cutaneous blood vessels and the terminations
of the cutaneous nerves. The deeper portion of the true skin is known as
the reticular portion, and is largely composed of adipose tissue.

#Blisters# result from the exudation of serous fluid beneath the horny
layer of the epidermis. The fluid may be clear, as in the blisters of a
recent burn, or blood-stained, as in the blisters commonly accompanying
fractures of the leg. It may become purulent as a result of infection,
and this may be the starting-point of lymphangitis or cellulitis.

The skin should be disinfected and the blisters punctured. When
infected, the separated horny layer must be cut away with scissors to
allow of the necessary purification.

#Callosities# are prominent, indurated masses of the horny layer of the
epidermis, where it has been exposed to prolonged friction and pressure.
They occur on the fingers and hand as a result of certain occupations
and sports, but are most common under the balls of the toes or heel. A
bursa may form beneath a callosity, and if it becomes inflamed may cause
considerable suffering; if suppuration ensues, a sinus may form,
resembling a perforating ulcer of the foot.

The _treatment_ of callosities on the foot consists in removing pressure
by wearing properly fitting boots, and in applying a ring pad around the
callosity; another method is to fit a sock of spongiopilene with a hole
cut out opposite the callosity. After soaking in hot water, the
overgrown horny layer is pared away, and the part painted daily with a
saturated solution of salicylic acid in flexile collodion.

[Illustration: FIG. 93.--Callosities and Corns on the Sole and Plantar
Aspect of the Toes in a woman who was also the subject of flat-foot.]

#Corns.#--A corn is a localised overgrowth of the horny layer of the
epidermis, which grows downwards, pressing upon and displacing the
sensitive papillae of the corium. Corns are due to the friction and
pressure of ill-fitting boots, and are met with chiefly on the toes and
sole of the foot. A corn is usually hard, dry, and white; but it may be
sodden from moisture, as in "soft corns" between the toes. A bursa may
form beneath a corn, and if inflamed constitutes one form of bunion.
When suppuration takes place in relation to a corn, there is great pain
and disability, and it may prove the starting-point of lymphangitis.

The _treatment_ consists in the wearing of properly fitting boots and
stockings, and, if the