It is, as a rule, but slightly elevated, is usually dark in color, and of the size of a pea or finger-nail.

Describe verruca plana juvenilis.

The warts are mostly pin-head in size, flat, but slightly elevated, rounded, irregular or square-shaped, and of a light yellowish-brown color. They bear resemblance to lichen pla.n.u.s papules. They are apt to be numerous, often becoming aggregated or fused, and occur usually in young children, and, as a rule, on the face and hands.

Describe verruca filiformis.

This is a thread-like growth about an eighth or fourth of an inch long, and occurring commonly about the face, eyelids and neck. It is usually soft to the touch and flexible.

Describe verruca digitata.

This is a variety of wart, which, especially about the edges, is marked by digitations, extending nearly or quite down to the base. It is commonly seen upon the scalp.

Describe verruca ac.u.minata.

This variety (_venereal wart_, _pointed wart_, _pointed condyloma_), usually occurs about the genitalia, especially upon the mucous and muco-cutaneous surfaces. It consists of one or more groups of ac.u.minated, pinkish or reddish, raspberry-like elevations, and, according to the region, may be dry or moist; if the latter, the secretion, which is usually yellowish and puriform, from rapid decomposition, develops an offensive and penetrating odor. The formation may be the size of a small pea, or may attain the dimensions of a fist.

What is the cause of warts?

The etiology is not known. They are more common in adolescent and early adult life. Irritating secretions are thought to be causative in the ac.u.minated variety. It is highly probable that a parasitic factor will finally be demonstrated. They are doubtless mildly contagious.

[Ill.u.s.tration: Fig. 33.

Verruca Ac.u.minata--about the a.n.u.s. (_After Ashton._)]

State the pathology of warts.

A wart consists of both epidermic and papillary hypertrophy, the interior of the growth containing a vascular loop. In the ac.u.minated variety there are marked papillary enlargement, excessive development of the mucous layer, and an abundant vascular supply.

Give the treatment of warts.

For ordinary warts, excision or destruction by caustics. The repeated application of a saturated alcoholic solution of salicylic acid is often curative, the upper portion being pared off from time to time. The filiform and digitate varieties may be snipped off with the scissors, and the base touched with nitrate of silver; or a ligature may be used.

Curetting is a valuable operative method. The growths may also be removed by electrolysis. When warts are numerous and close together parasiticide applications can be daily made to the whole affected region. For this purpose a boric acid solution, containing five to thirty grains of resorcin to the ounce, and Vleminckx's solution, at first diluted, prove the most valuable.

Verruca ac.u.minata is to be treated by maintaining absolute cleanliness, and the application of such astringents as liquor plumbi subacetatis, tincture of iron, powdered alum and boric acid. The salicylic acid solution may also be used. In obstinate cases, glacial acetic acid or chromic acid may be cautiously employed.

Naevus Pigmentosus.

(_Synonym:_ Mole.)

Describe naevus pigmentosus.

Naevus pigmentosus, commonly known as mole, may be defined as a circ.u.mscribed increase in the pigment of the skin, usually a.s.sociated with hypertrophy of one or all of the cutaneous structures, especially of the connective tissue and hair. It occurs singly or in numbers; is usually pea-, bean-sized or larger, rounded or irregular, smooth or rough, flat or elevated, and of a color varying from a light brown to black; the hair found thereon may be either colorless or deeply pigmented, coa.r.s.e and of considerable length. It is, as a rule, a permanent formation.

Name the several varieties of naevus pigmentosus met with.

Naevus spilus, naevus pilosus, naevus verrucosus, and naevus lipomatodes.

So-called linear naevus might also be considered as belonging in this group.

What is naevus spilus?

A smooth and flat naevus, consisting essentially of augmented pigmentation alone.

[Ill.u.s.tration: Fig. 34. Linear Naevus.]

What is naevus pilosus?

A naevus upon which there is an abnormal growth of hair, slight or excessive.

What is naevus verrucosus?

A naevus to which is added hypertrophy of the papillae, giving rise to a furrowed and uneven surface.

What is linear naevus?

Linear naevus is a formation usually of a verrucous character, more or less pigmented, sometimes slightly scaly, occurring in band-like or zoster-like areas, and, as a rule, unilaterally.

What is naevus lipomatodes?

A naevus with excessive fat and connective-tissue hypertrophy.

State the etiology of naevus pigmentosus.

The causes are obscure. The growths are usually congenital; but the smooth, non-hairy moles may be acquired.

Give the pathology of naevus pigmentosus.

Microscopical examination shows a marked increase in the pigment in the lowest layers of the rete mucosum, as well as more or less pigmentation in the corium usually following the course of the bloodvessels; in the verrucous variety the papillae are greatly hypertrophied, in addition to the increased pigmentation. There is, as a rule, more or less connective-tissue hypertrophy.

What is the treatment of naevus pigmentosus?

In many instances interference is scarcely called for, but when demanded consists in the removal of the formation either by the knife, by caustics, or by electrolysis. This last is, in the milder varieties at least, perhaps the best method, as it is less likely to be followed by disfiguring cicatrices. In naevus pilosus the removal of the hairs alone by electrolysis is not infrequently followed by a decided diminution of the pigmentation. In recent years both liquid air and carbon dioxide have also been used successfully in the removal of these growths.