ion soon forms, but the
dead part separates very slowly.

#Gangrene from Frost-bite.#--It is difficult to draw the line between
the third degree of chilblain and the milder forms of true frost-bite;
the difference is merely one of degree. Frost-bite affects chiefly the
toes and fingers--especially the great toe and the little finger--the
ears, and the nose. In this country it is seldom seen except in members
of the tramp class, who, in addition to being exposed to cold by
sleeping in the open air, are ill-fed and generally debilitated. The
condition usually manifests itself after the parts, having been
subjected to extreme cold, are brought into warm surroundings. The first
symptom is numbness in the part, followed by a sense of weight,
tingling, and finally by complete loss of sensation. The part attacked
becomes white and bleached-looking, feels icy cold, and is insensitive
to touch. Either immediately, or, it may be, not for several days, it
becomes discoloured and swollen, and finally contracts and shrivels.
Above the dead area the limb may be the seat of excruciating pain. The
dead portion is cast off, as in other forms of dry gangrene, by the
formation of a line of demarcation.

To prevent the occurrence of gangrene from frost-bite it is necessary to
avoid the sudden application of heat. The patient should be placed in a
cold room, and the part rubbed with snow, or put in a cold bath, and
have light friction applied to it. As the circulation is restored the
general surroundings and the local applications are gradually made
warmer. Elevation of the part, wrapping it in cotton wool, and removal
to a warmer room, are then permissible, and stimulants and warm drinks
may be given with caution. When by these means the occurrence of
gangrene is averted, recovery ensues, its onset being indicated by the
white parts assuming a livid red hue and becoming the seat of an acute
burning sensation.

A condition known as _Trench feet_ was widely prevalent amongst the
troops in France during the European War. Although allied to frost-bite,
cold appears to play a less important part in its causation than
humidity and constriction of the limbs producing ischaemia of the feet.
Changes were found in the endothelium of the blood vessels, the axis
cylinders of nerves, and the muscles. The condition does not occur in
civil life.

#Diabetic Gangrene.#--This form of gangrene is prone to occur in persons
over fifty years of age who suf