While cadences are indispensable, in music of clearly recognizable form, it is equally true that they must not be so emphatic as to check the current of melody and harmony too frequently or completely, or destroy the continuity and coherence of the members.
And it is therefore an almost invariable practice, especially in music of a higher order, to modify and disguise the cadences by some means or other; that is, to diminish the weight of the characteristic "longer tone,"-- to counteract, partially or entirely, the impression of actual cadential cessation, by continuing (instead of interrupting) the rhythmic pulse.

This is so very common, and so confusing a device, that the effect of the various methods employed to conceal or disguise a cadence must be thoroughly understood.
It is necessary to remember, always, the rule that governs the actual body of the phrase, and its possible preliminary tones; namely, that the vital, essential starting-point of a phrase (and other factors of musical form) is _the first primary accent_, the first beat of the first _full_ measure.

The length of the phrase is reckoned from this point, and consequently, the cadence-chord is entitled to all the beats that remain, from its accent to the very end of the final measure.

For example: [Illustration: Example 19.

Fragment of Mozart.] In this case the cadence-chord is not modified or disguised in the least, but takes full advantage of the six beats that make the sum of the fourth measure.
This important fact concerning the actual value of the cadence-chord remains unchanged, through all the licenses taken in disguising or (apparently) diminishing its value.