There exists without doubt a capillary phlebitis, and the vast importance of inflammation, and its consequence in these vessels, will be estimated when their great extent and functions are recollected. It is probably in this class of cases especially that the blood becomes contaminated with pus. [Illustration] Veins frequently become dilated or _varicose_; they assume a tortuous course, appear much enlarged, and present an elastic, soft feel, except in the situation of the valves, where they are more hard and incompressible: occasionally the tortuous windings form a bluish tumour of considerable size. The dilatation of the superficial branches is increased by heat, the skin being thus relaxed, so as to give less support. The limb is swollen and œdematous. The dilatation is generally supposed to be confined to the vessels near the surface, but it appears that the deep-seated ramifications are not exempt from the affection. When a dilated vein becomes inflamed, great pain is felt in the part; the vessel feels like a firm chord, its coats are much thickened, and its cavity proportionally contracted; lymph is effused, and by it the canal may be obliterated to a greater or less extent; a spontaneous cure is thus accomplished. In the lower limbs, the disease is often complicated with ulcers; and as long as the veins remain varicose, the ulcers are almost incurable, or if they are brought to cicatrise, the skin soon ulcerates again, and the disease is reëstablished. The coats of the vessel not unfrequently ulcerate, and blood is discharged in appalling profusion: such an occurrence may even prove rapidly fatal. Sometimes, though rarely, skin thinned by pressure from within gives way without previous ulceration, and profuse bleeding ensues.