first four bars. His
observations in connection with the latter have been examined in further detail
in more recent writings such as those of Réti, Walker and Leiken.
Leichtentritt also examines the issue of thematic unity in
the sonata. He observes that derivatives of the first subject manifest
themselves in the second subject, as well as the accompaniment to the melody of
the second subject.
As shown in Example 2, the second subject grows organically out of the first
through the rhythmic change of the first subject. Example 3 shows how the
accompaniment of the melody of the second subject makes use of a new rhythmic
variant of the first subject. A further link is shown in Example 4, where the
material in the right hand of bars 81 to 82 also derives from the first
subject. Leichtentritt calls this phenomenon of thematic integration the
"principe cyclique", and notes that it was used by Beethoven in his Piano
Sonata Opus 81a and last quartets as well as by Liszt in his sonatas.
