On Fugue

Fugue of Imitation is that, of which the Response is very nearly, but not entirely similar to that Subject, the composer being at liberty to introduce some alterations, and to curtail it, if he thinks fit.

Fugue of Imitation possesses still another privilege; which is, that the Consequent or Response has no fixed time or interval for responding to the Antecedent or Subject, but may enter at the most-favorable opportunity, or at any interval.

Thus the Response may be made, not only at the Unison, at the Fifth, at the Fourth, and at the Octave; but it may be likewise at the Third, at the Sixth, at the Second, at the Seventh, and at their compounds; by these means that variety, so desirable in music, and so much admired by listeners, is produced.

It has been already said, that the Subject of a Fugue should be of judicious dimensions, neither too long, nor too short; but in the kind of Fugue now in question, the Subject should always be very short, so that the Response shall not delay being heard.

When treating a Subject of Fugue of Imitation, it is possible to change into a fugue of this name, even a Tonal Fugue; by responding to a Subject of the nature of this latter Fugue, with the freedom of a fugue of imitation.

There is no Fugue, either Real, or Tonal, which, in several passages of its extent, is not liable to become transformed into Fugue of Imitation, on account of the Imitations which may be introduced, by taking a portion of the Subject, or of the counter-subjects; examples of this will be adduced, when the entire composition of a Fugue is in question. In accordance with what we have said, when a Subject occurs - even of Fugue of Imitation, composed of more than one portion, as thus:

Sometimes one, and sometimes the other of these two portions may be taken in the course of the Fugue, for making the imitations, and for inverting them by contrary movement, in order that from the conflict arising between the parts with these devices, a more-learned as well as agreeable effect shall be produced. The following little fugue by Padre Martini will serve as an example, and give an idea, of Fugue of Imitation.

Before proceeding to what concerns the entire composition of a fugue, it is essential to enter into some rather more circumstantial details relative to the Coda or Conclusion of a Subject, which has only hitherto been simply indicated; and then to speak of the digressions in the fugue, and lastly of Modulation.