A work in which the cyclic method is applied with almost unparalleled rigor and resourcefulness, and which is therefore worthy of detailed analysis, is the String Quartet in E major,[51] built up from four notes of a Gregorian chant, shown at Figure XXV. The swinging main theme of the first movement, derived from this fragment by a natural rhythmic and tonal proliferation (see Figure XXVIII, b), is not immediately stated, but is rather anticipated tentatively, and gradually allowed to take shape, by a process dear to the composer, first through imitative bits for the different instruments and then through a serious fugato (Figure XXVIII, a). Once achieved it is broadly treated, with a richly conceived tonal digression into E flat major and return. A second theme, of sinuous curve and fluent movement (Figure XXVIII, c), is reached through a transition passage of more animated rhythm. The themes thus stated, development begins: not a perfunctory worrying of the themes such as the "free fantasia" often degenerates into in the hands of composers possessed of neither freedom nor fancy, but a dynamic action and reaction of the themes such as d'Indy conceives development essentially to be. "Development," he says, "is ... the action of the themes and ideas, and consequently their reason for being, since an idea is of value only through the action it is capable of exercising. When there are several ideas ... the development expresses usually all the phases of a struggle between them, with the final triumph of one and submission of the other.... The themes comport themselves like living people: they act and move according to their tendencies, their sentiments, and their passions. These modifications show themselves both in the thematic elements which are elaborated as if to surpass themselves, or are restrained as if to become absorbed, and in the tonal trajectories which orient themselves toward light or toward darkness."[52] It will be seen that in this case the development first (pages 9 and 10) takes the aspect of a quiet presentation of the first theme in dark keys (E flat major, etc.) and then (from index number 10, through the whole of page 11) of a brief recurrence of the second theme and elimination of it with the reviving force of the first, moving through more energetic rhythms and brighter tonalities to final victorious reassertion. The themes are then recapitulated and the movement ends with the beautiful coda we have already examined.
The two middle movements, too complex to analyze in detail, are based on themes strikingly illustrative of what was said a moment ago as to cyclic form arising from the approach to a common theme from different angles, or under the influence of varying moods. That of the scherzo is the theme envisaged playfully (Figure XXVIII, d); that of the slow movement (Figure XXVIII, e) shapes itself in response to a more serious contemplation. It may be pointed out that these are no mere clever or learned jugglings with notes, such as arise sometimes from the abuse of the method; not only are they true textually to the theme, but each is a faithful expression of its own mood; the resulting music accordingly convinces us emotionally as well as intellectually.
The finale is a piece of writing extraordinary for the manifold resources developed out of the original theme, for the bold ingenuity of its polyphonic and rhythmic combinations, and for the variety of its emotional content. Its main theme comes from the original motive by inversion (Figure XXIX, a), and derives a certain amplitude from its three half-note rhythm proceeding deliberately against the more agitated two-four of other parts (especially the viola, at first, with a persistent figure taken also from the theme). Its second theme also traces its ancestry back to the first movement, but in a more elusive way; a comparison of Figure XXIX, b, with Figure XXVIII, c, will reveal the connection. The elaboration of these themes, and of the quaint staccato bridge passage between them, leads to most unexpected combinations. The fugato of the first movement reappears, but now inverted (Figure XXIX, c). At the top of page 58 we find the main theme in the second violin answered canonically by the viola, while the first violin sustains, high above, the original motive. Finally, after the themes have met all manner of vicissitudes and wandered through all sorts of keys, the original motive in its most conclusive form brings the final cadence in E major.
Figure XXIX.
(a) Main theme of Finale of String Quartet.
(b) Second theme.