The facial expression which marks the culmination of tumescence, and the approach of detumescence is that which is generally expressive of joy. In an interesting psycho-physical study of the emotion of joy, Dearborn thus summarizes its characteristics: "The eyes are brighter and the upper eyelid elevated, as also are the brows, the skin over the glabella, the upper lip and the corners of the mouth, while the skin at the outer canthi of the eye is puckered. The nostrils are moderately dilated, the tongue slightly extended and the cheeks somewhat expanded, while in persons with largely developed pinnal muscles the ears tend somewhat to incline forwards. The whole arterial system is dilated, with consequent blushing from this effect on the dermal capillaries of the face, neck, scalp and hands, and sometimes more extensively even; from the same cause the eyes slightly bulge. The whole glandular system likewise is stimulated, causing the secretions,--gastric, salivary, lachrymal, sudoral, mammary, genital, etc.--to be increased, with the resulting rise of temperature and increase in the katobolism generally. Volubility is almost regularly increased, and is, indeed, one of the most sensitive and constant of the correlations in emotional delight.... Pleasantness is correlated in living organisms by vascular, muscular and glandular extension or expansion, both literal and figurative." (G. Dearborn, "The Emotion of Joy," _Psychological Review Monograph Supplements_, vol. ii, No. 5, p. 62.) All these signs of joy appear to occur at some stage of the process of sexual excitement.