Clarence Dennis

Clarence Dennis, M. D., Ph.D., was an American cardiothoracic surgeon best known for his work in pioneering cardiopulmonary bypass . He had invented one of the first heartlung bypass machines, and in 1951 he became the first to use such a device during an openheart operation.

Dennis was born in St. Paul, Minnesota on June 16, 1909, the son of Warren, a surgeon, and Clara Van Orman Dennis. He completed his MD at Johns Hopkins in 1935 and did his surgical residency at the University of Minnesota.

Source: Wikipedia