English chemist and physiologist who first suggested the existence of oxygen, which he called spiritus nitroaereus. According to Mayow, the purpose of breathing was to acquire this special life-giving substance from the air. Mayow investigated the anatomical and physiological basis of respiration and called attention to the analogy between combustion and respiration. He was the first to argue that the seat of animal heat was in the muscles. In 1674 he published the first description of a case of mitral stenosis.