or even necrosis of skin. When ulcers form they are extremely
painful and slow to heal. When hair-bearing areas are affected,
epilation may occur without destroying the hair follicles and the hairs
are reproduced, but if the reaction is excessive permanent alopecia may
result.

_Chronic dermatitis_, which results from persistence of the acute form,
is most intractable and may assume malignant characters. X-ray warts are
a late manifestation of chronic dermatitis and may become malignant.

Among the _late manifestations_ are neuritis, telangiectasis, and a
painful and intractable form of ulceration, any of which may come on
months or even years after the cessation of exposure. _Sterility_ may be
induced in X-ray workers who are imperfectly protected from the effects
of the rays.

#Electrical burns# usually occur in those who are engaged in industrial
undertakings where powerful electrical currents are employed.

The lesions--which vary from a slight superficial scorching to complete
charring of parts--are most evident at the points of entrance and exit
of the current, the intervening tissues apparently escaping injury.

The more superficial degrees of electrical burns differ from those
produced by heat in being almost painless, and in healing very slowly,
although as a rule they remain dry and aseptic.

The more severe forms are attended with a considerable degree of shock,
which is not only more profound, but also lasts much longer than the
shock in an ordinary burn of corresponding severity. The parts at the
point of entrance of the current are charred to a greater or lesser
depth. The eschar is at first dry and crisp, and is surrounded by a zone
of pallor. For the first thirty-six to forty-eight hours there is
comparatively little suffering, but at the end of that time the parts
become exceedingly painful. In a majority of cases, in spite of careful
purification, a slow form of moist gangrene sets in, and the slough
spreads both in area and in depth, until the muscles and often the
large blood vessels and nerves are exposed. A line of demarcation
eventually forms, but the sloughs are exceedingly slow to separate,
taking from three to five times as long as in an ordinary burn, and
during the process of separation there is considerable risk of secondary
haemorrhage from erosion of large vessels.

_Treatment._--Electrical burns are treated on the same lines as ordinary
burns, by thorough purification and the appl