Term used to describe manner in which composer may change tempo, rhythm, and notes of a theme yet preserve its essential and recognizable characteristics. Employed by Liszt in his symphonic poems and by Elgar and Franck in syms. Hindemith's Symphonic Metamorphosis of Themes by Weber and Britten's 6 Metamorphoses after Ovid are modern examples of the device. Strauss's use of the term in his Metamorphosen refers to Goethe, not to mus. form.