, and
either a dry, antiseptic dressing powder or carbolated vaseline ointment
applied to exclude the air. Granulation tissue (proud flesh) should be
controlled by the application of silver nitrate in the form of a caustic
pencil.

Burns due to mineral acids may be first treated by flushing the parts
with a copious quantity of cold water or by the application of whiting
or chalk. Either use a large quantity of water at the start or use the
chalk first, then wash with water. If the irritant has been a caustic
alkali, such as potash, lye, ammonia, or soda, then vinegar should be
the first application. Stahl's liniment is probably the best general
application for all burns for the first week; then this should be
followed by the ordinary antiseptic wound dressings.

GANGRENE.

Gangrene, or mortification, denotes the death of the affected part, and
is mostly found attacking soft tissue near the surface of the body.
Gangrenous areas may occur as a result of shutting off their blood
supply. Constitutional diseases, such as ergotism, anthrax, and
septicemia, predispose to gangrene. As external causes we have acids and
alkalies, freezing and burning, contusions and continuous pressure that
interrupt the circulation. There are two forms of gangrene--dry and
moist. Dry gangrene is most often seen in horses from continuous lying
down (decubitus) or from uneven pressure of some portion of the harness.

_Symptoms._--There is a lack of sensation due to the death of nerves. In
dry gangrene the skin is leathery and harsh, while in moist gangrene the
tissues are soft, wrinkled, and friable; the hair is disturbed, and the
skin is usually moist and soapy and sometimes covered with blebs. The
tissue surrounding the moist gangrenous patch is usually inflamed,
swollen, and hot, but this is less noticeable in the case of dry
gangrene. Moist gangrene often spreads and involves deeper tissue,
sheaths of tendons and joints producing septic synovitis or septic
arthritis leading to pyemia and death. Dry gangrene is seldom dangerous,
but the rapidity of its spread will indicate its virulence.

_Treatment._--The preventive treatment consists in avoiding all the
influences that tend to disturb the nutrition of the tissues, such as
excessive cold or heat or continuous pressure. Gangrene following
decubitus may be prevented by using soft bedding and frequently turning
the animal from one side to the other. In dry gangrene moist heat in the
form