born May 3, 1860, Edinburgh, Scot.
died March 14/15, 1936, Oxford, Oxfordshire, Eng.
British physiologist and philosopher.
He developed procedures for studying the physiology of breathing and of the blood and devices for measuring hemoglobin and for analyzing blood gas and mixtures of gases. He discovered that breathing is regulated in large part by the effect of the amount of carbon dioxide in the blood on the brain's respiratory centre. He studied the effects of low air pressure, investigated the action of gases in mine suffocations and explosions (an important contribution to mine safety), and developed a staged decompression method for ascent from deep-sea dives. He also tried to clarify the philosophical basis of biology. He was the brother of Richard Burdon Haldane and the father of J.B.S. Haldane .