Later, Klemperer recalled an incident that occurred when Mahler was conducting in Vienna:
There were few soloists in the Phiharmonic's concerts at this period, and only the very best got a chance to appear. Mahler engaged [Ferruccio] Busoni, for instance, to play Beethoven's Concerto in E Flat Major. Traveling down from Berlin on the night express, Busoni reached Vienna just after 9:00 a.m. to find a message awaiting him at his hotel. It said to report to the Opera House at once, where Direktor Mahler had something important to tell him.
Without breakfasting, washing or shaving--a circumstance he found highly distasteful--he rushed to the Opera House. Mahler kept him waiting for an hour, then burst from his office and extended his hand. "Not to fast in the last movement, Herr Busoni--all right?" he said, and whistled the main theme. Then with an "Auf Widersehen! he vanished again.
