The _tuberculous ulcer_, so often seen in the neck, in the vicinity of joints, or over the ribs and sternum, usually results from the bursting through the skin of a tuberculous abscess. The base is soft, pale, and covered with feeble granulations and grey shreddy sloughs. The edges are of a dull blue or purple colour, and gradually thin out towards their free margins, and in addition are characteristically undermined, so that a probe can be passed for some distance between the floor of the ulcer and the thinned-out edges. Thin, devitalised tags of skin often stretch from side to side of the ulcer. The outline is irregular; small perforations often occur through the skin, and a thin, watery discharge, containing grey shreds of tuberculous debris, escapes. _Bazin's Disease._--This term is applied to an affection of the skin and subcutaneous tissue which bears certain resemblances to tuberculosis. It is met with almost exclusively between the knee and the ankle, and it usually affects both legs. It is commonest in girls of delicate constitution, in whose family history there is evidence of a tuberculous taint. The patient often presents other lesions of a tuberculous character, notably enlarged cervical glands, and phlyctenular ophthalmia. The tubercle bacillus has rarely been found, but we have always observed characteristic epithelioid cells and giant cells in sections made from the edge or floor of the ulcer. [Illustration: FIG. 16.--Bazin's Disease in a girl æt. 16.] The condition begins by the formation in the skin and subcutaneous tissue of dusky or livid nodules of induration, which soften and ulcerate, forming small open sores with ragged and undermined edges, not unlike those resulting from the breaking down of superficial syphilitic gummata (Fig. 16). Fresh crops of nodules appear in the neighbourhood of the ulcers, and in turn break down. While in the nodular stage the affection is sometimes painful, but with the formation of the ulcer the pain subsides. The disease runs a chronic course, and may slowly extend over a wide area in spite of the usual methods of treatment. After lasting for some months, or even years, however, it may eventually undergo spontaneous cure. The most satisfactory treatment is to excise the affected tissues and fill the gap with skin-grafts. [Illustration: FIG. 17.--Syphilitic Ulcers in region of Knee, showing punched-out appearance and raised indurated edges.]