Eli Whitney Debevoise, 90, a prominent attorney whose law firm represented Alger Hiss in the late 1940s and who served in several government positions. From 1951 to 1953, Debevoise served as assistant and deputy U.S. High Commissioner for Germany, the governing body of West Germany during the post-war period. In 1959 he was named chairman of the New York State Task Force on Youth and Juvenile Delinquency. He founded the firm of Debevoise & Stevenson in 1931, and worked there until age 87. The firm, now known as Debevoise & Plimpton handles both litigation and corporate law and has 330 lawyers in New York, Washington, Los Angeles, Paris and London. Hiss, a State Department official, was accused by confessed Communist courier Whittaker Chambers of helping transmit government secrets to the Soviet Union. He was convicted of perjury in 1950. After the Hiss trial, Debevoise engineered the Ford Motor Co.'s transition from a Henry Ford family property to a widely held public corporation. He was named for his great-great grandfather, Ely Whitney, inventor of the cotton gin. In New York City on Saturday.