Ulcers in any Region.-The fungous or exuberant ulcer is especially common in burns and other injuries when cicatricial contraction causes venous obstruction. These granulations bleed when touched. Burn or cut them off with a sharp knife, stop hemorrhage if there be any, and strap or use the rubber bandage.

Erethistic, irritable, or painful ulcers, which are very sensitive, are due to the exposure of a nerve-filament. They are especially found near the ankle, over the tibia, in the anus (fissure), or in the matrix of the nail (in ingrowing nail). Curette an erethistic ulcer, and touch with pure carbolic acid or with the solid stick of silver. Chloral, gr. xx to the ounce, allays the pain; so does cocaine for a time.

Phagedanic Ulcer.-The phagedænic ulcer, which means the profound microbic infection of tissues debilitated by local or constitutional disease, is commonly venereal. This ulcer has no granulations and is covered with sloughs; its edges are thin and undermined, and it spreads rapidly in all directions. It requires the use of strong caustics or the Paquelin cautery followed by iodoform dressing. Internally, use tonics and stimulants.

A rodent or Jacob's ulcer is a superficial epithelioma developing from sebaceous glands, sweat-glands, or hair-follicles. Decubital ulcer, or bed-sore, is due to pressure upon an area of feeble circulation.

Neuro-paralytic or trophic ulcer is due to impairment of the trophic centres in the cord.

The perforating ulcer, a name given by Vesigne, commonly affects the metatarso-phalangeal joint or the pulp of the great toe about a corn. The parts about the corn inflame, and pus forms which runs into the bone. A sinus evacuates the pus by the side of the corn. As this ulcer may be present in anæsthetic leprosy, paralyzed limbs, and tabes

See Treves in Lancet, Nov. 29, 1884.

dorsalis, and as the part on which it occurs is apt to be sweaty, cold, and possessed of impaired sensation, and as the sore may be hereditary, it is usually set down as trophic in origin. Treatment of a perforating ulcer consists, according to Treves, in going to bed and poulticing. Every time a poultice is removed the raised epithelium around the ulcer is cut away and then the poultice is reapplied. In about two weeks an ulcer remains surrounded by healthy tissue. Treves treats this sore with glycerin made to a creamy consistency with salicylic acid to each ounce of which mx of carbolic acid have been added. He directs the patient to wear during the rest of his life some form of bunion-plaster to keep off pressure. If in a perforating ulcer the bone is diseased, it must be removed. This ulcer tends to recur in the same spot or in adjacent parts, and it may be necessary to amputate the toe or the foot.

Epitheliomatous, sarcomatous, tuberculous, and syphilitic ulcers are considered under their respective heads.

Fistula. A fistula is an abnormal communication between the surface and an internal part of the body, or between two natural cavities or canals. The first form is seen in a rectal fistula, a urethral fistula, or a biliary fistula, and the second form is seen in a vesico-vaginal fistula. Fistulæ may result from congenital defect, as when there is failure in the closure of the branchial clefts, sloughing, traumatism, and suppuration. Fistulæ are named from their situation and communications. (Fig. 166).

A sinus is a tortuous track opening usually upon a free surface and leading down into the cavity of an imperfectlyhealed abscess. A sinus may be an unhealed portion of a wound. Many sinuses may be due to pus burrowing subcutaneously. A sinus fails to heal because of the presence of some fluid (as saliva, urine, or bile); because of the existence of a foreign body, as dead bone, a bit of wood,

a bullet, a septic ligature, etc.; or because of rigidity of the sinus-walls, which rigidity will not permit collapse. The walls of a tubercular sinus are lined with a material identical with the pyogenic membrane of a cold abscess. Sinuses may be due to the want of rest (muscular movements) and to general ill-health.

Treatment. In treating a fistula remove any foreign body, lay the channel open, curette, swab with pure carbolic acid, and pack with iodoform gauze. Fresh air, good food, and tonics should be ordered.

VII. MORTIFICATION OR GANGRENE.

Mortification or gangrene is death in mass of a portion of the living body-the dead portions being visible—in contrast to ulceration or molecular death, in which the dead particles are too small to be seen and are cast away. In gangrene the dead portions may either desiccate or putrefy. Gangrene may be due to tissue-injury, either chemical or mechanical, to failure of the general health, to circulatory impairment, or to microbic infection. Molar death of bone is called "necrosis." When the gangrened portion is entirely dead, the process is spoken of as "sphacelus."

Classification.-Gangrenes are divided into the following three great groups:

(1) Dry gangrene, which is due to circulatory interference, the arterial supply being decreased or cut off. As venous return is still active, all fluid is taken up from the tissues, which shrivel up and mummify.

(2) Moist gangrene, which is due to interference not only with arterial ingress, but also with venous return or capillary circulation, the dead parts remaining moist.

(3) Septic gangrene, arising from virulent septic matter. coming from outside.

There are many gangrenous processes which belong under one or other of the above heads, namely: congenital gangrene, a rare form existing at birth; constitutional gangrene, arising from a constitutional cause, as diabetes; cutaneous gangrene, which is limited to skin and subcutaneous tissue, as in phlegmonous erysipelas; gaseous or emphsematous gangrene, in which the subcutaneous tissues are filled with putrefactive gases and crackle on pressure; diabetic or glycamic, due to diabetes; hospital gangrene, which is defined by Foster as specific serpiginous necrosis, the tissues being pulpefied: some consider it a traumatic diphtheria; cold gangrene, a form in which the parts are entirely dead (sphacelus); hot gangrene, which presents some inflammation, as shown by heat; idiopathic gangrene, which has no ascertainable cause; mixed, which is partly dry and partly moist; primary, in which the death of the part is direct, as from a burn; secondary, which follows an acute inflammation; multiple, a gangrenous ecthyma; pressure, which is due to long compression; purpuric or scorbutic, which is due to scurvy; Raynaud's or idiopathic symmetrical, which is due to vascular spasm from nerve-disorder; senile, the dry gangrene of the aged; venous or static, which is due to obstruction of circulation, as in a strangulated hernia; trophic, which is due to nutritive failure by reason of disorder of the trophic nerves or centres; thrombotic, which is due to thrombus; embolic, which is due to embolus; and decubital gangrene, from bed-sores.

Dry or chronic gangrene, Pott's gangrene (Fig. 28), arises from deficiency of arterial blood. In a person with healthy arteries dry gangrene can result by injury of the main trunk of an artery (lodging of an embolus, ligation, or laceration). Gangrene only follows injury when the anastomatic circulation fails to sustain the part. When, for instance, an embolus lodges and causes gangrene, the case runs the following

course: Sudden severe pain at the seat of impaction, and also tenderness; pulsation above, but not below, this point; the limb below the obstruction is blanched, cold, and anæsthetic; within forty-eight hours, as a rule, the gangrene has mapped out its area; the limb becomes blue, reddish, greenish, and then black; the skin itself becomes shriveled and its outer layer stony or like horn. The entire part may become as dry as a mummy, but usually there are spots where some fluid remains, and these spots are soft and moist, and the dead tissue where it joins the living is sure to be moist. The contact of dead with living tissue causes

inflammation in the latter tissue, a bright-red line forms, and we have exudation, suppuration, and ulceration. This line of ulceration in the sound tissues is called the "line of demarcation," it being Nature's effort at amputation, which in time may get rid of a large portion of a limb, and then heal as any other ulcer.

Senile gangrene is a form of dry gangrene due to feeble action of the heart plus obliterating endarteritis or atheroma of peripheral vessels. The vessels do not properly carry blood, and may at any time be occluded by thrombosis. Senile gangrene most often occurs in the toe or the foot.