Finally, we will notice dancing movements. It is not only among birds that the courted female gazes with interest at the dancing of the male; we see it in all public dancing. This is one of the instances where visual play is as important as the movement, for even among the participants pleasure is heightened by the exciting spectacle of the other dancers,[152] and it is true the world over that spectators of a dance always become as passionately aroused as do the performers themselves. The piercing trills with which the women of some negro tribes at intervals accompany the dance of the males are surely not merely invitations to the latter, but indications as well of their own excitement. For this reason many onlookers are impelled to keep time with the rhythmic dance by clicking the tongue or clapping the hands. “The feeling of pleasure which is kindled in the performer,” says Grosse, “sheds its rays on the beholder as well.... In this way both become passionately excited, intoxicated by the sounds and movements; the transport constantly increasing, swells at last to veritable madness, which often results in violent outbreaks.”[153] The solo dances of primitive peoples presuppose an onlooking public more than mass dances do. Among Bushmen and Eskimos the men dance alone, while, according to Eyre, Australian women do it sometimes alone and sometimes in companies to, arouse the men.[154] Among the civilized people of the Orient professional dancing girls perform in the presence of men, in which case the spectators alone can be said to play. And the same is true of our ballet, which, indeed, except for its direct sexual effect, possesses but little pleasurable quality.[155] II. PLAYFUL USE OF THE MOTOR APPARATUS In this new section we by no means cut loose from what is sensory in a subjective sense, for of course we become conscious of our own movements only through the sensory paths of sight and what is collectively called touch, chiefly sensations of contact, and tendon and joint sensations. Yet from an objective standpoint we must enter upon the investigation of an entirely new province, where we shall be concerned not so much with the senses as with the manifold co-ordinated muscular movements of which our bodies are capable, and which are necessary or at least useful for the accomplishment of the tasks of life.