differences between the two forms which cannot be thus lightly passed over. So far as the Answer is concerned, it is enough to say that its Intervals do not furnish an exact reproduction of those of the Subject; being governed, as to their arrangement, by laws which scarcely fall within the scope of our present article. The Subject, on the other hand, presents so many varieties of form and expression, that it cannot be too carefully considered. In the hands of the Great Masters, it presents an epitome of the entire Fugue, into which nothing is admissible which is not in some way suggested by it: and, in order that it may serve this comprehensive purpose, it must needs be very carefully constructed. The Subjects employed by the great Fuguists are always found to be capable of suggesting a logical Answer, and one or more good [1]Counter-Subjects; of being conveniently and neatly broken into fragments, for purposes of collateral discussion; of intertwining their various members among the involutions of an ingenious Stretto; and of lending themselves to a hundred other devices, which are so intimately connected with the conduct of the Fugue itself, that the necessary qualities of the Subject will be better understood by reference to our general article on Tonal Fugue, than by separate description here.
IV. We have shown how the fathers of Composition treated the Canto fermo: how their immediate successors enveloped it in a network of ingenious Points of Imitation: how, by fusing the Points of Imitation, and the Canto fermo which suggested them, into a homogeneous Theme, the Polyphonic Composers gave birth to that important factor in Composition which we call a Subject: and how that Subject was treated by the great Fuguists of the 18th century. We have now to see how these Fuguists revived the Canto fermo, and employed it simultaneously with the newer Subject. Not that there was ever a period when it fell into absolute desuetude: but, it was once so little used, that the term, revived, may be very fairly applied to the treatment it experienced from Handel and Bach, and their great contemporaries.
And, now, we must be very careful about the terms we use: terms which we can scarcely misapply, if we are careful to remember the process by which the Subject grew out of the Canto fermo. The German Composer of the 18th century learned the Melody of the Chorale in his cradle, and used it constantly: treating 'Kommt Menschenkinder, rühmt, und preist,' and 'Nun ruhen alle Walder,' as Palestrina treated 'Ecce Sacerdos magnus,' and 'L'Homme armé.' Sometimes he converted the traditional Melody into a regular Subject, as in the 'Osanna' of the last-named Mass. Sometimes, he retained the long notes, enriching them with a Florid Counter-point, as in the 'Kyrie.' In the first instance, there was no doubt about the nomenclature: the term, Subject, was applied to the Choral Melody, as a matter of course. In the other case, there was a choice. When the Melody of the Chorale was made to pass through the regular process of Fugal Exposition, and a new contrapuntal melody contrasted with it, in shorter notes, the former was called the Subject, and the latter, the Counter-Subject. When the Counterpoint furnished the Exposition, and the Chorale was occasionally heard against it, in long sustained notes, the first was called the Subject, and the second, the Canto fermo. Seb. Bach has left us innumerable examples of both methods of treatment, in his 'Choral-Vorspiele,' 'Kirchen-Cantaten,' and other works. A fine specimen of the Chorale, treated as a Subject, will be found in the well-known 'S. Anne's Fugue.' In the Motet, 'Ich lasse dich nicht,'[2] the Chorale 'Weil du mein Gott und Vater bist,' is sung, quite simply, in slow notes, as a Canto fermo, against the quicker Subject of the Fugue. In the 'Vorspiel,' known in England as 'The Giant,' the Chorale 'Wir glauben all' an einen Gott,' forms the Subject of a regular Fugue, played on the Manuals, while a stately Counter-Subject is played, at intervals, on the Pedals. A still grander example is the opening Movement of the 'Credo' of the Mass in B minor, in which the Plain Chaunt Intonation, 'Credo in unum Deum,' is developed into a regular Fugue, by the Voices, while an uninterrupted Counterpoint of Crotchets is played by the instrumental Bass. In neither of these cases would it be easy to misapply the words Subject, Counter-Subject, or Canto fermo; but, the correct terminology is not always so clearly apparent. In the year 1747, Bach was invited to Potsdam by Frederick the Great, who gave him a Subject, for the purpose of testing his powers of improvisation. We may be sure that the great Fuguist did full justice to this, at the moment: but, not contented with extemporising upon it, he paid the Royal Amateur the compliment of working it up, at home, in a series of Movements which he afterwards presented to King Frederick, under the title of 'Musikalisches Opfer.' In working this out, he calls the theme, in one place, 'Il Soggetto Reale'; and, in another, 'Thema regium.' It is quite clear that in these cases he attached the same signification to the terms Thema and Soggetto; and applied both to the principal Subject; treating the Violin and Flute passages in the Sonata, and the florid Motivo in the Canon, as Counter-Subjects. But, in another work, founded on a Theme by Legrenzi, he applies the term 'Thema,' to the principal Motivo, and 'Subjectum,' to the subordinate one.[3] We must suppose, therefore, that the two terms were in Bach's time, to a certain extent interchangeable.
Handel, though he did occasionally use the Canto fermo as Bach used it, produced his best effects in quite a different way. In the 'Funeral
- ↑ See Counter Subject.
- ↑ Ascribed by Schicht and Albrechtsberger to Sebastian Bach; but now more frequently attributed to Johann Christoph. [See vol. i, p. 111a.]
- ↑ 'Thema Legrenzianum pedaliter elaboratum cum subjecto.' The original MS. of this work has disappeared. Messrs. Peters, of Leipzig, have published it in Cahier 4 of their edition of the Organ Works, on the authority of a copy by Andreas Bach.
