In the burns of the third degree the inflammation or destruction may be su perficial, extending over considerable area, or deep, affecting the subcutaneous tissues, muscles, and even bones. In those of the superficial variety the ex tent of surface-involvement may be vari able, in one instance occupying a por tion comparing with the size of the hand, and in others being observed upon por tions ranging from six or seven inches to areas as large as one limb or even one-third or one-half of the surface of the body. In this variety the epidermis alone may be destroyed and expose the corium to view, covered with particles of charred cuticle, or the corium itself may share in the destruction, being deposited over the affected areas in strips of dried eschars. The parts uncovered by these destructive influences present, either the corium or subcutaneous tissue, a highly vascular aspect, from which there is a continuous exudation of serum inter mingled with the escaping blood. The dead tissues vary in proportion according to extent of heat, its length of contact, the thinness or density of the part in volved, and the amount of surface en compassed. They may be thin or thick, large or small, and retain their hold for longer or shorter periods.
Resolution takes place in the uncov ered variety in the same manner as de scribed under the foregoing degree, while in the covered variety granula tions spring up beneath the charred re mains which, after a time, desiccate and fall off, exposing a similar surface to that of the second degree.
In the deeper form of burn the extent of surface involved may be small or large, but may dip down to varying depths. It may be limited to the de struction of the skin (epidermis and corium) and the subcutaneous tissues, or it may expose the muscles, attack the nerves and blood-vessels (allowing haem orrhage), and even the bone. The amount of charring will usually be very great and will lay about in masses over the burned surface, thus preventing a view of the destruction beneath. In some cases the degree of loss will be so enormous that the bone will be entirely stripped of all covering. Ilmmorrhages will often be encountered and may re sult fatally. Fractures of bone will oc casionally complicate matters. This variety will show both the first and sec ond degrees at areas remote from the greatest destruction. Resolution even in the milder cases is slow, and before such happens surgical interference may be demanded. The same appearances may be noted throughout its process as found in the superficial variety, but to a different degree. The causes which bring about this form of burning are usually dry heat (flames or contact with electric wires), and it generally causes much greater destruction than will moist heat. The effect upon the system is
generally of an alarming character, and shock may carry off the person before relief can even be attempted.
Electric and X-ray Burns. — Burns from electricity may be observed in all the varieties mentioned above. They may follow direct or indirect contact. Examples of direct contact are observed after handling live (charged) wires, and may be found to destroy all parts with which it comes into touch, or life even may be the forfeit.
Case of severe electrical burn in an electrician employed in the electric plant used to furnish power to the city street car line and to the are and incandescent lights of the city. The patient had acci dentally brought his back in contact with the positive and negative keys of the switchboard of arc-line furnishing 96 street-lamps and carrying 4000 volts of electricity. He was released by the tissues' being burned away in two pits about three inches in diameter and down to the bony structures. The intervening space between these pits, which were ten inches apart, was roasted, and after the lapse of a few weeks was lifted out. It weighed two pounds and a half. The sloughing was such that the cotton, bandages, clothing, and bed were sat urated with pus. Recovery. J. F. Weathers (N. Y. 'Med. Jour., Apr. 2, '98).
The following peculiarities attributed to electrical burns: At first they look dry, crisp, and bloodless, and are exca vated. But serious oozing and hyper emia occur within thirty-six hours, pain is moderate, and the systemic shock con siderable. N. W. Sharp (Phila. lied. Jour., Jan. 29, '98).
A most recent form of burning of the skin from the indirect contact of elec tricity is by the x-ray apparatus. Close proximity to the ray by either covered or uncovered parts result either in a super ficial or deep inflammation of the skin. It. may be observed a few hours after ex posure to the rays or may be delayed for several weeks. Gilchrist, of Baltimore, in a case did not see any effect for sev eral (three) weeks after exposure, while Crocker, of London, observed a case in which the effects were produced in one day thereafter. This form of burning attacks the skin alone in some instances, while in others the deeper structures, as the muscles, tendons, nerves, and bones (periostitis and ostitis resulting) are in volved. The effects may remain for days, weeks, or even months after the application. X-ray burns are supposed by some to be produced by the action of the ray or by particles of aluminium or platinum reaching and being deposited in the tissues by others.