#Methods of Infection.#--In marked contrast to what obtains in the infective diseases that have already been described, tuberculosis rarely results from the _infection of a wound_. In exceptional instances, however, this does occur, and in illustration of the fact may be cited the case of a servant who cut her finger with a broken spittoon containing the sputum of her consumptive master; the wound subsequently showed evidence of tuberculous infection, which ultimately spread up along the lymph vessels of the arm. Pathologists, too, whose hands, before the days of rubber gloves, were frequently exposed to the contact of tuberculous tissues and pus, were liable to suffer from a form of tuberculosis of the skin of the finger, known as _anatomical tubercle_. Slight wounds of the feet in children who go about barefoot in towns sometimes become infected with tubercle. Operation wounds made with instruments contaminated with tuberculous material have also been known to become infected. It is highly probable that the common form of tuberculosis of the skin known as "lupus" arises by direct infection from without. [Illustration: FIG. 33.--Tubercle Bacilli in caseous material × 1000 diam. Z. Neilsen stain.] In the vast majority of cases the tubercle bacillus gains entrance to the body by way of the mucous surfaces, the organisms being either inhaled or swallowed; those inhaled are mostly derived from the human subject, those swallowed, from cattle. Bacilli, whether inhaled or swallowed, are especially apt to lodge about the pharynx and pass to the pharyngeal lymphoid tissue and tonsils, and by way of the lymph vessels to the glands. The glands most frequently infected in this way are the cervical glands, and those within the cavity of the chest--particularly the bronchial glands at the root of the lung. From these, infection extends at any later period in life to the bones, joints, and internal organs. There is reason to believe that the organisms may lie in a dormant condition for an indefinite period in these glands, and only become active long afterwards, when some depression of the patient's health produces conditions which favour their growth. When the organisms become active in this way, the tuberculous tissue undergoes softening and disintegration, and the infective material, by bursting into an adjacent vein, may enter the blood-stream, in which it is carried to distant parts of the body. In this way a _general tuberculosis_ may be set up, or localised foci of tuberculosis may develop in the tissues in which the organisms lodge. Many tuberculous patients are to be regarded as possessing in their bronchial glands, or elsewhere, an internal store of bacilli, to which the disease for which advice is sought owes its origin, and from which similar outbreaks of tuberculosis may originate in the future.