The scalp is sometimes, though rarely, the seat of malignant ulcer. In the early stage the ulceration is not of great extent, and affects only the soft parts; perhaps it is confined at first to the common integument, but is extremely apt to extend to the deeper layers which invest the cranium, and even to the bone itself. It is by no means uncommon to find the cranium very extensively diseased, though the affection originated in the superimposed soft parts. Such ulceration of the bone is of a peculiarly destructive nature; it is a disease of the osseous tissue, corresponding to the most malignant ulceration of the soft parts. The bone around the ulcerated cavity is spongy and soft, its margin is irregular, and bristles with numerous spiculæ; the centre is composed of soft morbid deposit, entangling small portions of bone which have become detached, and flabby, almost lifeless granulations shoot from the distempered mass. Such disease, when the patient does not soon succumb to its virulence, advances to a frightful extent, affecting a large surface, destroying the whole thickness of the bone, and even exposing the internal parts. In a case of this description, which occurred in the Royal Infirmary under my care, the anterior half of the cranium was totally destroyed, the left orbit contained a putrid mass, consisting of the disorganised eye mixed with pus and bloody fluid; the dura mater was exposed, and sloughed at several points, and the unhealthy discharge from the parts lodged on the surface of the brain. In malignant diseases of scalp, as of other parts, the lymphatics become secondarily affected: the absorbents feel hard and thickened, the glands in the neighbourhood enlarge and ulcerate, and the sore thereby formed soon assumes the characters of decided malignancy,—hard everted edges, an angry surface, and fetid thin discharge.