s rule must be maintained in order to prevent a degradation of
the object of musical expression. The vile, the ugly, the painful are
not fit subjects for music; music renounces, contravenes, negatives
itself when it attempts their delineation.

A classification of Programme music might be made on these lines:

[Sidenote: _Kinds of Programme music._]

I. Descriptive pieces which rest on imitation or suggestion of natural
sounds.

II. Pieces whose contents are purely musical, but the mood of which is
suggested by a poetical title.

III. Pieces in which the influence which determined their form and
development is indicated not only by a title but also by a motto which
is relied upon to mark out a train of thought for the listener which
will bring his fancy into union with that of the composer. The motto
may be verbal or pictorial.

IV. Symphonies or other composite works which have a title to indicate
their general character, supplemented by explanatory superscriptions
for each portion.

[Sidenote: _Imitation of natural sounds._]

[Sidenote: _The nightingale._]

[Sidenote: _The cat._]

[Sidenote: _The cuckoo._]

The first of these divisions rests upon the employment of the lowest
form of conventional musical idiom. The material which the natural
world provides for imitation by the musician is exceedingly scant.
Unless we descend to mere noise, as in the descriptions of storms and
battles (the shrieking of the wind, the crashing of thunder, and the
roar of artillery--invaluable aids to the cheap descriptive writer),
we have little else than the calls of a few birds. Nearly thirty years
ago Wilhelm Tappert wrote an essay which he called "Zooplastik in
Toenen." He ransacked the musical literature of centuries, but in all
his examples the only animals the voices of which are unmistakable are
four fowls--the cuckoo, quail (that is the German bird, not the
American, which has a different call), the cock, and the hen. He has
many descriptive sounds which suggest other birds and beasts, but only
by association of idea; separated from title or text they suggest
merely what they are--musical phrases. A reiteration of the rhythmical
figure called the "Scotch snap," breaking gradually into a trill, is
the common symbol of the nightingale's song, but it is not a copy of
that song; three or four tones descending chromatically are given as
the cat's mew, but they are made to be such only by placing the
syllables _Mi-au_ (t