and only requires time to resume its former severity. Eczema, as a complication, requires treatment appropriate to that condition; callosities can be softened by strong potash lotions (one to two), or continuous applications of soft soap, or removed by salicylic acid plaster. The larger growths of I. hystrix should only be interfered with if they are in inconvenient positions, and can then be excised or scraped with a sharp spoon. The smaller papillary growths may be removed by the continuous application of tar ointment, and though many of them return, some will be permanently removed. A more pleasant application, and one which has been more successful than tar in my hands, is to paint the growths, after removing the horny caps, with a saturated solution of salicylic acid in alcohol. In this way I have got rid of large areas of minor growths. Internal treatment in all forms is absolutely useless.

KERATOSIS PILARIS.

Synonyms. Pityriasis pilaris; Lichen pilaris.

Definition.-An accumulation of horny cells, which plug the orifice of the hair follicles, and thus form small papules.

This disease is still called lichen pilaris by some authors, but it differs from the lichen class in not being of inflammatory origin. Symptoms-It consists of pin's-head-sized convex papules of the same color as the normal skin, or of grayish or blackish hue from adherent dirt; each of the papules is formed at the orifice of the hair follicle, and can be completely picked out by the nail, leaving a depression. Sometimes the hair pierces the papule, but more frequently it is coiled within or broken off at the surface, showing only a dark dot. The adjacent skin is normal in color, but often xerodermatous, or even ichthyotic, and this, with the hard papules, produces a very rough, nutmeg-grater sensation.

It occurs chiefly on the extensor aspect of the limbs, especially the arms and thighs, and occasionally on the trunk; but it varies in extent and development, sometimes being scarcely noticeable, at others very conspicuous, from the number and size of the papules.

Etiology. It is most common in those who seldom or never take baths, but it may occur in others from the time of puberty and onwards, and is always present in a high degree in the ichthyotic.

Diagnosis. It is in many respects like a late stage of true lichen pilaris, but it lacks the central horny spine of that affection, is essentially chronic, and there is no inflammation at the commencement. It closely resembles cutis anserina, but that is a transitory condition, lasting very little longer than the cold or fear which produced it, and its papule cannot be removed by the nail.

From lichen scrofulosus, and the papular syphilide with similar characters, it may be distinguished by the positions, the greater prominence and hardness of the papules, and by the constitutional condition present with these two inflammatory conditions. Treatment. This is much the same as that of xeroderma, viz., alkaline and vapor baths, soft-soap inunctions, followed by warm baths; or the inunction of oily substances of various kinds may be rubbed in, in the same way as is described under ichthyosis.

PAPILLOMA OF THE SKIN.*

Corns, warts, horns, and some nævi, are all considered by general pathologists as examples of "papilloma of the skin;" and various kinds of tumors, such as sarcoma, carcinoma, epithelioma, and fibroma, as well as morbid processes like syphilis, lupus, eczema, and sycosis, are liable to develop papillary growths. An attempt has, however, been made by Neumann, Duhring, and some other dermatologists to give the term a special meaning, on the strength of certain cases which have been reported as inflammatory skin papilloma by Weil and Roser, and under other names by various writers. It consists of a raised cauliflower excrescence, very like verruca acuminata, already described, varying in size, with fissures and sinuses, which secrete a yellowish, puriform, and sometimes offensive fluid, occurring at any part of the body and at any time of life.

* Literature -Hardaway, "Clinical Study of Papilloma Cutis," Amer. Arch. of Derm., vol. vi (1880), p. 387,-a good general review of the whole subject. Morrow, "Tuberculosis Papillomatosa Cutis," Amer. Jour. Cut. and Gen.-Ur. Dis., vol. vi (1888), pp. 361 and 401,-well illustrated, gives an account of very extensive primary growth, and discusses the question of papilloma. Das entzündliche Haut-Papilloma," Roser, Arch. der in Heilkunde, 1866. Weil in Viertelj. f. Derm. u. Syph., 1874, p. 37, with colored plate.

I once saw a patch of this kind on the hip of a tubercular man of twenty-five, about one inch in diameter, projecting about onefourth of an inch, with a scabbed covering, and hypertrophied, readily bleeding papillæ. There was no history of previous lesions, but Hardaway thinks such growths are always secondary to ulcers or other lesions, and calls them all symptomatic papillomata. Beigel's* oft-quoted case of papilloma area elevatum in a child æt. twelve months, suffering from convulsions, was evidently a case of bromide rash, in which the appearance of the papilloma is not infrequently produced when the scab is removed from the larger lesions, and they are also sometimes followed by papillary hypertrophy. The term "neuropathic papilloma" is often applied to the band form of warty growths, which really belong to the same category as ichthyosis hystrix.

VERRUCA (a Wart).

Synonyms.-Wart; Fr., Verrue; Ger., Warze.

Definition. A small papillary growth, variable in size, shape, and consistency.

Warts are very variable in aspect and development, and have names accordingly, which are convenient for description.

Verruca Vulgaris is the form so common on the hands, especially in young people, where it forms a hemp-seed to a splitpea-sized, hard, sessile, slightly conical elevation, with truncated top.

The upper and greater visible portion of it is horny, and the surface is smooth, or studded with minute, moniliform elevations, formed by the close aggregation of hypertrophied, horny-capped papillæ, which, by unequal growth, often break up the whole tumor into irregular, craggy lobulations. When first formed, they are the normal color of the skin, but the older and rougher they are the more discolored they become, and are then some shade of yellow, brown, green, or even black. They are single or multiple, isolated or aggregated into close or loose irregular groups, and, while generally seen on the hands, may come anywhere.

Path. Trans., vol. xx, p. 414.

Verruca Plana is flat and very slightly elevated, from a pin's head to half an inch in diameter, sometimes single, but often very numerous.

In young people they are generally quite small, and occur chiefly on the face, especially the forehead, and, to a less degree, on the backs of the hands; they may or may not be slightly pigmented, are both disseminated and in irregular groups, and occasionally have a unilateral distribution. They are often quite square, and bear a very close resemblance to the papules of lichen planus in shape and color; but lichen planus is rare on the face and scalp, where these lesions chiefly appear. Darier's* histological examination of them showed that the chief changes were hypertrophy of all the layers of the epidermis, with elongation of the papillæ.

In old people, they are seen chiefly on the back and arms, are generally pigmented from brown to black (verruca senilis, keratosis pigmentosa), associated with other signs of senile degeneration of the skin, and may itch severely. Although usually flat, they are sometimes considerably raised above the surface, and obviously papillomatous.

They are said to be very numerous sometimes in cancerous patients, and I have seen a very copious crop on the chest, associated with acute eczema, in an elderly woman.

These warts have been histologically investigated by Neumann, Balzer, Handford, Pollitzer,† etc. The last-named wishes to revert to the old term of seborrhoeic wart. He has examined eight warts carefully, and dismisses Neumann's and Balzer's descriptions as fanciful. The discoloration he attributes to the concretion of dirt and fatty scales. The stratum corneum is slightly, and the rete considerably, thickened. Epithelioid cells are arranged in groups and lines among the connective-tissue bundles of the corium throughout its whole depth; but the greatest peculiarity, he thinks, is the infiltration of fat in the epithelial cells, from the rete to the coil glands inclusively. He regards the warts as growths from "misplaced" embryonic cells.

Verruca Digitata.-The hypertrophied papillæ are here separated nearly or quite down to the base, and form finger

* Ann. de Derm. et de Syph., vol. ix (1888), p. 619; abs. Brit. Jour. Derm., vol. i (1888), p. 82.

Brit. Jour. Derm., vol. ii (1890), p. 199, with plate. He quotes the descriptions of the other observers.

like elevations with a horny cap, the rest being comparatively soft; they are aggregated into small groups, or occasionally large patches, and occur chiefly on the scalp.

Verruca Filiformis. These are a small variety of the previous form; they are of small diameter, or even filiform, with pointed end, not more than one-eighth of an inch long, and occur singly, or in small groups on the face, especially the eyelids, and on the neck.

Verruca or Condyloma Acuminata. Synonyms.—Moist or venereal wart; Fr., Végétations dermiques; Ger., Spitzenwarze; Spitzencondyloma.

The most common position for these is about the anus, perinæum, in the sulcus, behind or on the glans penis, between the labia, and in the vagina, less frequently in the axillæ, under the mammæ when they overhang, in the umbilicus, round the mouth, or on the toes. When they are on the free surface, where they are dry, they are the color of the normal skin; but in moist. situations, where they are subject to heat, maceration, and friction, they are covered with a whitish or yellowish, puriform secretion, which soon becomes highly offensive. They are made up of closely aggregated projections, which may be acuminate, tufted, or club-shaped, sessile or pedunculated, protruding much or little; they grow luxuriantly, increasing by peripheral additions, and, according to their aggregation, subjection to pressure, luxuriance of growth, and the liveliness of the imagination of the describer, imitate various vegetable productions, and get such names as cauliflower, framboesia, fungous, mulberry or racemose, cockscomb, etc., appended to them. They may grow rapidly or slowly, and though parts of them may atrophy, on the whole they increase, exhibiting less tendency to spontaneous disappearance than is generally exhibited by other forms of wart. The large, rapidly growing warts seen in pregnant women are an exception, as they generally disappear spontaneously after parturition.

Etiology.-There is little fact, but much theory, with regard to their etiology. All ages and both sexes are liable to them, some forms being more common in the young than in the old. With regard to the moist form, or verruca acuminata of mucous