BY 1928, WALTER BRENNAN HAD APPEARED IN DOZENS OF UNCREDited roles as a customer in a store, a lunch counterman, a lumberjack, a yacht crewman, a cashier, a gangster, a pool hall shark, a ranch foreman, a train conductor, a clown, and a musician. If you watch any of these films, don't blink--you may miss him. At this point, we are talking about a career that can be telescoped into a few minutes or so of film.