Burns by Acids and Corrosive Agents.—The injury produced by a mineral acid, the caustic alkalies, etc., has frequently been the source of judicial inquiry. “Vitriol-throwing,” as it has been termed, has been and occasionally is resorted to with malicious intent to injure. No case of death resulting directly and solely from this cause is recorded, but grave injuries, involving loss of sight, etc., have resulted. A case is referred to by Taylor[701] where sulphuric acid was poured into the ear of a woman while asleep by her husband. Death ensued, after six weeks, from disease of the brain resulting indirectly from the use of the acid.
The appearances of a burn by a mineral acid are distinguished from heat burns with little difficulty. The eschar which results is not dry and leathery, as in a burn by heat, but soft and readily sloughing away. There is no redness around the site of the injury, the color of the burn being uniform, and no blisters are formed. There is no blackening of the skin and the hairs are not scorched. The color of the skin around the injured portion may afford valuable evidence of the nature of the agent employed. Nitric acid produces a yellow stain, sulphuric acid a dark brown, and chlorohydric acid a brownish-yellow stain.[702] The clothing also is capable of affording characteristic evidence by the discolorations produced; and the destructive agent employed may be determined by a chemical analysis of the fabric.[703]
It is not possible to distinguish a post-mortem from an ante-mortem burn by an acid when no vital reaction has taken place.
THE CLASSIFICATION OF BURNS.
A classification of burns according to the severity of the injury inflicted is the most practical course. Upon this plan, burns may be divided into four general classes:
I. Burns in which the skin or subcutaneous cellular tissues only are injured.
II. Burns which involve the muscles, nerves, and blood-vessels.
III. Burns involving the internal organs and bones.
IV. Burns in which the other three classes are variously mixed.