316. At bar 27 the third stretto is introduced. The interest is here heightened by bringing in the imitations at a closer distance—one crotchet instead of half a bar. Variety is also obtained by introducing all the voices in the octave. We have marked the entries with 'A' instead of 'S,' because the G natural of the tenor in the 28th bar proves the key of the music to be D. The 'A—?' in the alto of the same bar indicates an incomplete entry. Another, similarly marked, will be seen in bar 44.
317. Another series of close imitations will be found in the fourth episode (bars 29 to 33). This leads to the fourth middle entry—another stretto for three voices, each a sixth above the preceding, and at a crotchet's distance. This stretto is an advance upon the preceding, inasmuch as now all the three voices complete the subject.
318. The fifth and last episode leads to the final section of the fugue, in which the subject is once more introduced in the tonic key (bar 40). It is now accompanied with simultaneous double counterpoint in the tenth and octave (compare bar 40 with bar 3). The entry of the answer at bar 43, with chromatic alterations, leads to the last and closest stretto. This is the stretto maestrale, already quoted and described in § 278, and it is followed by a short coda, in which the figure of imitation, so often referred to, is maintained to the very last note.
319. It will be seen that this fugue differs in many important respects from the fugue in E minor, and nearly every leading feature of a fugue which is not shown in the one is illustrated by the other. One point of difference is that in the former there are scarcely any rests; all the voices are almost continuously occupied. In the fugue in D, on the other hand, we find not only one, but in bar 16 two voices resting at once. It is generally better to give occasional rests to some of the voices. After such a rest, the voice that has been silent should enter with the subject, or with some decided feature of the counterpoint (see the entries in bars 17 and 18), and not drop in, as it were, incidentally, and without anything particular to say.
320. Another point to notice in this fugue is that nearly all the entries of the subject are preceded by a rest. That this is not absolutely necessary was seen from the fugue in E minor, in which very few of the entries are so approached; but it is nevertheless preferable as marking the entrance of the subject more clearly. Where this cannot well be managed, the next best thing is to approach the entry by a leap, as in the fugue in D, bars 27, 33, and 43.
321. In bars 16, 20, and 27 of the fugue in D will be seen full cadences, and at bars 10, 33, and 44, inverted cadences. The latter are very common, the former are rarer. It must be remembered that when a full cadence is employed in a fugue, the music must never come to a standstill; the last note of the cadence must always be a starting point for a new entry,
