+Treatment.+ This should be preventive by protecting the feet, wearing warm clothing, by exercise, and the administration of tonics. Local immersion of the affected part in hot saturated solution of alum relieves the venous congestion and the itching. In severe cases, heating too rapidly, or overheating, should be prevented so as not to restore a too rapid reaction. A strong faradic current, ten minutes thrice daily, or the electric bath, ten to fifteen minutes daily, is beneficial. In ordinary cases, balsam of Peru or 10 per cent. ichthyol ointment, rubbed in, is all that is required. When there is ulceration, antiseptic dressings should be applied. CHAPTER VIII +FISTULAE; FISSURES; SINUSES; ABSCESSES; FURUNCLES; ULCERS+ A +Fistula+ (pl. fistulae) 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, the second in vesicovaginal fistula. Fistulae may result from a congenital defect and can arise from sloughing, traumatism and suppuration. Fistulae are named from their situation and communication. A +Fissure+ is a crack and in podiatry, has special reference to a condition found in the toeweb. A +Sinus+ is a tortuous track opening usually upon a free surface and leading down into the cavity of an imperfectly healed 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 irritant fluid (as saliva, urine) or, because of the existence of some foreign body, as dead bone, a bit of wood, a bullet, a septic ligature, or because of rigidity of the sinus wall, 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 maintained by want of rest (muscular movements) and by general ill-health. +Treatment.+ In treating a fistula, remove any foreign body; lay the channel open, curet, touch with pure carbolic acid, and pack with iodoform gauze. In obstinate cases, entirely extirpate the fibrous walls; sew the deeper parts of the wound with buried catgut sutures, and approximate the skin surfaces with interrupted sutures of silkworm gut. Fresh air is necessary; nutritious food and tonics must be ordered. +Acute Abscesses.+ An abscess may be defined as a circumscribed cavity of new formation, containing pus. An essential part of this definition is the assertion that the pus is in a cavity of new formation; is an abnormal cavity; hence pus in a natural cavity (pleural or synovial) constitutes a purulent effusion, and not an abscess, unless it is encysted in these localities by walls formed of inflammatory tissue. An acute abscess is due to the deposition and multiplication of pyogenic bacteria in the tissues or in inflammatory exudates.