John Beresford Leathes

John Beresford Leathes (5 November 1864 – 14 September 1956) was a British physiologist and an early biochemist. a descendant of a Dr. Butt who was a physician to Henry VIII,

Leathes was a student demonstrator in Anatomy at Guy's, and during 1894–95 was a demonstrator there in Physiology under his friend Ernest Starling. He could not train as a surgeon owing to his poor eyesight. In 1895 he was elected a member of The Physiological Society. From 1895 to 1897 Leathes was studying in Bern before moving to Strasbourg (1898–99) where he studied under Oswald Schmiedeberg. On returning to London in 1899 Leathes was appointed Lecturer in Physiology at St Thomas's Hospital Medical School.

During World War I he was in charge of the nephritis wards at the Northern General Hospital in Sheffield and was appointed to the staff of the hospital as Honorary Physiologist in addition to being responsible for the establishment of biochemical laboratories at the two general hospitals in the city in 1919. He represented Sheffield University on the General Medical Council from 1919 to 1938, and for 10 years was an editor of The Journal of Physiology. Leathes remained at Sheffield until his retirement in 1933.

Leathes was elected a Fellow of the Royal Society in 1911. In 1921 he was made a Fellow of the Royal College of Physicians of London, where in 1923 he delivered the Croonian Lecture, and in 1930 the Harveian Oration. He was awarded Honorary Doctor of Science degrees by the University of Manchester and the University of Sheffield. in London in 1896. Their daughter Margaret Leathes married Lionel Penrose MD, FRS, Professor of Genetics at University College, London in 1928, and was the mother of Oliver Penrose, the theoretical physicist; Sir Roger Penrose, a mathematical physicist; Jonathan Penrose, the chess player and Shirley Hodgson, a geneticist.

Publications Problems in Animal Metabolism; A Course of Lectures Given in the Physiological Laboratory of the London University at South Kensington in the Summer Term, 1904 London : John Murray, (1906) The Fats London : Longmans & Co., (1910)