The skin, particularly on the face, takes the greatest variety of tints, from a violet red to a livid pallor, under the influence of physical or moral causes, which quicken or retard the circulation of the blood; but besides the colouring of the face, it is the movement of the muscles, and the expression of the eyes, which gives it a definite signification.
In a feeble man the motion of the heart is retarded, or sometimes hurried, as if to make up in the number of its beats for their want of energy; the blood is not sent to the surface in sufficient quantity, and the face is pale; but the languor of form and look denote the cause of the pallor.
Cold causes contraction of the tissues, the circulation is impeded on the surface of the body, the features seem pinched, the lips, nose, and cheeks take a livid leaden hue; chills sometimes shake the limbs and the lower jaw; on the face, as well as over the whole body, the integument is the seat of a painful constriction, but the eyes only express suffering. When an assassin reproached Bailly with being afraid, he replied, "No, my friend, I am cold".
Violent exercise, joy, confusion, fury, all quicken the action of the heart, and precipitate the movement of the blood through the teguments, which relax or yield to the impulsion of the fluid; but the open mouth, the dilated nostrils, the heaving chest, the strong and rapid respiration, express, as well as the features, an agitation purely physical, and we are not tempted to assign a moral cause for the flush which follows muscular effort. The serenity and expansion of the features, the smile, the brightness and happiness expressed in the eye when the face is flushed with joy, have nothing in common with the downcast eyes, the falling lip, the muscular weakness, and embarrassed manner of the man who reddens with confusion. We easily recognize also the haggard and threatening eyes, the knitted brow, the compressed lips, and the violently contracted or strongly agitated muscles of a man who is a prey to anger, and in whom the blood, at first impeded in its course, now in its reaction forcibly injects the integuments.
We see by these few examples that the colouring of the skin, varying under the influence of the most diverse causes, is an important element in physiognomy, though its signification is doubtful, and must be completed by the expression of all the other features, or of the body.