There is a natural tendency in pus to work toward the surface. The general system is usually protected from the absorption of pus by a wise provision of nature in surrounding the pur ulent matter with a wall of resistance which prevents its absorption. When an abscess occurs near the surface, it should be treated by hot fomentations or poultices, and may generally be allowed to open and discharge by the natural process unless it is so situated that on objectionable scar would result. Large abscesses should be opened freely by means of the scalpel, Fig. 388, bistoury, Fig. 389, or lancet.

Fig. 388. Bistoury.

Fig. 388. Bistoury.

Fig. 389. Lancet.

Fig. 389. Lancet.

Chronic abscesses are sometimes difficult to cure, on account of the discharge being kept up. In these cases, it is necessary to wash out the cavity of the abscess daily with carbolic acid lotion, ten or twenty drops to the ounce of water. In some cases, permanganate of potash, two ounces to the pint of water, and a weak solution of iodine, are useful. An excellent means of lessening the amount of discharge from a large abscess is to inject a saturated solution of tannin,