Suppuration, or the formation of pus, is one of the results of inflammation. Pus, or matter, is generally supposed to be composed of foul elements from the blood; but it has been shown by careful microscopical examination that pure pus is chiefly made up of corpuscles or globules, so closely resembling the white globules of the blood as to be almost indistinguishable from them. There is some discussion among pathologists as to the source of these corpuscles, some claiming that they are really white blood corpuscles which have left the blood-vessels, while others claim that they are formed in the tissues where the pus is produced. Recent investigations on the subject seem to show that both views are in a measure correct, both the blood and the tissues contributing to the formation of pus.

Pus may be formed upon an open surface, as in the suppuration of a wound, or it may be confined in a cavity in the tissues. The accumulation of pus in the tissues is termed an abscess. When such an accumulation is the result of acute inflammation, it is termed an acute abscess. The occurrence of suppuration in an inflamed part is generally indicated by a marked increase of pain and fever. The pain is generally described as heavy. When the abscess is near the surface, the swelling becomes pointed, and feels soft under the finger. By degrees, the outer wall of the abscess becomes thinner, until finally the red color disappears and little blisters are seen just beneath the surface of the skin, which mark the point at which the opening is usually formed, being at first a small, round hole which is soon considerably enlarged by ulceration. In some cases abscess, or formation of pus, is indicated by a chill, or several chills in succession. This is especially the case in abscess of the liver, kidneys, and ovaries. Abscesses in internal organs are also often accompanied by profuse sweats.