Where pus has formed in relation to important structures—­as, for example, in the deeper planes of the neck—­Hilton’s method of opening the abscess may be employed.  An incision is made through the skin and fascia, a grooved director is gently pushed through the deeper tissues till pus escapes along its groove, and then the track is widened by passing in a pair of dressing forceps and expanding the blades.  A tube, or strip of rubber tissue, is introduced, and the subsequent treatment carried out as in other abscesses.  When the drain lies in proximity to a large blood vessel, care must be taken not to leave it in position long enough to cause ulceration of the vessel wall by pressure.

In some abscesses, such as those in the vicinity of the anus, the cavity should be laid freely open in its whole extent, stuffed with iodoform or bismuth gauze, and treated by the open method.

It is seldom advisable to wash out an abscess cavity, and squeezing out the pus is also to be avoided, lest the protective zone be broken down and the infection be diffused into the surrounding tissues.

The importance of taking precautions against further infection in opening an abscess can scarcely be exaggerated, and the rapidity with which healing occurs when the access of fresh bacteria is prevented is in marked contrast to what occurs when such precautions are neglected and further infection is allowed to take place.

Acute Suppuration in a Wound.—­If in the course of an operation infection of the wound has occurred, a marked inflammatory reaction soon manifests itself, and the same changes as occur in the formation of an acute abscess take place, modified, however, by the fact that the pus can more readily reach the surface.  In from twenty-four to forty-eight hours the patient is conscious of a sensation of chilliness, or may even have a rigor.  At the same time he feels generally out of sorts, with impaired appetite, headache, and it may be looseness of the bowels.  His temperature rises to 100 or 101 F., and the pulse quickens to 100 or 110.

On exposing the wound it is found that the parts for some distance around are red, glazed, and oedematous.  The discoloration and swelling are most intense in the immediate vicinity of the wound, the edges of which are everted and moist.  Any stitches that may have been introduced are tight, and the deep ones may be cutting into the tissues.  There is heat, and a constant burning or throbbing pain, which is increased by pressure.  If the stitches be cut, pus escapes, the wound gapes, and its surfaces are found to be inflamed and covered with pus.