Different degrees of injury are inflicted on the surface from the application of heated solids or fluids. The term scald is generally confined to the effects of heated fluids, whilst burn denotes the consequences of the application of a heated solid, or of ignited combustible matter; the latter class of accidents is, in general, the more serious, yet the former, though not injuring the skin deeply, gives rise to the most alarming symptoms when a large extent of surface is affected. A slight degree of heat is productive only of redness of the surface, with a sharp hot pain, and these symptoms may subside with or without vesication. However, effusion of serum under the cuticle often takes place almost immediately after the contact of the heated body—the cuticle may be destroyed by the intensity of the injury—or the true skin may die, either partially or throughout its whole thickness, and the subjacent parts be at the same time injured to a greater or less depth. But parts, not severely injured at first, may afterwards perish, violent inflammatory action being excited, which terminates in sloughing. The neighbouring parts have their vitality much diminished, by the direct influence of the injury; and hence, when these parts come to be the seat of increased action, sloughing almost inevitably ensues, from the want of corresponding power. From the same cause, subsequent sores are tedious in healing, being so far debilitated as to be unable to assume full vigour; even slight ulcerations following vesication contract very slowly; the granulations are flabby, and the discharge profuse and thin. The inflammation is often at first very violent, and kept within bounds with difficulty. Burns of the trunk, particularly of the genital organs, are to be considered as attended with much danger. And extensive burns and scalds, wherever situated, are always to be dreaded. Violent constitutional irritation takes place, dyspnœa is apt to occur, with effusion into the chest of serum, or a sero-purulent fluid; and the nervous system ultimately becomes oppressed. Great sinking of the vital powers is generally the immediate consequence of extensive and severe burns; there is shivering, weakness of the pulse, cold extremities, anxiety, and vomiting, requiring the exhibition of warm drinks, and even sometimes of cordials, opium, or strong stimulants. These must, however, be given with a sparing hand, or the depression following the excitement is with difficulty got over. Nor can it be matter of surprise that such serious effects occur, when we reflect on the extreme sensibility, and highly organised state of the affected part, and the important functions which it is intended to perform, as well as those sympathies which it holds with internal parts, on which life principally depends.