Treatment.—­The quickest way to get rid of a mole is to excise it; if the edges of the gap cannot be brought together with sutures, recourse should be had to grafting.  In large hairy moles of the face whose size forbids excision, radium or the X-rays should be employed.  Excellent results have been obtained by refrigeration with solid carbon dioxide.  In children and women with delicate skin, applications of from ten to thirty seconds suffice.  In persons with coarse skin an application of one minute may be necessary, and it may have to be repeated.

#Horns.#—­The sebaceous horn results from the accumulation of the dried contents of a wen on the surface of the skin:  the sebaceous material after drying up becomes cornified, and as fresh material is added to the base the horn increases in length (Fig. 100).  The wart horn grows from a warty papilloma of the skin. Cicatrix horns are formed by the heaping up of epidermis in the scars that result from burns. Nail horns are overgrown nails (keratomata of the nail bed), and are met with chiefly in the great toe of elderly bedridden patients.  If an ulcer forms at the base of a horn, it may prove the starting-point of epithelioma, and for this reason, as well as for others, horns should be removed.

[Illustration:  FIG. 100.—­Sebaceous Horn growing from Auricle.

(Dr. Kenneth Maclachan’s case.)]

#New Growths in the Skin and Subcutaneous Tissue.#—­The Angioma has been described with diseases of blood vessels. Fibroma.—­Various types of fibroma occur in the skin.  A soft pedunculated fibroma, about the size of a pea, is commonly met with, especially on the neck and trunk; it is usually solitary, and is easily removed with scissors.  The multiple, soft fibroma known as molluscum fibrosum, which depends upon a neuro-fibromatosis of the cutaneous nerves, is described with the tumours of nerves.  Hard fibromas occurring singly or in groups may be met with, especially in the skin of the buttock, and may present a local malignancy, recurring after removal like the “recurrent fibroid” of Paget.  The “painful subcutaneous nodule” is a solitary fibroma related to one of the cutaneous nerves.  The hard fibroma known as keloid is described with the affections of scars.

#Papilloma.#—­The common wart or verruca is an outgrowth of the surface epidermis.  It may be sessile or pedunculated hard or soft.  The surface may be smooth, or fissured and foliated like a cauliflower, or it may be divided up into a number of spines.  Warts are met with chiefly on the hands, and are often multiple, occurring in clusters or in successive crops.  Multiple warts appear to result from some contagion, the nature of which is unknown; they sometimes occur in an epidemic form among school-children, and show a remarkable tendency to disappear spontaneously.  The solitary flat-topped wart which occurs on the face of old people may, if irritated, become the seat of epithelioma.  A warty growth of the epidermis is a frequent accompaniment of moles and of that variety of lupus known as lupus verrucosus.