Boil, an inflamed tumor, which begins as a pimple in the skin, and continues to increase until it becomes as large as a walnut, or even larger. It is of a conical shape, somewhat red or dusky, and hard, with burning heat and pain. Between the fourth and eighth day it becomes very prominent, and begins to "point;" a speck of matter may be seen on the summit, which gradually softens; the skin at lasts bursts at that point, and matter mixed with blood is discharged through a small opening A day or two after this, the core, which is supposed to be a portion of dead connective tissue, finds its way out, or may be forced out by gentle pressure, leaving an open cavity which soon fills up, and heals about the 12th or 14th day. Boils may appear on any part of the body, but they commonly form on the face or on the neck, in the armpits or inside of the thighs, on the hips or in the groin; and there are generally several, either at the same time or following one another. They seem to be caused by fatigue in some form, anxiety of mind, fatigue of the digestive organs, and general fatigue of body or of mind, or both. By lancing the pimple on its first appearance, the formation of the boil is often prevented.
If allowed to mature and go on to suppuration, the pain may be relieved and the process hastened by the application of warm poultices. The period of suppuration may be distinguished by the pain, which becomes more severe and throbbing in character, by an oedematous condition of the skin over its most prominent portion, and by a sense of deep-seated fluctuation communicated to the fingers, when the tumor is compressed alternately from side to side. As soon as the formation of pus is indicated by the above signs, the most effectual treatment, both for the relief of pain and for the rapidity of cure, is to make a free incision into the substance of the boil, deep enough to reach its central cavity and allow the evacuations of the pus. When the boil is allowed to burst of itself, the opening is usually small, and the core remains some time before it is discharged, unless it be drawn out. The cavity soon heals after the core is discharged, and nothing is usually required but simple dressing.