Picture this: Harry Langdon, well past his silent-comic stardom, cast as a Communist streetsweeper, half-singing his denunciations of "Those idle rich shirkers/ Who live off us workers." Hallelujah, I'm a Bum...has to be among the most unusual films ever to come out of Hollywood. The swatches of Lorenz Hart's "rhythmic dialogue" resemble earlier experiments by René Clair, Rouben Mamoulian, and Ernst Lubitsch, but none of them took their poets from Central Park tramps and thus none made a film half so odd. (With his) engaging singing of "I find great enjoyment/ From unemployment" to his black pal Edgar Connor...Al Jolson's performance as the bums' leader is much more appealing than in his breakthrough early-sound films, even if his exuberance, as always, looks a bit forced. Lewis Milestone directs with a sure touch...and the film is never less than surprising.-Scott Simmon, Mary Pickford Theater Preserved from nitrate negative.