BURNS.
Definition.—A burn is a high grade of acute inflammation, following the direct or indirect application of dry or moist heat to a portion of the cutaneous or mucous surfaces.
Varieties. — For ease of comprehen sion burns have been separated into grades according to their severity. The character of inflammation observed in these grades is governed by the exciting agent, its capacity for the absorption of heat, the duration of its contact, and the susceptibility of the part acted upon. Solid substances (copper and iron) and the fixed oils (olive and linseed) cause a greater impression than volatile (alco hol, ether, and chloroform) or aqueous (water and vapors) materials. Certain articles, owing to their tenacity (copper), although absorbing the same amount of heat as others (iron), cause more decided destruction.
The length of contact, giving in the shorter periods a superficial incineration and in the longer a deeper destruction, is I of importance in determining the grade r of inflammation. The more dense and thick portions of the skin (buttocks, palms, and soles) offer greater resist ance than those of thinner (face, neck, and abdomen) texture.
The effect upon the system will de pend upon the character of person at tacked, those of stronger constitutions being the more able to controvert shock than those of weaker frame.
A temperature, slightly increased above the normal (as, for instance, 100° F.), produces only a slight hypenernia (first degree: dermatitis ambustionis erythematosa), which may disappear shortly after breaking the contact, while a rise to 150° F. will cause some appear ance of vesicles and bulla (second de gree: dermatitis ambustionis vesiculosa et bullosa) and destruction of the epi dermis, the effect of which is not re lieved for days after the removal of the burning substance, and yet, on the other hand, heat at the boiling-point of water (212° F.) may cause a complete carbon ization of the part, resulting in the formation of eschars varying in color from a yellow up to a dark brown or black or, in other words, the production of gangrene (third degree: dermatitis ambustionis escharotica seu gangrenosa).
Symptoms. — The effects of a burn upon the body-structure are both local and constitutional. The former often results in great disfiguration or destruc tion of tissue, while the latter depresses the vital forces or terminates in death.