Two specially interesting motives are operative in producing playful voice practice—namely, the stimulus of what is agreeable and the stimulus of difficulty—and these we will find introducing us to the formal side of poetry. The pleasurable stimulus here takes the form of enjoyment of the repetition of like and similar sounds of a particular stress. This pleasure in repetition is a remarkable thing from many points of view; on the motor side there is a tendency to use the original sound as a model for the new one (Baldwin’s circular reaction), while in listening to self-originated tones and sounds primary memory is employed, that lingering of what has been heard in the consciousness which makes it possible to secure harmony of the new note with the previous one. The rhythm which we have been investigating is a simple form of such repetition, and a child will enjoy it in poetry as much as in music. At about the beginning of the fourth year children are often observed to make the attempt to talk in measure and assume the rôle of the productive artist. In general, the result is a senseless succession of words and syllables arranged rhythmically.[72] Marie G—— frequently pretended to read such jingles to her dolls. The measure most popular with children seems to be the trochaic.[73] This partiality still earlier takes in whole groups of sounds, as the mechanically measured repetition of the lall-monologue bears witness. Perez gives two good examples. “A little girl,” he says, “repeated from morning till night, for fourteen days, _toro_, _toro_, _toro_, or else _rapapi_, _rapapi_, _rapapi_, and took great delight in the monotonous rhythm. Another child, nearly three years old, kept up these refrains in speaking or crying, and would take a great deal of trouble to use them in answering questions, although his parents made every effort to rid him of this vagary. For three months this little parrot continued to repeat in a loud voice the syllables, unintelligible to himself or any one else,[74] _tabillè_, _tabillè_, _tabillè_.” R. M. Meyer, who sees in the meaningless refrain the germ of poetry, will find in such extraordinary persistence a confirmation of his view.[75] It is difficult to say whether there is not an inherited tendency connected with courtship in the instinctive impulse toward the gratification of such motor and sensor apparatus as is involved in this. Be that as it may, it is undeniable that the repetition of meaningless rhymes, as well as of reasonable words and passages, is important to poetry as a whole. I would refer in this connection to Grosse’s Beginnings of Art, and for my own part confine myself to selecting a few interesting examples. The first is the chain rhyme, such as always delights a child. The following is from a favourite song of theirs: