ONYCHOMYCOSIS.

The nails may be attacked both by the trichophyton and by the achorion, either of which is probably conveyed by scratching other affected parts. The nail tends to become elongated and curved over the end of the finger, with a thick edge, rough, uneven surface, and dirty yellow color; it is also brittle and readily splits. In favus sometimes a distinct cup forms under the nail. If fragments or scrapings are soaked with potash, and examined under the microscope, chains of spores of one or other fungus are seen.

Treatment. The nails should be scraped thin, softened with alkaline solutions, and soaked in lotions of sulphurous acid, or hyposulphite of soda. The alternate application to the scraped nail of liquor potassæ, diluted with an equal part of water, for fifteen minutes, and of a lotion of perchloride of mercury (4 grains to half an ounce each of rectified spirit and water) for twenty-four hours, is recommended by Dr. Harrison. Neumann also recommends corrosive sublimate (2 grains to the ounce). Complete removal of the nail may be desirable, the lotions then being applied to the matrix.

TINEA VERSICOLOR.

This is a not uncommon affection of the skin, no doubt produced by contagion, and fostered by warmth and moisture. It is more frequent in men, and especially in those who wear flannel underclothing. It is not often conveyed directly by contact-for instance, from husband to wife.

The disease begins as a small circular spot, of a yellowish-brown color, which is slightly raised above the skin, and from which a few whitish scales can easily be detached by scraping with the finger nail or a scalpel. The patches extend, and fresh ones form, so that soon a large part of the chest, where it is commonly seen first, is covered with a brown, or brownish-yellow, irregular patch, with a convex or scalloped margin; and on the healthy skin adjacent are numerous small isolated patches from a quarter to half an inch in diameter. The disease occurs only on covered parts, and is most abundant on the front and back of the chest and the abdomen. The scrapings examined in potash under the microscope show epithelial plates with the characteristic fungus-Microsporon furfur-forming a network of branching mycelium threads, with little groups of the relatively large conidia, like bunches of grapes. The affection does not cause much trouble beyond some itching, and is frequently ignored by the patient; but the great extent which the discoloration may sometimes reach has led to its being mistaken for Addison's disease and other pigment affections. The peculiar color, the convex edge, and the ready desquamation of the surface should be quite distinctive, and the diagnosis is at once confirmed by the microscope.

Treatment. It is quickly cured by rubbing in lotions of hyposulphite

of soda (1 in 8) or of sulphurous acid. It may, however, return if the same underclothing is used without thorough washing and disinfection.

ANIMAL PARASITES.

SCABIES.

Scabies, or itch, is a multiform disease of the skin, due to the irritation of the itch-acarus, Sarcoptes hominis. The female acarus is oval in shape, of an inch in length, presents in front four little nipple-shaped processes provided with suckers on stalks, and behind four similar processes provided with long bristles. The male is smaller, has four suckers in front, two suckers and two bristles behind. The female, after impregnation, bores her way under the skin in an oblique direction, so that as the superficial layers of the epidermis are detached by friction, she still remains the same depth from the surface. As she proceeds she lays her eggs, one or two daily, it is said, and she may thus burrow through the skin in an irregular line for a third or half an inch. Such a burrow (cuniculus) or "run" may be recognized on the surface of the skin by the following points: At one end the epidermis is broken or frayed, and the free edges are dirty; at the other end is a minute white-pointed elevation, in which the acarus lies; the burrow itself, between these points, is a sinuous black line. The whole burrow may be snipped off by a pair of scissors curved on the flat, or shaved off with a scalpel, and if this be moistened with potash and examined, there will be seen the female acarus, and behind her, filling the burrow, her eggs in every stage of incubation, with minute black spots of excremental matter among them. As the skin desquamates, the most developed ova come to the surface, and are hatched. The male does not burrow, but remains on the surface, where he may sometimes be accidentally caught.

As a result of the invasion of itch-acarus, there are considerable itching and dermatitis of variable extent and character. The itching is mild or severe, but not generally so bad as that caused by pediculi. It is worst at night when the patient is warm in bed. The dermatitis consists of papules, vesicles, pustules, or even bullæ, which generally appear in the neighborhood of the burrows, but also in parts more remote. Not infrequently a vesicle or pustule forms in the burrow itself. In addition to these lesions, patches of eczema, impetiginous crusts, and urticarious wheals are often present. There is, thus, very great variety in the lesions in different cases. In some cases the burrows are numerous, with few inflammatory lesions; in others, vesicles and pustules are abundant, and burrows are with difficulty found. In some cases there are more papules, in others more pustules. The parts of the

body especially liable to the attacks of the acarus are the skin between the fingers, the front or inner side of the wrists, the front of the forearm, the ankle and foot, the axilla, the groin and the genitals, the inner side of the thigh and the nates; and the eruption spreads beyond these parts, on to the abdomen from the groin, or along the inner side of the leg or thigh. The back, shoulders, and chest are but little affected; and the face, neck, ears, and scalp nearly always escape. The occupation of the patient may have influence upon the localization. Hebra was in the habit of recognizing the occupation of a cobbler by the predominance of itch-lesions on the buttock. On the other hand, occupations involving the immersion of the hands in materials (oily or otherwise) antagonistic to the acarus would prevent their presence in this typical situation. In children, the lesions are more wide-spread, the feet and ankles are commonly affected, and pustules are frequently present.

Diagnosis. Nevertheless, the localization is an important guide to diagnosis. An itching eruption of mixed papules, vesicles, and pustules, occurring mainly about the fingers and wrists, and also in the other situations mentioned, should lead to a careful search. If a burrow can be found the minute white elevation at the cleaner end should be looked for, and its epidermis carefully scratched through with the point of a needle; the acarus may then be picked out, as it readily adheres to the surface of the needle. If this cannot be done it is best to snip off the whole burrow, and to examine for ova or fragments of the acarus under the microscope. Finally, where there has been much inflammation, so that burrows cannot be found, the crusts may be removed, boiled in potash or soda, the fluid allowed to settle in a conical glass, and the sediment examined for fragments of acarus.

Treatment.-Itch is generally quickly cured by the free inunction of sulphur ointment. This should be done at night, and the ointment should be left on, covered by suitable clothing, until the morning, when it may be washed off in a hot bath. The same process may be repeated on two successive nights. The disagreeable odor of sulphur ointment may be lessened by the addition of balsam of Peru. For some skins, sulphur ointment is too irritating, and requires dilution. An ointment of styrax (prepared storax 145 grains, sp. vini rect. 3j, lard 1 ounce, Guy's Hosp. Pharm.) is also a more pleasant, less irritating, and yet effectual preparation. Vlemingkx' solution may also be used, or sulphur baths (potassium sulphide 4 ounces in 30 gallons of water). It must be remembered that the itching may continue some time after the acarus has been destroyed. In order to prevent the recurrence of the disease, it is necessary that new clothes should be worn, and that the old ones should be quite disinfected by baking.

PHTHEIRIASIS.

(Pediculosis.)

The pediculi or lice which infest the human race are of three species-the Pediculus capitis, or head louse; P. corporis, vel vestimentorum, the body louse; and P. pubis, or crab-louse.

PEDICULUS CAPITIS.

The head louse is about 2 mm. long by 1 broad, and breeds in the hair of the scalp. Its ova are found adherent to the hairs, and are called nits. They are about 1⁄2 mm. in length, whitish, somewhat conical in shape, with the apex always toward the scalp; and they are fixed to the hair by a cylindrical sheath of chitinous material, extending some little distance beyond the apex. The irritation of the pediculus leads to constant scratching, and pustular eczema (or contagious impetigo, Crocker). This eruption is most common, and severe in the occipital region, and the sub-occipital glands are mostly enlarged as a consequence, and may suppurate.

The Diagnosis is not difficult. If the pediculi are not at once seen, the nits, which are readily distinguished on careful examination from scurf, will show at once that there are or have been pediculi. The position of the crusts at the back of the head is also strongly in favor of pediculi.

Treatment. The insects can generally at once be destroyed by the use of white precipitate ointment; but if there is much eczema or impetigo the hair should be cut over it, and the crusts removed. Hebra recommended pouring petroleum oil over the head as a rapid and certain means of killing the animals. The nits are not easily detached from the hairs; the cement is very resistant to acids, alkalies, and spirit; but dilute acetic acid (1 in 4) is said to soften it. They can always be slid off the hair, or may be sometimes combed off; but if very numerous, it is probably best to cut the hair.

PEDICULUS VESTIMENTORUM.

This species is larger than the head louse, being from 2 to 3 mm. long, and 1 to 11⁄2 broad. It only occurs on the parts covered with clothes, and chiefly about the back and front of the chest, loins, and abdomen. Occasionally the upper arms, thighs, and even legs may be attacked, but never the face or the hands. The body louse causes a severe prurigo, with intense itching, which leads to proportionately violent scratching. All the lesions. described under prurigo (see p. 816) may occur, papules, blood crusts, scratch marks, elongated scars the remains of the same, and, after a time, intense pigmentation.

It occurs especially in old people, among the poorer classes, who have been allowed, from want of proper attention, to lapse into conditions of

filth and neglect. The disease has then been called prurigo senilis, and also vagabond's disease.

In its milder forms it presents only scattered papules, blood crusts, and scratch marks over the upper part of the back and shoulders.

Diagnosis.-A pruriginous eruption of this kind over the back and shoulders should always suggest a search for the pediculus vestimentorum. It is commonly found in the "gathers," under the neck band of the shirt, or under the shelter of any edge projecting on the inner side; and it is recognized by its long oval shape, and its gray color, with a central dark-red or black spot.

Treatment.-Ung. hydrarg. ammoniati or ung. staphysagriæ, smeared over the skin, will kill the pediculi. A complete change of clothes, in which the eggs are certainly incubating, is of course necessary; and the clothes must be baked if they are to be worn again.

PEDICULUS Pubis.

The crab louse is smaller than either of the other species, measuring from 1 to 11⁄2 mm. long, and 1 to 11⁄2 broad. It has an almost square body, and six long legs, with claws by which it clings firmly to the hairs of the part. It is not only found in the pubic hair, but is occasionally conveyed to the eyebrows, eyelashes, whiskers or beard. The eggs are attached to the hairs close to the skin. Itching leads to scratching, and an eczematous rash is the result. Removal of the hair quickly cures the trouble; or the pediculi may be killed by the means above mentioned.

ADDENDUM.

THE EPIDEMIC OF 1889-90.

While this work is on the point of appearing, an epidemic, known as the Russian influenza, is sweeping over Europe. It first appeared in Russia, and successively invaded Vienna, Berlin, Paris, and other Continental cities; and cases became numerous in England in December, 1889. The disease begins, as a rule, suddenly, with rigor, severe frontal headache, and muscular pains in the loins, thighs, calves, and other parts of the body. The temperature rises within a few hours to 102°, 103°, or 104°. The disease differs from the illness described on page 83, in that there is rarely any pronounced coryza, though there may be a little bronchial catarrh. The temperature falls within twenty-four or thirty-six hours; but the general pains in the limbs may continue some time longer, and a sense of extreme prostration, which is present from the first, persists for some days after the