This episode's headline: Newsmaker; No to Perot; Hooked on Heroin; Food for Thought; Gorillas in our Midst. ANCHOR: JIM LEHRER; GUESTS: WILLIAM PERRY, Secretary of Defense; PAUL KIRK, Commission on Presidential Debates; PAT CHOATE, Reform Party VP Candidate; MARIAN BURROS, New York Times; CORRESPONDENTS: ELIZABETH FARNSWORTH; MARGARET WARNER; ROD MINOTT; ROGER ROSENBLATT;