born June 9, 1911, South Bend, Ind., U.S.
died Jan. 2, 2005, New York, N.Y.
U.S. biologist.
He received an M.D. (1937) at Johns Hopkins School of Medicine. With DNA . In their classic experiments (1944), the introduction of certain material from one type of pneumococcus bacteria into another type transformed the receiving bacteria into the type from which the material had been taken. The substance responsible for the change was DNA.