The scales of the squamous syphilide are usually dirty gray in color and more or less scanty; the patches are coppery in hue, and usually several or more characteristic scaleless, infiltrated papules are to be found. The face, palms, and soles are often the seat of the syphilitic eruption; and, moreover, _concomitant symptoms of syphilis_, such as sore throat, mucous patches, glandular enlargement, rheumatic pains, falling out of the hair, together with the history of the initial lesion, are one, several, or all usually present. #How does seborrh[oe]a differ from psoriasis?# Seborrh[oe]a of the scalp is usually diffused, with but little redness and no infiltration; moreover, the scales of seborrh[oe]a are greasy, dirty gray or brownish, while those of psoriasis are dry and comonly whitish or mother-of-pearl colored. Psoriasis of the scalp rarely exists independently of other patches elsewhere on the general surface. That variety of seborrh[oe]a, commonly known as eczema seborrhoicum, presents at times, both on scalp and general surface, a strong resemblance to psoriasis, but the character of the scales and distribution of psoriasis, as above stated, are distinguishing points; seborrh[oe]a, moreover, favors hairy surfaces and in extensive examples the scalp, eyebrows, sternal, and pubic regions rarely escape. #How does psoriasis differ from ringworm?# By its greater scaliness, by its higher degree of inflammatory action, and by its larger number of patches, as also by its history. In ringworm _all_ the patches tend to clear up in the centre; in psoriasis this is rarely, if ever, so. If there is still any doubt, microscopic examination of the scrapings will determine. #Give the prognosis of psoriasis.# The prognosis is usually favorable, so far as concerns the immediate eruption, but as to recurrences, nothing positive can be stated. In rare instances, however, the cure remains permanent. #How is psoriasis treated?# Both constitutional and local remedies are demanded in most cases. #Do dietary measures exert any influence?# As a rule, no; but the food should be plain, and an excess of meat avoided. #Name the important constitutional remedies usually employed in psoriasis.# _Arsenic_ is of first importance. It is not suitable in acute or markedly inflammatory types; but is most useful in the sluggish, chronic forms of the disease. The dose should never be pushed beyond slight physiological action. It may be given as arsenious acid in pill form, one-fiftieth to one-tenth of a grain three times daily, or as Fowler's solution, three to ten minims at a dose. _Alkalies_, of which liquor potassae is the most eligible. It is to be given in ten to twenty minim doses, largely diluted. It is valuable in robust, plethoric, rheumatic or gouty individuals with psoriasis of an acute or markedly inflammatory type; it is not to be given to debilitated or anaemic subjects.