Ill: 204 EXPRESSION OF JOY: CHAP. VIII. Mi ened, and the skin on the bridge becomes finely wrin- kled in transverse lines, with other oblique longitudinal lines on the sides. The upper front teeth are commonly exposed. A well-marked naso-labial fold is formed, which runs from the wing of each nostril to the corner of the mouth; and this fold is often double in old per- sons. A bright and sparkling eye is as characteristic of a pleased or amused state of mind, as is the retraction of the corners of the mouth and upper lip with the wrinkles thus produced. Even the eyes of microcepha- lous idiots, who are so degraded that they never learn to speak, brighten slightly when they are pleased.12 Under extreme laughter the eyes are too much suffused with tears to sparkle; but the moisture squeezed out of the glands during moderate laughter or smiling may aid in giving them lustre^ though this must be of alto- gether subordinate importance, as they become dull from .grief, though they are then often moist. Their bright- ness seems to be chiefly due to their tenseness,13 owing to the contraction of the orbicular muscles and to the pressure of the raised cheeks.- But, according to Dr. Piderit, who has discussed this point more fully than any other writer,14 the tenseness may be largely attrib- uted to the eyeballs becoming filled with blood and other fluids, from the acceleration of the circulation, conse- quent on the excitement of pleasure. He remarks on the contrast in the appearance of the eyes of a hectic pa- tient with a rapid circulation, and of a man suffering from cholera with almost all the fluids of his body drained from him. Any cause which lowers the circula- tion deadens the eye. I remember seeing a man utterly 12 C. Vogt, ' Memoire sur les Microc6phales,' 1867, p. 21. 13 Sir C. Bell, ' Anatomy of Expression,' p. 133. Physiognomik,' 1867, s. 63-67.