_Pathology of Burns._--Much discussion has taken place regarding the explanation of the rapidly fatal issue in extensive superficial burns. On post-mortem examination the lesions found in these cases are: (1) general hyperæmia of all the organs of the abdominal, thoracic, and cerebro-spinal cavities; (2) marked leucocytosis, with destruction of red corpuscles, setting free hæmoglobin which lodges in the epithelial cells of the tubules of the kidneys; (3) minute thrombi and extravasations throughout the tissues of the body; (4) degeneration of the ganglion cells of the solar plexus; (5) œdema and degeneration of the lymphoid tissue throughout the body; (6) cloudy swelling of the liver and kidneys, and softening and enlargement of the spleen. Bardeen suggests that these morbid phenomena correspond so closely to those met with where the presence of a toxin is known to produce them, that in all probability death is similarly due to the action of some poison produced by the action of heat on the skin and on the proteins of the blood. #Clinical Features--Local Phenomena.#--The most generally accepted classification of burns is that of Dupuytren, which is based upon the depth of the lesion. Six degrees are thus, recognised: (1) hyperæmia or erythema; (2) vesication; (3) partial destruction of the true skin; (4) total destruction of the true skin; (5) charring of muscles; (6) charring of bones. It must be observed, however, that burns met with at the bedside always illustrate more than one of these degrees, the deeper forms always being associated with those less deep, and the clinical picture is made up of the combined characters of all. A burn is classified in terms of its most severe portion. It is also to be remarked that the extent and severity of a burn usually prove to be greater than at first sight appears. _Burns of the first degree_ are associated with erythema of the skin, due to hyperæmia of its blood vessels, and result from scorching by flame, from contact with solids or fluids below 212° F., or from exposure to the sun's rays. They are characterised clinically by acute pain, redness, transitory swelling from œdema, and subsequent desquamation of the surface layers of the epidermis. A special form of pigmentation of the skin is seen on the front of the legs of women from exposure to the heat of the fire. _Burns of Second Degree--Vesication of the Skin._--These are characterised by the occurrence of vesicles or blisters which are scattered over the hyperæmic area, and contain a clear yellowish or brownish fluid. On removing the raised epidermis, the congested and highly sensitive papillæ of the skin are exposed. Unna has found that pyogenic bacteria are invariably present in these blisters. Burns of the second degree leave no scar but frequently a persistent discoloration. In rare instances the burned area becomes the seat of a peculiar overgrowth of fibrous tissue of the nature of keloid (p 401).