 Whenever Lina is happy with Johnny — starting with a ball organised by General McLaidlaw — Johann Strauss's waltz "Wiener Blut" is played in its original, light-hearted version.At one point, when she is suspicious of her husband, a threatening, minor-key version of the waltz is employed, metamorphosing into the full and happy version after the suspense has been lifted.At another, Johnny is whistling the waltz.