Evacuation of the Abscess and Injection of Iodoform.—­The iodoform is employed in the form of a 10 per cent. solution in ether or the same proportion suspended in glycerin.  Either form becomes sterile soon after it is prepared.  Its curative effects would appear to depend upon the liberation of iodine, which restrains the activity of the bacilli, and upon its capacity for irritating the tissues and so inducing a protective leucocytosis, and also of stimulating the formation of scar tissue.  An anaesthetic is rarely called for, except in children.  The abscess is first evacuated by means of a large trocar and cannula introduced obliquely through the overlying soft parts, avoiding any part where the skin is thin or red.  If the cannula becomes blocked with caseous material, it may be cleared with a probe, or a small quantity of saline solution is forced in by the syringe.  The iodoform is injected by means of a glass-barrelled syringe, which is firmly screwed on to the cannula.  The amount injected varies with the size of the abscess and the age of the patient; it may be said to range from two or three drams in the case of children to several ounces in large abscesses in adults.  The cannula is withdrawn, the puncture is closed by a Michel’s clip, and a dressing applied so as to exert a certain amount of compression.  If the abscess fills up again, the procedure should be repeated; in doing so, the contents show the coloration due to liberated iodine.  When the contents are semi-solid, and cannot be withdrawn even through a large cannula, an incision must be made, and, after the cavity has been emptied, the iodoform is introduced through a short rubber tube attached to the syringe.  Experience has shown that even large abscesses, such as those associated with spinal disease, may be cured by iodoform injection, and this even when rupture of the abscess on the skin surface has appeared to be imminent.

Another method of treatment which is less popular now than it used to be, and which is chiefly applicable in abscesses of moderate size, is by incision of the abscess and removal of the tuberculous tissue in its wall with the sharp spoon.  An incision is made which will give free access to the interior of the abscess, so that outlying pockets or recesses may not be overlooked.  After removal of the pus, the wall of the abscess is scraped with the Volkmann spoon or with Barker’s flushing spoon, to get rid of the tuberculous tissue with which it is lined.  In using the spoon, care must be taken that its sharp edge does not perforate the wall of a vein or other important structure.  Any debris which may adhere to the walls is removed by rubbing with dry gauze.  The oozing of blood is arrested by packing the cavity for a few minutes with gauze.  After the packing is removed, iodoform powder is rubbed into the raw surface.  The soft parts divided by the incision are sutured in layers so as to ensure primary union.  If, on the other hand, there is fear of a mixed infection, especially in abscesses near the rectum or anus, it is safer to treat it by the open method, packing the cavity with iodoform worsted or bismuth gauze, which is renewed at intervals of a week or ten days as the cavity heals from the bottom.