1. The toccatas of Buxtehude and his predecessors show how Illustrations of Bach's method. an effective musical scheme may be suggested by running over the keyboard of an organ as if to try (toccare) the touch, then bursting out into sustained and full harmony, and at last settling down to a fugue. But before Bach no one seemed able to keep the fugue in motion long enough to make a convincing climax. Very soon it collapsed and the process of quasi-extemporization began again, to culminate in a new fugue which often gave the whole work a happy but deceptive suggestion of organic unity by being founded on an ingenious variation of the subject of the first fugue. But in Bach's hands the toccata becomes one of the noblest and most plastic of forms. The introductory runs may be disjointed and exaggerated to grotesqueness, until the gaps between them gradually fill out, and they build themselves up into grand piles of musical architecture, as in the organ toccata in C; or they may be worked out on an enormous scale in long and smooth canonic passages with a definite theme, as in the greatest of all toccatas, that in F for organ, which is most artistically followed by a fugue unusually quiet for its size. In one instance, the toccata at the beginning of the E minor clavier-partita, the introductory runs, though retaining much of the extempore character from which the form derives its name, take shape in a highly organized and rounded-off group of contrasted themes. The fugue follows without change of time, and is developed in so leisurely a manner that it is fully as long as a normal fugue on a large scale by the time it reaches what sounds like its central episode. At this point some of the introductory matter quietly enters, and leads to a recapitulation of the whole introduction in the key now reached. The obvious sequel would be a counter-development of the fugue, at least as long as what has gone before, as in the clavier-toccata in C minor; but Bach does not choose to weary the hearer and weaken the impression of breadth he has already made here. Instead, he expands this restatement of the introduction, and makes its harmonies deliberately return to the fundamental key, and thus in an astonishingly short time the toccata is brought to a close with the utmost effect of climax and finality. The same grasp of all the possible meanings of an artistic device shows itself in his treatment of the other features of toccata form. With his variety of proportion and flow he has no need to break off the fugue like earlier composers: but all the old devices by which the division into sections was managed are turned to account by him, and almost every toccata has its own scheme of contrasted movements, always based on the old natural idea of the growth of an organized music from a chaos of extemporization.
If this is Bach's treatment of a comparatively small and specialized art-form, it is obviously impossible to reduce the scantiest account of the rest of his work into practical limits here, nor is there as yet a sufficient body of accepted criticism of Bach for such an account to carry further conviction than an expression of individual opinion. Fortunately, however, Bach was constantly re-arranging his own compositions; indeed he evidently regards adaptability to fresh environment as the test of his finest work: and we cannot do better than review the evidence thus given to us,—evidence which only Beethoven's sketch-books surpass in significance.
2. The successful transplanting of a work of art to a fresh environment is obviously a convincing test of our definitions of the art-forms concerned, if only we take care to distinguish between the alterations produced by the change of environment and those that imply the composer's dissatisfaction with the original version. In Bach's case this seldom causes much difficulty; his methods of adaptation are so logical and so varied as to form a scheme of musical morphology with all the interest and none of the imperfections of the geological record; and the few cases in which a work owes its changes to the need for improvement as well as adaptation cause no confusion, but rather form a link between the pure adaptations and the numerous revisions of his favourite works without change of medium. There is, for example, no difficulty in separating the element of corrective criticism from that of the impulse to give an already successful composition a larger or more permanent form, in such cases as the transformations undergone by the movements of the birthday cantata, Was mir behagt ist nur die muntre Jagd, during their distribution among the church cantatas, Also hat Gott die Welt geliebt and Man singet mit Freuden vom Sieg. The fine bass aria, "Ein Fürst ist seines Landes Pan," was obviously ill-proportioned, with its breakneck return to the tonic and its perfunctory close; and Bach's chief concern in adapting it for its place as the aria, "Du bist geboren mir zu Gute," in Also hat Gott, was to remedy this defect. On the other hand, the use of the delightful ritornello for violoncello from the little aria, "Weil die wollenreichen Heerden," in the birthday cantata, and the restoration of the rejected long instrumental fugato that was to follow, were obviously brought about by the conception of the entirely new material for the voice in the famous aria, "Mein gläubiges Herze." And when the last chorus of Was mir behagt became the first chorus of Man singet mit Freuden, it was expanded to the proportions necessary for a triumphant opening (as distinguished from a cheerful finale) by the adroit insertion of new material between every joint in the design. This material, being new, could not produce the effect of diffuseness that would result from the expansion of the old material already complete in its simplest form, and thus this instance does not imply criticism.
A highly interesting example of pure self-criticism is the Passion according to St John, which was twice revised, and each time reduced to a smaller scale by the omission of some of its finest numbers. The final result was a work of perfect proportions, and of the rejected numbers one (a magnificent aria with chorale) remained unused, two were replaced by finer substitutes, others took shape as one of the most complete and remarkable of the church cantatas, Du wahrer Gott, while the greatest of the figured chorales was transferred to the Passion according to St Matthew, of which it now crowns the first part.
3. Such instances of self-criticism might be paralleled in the works of other composers; but there is no parallel in music to Bach's power of reproducing already perfect works in different media. Here Bach reveals to us identities in difference which we should otherwise never have suspected. Of course it is possible to arrange works in different ways without illustrating any profound identities at all. Handel, for instance, collected several of his favourite choruses in an enormous instrumental concerto (see vol. 46 of the Händel-Gesellschaft), and the result in the case of a chorus like "Lift up your Heads" was ridiculous. Bach, however, does not arrange old work merely to please a court where it was already admired. He never leaves it in a state of mere make-shift, though he cannot always attain his evident aim of a new originality. His methods of orchestration and the profoundly significant identity of certain forms of chorus with certain concerto forms may better be described under their proper headings (see articles Instrumentation and Concerto). Here we will attempt first to show, by illustrations of Bach's power of adding parts to already complete harmonic and contrapuntal schemes, what was his conception of the nature of an art-form, and secondly, by means of a short analysis of cases in which he adapts the same music to different words, to define his range of expression.
Bach arranged all his violin concertos for clavier, including two that are lost in the original version. Here his power of providing new and apparently necessary material for the left hand of the cembalist (or, in the double concertos, two left
hands) without disturbing the already complete score, is astonishing; and it fails only in the slow movements, which he prefers to leave obviously in the condition of an arrangement rather than to spoil their broad cantabile style by a too polyphonic bass.
But these cases are insignificant compared with such transformations as that of the prelude of the E major partita for unaccompanied violin into the sinfonia for organ obligato accompanied by full orchestra (including three trumpets and a pair of drums) at the beginning of the church cantata, Wir danken dir, Gott. The original version is perhaps the most complete and natural of the violin solos, for its arpeggios produce full harmony without recourse to that constant attempt to play on all four strings at once, which makes the performance of the polyphonic movements a tour de force in which steady rhythm is nearly impossible. Yet in the sinfonia its proportions seem to reveal themselves for the first time. Not a bar is displaced and not a note of the new accompaniment is unnecessary. The whole is almost entirely without themes; for even this, the largest of all arpeggio-preludes, consists essentially of the gradual unfolding of a scheme of harmony in which rhythmic and melodic organization is reduced to a minimum. Only in the first line does the incisive initial figure persist a little longer in the new accompaniment than in the original solo, but on the last page it reappears and pervades the whole orchestra, even the drums thundering out its rhythm at the climax where the holding-notes of the trumpet span the torrent of harmony like a rainbow.
Deeper still is the thought that underlies the transformation of two movements of the great violin-concerto in D minor (unfortunately lost except in its splendid arrangement for clavier) into parts of the church cantata, Wir müssen durch viel Trübsal in das Reich Gottes eingehen. In both movements the violin is replaced by the organ an octave lower, the orchestral accompaniment remaining where it was. This treatment, with the addition of new and plaintive parts for wind instruments, turns the already very long and sombre first movement into an impressive idealization of the "much tribulation" that lies between us and the kingdom of heaven. The slow movement is still more solemn, and is arranged in the same way as regards the instruments; but from the first note to the last a four-part chorus sings, to the words of the title, a mass of quite new material (except for the bass and for numerous imitations of the solo-part), treated with every variety of vocal colouring and a grandeur of conception which is not dwarfed even by the Passion according to St Matthew.
4. The four short masses, the Christmas oratorio and the B minor mass, contain every variety of adaptation from earlier work. The four short masses are indeed obviously compiled for use in a church where the orchestra was small. Only four movements in the whole collection are not traceable to other extant works; all the rest comes from church cantatas. The adaptations are not always significant; no attempt, for example, is made in the G minor mass to conceal how unfit for a Kyrie eleison is the tremendous denunciatory chorus, Herr, deine Augen sehen nach dem Glauben. But the F major and G major masses are very instructive; and the A major mass, except for the damage done to the instrumentation, is a work that no one would conceive to be not original. The Kyrie is one of Bach's most individual utterances and could surely never have fitted any other text, but we should say the same of the Gloria if we did not possess the church cantata, Halt im Gedächtniss. The Gloria begins with a triumphant polyphonic chorus accompanied by a spirited symphony for strings. At the words "et in terra pax" the time changes, and two flutes softly accompany a single solemn melody in the altos. At the "laudamus te" the material of the beginning returns, and is interrupted again by the calm slow movement, this time in another key and for another voice, at the words "adoramus te." Twice the "laudamus" and "adoramus" alternate in a finely proportioned design; at last the words "gratias agimus tibi propter magnam gloriam tuam" are set for the full chorus to the music of the slow movement, the strings join with the flutes, and this most appropriate setting of those words is finished. And yet it is quite impossible to regard this as superseding the last chorus of Halt im Gedächtniss. Not one bar or harmony of the framework differs; yet the two versions are two independent works of art. In the cantata the beginning is for instruments only; when the slow movement (here adequately scored for a flute and two oboe d' amore) begins, the basses, permanently separated from the rest of the chorus, sing "Peace be unto you." The other voices then sing the triumph of the faithful helped by the Saviour in their battle against the world. The slow movement is, of course, set for bass alone throughout, and at the last recurrence of the allegro the bass continues to sing "Friede sei mit euch" through the rest of the chorus, as if leading the chorus of humanity through strife to the kingdom of heaven, and then the single voice of peace remains to the end. Hardly a bar of the chorus-material is on the same themes in the two versions.