In this case, it is evident, we have to do with a greeting of the laughable which will vary greatly according to the psycho-physical condition of the child. The same child that laughs at a new sound to-day will to-morrow, when in another mood, be disturbed by a quite similar surprise of the ear. But more is involved in this laughter. The sudden and slightly disturbing attack of the ear by new sounds is apt to wear for the child’s consciousness a game-like aspect. We have only to think of the nursery rhymes, alluded to by Miss Shinn, in which the excitement of fun is secured by an explosive shock at the end, games closely analogous to the rides which terminated in a good bump. In these rhymes the fun lies in the shock, though only half-unexpected—a shock which has in it the very soul of frivolous play, since it comes at the end of a series of quiet orderly sounds. May not the new sounds, the guttural utterances and the rest, affect a child in a like manner as a kind of disorderly play? For a child’s ear, pitched for the intrinsic character of a sound, they may hold much which is expressive of the play-mood. This will apply not only to utterances like the “Pah! Pah!” which are clearly recognised as play, but to many others produced by a nurse or a mother who is given to entertaining. Perhaps the gurgling sounds which moved the mirth of Preyer’s boy appeared laughter-like. This tendency to look on certain sounds as a kind of play seems to supply a psychical link in the development of a feeling for the odd and out-of-the-way as such. We have seen how the play-impulse “tries it on” when the restraints of rule grow too irksome. I suspect that the mirthful appreciation of the queer and out-of-the-way grows out of this inclination to a playful disorderliness or law-breaking. A child is apt to feel oppressed with the rules of propriety {212} imposed on him. By these rules quite a terrible multiplicity of noises is branded as “naughty,” and the prohibition tends to fix the playful impulse precisely in the direction of the forbidden sounds. Children have a way, moreover, of projecting their experiences and their inclinations into things which we call lifeless. What more natural, then, that they should feel these incursions of violent and quite improper-sounding noises to be a kind of playful throwing aside of order and rule? In the domain of the visible world, suddenness of presentation rarely reaches, perhaps, the point of shock or joltiness. Yet there is ample scope, here, too, for the working of the unexpected on the child’s sensibilities. The first visual excitants of laughter, the sudden uncovering of the face in bo-peep, the unexpected return of the familiar face after an interval of absence, the instant transformation of the accustomed features when the mother “makes a face,” show how directly the surprisingly new may act on the young muscles of laughter.