100. If we examine and compare all the examples we have given of subjects founded upon the notes of the tonic chord, and taking real answers, we shall find that there is an important principle involved in all of them. We have already shown that the tonal answer is the result of the old modal systems (§§ 84, 85), which prevailed before modern tonality, as now understood, was fixed. In all these cases, however, the old rule gives way to a higher and more important law, to which reference has already been made, and which has a wider application. This is the broad principle which is the very basis of fugal answer—that tonic harmony should be answered by dominant, and dominant by tonic. If we look at the tonal answers already given—for instance, § 93 (c), (d)—we shall find that the strong suggestion of tonic harmony in the first three notes of the subject is not replied to by an equally strong suggestion of dominant harmony in the first three notes of the answer. In both these examples the second note destroys the feeling of the dominant at once. When the dominant as the second note of the subject is not followed by another note of the tonic chord, the feeling of the tonic harmony is not so pronounced; and here a tonal answer may frequently be employed with advantage. In this case, however, adherence to the old rule will sometimes injure the form of the answer. This will be seen in the following example—
Here the character of the subject is entirely ruined by the monotonous repetition of the F's in the answer. A real answer here would have been far more effective. In example (d) of § 91, where Handel has given a real answer, the effect of a tonal answer would have been even worse—
101. The rule for the guidance of the student to be deduced from the examples given is as follows:—
If a subject commence with the leap from tonic to dominant, and the following note is not a note of the tonic chord, a tonal answer is generally, though not invariably, preferable; but if at least the first three notes of the subject are all notes of the tonic chord, the answer, provided that no modulation takes place to the key of the dominant, may be either real or tonal.
