thereby communicate strength to the weakened organ. On this principle, even when no important error of function is obvious, we should have recourse to our tonic, our alterative, and our nutritive remedies in sycosis, lichen circinatus, and lichen marginatus, and also in onychogryphosis.

In lichen marginatus I have prescribed the nitrohydrochloric acid with gentian; citrate of iron, and quinine with tincture of orange-peel; and the liquor hydrargyri perchloridi with liquor cinchona.

It may be expected that I should say a few words with regard to epilation or the avulsion of the hair in tinea, a treatment practised abroad, but which has happily gained no footing in this country. This practice is founded on the parasitic theory of the disease; the hairs of the affected follicles are plucked out, and the plucked surface mopped with a solution of the perchloride of mercury, which is supposed, not as might be rationally imagined, to stimulate the follicles to a more healthy action, but to destroy the vegetable parasites. No doubt the avulsion is frequently followed by cure, just as the drawing of a tooth may relieve the pain of an inflamed dental alveolus, and just as we find the avulsion of the hairs of the beard in the pustular folliculitis of mentagra beneficial; but, unless we desire to perpetrate unnecessary pain and cruelty, a better result may be obtained by more lenient means.

DISEASES OF THE NAILS.

The third subject which I have to bring before you in the present course of lectures. is that of the aberrations of growth and the diseases of the nails, the onychopathic affections. The nails are a part of the epidermis, and their diseases, therefore, are very nearly allied with the diseases of the pigmentary function of the epidermis as well as with the structural changes constituting the dermatophytic diseases.

One of the most obvious of the abnormal changes met with among nails is that of extreme growth in length. In the preparations numbered 529, 530, and 531 of the Dermatological Collection, we have examples of nails taken from the great toe, and ranging in length from between two to three inches. Similar examples are seen in the "General Series " in the preparations numbered 2309, 2310, and especially in Nos. 2318 and 2319. These monster growths lose almost entirely the figure of the ordinary nail; they are no longer flat, smooth, and shell-like as are the original nails, but assume the characters of a horn, more or less cylindrical in figure, more or less curved and twisted, and grooved along the under side, in the situation corresponding with the bed of the nail. Such a state is the consequence of neglect; the nails grow more or less perpendicularly from their matrix, and when torn off, present at their base a conical cavity, in which the hypertrophied matrix is contained. In structure, these horn-like nails are laminated, and have the aspect of being composed of a succession of cones packed one within the other, an appearance which is due to the conical projection of the lunula. Strictly speaking, they are, therefore, not mere growths in length, corresponding with the ordinary growth of the nail, but, in reality, growths in thickness.

Although the specimens before us are of considerable length, and more like horns than nails, they are small as compared to some that have been described by authors, which are said to have reached the dimensions of four and five inches.

Sometimes, instead of manifesting an apparent growth in length, they increase in thickness by the deposition on their under surface of successive lamellæ of epidermic substance. In this way they are apt to constitute a prominent mass of horn substance, corresponding in horizontal dimensions

with that of the original nail; these masses are occasionally shed, sometimes normally, and sometimes as a consequence of pressure or injury, and in such cases they leave a thin lamina upon the bed and matrix of the nail, which subsequently undergoes a similar process of stratified growth. I have met with several persons affected with this form of onychauxis who shed their great toe-nails twice, or oftener, in the year.

In No. 2309, the nail of the great toe was curved outwards in its growth and lies across the second toe.

In No. 2310, the great toe-nail presses against the second toe and has pushed it aside, the nail of the second toe curves over its tip, and the nails of the rest of the toes are more or less abnormal.

In opposition to excessive dimensions we sometimes meet with examples of absence of growth of the nails. In consequence of the undeveloped condition of the papillæ of the matrix and bed of the nail, epidermic matter is not produced in greater quantity than on the adjacent skin, and is, therefore, wanting in the horny properties appertaining to healthy nails. The surface of epidermis takes the figure of the underlying matrix and bed, it is smooth and polished in consequence of the absence of the root papillæ, and it exfoliates when it attains a thickness somewhat greater than that of the epidermis.

The nails are also, not unfrequently, curiously modified in shape. This we see illustrated in the broad and expanded nail which accompanies the club-shaped fingers of struma. The nails themselves are thin; they curve over the extremities of the fingers, curvatura unguis, and have received the names of hooked nails and ungues adunci; sometimes the nails present a remarkable convexity in the longitudinal direction and have been termed keel-shaped, whilst subjectively this state of the

nail has been denominated arctura unguis and gryphosis. When nails of this sort grow considerably they have the appearance of talons rather than of nails, like the specimens we have previously examined.

The preparations Nos. 2320 and 2321, are examples of this arctura unguis, this keel-like prominence of the nails, corresponding with a similar prominent ridge of the matrix, whilst No. 2322 presents us with a nail which resembles very curiously, the beak of a bird.

I was much struck with the appearance of a shovel-shaped form of nail which I observed in a patient recovering from acute dermatitis (pityriasis rubra) after a long illness. The fingers and toes of this patient were greatly contracted in bulk; the newly-formed nail corresponded with this lateral contraction, whilst the old portion of the nail which had occupied a broader bed was singularly expanded, and the nail resembled the household implement denominated a dust shovel.

Înstead of presenting their normal convexity of surface, the nails are occasionally concave and thin, sometimes concave longitudinally and sometimes transversely, but without alteration in structure. There is a want of substantial material of the matrix and of the cushion beneath it, a consequent imperfect formative power, and a feebleness of resistance which permits the encroachment of the adjacent soft parts on the territory of the nail.

Thinness of the nails is often accompanied with brittleness and a tendency to crack in a longitudinal direction. This state of the organ has been termed fissura unguis, and is a source of great vexation and discomfort to the sufferer. There may be five or six of these longitudinal cracks, the surface as well as the end of the nail becoming splintered and ragged. The splintered edges catch in the dress, they are apt to be torn, and the bed of the nail is

wounded and bleeds, and is continually kept in a painful and tender state. There may be no disease of the nail, beyond that of defective nutritive power.

Of a somewhat similar nature and depending on absence of nutritive power, is that longitudinal imperfection of the solidity of the organ which has

received the name of fibrous nail. In this case there is no deficiency of quantity as to material, but an absence of cohesion of its longitudinal strands. The nail does not break through as in the instance of the fissured nail; there is consequently no pain or bleeding, or tearing of the derma, and the annoyance of the complaint is limited to the inconveniences of roughness, adhesiveness, and deformity of appear

ance.

We may enumerate likewise as belonging especially to the structural formation of the organ, certain abnormalities which appear in the nail under the form of small opaque white spots; they are more common in children than in adults, and have been termed by the Latins mendacia, probably significative of "faults," in the sense in which we use the latter term in geology. They are called "selene," from their whiteness; and "flores unguium," as implying an efflorescence; and probably represent the rude knocks which the matrix of the root of the nail receives in the gambols of youth; such faults are occasionally seen in the teeth as well as in the nails.

The normal transparency of the nail renders these spots the more conspicuous, and enables us to recognise morbid processes in operation beneath it. Thus a bruise, which is accompanied with extravasation of blood, is sometimes made manifest beneath the nail by a purple spot, constituting ecchymoma unguis. Pus may be seen under the nail in some cases of whitlow. The macula of a syphilitic eruption are occasionally visible under the nail;