The one-step and other dances had been done to the tempo of Memphis Blues. ... When St Louis Blues was written the tango was in vogue. I tricked the dancers by arranging a tango introduction, breaking abruptly into a low-down blues. My eyes swept the floor anxiously, then suddenly I saw lightning strike. The dancers seemed electrified. Something within them came suddenly to life. An instinct that wanted so much to live, to fling its arms to spread joy, took them by the heels.