The blood disappears from the facial capillary system as it enters it; in an instant the passions will successively produce there the bright red of a paroxysm of fever, the whiteness of syncope and all the intermediate shades. It is even the extreme ease with which this fluid penetrates this system, that renders the face well adapted to serve as a kind of picture, which the passions paint by turns with a thousand shades, that are effaced, altered, modified and return again according to the state of the mind. I would observe upon this subject that the passions have in the face three means of expression; 1st, the capillary system, a means wholly involuntary, and which often betrays what we wish to conceal; 2d, the muscular motion, which, by contracting or expanding the features, expresses the melancholy or gay emotions, and to which belongs as effects, the various wrinkles of which we have spoken; 3d, the state of the eye, an organ, which, as Buffon has remarked, not only receives the sensations, but also expresses the passions. The two last means are to a certain extent voluntary; we can at least disguise them; whereas we cannot deceive by the first. The actor imitates anger, joy, &c. because we can give these passions by contracting the eye-brows, by dilating the face in laughing, &c. But it is the rouge of the actress that imitates modest chastity; it is by removing this rouge that she imitates the paleness of fear, horror, &c. I will add another essential observation in respect to the facial capillary system; it is that it appears that its tendency to receive blood, disposes it to become the more frequent seat of many affections. We know, 1st, that erysipelas is much more frequent in this than in other parts; 2d, that the variolous pustules are remarkably conspicuous here; 3d, that many eruptions are more abundant here than elsewhere. From all that we have just said, it is evident that it is necessary to distinguish two portions in the capillary system exterior to the chorion. 1st. One is constantly filled with the colouring substance of the skin, a substance which appears to be stagnant like that of the hair of the head, and that of the hair of the body, which is subjected only to the slow and insensible motion of composition and decomposition and which never exhibits that sudden increase or diminution of which we have just spoken. 2d. The second is constantly pervaded by many fluids which continually succeed each other there, and which constantly escape by transpiration, and which are replaced by the blood, that insinuates itself into this portion of the capillary system. These two portions are entirely independent, and have probably no kind of communication.