Glenn Allan Millikan

Glenn Allan Millikan (1906 to 1947) was an American physiologist, inventor and mountaineer who invented the first practical, portable oximeter in 1940 to 1942 and introduced the word oximeter. The son of the physicist Robert Andrews Millikan, he studied at Harvard University and the University of Cambridge, where he built a dual wavelength colorimeter for measuring blood oxygen and won a four year scholarship from Trinity College for the work. Stranded in the United States by the outbreak of the Second World War, he worked at the University of Pennsylvania on bioluminescence. In 1940 his former Cambridge advisor Lord Adrian asked him to help the Royal Air Force with a reliable breathing apparatus for pilots, and he built the oximeter that clipped to the earlobe and presented it to the American Physiological Society in 1941. He became head of physiology at Vanderbilt University School of Medicine in 1946 and was killed by a falling rock while climbing in Tennessee in 1947.