If nothing else had been performed this week at the San Francisco Symphony, the Scherzo from Erwin Schulhoff's Fifth Symphony would have been worth the ticket. James Conlon has become an authority in recent years on the subject of "Entartete Musik,” which is to say, music forbidden performance by the Nazis. And he had the daring to program just what he thought the audience would enjoy. I made a point after the concert of listening to several complete symphonies by Schulhoff and concluded Conlon was right to include just the Scherzo from the Fifth Symphony in his program, at least this time around. The music was both remarkably exciting (about which more in a moment), not too long and utterly hilarious, due to the brilliant and edgy talk Conlon gave from the podium before performing it.