Smiling involves a complex group of facial movements. It may suffice to remind the reader of such characteristic changes as the drawing back and slight lifting of the comers of the mouth, the raising of the upper lip, which partially uncovers the teeth, and the curving of the furrows betwixt the comers of the mouth and the nostrils (the naso-labial furrows) which these movements involve. To these must be added the formation of wrinkles under the eyes—a most characteristic part of the expression—which is a further result of the first movements. The increased brightness of the eyes is probably the effect of their tenseness, due to the contraction of the adjacent muscles and the pressure of the raised cheek, though {27} an acceleration of the circulation within the eyeball may have something to do with it. These facial changes are common to the smile and to the laugh, though in the more violent forms of laughter the eyes are apt to lose under their lachrymal suffusion the sparkle which the smile brings. As a characteristic group of facial movements the smile is excellently well suited for its purpose—the primitive and most universal expression of a pleasurable or happy state of mind. It forms, in respect of certain of its features at least, a marked contrast to the expression of opposite feelings. Thus it is far removed, and so easily distinguishable, from the facial expression during weeping, _viz._, the firmly closed eyelids and the wide opening of the mouth in the form of a squarish cavity; as also from the face’s betrayal of low spirits and “crossness,” in the depressed corners of the mouth, the oblique eyebrows and the furrowed forehead. I have spoken here of the primitive unsophisticated smile as it may be observed in children and those adults who have not learned to control the primitive, and instinctive movements of the face. Among the cultivated classes of a civilised community, this primitive smile is not only restrained and modified, but serves other uses than the confession of the elemental experiences of pleasure and gladness. With the contemptuous smile, the slightly ironical smile of the superior person, the bitter, sardonic smile, we shall have happily but little to do here. It is enough to remark that these differentiations answer closely to those of laughter, and so further illustrate the organic affinity of the two.