BY THOMAS H. WELLER AND FREDERICK C. ROBBINS

THE INVESTIGATIVE CAREER of John Enders comprised three phases. For eight years he focused on pathogenic bacteria, in particular the pneumococcus. Switching in 1939 to the study of viruses, he refined tissue culture techniques for the study of viruses in vitro and made significant discoveries regarding mumps. This work prepared the way for the cultivation in 1949 of the polio viruses in non-nervous tissues, for which he was the corecipient of the 1954 Nobel Prize in Physiology or Medicine. Never one to rest on his laurels, Enders turned his focus to measles. This work led to the eventual production of a measles vaccine. By 1959, however, his research focus had shifted once again, this time to the problem of viral host-cell resistance and viral oncogenesis—the subject of the final segment of a magnificently productive investigative career.

John Franklin Enders was born February 10, 1897, in West Hartford, Connecticut. His father headed the Hartford National Bank, and he was the first of four children in a family whose economic means were, as he once observed, ''above average.'' Raised in a family whose business centered on finance and trade, he had little contact with science as a