The first bar of (a) consists of the codetta, with the addition of a middle part; the rest of it, as will be seen, is made out of the first notes of the countersubject. At (b) the same theme is seen in the bass, with free upper parts; while at (c) it is treated sequentially, the outer parts which move in tenths imitating the inner parts moving in thirds. Here again, though the fugue is for four voices, two out of the three episodes are in only three parts.
222. In § 191 we gave the subject of the seventh fugue in the 'Wohltemperirtes Clavier.' In the second bar was seen a codetta before the entry of the answer, the reason for which we showed. From this codetta the episodes of the fugue are chiefly developed.
J. S. Bach. Wohltemperirtes Clavier, Fugue 7.
In this episode the codetta is treated by sequential imitation between the outer parts with a middle part, made from the augmentation of the semiquaver figure of the bass. The first part of the next episode