_Artificial Hyperæmia._--As has been explained, the induction of hyperæmia by the method devised by Bier, constitutes one of our most efficient means of combating bacterial infection. The treatment of tuberculosis on this plan has been proved by experience to be a valuable addition to our therapeutic measures, and the simplicity of its application has led to its being widely adopted in practice. It results in an increase in the reactive changes around the tuberculous focus, an increase in the immigration of leucocytes, and infiltration with the lymphocytes. The constricting bandage should be applied at some distance above the seat of infection; for instance, in disease of the wrist, it is put on above the elbow, and it must not cause pain either where it is applied or in the diseased part. The bandage is only applied for a few hours each day, either two hours at a time or twice a day for one hour, and, while it is on, all dressings are removed save a piece of sterile gauze over any wound or sinus that may be present. The process of cure takes a long time--nine or even twelve months in the case of a severe joint affection. In cases in which a constricting bandage is inapplicable, for example, in cold abscesses, tuberculous glands or tendon sheaths, Klapp's suction bell is employed. The cup is applied for five minutes at a time and then taken off for three minutes, and this is repeated over a period of about three-quarters of an hour. The pus is allowed to escape by a small incision, and no packing or drain should be introduced. It has been found that tuberculous lesions tend to undergo cure when the infected tissues are exposed to the rays of the sun--_heliotherapy_--therefore whenever practicable this therapeutic measure should be had recourse to. Since the introduction of the methods of treatment described above, and especially by their employment at an early stage in the disease, the number of cases of tuberculosis requiring operative interference has greatly diminished. There are still circumstances, however, in which an operation is required; for example, in disease of the lymph glands for the removal of inert masses of caseous material, in disease of bone for the removal of sequestra, or in disease of joints to improve the function of the limb. It is to be understood, however, that operative treatment must always be preceded by and combined with other therapeutic measures. TUBERCULOUS ABSCESS The caseation of tuberculous granulation tissue and its liquefaction is a slow and insidious process, and is unattended with the classical signs of inflammation--hence the terms "cold" and "chronic" applied to the tuberculous abscess. In a cold abscess, such as that which results from tuberculous disease of the vertebræ, the clinical appearances are those of a soft, fluid swelling without heat, redness, pain, or fever. When toxic symptoms are present, they are usually due to a mixed infection.