebrated and remembered.
