Injuries resulting from corrosive liquids such as sulphuric acid, nitric acid, caustic potash, carbolic acid, etc., are properly termed burns. A heated solid such as iron may produce a burn of great intensity from the blistering of the skin to the charring of the underlying tissues. Metals heated above 212 degrees Fahrenheit will produce redness, vesication and coagulation of the blood. Molten metals cause burns or scalds very similar to those produced by heated solids. Boiling oil produces severe burns. If a part is severely scalded with boiling water, the skin may appear sodden, blistered, and of an ash grey color, but never produces blackening or charring of the cuticle. Phosphorous burns are usually very severe and of great depth, while the area of skin destroyed is usually small. Gunpowder burns caused by explosions are often of great superficial extent, extensive scorching and numerous carbon particles are commonly found imbedded in the true skin. Petroleum burns are generally severe, as usually all or nearly all the body is scorched and blackened. Burns from flame, extensive scorching with burnt hair is a usual feature in a flame burn. Burns from explosions of fire damp in coal mines are frequently of great extent and present the appearance of great scorching, and very often a quantity of coal dust will be found imbedded in the true skin. There are six degrees of burns as follows: (a) Simple hyperemia of the skin, (b) dermatitis, with vesicles or bullae, (c) necrosis of the superficial layer of the skin, (d) complete necrosis of the skin, (e) necrosis of the skin, superficial fascia and muscles, and (f) complete carbonization of the part.