#Lymphangitis.#--Inflammation of peripheral lymph vessels usually results from some primary source of pyogenic infection in the skin. This may be a wound or a purulent blister, and the streptococcus pyogenes is the organism most frequently present. _Septic_ lymphangitis is commonly met with in those who, from the nature of their occupation, handle infective material. A _gonococcal_ form has been observed in those suffering from gonorrhœa. The inflammation affects chiefly the walls of the vessels, and is attended with clotting of the lymph. There is also some degree of inflammation of the surrounding cellular tissue--_peri-lymphangitis_. One or more abscesses may form along the course of the vessels, or a spreading cellulitis may supervene. The _clinical features_ resemble those of other pyogenic infections, and there are wavy red lines running from the source of infection towards the nearest lymph glands. These correspond to the inflamed vessels, and are the seat of burning pain and tenderness. The associated glands are enlarged and painful. In severe cases the symptoms merge into those of septicæmia. When the deep lymph vessels alone are involved, the superficial red lines are absent, but the limb becomes greatly swollen and pits on pressure. In cases of extensive lymphangitis, especially when there are repeated attacks, the vessels are obliterated by the formation of new connective tissue and a persistent solid œdema results, culminating in one form of elephantiasis. _Treatment._--The primary source of infection is dealt with on the usual lines. If the lymphangitis affects an extremity, Bier's elastic bandage is applied, and if suppuration occurs, the pus is let out through one or more small incisions; in other parts of the body Klapp's suction bells are employed. An autogenous vaccine may be prepared and injected. When the condition has subsided, the limb is massaged and evenly bandaged to promote the disappearance of œdema. _Tuberculous Lymphangitis._--Although lymph vessels play an important rôle in the spread of tuberculosis, the clinical recognition of the disease in them is exceptional. The infection spreads upwards along the superficial lymphatics, which become nodularly thickened; at one or more points, larger, peri-lymphangitic nodules may form and break down into abscesses and ulcers; the nearest group of glands become infected at an early stage. When the disease is widely distributed throughout the lymphatics of the limb, it becomes swollen and hard--a condition illustrated by lupus elephantiasis. _Syphilitic lymphangitis_ is observed in cases of primary syphilis, in which the vessels of the dorsum of the penis can be felt as indurated cords.