_Sallow Complexion._—This is generally caused by disorders of the liver, and is most frequently met with in hot countries. It is seen in chronic dyspeptics, and, indeed, in most forms of chronic disease, and is not only a symptom of the disordered bodily state, but a cause of its perpetuation. This appearance of the skin is due to the accumulation of effete matters in it and to its impaired nutrition, and this state exists not only in the skin, but in the whole body. _Pimples, or Blackheads, and Acne._—These are affections of youth, and are generally seen together, the last-named being simply a second stage of the first. Pimples, or blackheads, appear as small elevations in the skin, with a small black point in the center. The cause of the pimple is the alteration in the quality of the sebum, the oily secretion, which becomes and remains a hard mass in the excretory ducts of the sebaceous glands and plugs up its external opening. The dust of the air becomes mixed with the fat, and thus makes a black point. When the ducts cannot get rid of the sebum, they become stopped up, and in consequence become swollen. This irritation spreads to the adjacent tissues, and so inflammation arises. Finally, the contents of the duct undergo degeneration, suppuration occurs, and the contents become mixed with pus, small abscesses result at various depths in the skin, and so require more or less time to break out. This inflammatory condition of the sebaceous glands with their ducts is apt to become chronic and may prove an obstinate affection. It occurs most commonly about the face, on the back between the shoulders, or on the chest. The skin is rough to the touch, the ducts of the sebaceous glands are enlarged, and the skin is greasy. _Eczema._—This is the most common of all skin affections. It is a non-contagious, inflammatory disease of the skin, sometimes acute, but more often chronic, attended with itching and desquamation or loss of cuticle. With the itching may be a feeling of heat and tension in the part. Eczema is a local disease, brought about by a local irritation in the skin; but, in addition to this, there is generally a predisposing cause, as some disorders of the digestive tract, a bad condition of the blood, and so forth. The skin, like other organs of the body, depends on the whole system for its nutrition. When this nutrition is not sufficient, the skin appears pale, of a peculiar color, and is easily taken up in folds, an evidence of poor nutrition of the skin. When the skin is not properly nourished, every slight irritation is liable to produce eczema.