nocked or
irritated.

#What course do cutaneous horns pursue?#

Their growth is usually slow, and, after having attained a certain size,
they not infrequently become loose and fall off; they are almost always
reproduced.

#What is the cause of these horny growths?#

The cause is not known; appearing about the genitalia, they usually
develop from acuminated warts. They are rare formations.

#State the pathology of cornu cutaneum.#

Horns consist of closely agglutinated epidermic cells, forming small
columns or rods; in the columns themselves the cells are arranged
concentrically. In the base are found hypertrophic papillae and some
bloodvessels. They have their starting-point in the rete mucosum, either
from that lying above the papillae or that lining the follicles and
glands.

#Does epitheliomatous degeneration of the base ever occur?#

Yes.

#State the prognosis.#

Cutaneous horns may be readily and permanently removed.

#What is the treatment?#

Treatment consists in detachment, and subsequent destruction of the
base; the former is accomplished by dissecting the horn away from the
base or forcibly breaking it off, the latter by means of any of the
well-known caustics, such as caustic potash, chloride of zinc and the
galvano-cautery.

Another method is to excise the base, the horn coming away with it; this
necessitates, however, considerable loss of tissue.

#Verruca.#
(_Synonym:_ Wart.)

#What is verruca?#

Verruca, or wart, is a hard or soft, rounded, flat, acuminated or
filiform, circumscribed epidermal and papillary growth.

#Name the several varieties of warts met with.#

Verruca vulgaris, verruca plana, verruca plana juvenilis, verruca
digitata, verruca filifortnis and verruca acuminata.

#Describe verruca vulgaris.#

This is the common wart, occurring mostly upon the hands. It is rounded,
elevated, circumscribed, hard and horny, with a broad base, and usually
the size of a pea. At first it is smooth and covered with slightly
thickened epidermis, but later this disappears to some extent, the
hypertrophied papillae, appearing as minute elevations, making up the
growth. One, several or more may be present.

#Describe verruca plana.#

This is the so-called flat wart, and occurs commonly upon the back,
especially in elderly people (_verruca senilis_, _keratosis pigmentosa_).
It is, as a rule, but slightly e