A tubercule is an infective granuloma, appearing to the unaided vision as a semitransparent mass, gray in color, and the size of a mustard seed. The microscope shows that a tubercule consists of a number of cell clusters, each cluster consisting of one or of several polynucleated giant cells, surrounded by a zone of epitheloid cells which are surrounded by an area of leucocytes. Giant cells, which also form by coalescence of the epithelioid cells, are not always present. The bacillus, when found, exists in the epithelioid cells, and sometimes in the giant cells; it may not be found, having once existed, but having been subsequently destroyed. It is often overlooked. In an active tubercular lesion, even if the bacillus be not found, injection of the matter into a guinea-pig will produce lesions in which it can be demonstrated. A tubercule may caseate, a process that is destructive and dangerous to the organism. Caseation forms cheesy masses, which may soften into tubercular pus, may calcify, and may become encapsulated by fibroid tissue. Tubercular disease of the bones and joints have already been described in a previous chapter. +Treatment.+ Destroy the bacilli present and radically remove infected areas which are accessible. Incomplete operations are apt to be followed by diffuse tuberculosis. Bier’s venous or obstructive hyperemia is especially to be recommended in tuberculosis of the ankle joint (for technic, see chapter on Therapeutics). Plenty of fresh air, good nourishing food and tonics are indicated as a routine treatment. +Tetanus.+ Tetanus is an infectious disease, invariably preceded by some injury. The wound may have been severe or it may have been so slight as to have attracted no attention. The disease is commonest after punctured wounds or lacerated ones of the hands or feet, and before it appears, a wound is apt to suppurate or slough, but in some instances the wound is found soundly healed. Tetanus is due to infection by a bacillus (first described by Nicolaier, and first cultivated by Kitasato), the toxic properties of which, absorbed from the infected area, poison the nervous system precisely as would dosing with strychnine. +Symptoms.+ The onset is usually within nine days of an accident. At first, the neck feels stiff and there is difficulty in swallowing, and then the jaw also becomes stiff. The neck becomes like an iron bar, and the jaws are rigid as steel. If the injury is on the foot, that extremity usually is found to be rigid. Opisthotonos is present and spasms are very marked. Swallowing in many cases is impossible. The mind is entirely clear until near the end, one of the worst elements of the disease.