Although the problem involved in the structure of primitive poetry is better understood now than it was a few years ago, and although many energetic efforts are being made to obtain adequate collections, the material for the study of this subject is still quite insufficient. Travellers are rarely trained in the art of recording songs and are apt to give us only the simplest forms that offer the least difficulties, or to summarize their observations in descriptions that are altogether too often misleading. Exact observations show that rhythmic complexity is quite common. Regular rhythms consist of from two to seven parts, and much longer groupings occur without recognizable regularity of rhythmic structure. Their repetition in a series of verses proves that they are fixed units. On account of the physiologically determined emotional quality of rhythm it enters into all kinds of activities that are in any way related to emotional life. Its exciting effect manifests itself in religious songs and dances. Its compelling control may be observed in war songs; its soothing effect appears in melodies; its esthetic value is seen in song and decorative art. The origin of rhythm must not be looked for in religious and social activities but the effect of rhythm is akin to the emotional states connected with them and, therefore, arouses them and is aroused by them. I believe the great variety of forms in which rhythmic repetition of the same or similar elements is used, in prose and in poetry as a rhythm of time, in decorative art as a rhythm of space,—shows that Bücher’s theory according to which all rhythm is derived from the movements accompanying work cannot be maintained, certainly not in its totality. Wundt derives the rhythm of the songs used in ceremonies from the dance, that of the working song from the movements required in the performance of work,—a theory practically identical with that proposed by Bücher, since the movements of the dance are quite homologous to those of work. There is no doubt that the feeling for rhythm is strengthened by dance and the movements required in the execution of work, not only in the common work of groups, of individuals who must try to keep time, but also in industrial work, such as basketry or pottery that require in their execution regularly repeated movements. The repetitions in prose narrative as well as the rhythms of decorative art, so far as they are not required by the technique, are proof of the inadequacy of the purely technical explanation. The pleasure given by regular repetition in embroidery, painting, and the stringing of beads cannot be explained as due to technically determined, regular movements, and there is no indication that would suggest that this kind of rhythm developed later than the one determined by motor habits.