418. The first line of the choral is announced as a fugue subject in the tenor, and answered by the alto in bar 3. The treble gives the subject again in bar 6, and the bass (pedals) joins in with the subject at bar 8. The subject, and not the answer, is given to the bass, because, as we see from the rest of the fugue, this part has the character of a canto fermo, and gives nothing but the simple choral, line by line, throughout the piece. We therefore find the subject here instead of the answer, as in an ordinary fugal exposition. It will be seen that the canto fermo is here only in notes of the same length as the other parts. More usually, as in our next example, the plain choral is given in longer notes.
419. At bar 10 begins the exposition of the second line of the choral. Here we see a little irregularity of treatment. The theme in an ornamented form appears in the tenor, and is imitated in stretto in the next bar by the treble. At bar 13, the answer is repeated, not by the alto (which had not had it),
