On the other hand, it limits the verse form in several directions.  The general dynamic relations and the individual accents must conform to the types possible with rhyme.  The expressional changes of pitch, which constitute the ‘melody,’ or the ‘inflections’ of the sentences, play an important part.  The dynamic and melodic phases of spoken verse which have important relations to the rhyme are not determined by the mere words.  The verses may scan faultlessly, the lines may read smoothly and be without harsh and difficult combinations, and yet the total rhythmic effect may be indifferent or unpleasant.  When a critic dilates on his infallible detection of an indefinable somewhat, independent of material aspects of the verse and traceable to a mystic charm of ‘thought,’ it may very well be that the unanalyzed thing lies in just such dynamic and melodic conditions of rhythm and rhyme.

The most primitive characteristic of music is the ensemble.  Savage music is often little else than time-keeping.  When the social consciousness would express itself in speech or movement in unison, some sort of automatic regulation is necessary.  This is the beginning of music.  The free reading of verse easily passes over into singing or chanting.  When this happens, the thing most noticeable in the new form is its regulated, automatic and somewhat rigid character.  It is stereotyped throughout.  Not only are the intervals and accents fixed, but the pitch and quality changes are now definite, sustained and recurrent.  The whole sum of the motor processes of utterance has become cooerdinated and regulated.  Along with this precision of all the movements comes a tendency to beat a new rhythm.  This accompanying rhythm is simpler and broader in character; it is a kind of long swell on which the speech movements ripple.  This second rhythm may express itself in a new movement of hand, head, foot or body; when it has become more conscious, as in patting time to a dance or chant, it develops complicated forms, and a third rhythm may appear beside it, to mark the main stresses of the two processes.  The negro patting time for a dance beats the third fundamental rhythm with his foot, while his hands pat an elaborate second rhythm to the primary rhythm of the dancers.

The essential character of musical rhythm, as contrasted with the rhythm of both simple sounds and of verse, is just this cooerdination of a number of rhythms which move side by side.  This is the reason for the immense complexity and variety of musical rhythms.  The processes check each other and furnish a basis for a precision and elaborateness of rhythmical movement in the individual parts which is quite impossible in a simple rhythm.