changes that are almost radical in
their nature, and therefore appear to modify the form itself. These
important changes chiefly _affect the Second Part, when it reappears as
"Fourth" Part_. When the alteration of the Second Part (that is, the
difference between Part IV and Part II) is sufficiently radical to
suggest the presence of a virtually new Part, the design is called the
Five-part Song-form. The possible repetition of the First Part, it
will be inferred, does not affect this distinction in the least; it
hinges solely upon the treatment of the reproduction of _Part Two_.
For illustration:

[Illustration: Diagram of Parts.]

The Five-Part form is illustrated in the 14th Song Without
Words;--(first, number the measures; observe that the two endings of
Part I are to be counted as the _same measure_, and not separately;
they are both measure 8):--Part I extends to the double-bar, and is
repeated literally, only excepting the _rhythmic_ modification of the
final measure; Part II extends from measure 9 to 23; Part III, measures
24-35; Part IV, measures 36-47; Part V, measures 48-60; coda to the
end. The comparison of Part IV with Part II discloses both agreement
and diversity; they are, obviously, _practically the same Part_, but
differ in key, in form, and in extent. The comparison of Parts I, III,
and V reveals a similar condition, though the agreement here is much
closer, and each confirms the leading statement.

A more characteristic example will be found in the familiar F major
_Nachtstueck_ of Schumann, op. 23, No. 4, which see:--Part I extends
from measure 2 to 9 (after 1 1/2 measures of recitative introduction);
Part II, measures 10-13; Part III, measures 14-21; Part IV, measures
22-32; Part V, measures 33-40; codetta to end. The Fourth Part bears
very little resemblance to the Second, and assumes rather the character
of a wholly independent Part.

GROUP OF PARTS.--In some, comparatively rare, instances, the
arrangement of perfect cadences is such that,--coupled with
independence of melodic formation and character,--the composition seems
to separate into _four or more individual sections_ or Parts, with or
without a recurrence of the First one; or into three _different_ Parts,
lacking the evidence of the return to the beginning. When such
irregularities are encountered, or when any conditions appear which
elude or baffle natural classification among the Three-Part Song-forms
(simple or enlarged