ulcer consists of embryonic tissue and corresponds with the abscess-wall. An abscess arises from molecular death in the tissues; an ulcer, from molecular death of a free surface. An ulcer must not be confounded with an excoriation. In an ulcer the corium is always, and the subcutaneous tissue is generally, destroyed, and a scar is left after healing. In an excoriation the mucous layer of epithelium is exposed, or this is destroyed and the corium exposed. The corium is never destroyed, and no scar remains after healing.

Necrosis can arise from—(1) Inflammation. The pressure of the exudate can cut off the circulation, or bacteria may directly destroy tissue. Suppuration occurs. (2) The action of pus cocci, causing primary cell-necrosis. (3) Bacteria of putrefaction and cocci of suppuration acting upon a wound. (4) Traumatism or irritants, producing at once stasis, which is added to by secondary inflammation, the exudate undergoing purulent liquefaction. (5) Prolonged pressure. (6) Deficient blood-supply. (7) Faulty venous return. (8) Degeneration of a neoplastic infiltration (gummatous, malignant, or tubercular). (9) Trophic disturbance. (10) Nutritional disturbances (as scurvy). Most ulcers are due to pus cocci, and even those that arise from something else (as gummatous degeneration) are apt to suppurate.

Classification.-Ulcers are classified into groups according to the condition of the ulcer and the associated constitutional state. In the first group we find the varicose, hemorrhagic, acute, chronic, irritable, neuralgic, etc. In the second group are placed the strumous, syphilitic, senile, scorbutic, etc. All ulcers, whatever their origin, are either acute or chronic, and such conditions as great pain, hemorrhage, œdema, exuberant granulations, phagedæna, sloughing, struma, gout, syphilis, scurvy, etc. are to be looked upon as complications. The leg is so common a site of ulcers as to warrant special description.

Acute ulcer of the leg may follow an acute inflammation and may be acute from the start, or may be first chronic and become acute. It is characterized by rapid progress and intense inflammation. In shape these ulcers are usually oval. The bottom of an acute ulcer is covered with a mass of gray aplastic lymph, or it may have upon it large greenish sloughs. The edges are thin and undermined. The discharge is very profuse and ichorous, excoriating the surrounding parts. The adjacent surface is inflamed and odematous. There is much burning pain. When the ulcer spreads with great rapidity and becomes deeper as well as larger in surface-area, it is called "phagedænic." If sloughs form, this indicates that tissue-death is going on so rapidly that the dead portions have not time to break down and be cast off. Limited stasis produces molecular death; more extensive stasis, a slough. Constitutionally, there is gastro

intestinal derangement, but rarely fever.

Treatment. In treating an acute ulcer of the leg, give a dose of blue mass or calomel, followed in eight or ten hours by a saline (3ij each of Rochelle and Epsom salt). Order light diet. Deny stimulants except in diphtheritic ulcer. Administer opium if pain is severe. Use a spray of peroxide and the scissors and forceps to get rid of sloughs, and after their removal wash the ulcer with corrosive sublimate. If the sloughs cannot be removed, use the antiseptic poultice. After asepticizing, local bleeding is of great value. Tie a fillet below the knee, make multiple punctures, and let the patient sit with his leg in tepid water until eight or ten ounces of blood have been lost; then untie the fillet and dress with antiseptic poultices, keeping the leg elevated. In two days paint around the ulcer with equal parts of tincture of iodine and alcohol, and repeat this treatment every day, dressing the ulcer with iodoform, covering it with gauze, and producing pressure by means of a roller.

Many cases do very well on the local use of lead-water and laudanum and the roller after bleeding. If the discharge is offensive, use gr. iij of chloral to every 3j of lead-water. The use around an acute ulcer of a 25 per cent. ointment of ichthyol is highly valuable. If sloughs continue to form, touch with a 1:8 solution of acid nitrate of mercury or with a pure solution of carbolic acid and reapply antiseptic poultices. If an ulcer continues to spread, clean it up with peroxide of hydrogen, dry with absorbent cotton, touch with nitrate-of-mercury solution (1: 8), and apply a poultice. Do this every day until it ceases to extend and granulations begin to form.

In an ulcer covered with a great mass of aplastic lymph, touch it daily with solution of silver nitrate (gr. xl to 3j) or with acid nitrate of mercury (115) and dress with iodoform and gauze. Give internally tonics, stimulants, and good food. In any case, when granulations form we should dress antiseptically with dry dressings, but we can employ a nonirritant ointment, such as cosmoline. If granulation is slow, touch every day with a solution of silver nitrate (gr. x to 3j) and dress antiseptically, or with a stimulating ointment (resin cerate or 3j of ung. hydrarg. nitratis to 3vij of ung. petrolii), or with an ointment of copper sulphate, gr. iij to 3j, or with 3 drops of nitric acid to 3j of gum Arabic or cotton.

Chronic ulcer of the leg is characterized by low action and slow progress. It may be chronic from the start, or it may result from acute ulcer. More usually it is found as a solitary ulcer two inches above the internal malleolus. Syphilitic ulcers occur in a group, are often crescentic, and are frequent upon the front of the knee. A chronic ulcer is circular or oval, and is surrounded by congested, discolored, and indurated skin, this induration being due to embryonic tissue, and there is often eczema or a brown pigmentation of the neighboring skin. The bottom of the ulcer is uneven, and

usually possesses granulations each of which is the size of a pin-point, red, and which may be exuberant or may be oedematous. If granulations are absent, the ulcer has the appearance of a bit of liver. The edges are thick, turned out, and not sensitive to the touch. Occasionally they are thin and undermined. Some ulcers are thick, indurated, and adherent; this prevents healing by antagonizing contraction.

Treatment. In treating a chronic ulcer, give a saline every day or so. Treat any existing diathesis. Insist on rest and, if possible, elevation. Asepticize the ulcer. Draw blood by shallow scarifications of the bottom of the ulcer and the skin. If the ulcer is adherent, make incisions like either of those shown in Figure 27, each cut going through the deep fascia. These incisions, besides permitting contraction, allow granulations to sprout in them, which eventuate in the absorption of the exudate. After incision keep the part elevated and dressed antiseptically herent Ulcer. for two days. In two days after scarification or incision, scrape the ulcer with a curette until sound tissue is reached, and make radiating incisions through its edge. Use antiseptic poultices for two days more, then paint around the ulcer with tincture of iodine and alcohol (1 : 3) and dress the leg with hot lead-water and laudanum. When healing begins, treat as outlined for healing acute ulcer (p. 103).

FIG. 27.-Incisions for Ad

Complications.-Remove by scissors and forceps any useless tissue. Take out dead bone; slit sinuses; trim overhanging edges. Treat eczema by attention to the bowels and stomach, and locally by washing with Johnson's ethereal soap and by the use of powdered oxide of zinc or borated talcum, the leg being wrapped in cotton. Avoid ordinary soap, grease, and ointment. Varicose veins demand either ligation in several points, excision, obliteration with Vienna

paste, or the continued use of a flannel roller or a Martin bandage. Inflammation is met by rest, elevation, and painting the neighboring parts with dilute iodine, and by the use of a hot solution of lead-water and laudanum. For calloused edges employ radiating incisions or cut them away. Ordinary thick edges can be strapped. In strapping use adhesive plaster and do not completely encircle the limb. When the parts are adherent, completely or partly surround the sore with a cut through the deep fascia. If the bottom of the ulcer is foul, dry it and touch with a solution of acid nitrate of mercury (18) or with a solid stick of silver nitrate. Repeat this every third day and dress with an antiseptic poultice until granulations appear. Superfluous granulations (proud flesh) should be cut away or mowed down with silver nitrate.

When a man having an ulcer must go out, use a firmlyapplied roller, or, better still, a Martin bandage. This bandage, which is made of red rubber, limits the amount of arterial blood going to the ulcer and favors venous flow from the sore and its neighborhood. The bandage should be used as follows: Before getting out of bed, spray the sore with hydrogen peroxide by means of an atomizer, dry off the froth with cotton, wash the leg with soap and water, dry it, and put on the bandage-all of which should be done before putting a foot to the floor. At night, after getting in bed, take off the bandage, wash with soap and water, and dry it, and again cleanse the leg and ulcer. If these rules are not strictly observed, the Martin bandage will produce pain, suppuration, and eczema of the leg. Irritable ulcer is due to exposure of a nerve and destruction of its sheath. Find with a probe the painful granulation and divide it with a tenotome, or curette the ulcer or burn it with solid stick of silver nitrate. If healing entirely fails, skin-graft. There are two methods of skin-grafting-(1) Reverdin's and (2) Thiersch's. (See Plastic Surgery.)