the
separation of the cuticle into scales and a gradual thickening of the
skin.

CAUSES. Three forms of constitutional derangement predispose the system
to eczema; nutritive, assimilative, and nervous debility. In the former,
there is a diminution of nutritive power, so that the patient becomes
weak and emaciated. Assimilative debility is indicated by an impaired
digestion and a consequent suppression, or an abnormal state of the
secretions. Eczema occasioned by nervous debility, is accompanied by all
the morbid conditions incident to irritation and exhaustion of the
nervous system. Eczema may be excited by a violation of the rules of
hygiene, as undue exposure, or sudden transition from heat to cold,
deficient or excessive exercise, impure air, or improper clothing.

PSORIASIS. Psoriasis may be defined as a _chronic form of eczema_. The
transition of the last stage of eczema into psoriasis is indicated by a
tendency of the inflamed, thickened, scaly skin to become moist when
rubbed. It usually appears in patches on various portions of the body.
The skin is parched and highly discolored. The hairs are harsh and
scanty. The patient is constantly tormented by an unbearable itching
sensation and, if the skin is rubbed, it exudes a viscous or sticky
fluid. These are the characteristic signs of psoriasis. It generally
appears on the flexures, folds and crooks of the joints, the backs and
palms of the hands, the arms, and the lower portions of the legs.

PITYRIASIS. (_Branny Tetter_, or _Dandruff_.) This affection is a mild
form of psoriasis, from which it may be distinguished by a more
superficial congestion or inflammation of the affected parts, the
absence of swelling, and the formation of smaller scales, having the
form and appearance of _fine bran_. It generally appears on the scalp,
sometimes extends over the face, and, in rare instances, affects the
entire surface of the body. The signs peculiar to this disease are
slight inflammation, itching, and the formation of minute scales.

CAUSES. Pityriasis is caused by nutritive debility, and is often
associated with erysipelas, rheumatism, and bronchitis.

LICHEN. (_Papular Rash_.) Lichen is a term used to designate an eruption
of minute conical pimples, which are more or less transparent, red, and
occasion great annoyance. The eruption is attended with a severe, hot,
prickling sensation, as if the flesh were punctured with hot needles.
The pimples contain no pus, but i