born Sept. 4, 1906, Berlin, Ger.
died March 9, 1981, Pasadena, Calif., U.S.
German-born U.S. biologist.
He received his Ph.D. from the University of Göttingen in 1930, and in 1937 he immigrated to the U.S., where he joined the California Institute of Technology faculty. In 1939 he discovered a one-step process for growing bacteriophages that would induce a phage, after an hour of inactivity, to multiply to produce several hundred thousands of progeny. In 1946 he and A.D. Hershey independently discovered that the genetic material of different kinds of viruses can combine to create new types of viruses, a process previously believed to be limited to higher, sexually reproducing forms of life. In 1969 he shared a Nobel Prize with Hershey and their colleague Salvador Luria .