1. Mildest degree of superficial inflammation in the cutis next the epidermis, characterized by dilatation of the blood and lymph vessels, and slight oedema of the papillary layer.

2. Oedema of the transitional epithelial cells interfering with normal cornification, and presented to the naked eye in scale formation. (Parakeratosis.)

3. Oedema between the same cells, the pressure separating them and forming little lakes of fluid, so that the epidermis has the appearance of a sponge (spongiosis), as you see in one of the slides. This is presented to the naked eye partly in the oedema and swelling and partly in the vesicle-formation.

4. Proliferation of the prickle cells (acanthosis), presented to the naked eye in the papules and infiltration and thickening of the skin in chronic eczemas.

These changes, according to Unna, are due to "serotaxis" or the action of an irritant on the skin by which the epithelial cells are stimulated to secrete a poisonous ferment which causes dilatation of the vessels in the cutis and a corresponding outpouring of lymph to counteract the action of the poisonous ferment. It is a similar process which takes place in a superficial burn of the skin, or irritation of chemicals, or poisons such as Rhus tox. Unna invariably finds various cocci in the upper part of the vesicle, which he claims are the source of irritation which cause the serotaxis. Bockhart presents a plausible theory in this connection and says that eczema results from staphylotoxin secreted by staphylococci, which in a quiescent state reside in the hair follicles of the predisposed. These become active of some external or internal irritation, make their way between the epithelial cells, setting up serotaxis and, if particularly virulent, chemotaxis as well. By this latter process leucocytes are attracted and the result is the development of a suppuration. These theories have much to support them and suggest both surgical (antiseptic) and medical treatment.

In the cells of the corneal layer of the normal skin, as Ranvier has shown, there is a fatty or waxy substance which prevents the loss and absorption of watery fluids. This substance is supposed to be a final transformation of the keratohyalin granules of the granular layer, which are supposed to be separation products of the spongioplasm of the prickle cells. In eczema, these cells being oedematous and thus chemically changed, keratohyalin is imperfectly developed and hence also the fatty or waxy matter in the corneal layer. This will account in part for the leakage of fluid on the surfaces of a moist

eczema and suggests a treatment to supply the waterproof material to prevent the leakage which interferes with healing.

In the normal skin, too, the peripheral portion of the spongioplasm and the prickles of the prickle cells persist in the corneal layer as a hard substance called keratin, and the prickles serve to suture the cells closely together, making the corneal layer tough and firm, so that the pressure of the lymph beneath causes it to raise up into vesicles and stretch without rupturing easily. In eczema the formation of keratin (cornification) takes place imperfectly. The prickles do not persist as keratin and the result is that the defective horn cells are separated by air spaces forming between them and they scale off in various sized flakes. Or, instead of this defective cornification we may find excessive cornification (hyperkeratosis) the keratin being formed in excess through the constant irritation, just as occurs in the formation of a corn or calluses in the palms of the hand from manual labor.

Again, in the normal skin, reproduction of epithelial cells takes place only in the basal layer, the daughter cells forming the prickle layer and not reproducing. In eczema, however, as in some other diseases (epithelioma for instance) the daughter cells continue to multiply by mitosis. The result is a greater or lesser enlargement of the prickle layer, not only because of the intra-and inter-cellular edema, but also because of an actual increase over the normal of the number of cells. The crowding is great and the interpapillary processes of the epidermis are squeezed and distorted into all sorts of forms, while their nerves and the nerves and vessels in the papillæ of the cutis are also put to great inconvenience, so that it is no wonder there is œdematous swelling, thickening of the skin and great itching in some well-marked cases of eczema. The reproducing daughter cells are so weakened that they cannot develop into normal horn cells and they are also less resistant to the action of various chemical and physical agents than the normal cells. This fact is taken advantage of in the treatment by such physical agents as the Finsen Light and the X-Ray. Different combinations of the four changes mentioned constitute the elementary types of eczema,-erythematous, squammous, papular, vesicular. Added to these we have complications, such, for instance, as secondary infection with pus-producing cocci, constituting the pustular and crusted forms of the disease. But time will not permit a description of these advanced types of the disease.

As a result of our study of the pathological changes taking place in eczema we draw the following conclusions and base our treatment somewhat upon them.

1. Constitutional predisposition exists in some but not all cases of eczema.

2. Eczema is not the external expression of an internal disease. but the latter may develop the proper irritant in the skin to cause eczema either directly, or indirectly by favoring germ development.

3. Eczema may be entirely of local origin, some local irritation developing a suitable soil for the pathogenic germs or possibly itself starting the process independent of germs.

4. Elementary eczematous lesions may become inoculated with other infections, producing complicated types.

5. The old idea of "driving in" the disease by local treatment is not supported by scientific investigation. Internal congestions or inflammations are frequently relieved by external irritation (counterirritation), and so they continue unrelieved or possibly aggravated by removing the counter-irritation of an eczema.

TREATMENT.

In this paper we shall not concern ourselves with the constitutional treatment, though this should always be carefully prescribed according to indications. In all cases some form of local treatment will be found of value if not curative. This is founded upon the local pathology and includes measures to dehydrate the water-soaked epidermis, to anoint the same, to relieve the inflammation, to relieve the itching, to destroy offending germs, to soften and remove the horn layer when hyperkeratinized (hyperkeratosis), to reduce the proliferated prickle layer (acanthosis), to protect the diseased skin from further irritation, etc., etc. Dehydration is accomplished principally by the use of absorbent powders or alcohol. The best powders for absorbing fluid are the vegetable powders, and rice starch is most frequently used for this purpose. But it is apt to become dry, hard and caked, so a mineral powder is usually mixed with it. The powders so used are zinc oxide, magnes. carb., terra silicea, talcum, chalk, bolus alba and rubra, etc. Of these magnes. carb. and zinc oxide are perhaps most absorbent. A favorite absorbent powder in my practice is Unna's pulvis cuticolor:

Take of Bolus rubr. 0.5; Bolus alb. 2.5; Magnes. carb. 4.0; Zinc oxid. 5.0; Aml. oryz. 8.0; f. pulv. subt.

The powder may be applied dry in moist eczemas, or in the form of a paste as Lassar's paste, or Unna's zinc or zinc sulphur paste, as follows:'

Take of Zinc. oxyd. 24.0; Terr. silic. 4.0; Ol. Benzoinat. 12.0; adip. benz. 60.0; M. f. past. Sulphur may be used in this recipe by

substituting 10 grammes or so for a like amount of the zinc oxide. This anoints the skin at the same time it dehydrates.

But alcohol is a much simpler and very effectual dehydrant. It may be used as a spray in combination with ether, or it may be applied in the form of a fomentation. It is better to use it in an 80 per cent solution with 5 per cent glycerine to prevent evaporation. A case illustrating the use of alcohol for this purpose is the following:

Case 1.-Mr. A., age 36, has eczema of extremities every winter, but is free in the summer. It appears as an erythematous patch, on which papules and vesicles soon develop. Itching is intense, especially after bathing or exposure to cold. A few applications of alcohol and glycerine give prompt relief and if used after bathing keeps the skin free from the disease. There are no constitutional symptoms. The disease first appeared while taking prolonged baths in the winter 12 years ago.

The use of these three prescriptions alone, absorbent powder, alcohol, zinc or zinc sulphur paste, often suffice to clear up acute or sub-acute eczemas, if of the moist type, and will cure a very large percentage of all eczemas.

Frequently these cases become suppurative in character from secondary infection with pus cocci, and pustules and crusts form. This is often the case in nursing babies, and is then a source of great distress not only to the child but to the mother and those who have the care of it. The parts itch severely and the child cannot keep from scratching, which adds to the difficulty. The family physician often finds these cases the most trying. The following case is a fair sample.

Case 2.-Referred by Dr. O. LeSeure. Baby, 6 months old. Has had eczematous eruption on scalp, face and body since two weeks old, and most of the time the face and scalp have been a mass of thick yellow crusts, as they are at present. Here and there are raw, red weeping surfaces where the crust has been scratched off. The eruption on the body is erythematous and papular. The mother nurses the child, but it has a great deal of fermentation. Otherwise it is perfectly healthy, happy and growing nicely. The itching at night is severe enough to cause much loss of sleep.

Our indications for treatment here were: 1. Prevent further irritation and infection through scratching; 2. To remove the crusts and render as nearly aseptic as possible; 3. To dehydrate and anoint.

The first indication was met by rolling a piece of sheet celluloid about three inches wide about the elbow and fastening it to the shoulder with a safety pin. This kept his arms straight, yet allowed him considerable liberty, so that he did not object. His father's starched

cuffs answered very well temporarily. The crusts were removed by the free use of olive oil, saturating pieces of lint beneath an oil muslin bonnet, for 24 hours. Then the hair was cut and the face and scalp cleansed as thoroughly as possible with the oil, and alcohol (the latter not being used on raw places). Then pulvis cuticolor was applied freely for 24 hours, and this was followed by the application of zinc paste on lint, which was held in place by zinc gelatin painted on while warm. This is made as follows:

Dissolve 15 grammes of white gelatin in 45 of distilled water and 25 of glycerine by heating; then stir in 15 grammes of zinc oxide until thoroughly mixed and the whole becomes creamy and smooth. When cold it soon solidifies, and can be dissolved by heating in a double boiler when wanted for use. It should be applied with a small paint brush having stiff bristles. After applying and before drying tufts of cotton should be dabbed on it to prevent its surface sticking.

After a few hours of this treatment the face was quite free from moisture, only an erythema remaining. Two per cent ichthyol was now added to the zinc gelatin and this painted on the face over one layer of gauze, and the surface dusted with pulv. cuticolor until dry. In another 2 hours the face was perfectly free from eruption. Occasional relapses followed during teething, attacks of indigestion, etc.,` but these were promptly controlled by the use of the zinc paste and powder. Internally the child had lycopod., nux, carbo veg., etc.

When eczema becomes very chronic and thickening and infiltration of the skin (acanthosis) are marked, and itching is severe, reducing agents are indicated. These include ichthyol, thiol tumenol, balsam Peru, tar, chrysarobin, pyrogallol, resorcin, beta naphthol, phenol, cresol, anthrarobin, or sulphur. These must be used with great care, as all have other properties besides those of reducing the acanthosis. The first two, for instance, subdue inflammation, and would consequently be better indicated where this is a prominent feature in the case. The next three with phenol and cresol, relieve itching. Ichthiol and sulphur destroy cocci. It is better to begin with weak pastes or ointments of these drugs in indicated cases and increase as needed. Any text-book will give the amounts and indications, so that I need not burden my paper with the matter. Only one formula, a dernier resort, which has proven very effectual in my hands in the most obstinate cases will I mention here. It is: Chrysarobini, Pyrogalloli, Kesorcini, Acidi salicylici aa 2.5, Ichthyolie 10.0, Vaselini 80.0. M. F. Ungt. Apply twice a day till peeling takes place.

It must not be used over very large areas or near the eyes or mucous membranes. It should be spread on lint and covered with oil