A burn is produced by dry heat, a scald by moist heat; the effect and
treatment of both are practically identical. Burns are commonly
divided into three classes, according to the amount of damage
inflicted upon the body.

_First Class._--There is redness, pain, and some swelling of the skin,
followed, in a few days, by peeling of the surface layer (epidermis)
and recovery. Sunburn and burns caused by slight exposures to gases
and vapors fall into this category.

=Treatment.=--The immediate immersion of the part in cold water is
followed by relief, or the application of cloths wet with a saturated
solution of saleratus or baking powder is useful. Anything which
protects the burned skin from the irritating effect of the air is
efficacious, and in emergencies any one of the following may be
applied: starch, flour, molasses, white paint, or a mixture of white
of egg and sweet oil, equal parts. Usually after the first pain has
been relieved by bathing with soda and water, or its application on
cloths, the employment of a simple ointment suffices, as cold cream or
vaseline.

_Second Class._--In this class of cases the inflammation is more
severe and the deeper layers of the skin are involved. In addition to
the redness and swelling of the skin there are present blisters which
appear at once or within a few hours. The general condition is
affected according to the size of the burn. If half of the body is
only reddened, death usually results, and a burn of a third of the
body is often fatal. The shock is so great at times that pain may not
be at once intense. Shock is evidenced by general depression, with
weakness, apathy, cold feet and hands, and failure of the pulse. If
the patient rallies from this condition, then fever and pain become
prominent. If steam has been inhaled, there may be sudden death from
swelling of the interior of the throat, or inflammation of the lungs
may follow inhalation of smoke and hot air.

_Third Class._--In this class are included burns of so severe a nature
that destruction and death of the tissues follows; not only of the
skin but of the flesh and bones in the worst cases. It is impossible
to tell by the appearance of the skin what the extent of the
destruction may be until the dead parts slough away after a week or
ten days. The skin is of a uniform white color in some cases, or may
be of a yellow, brown, gray, or black hue, and is comparatively
insensitive at first. Pus ("matter") begins