This variety of ulcer is seen more frequently in males than in females, and it is almost exclusively confined to adults, especially between the ages of forty and sixty. Occupations requiring standing or walking are strong predisposing causes, provided a tendency to the disease exists. A poor fitting shoe and deformities of the foot giving rise to excessive pressure or irritation, are of much importance in determining the appearance and location of the ulcer. It rarely appears in children, unless it is associated with spina bifida. +Symptoms.+ Perforating ulcer has a marked tendency to develop where pressure and irritation are greatest, which is almost always upon the sole of the foot at the junction of the great or little toe with the metatarsus. It may occur, however, upon the heel, the sides of the foot, the plantar surface of any portion of the great toe, or even upon the centre of the sole, these unusual situations being most commonly found associated with diabetes. When talipes or hammertoe exists, the ulcer is apt to occur wherever pressure is pronounced, even upon the dorsum of the foot or the ends of the toes. Usually but one foot is affected, although both feet may be involved, in which case the disease is termed symmetrical. Three stages may be recognized in the development of the ulcer: (1) the formation of callosities, (2) superficial ulceration, (3) deep ulceration. Very frequently in tabes and in diabetes, a purulent blister is the first indication of trouble, but usually a marked epithelial thickening, in the form of a corn or a bunion, is the initial symptom. Sooner or later the centre of a callosity breaks down into a bluish, unhealthy, indolent, superficial ulcer, secreting a small quantity of watery pus, and with an offensive odor. The sore is circular as though punched out of the callous tissue, the latter at times so thickened and overhanging that the ulcer is almost concealed beneath it. There is little or no tendency to heal, even under exacting treatment, and if recovery should take place, a speedy relapse is the rule, even with the patient remaining in bed. The indolent and foul ulcer tends to eat deeply into the adjacent tissues, progressively involving bursae, tendons, muscles, joints, and bones. A deep round hole results, which may even perforate the foot. The most striking symptoms are chronicity, stubborn resistance to treatment, and the absence of pain and tenderness.