Chapter XIX: Part 19

Definition. Dog, anatomical factors. Symptoms: protrusion of bulb
through palpebral orifice, orbicular spasm, vessel, muscle, nerve
stretching or tearing. Sphacelus. Panophthalmia. Fracture of orbit.
Treatment: early reduction, antisepsis, astringents, scarify sclera,
cold, astringents, puncture aqueous with hypodermic needle, enlarge
palpebral opening, suture and compress, remove foreign bodies and
injurious fragments of tissues, enucleation.

_Definition._ Displacement of the globe of the eye out of the orbit and through the eyelids.

_Causes._ Among domestic animals the condition is most frequently seen in the dog, which is predisposed by reason of the normal prominence of its eye, the width of the aperture between the lids and the absence of the orbital process of the frontal bone. Blows upon the region and the insertion of pointed bodies, (teeth, horns, etc.), which can act as levers using the margin of the orbit as a fulcrum are especially liable to cause the lesion. Dog fights are the most common occasions. Other animals may also suffer but not at all frequently.

_Symptoms and lesions._ In the simplest form the bulb is displaced forward out of the orbit and through the palpebræ which latter contract spasmodically behind it and effectually prevent a spontaneous reduction. The optic nerve, muscles, and vessels are unduly stretched and the circulation in the bulb is seriously impaired, so that even in the least complicated cases any undue delay in reducing the dislocation will lead to serious and destructive changes in the eye. Sphacelus of the globe is not uncommon under such conditions.

In the more complicated cases, the conjunctiva, palpebræ, nictitans, muscles, nerves, etc., maybe more or less lacerated and the globe itself may be seriously damaged either by internal lesion or by an external trauma. In all these cases there is most imminent danger of general infective inflammation of the eye, of panophthalmia, and even of secondary general infection of the system. Fracture of the bones of the orbit may also be looked for.

_Treatment._ When dislocation is uncomplicated and recent, say of a few hours standing only, it may be reduced and a favorable issue secured. The bulb should be first washed with water which has been sterilized by boiling or rendered antiseptic with sublimate (1 ∶ 5000), and can usually be pressed back by steady uniform pressure. The insertion under one lid of a small spatula bent at the end or the one limb of a lid speculum may assist in difficult cases. When replaced the parts may be again washed with antiseptic solution and covered by a bandage wet with an astringent collyria.

When the condition has been neglected for a day or more the bulb is congested and swollen so that its return is rendered much more difficult, and its subsequent retention may require much care and ingenuity. The reduction of the turgid globe may be assisted by opening the veins and arteries on the sclera, by astringent applications, by massage, and in obstinate cases by evacuation of a portion of the aqueous humor, by the aid of a fine aseptic needle. Finally the palpebral opening may be enlarged by incising the outer canthus with a probe pointed bistuory. When the eye has been replaced in its socket this must be closed by suture. For the retention of the eye in such cases a bandage may suffice, or this failing, the lids may be held together by strips of adhesive plaster, or by collodion. In very difficult cases Lafosse and Trasbot recommend sutures through the skin 1½ to 2 inches from the palpebral borders and the whole covered with a bandage impregnated with an antiseptic and astringent collyrium.

It is not requisite to keep the bandage in position for over four or five days as the swelling of the eyelids and other adjacent structures effectually prevents any tendency to repetition of the luxation, and the eye may be treated like an ordinary traumatic lesion.

At the outset, and later if need be, any foreign body in the orbit should be removed and any detached pieces of bone which cannot be retained firmly in position, and which are liable to prevent healing or to determine infection of the wound.

In the worst cases and in those that have been neglected until gangrene or panophthalmitis threatens, the removal of the eyeball may be the only resort. The animal may be anæsthetized by chloroform or ether, or locally by cocaine. The conjunctiva covering the sclera is then pinched up with forceps and cut through with scissors, this is continued all around the globe. Then the recti muscles, the superior and inferior oblique muscles, the retractor and finally the optic nerve are cut through with a pair of scissors curved on the flat. The divided ends of the muscles are now sutured together around the nerve which has been cut shorter, and the cavity irrigated by a cold antiseptic solution. Bleeding vessels may be twisted through with forceps if the flow is not readily checked by cold irrigation. Or a pledget of cotton dipped in tincture of muriate of iron may be loosely inserted (firm pressure would be unnecessarily painful). As a subsequent dressing, standard sulphurous acid solution, glycerine and water in equal proportions, or other antiseptic dressings may be applied.

ARTIFICIAL EYE.

These are largely in use in the human being, and have been employed in the lower animals in different cases, especially in the horse, with excellent effect. The advantages may be summed up in this, that they do away with the unsightly appearance of an empty orbit with the edges of the lids turned into the dark aperture, enhance the value by restoring the face to nearly the natural appearance, and prevent the lodgment of dust and insects in the cavity.

The artificial eye may be made to appear more natural if made of glass, yet when made of horn or still better of hard rubber, colored like the normal iris and pupil, it has the advantage of greater lightness. It must be perfectly smooth so as to cause no discomfort, and should never be introduced so long as there is any irritation in the stump or conjunctiva. It may be slipped in like a button, first beneath the deeper upper lid, and then beneath the lower, and should be worn only while at work and so long as it causes no irritation nor purulent discharge. On the return of the animal to the stable, the artificial eye is taken out, washed and placed in clean pure water. The orbit should be sponged out with a weak collyrium (boric acid 1 ∶ 100).

In man, excentration is sometimes substituted for enucleation, the cornea is removed together with the lens, vitreous, choroid and retina, leaving only the sclera which contracts into a dense scar tissue with the muscles attached. Or an artificial vitreous of glass or unoxidizable metal is introduced around which the sclera is allowed to heal. This introduces an additional element of danger over the formation of a simple sclerotic stump, but, when successful, it affords a better support to the artificial eye, turning it freely in harmony with its fellow and giving it a more natural aspect.

STRABISMUS. SQUINTING. LACK OF MUSCULAR BALANCE.

Causes: paralysis of eye muscles, bulb rolls from affected muscle,
spasm of eye muscles, bulb rolls toward affected muscle, convergent
squint most common. Hold head still and move object in front of eyes,
imperfect movement toward paretic muscle or away from the spastic one.
Ptosis. Overfatigue. Debility. Nerve or brain lesion. Dislocation of
bulb. Treatment: treat any transient etiological factor, cerebral
congestion, parasitisms, debility, anæmia. Tenotomy of rectus: advance
of paretic rectus.

Strabismus may be due to a variety of causes, among others to the following:

=Paralysis= of one of the ocular muscles. When the eyes are turned in the direction away from the affected muscle the muscle is deficient in power. It may be the external rectus (abducent nerve) producing convergent squint. It may be of the superior oblique muscle (4th or pathetic nerve) causing a faulty movement of the eye downward and inward or a slightly convergent squint. Divergent squint commonly indicates paralysis of upper, lower and inner recti, and the inferior oblique (3d or oculo motor nerve): this is usually associated with ptosis or drooping of the upper lid, the levator of which is supplied by the same nerve. The existence of squint is usually so marked that no special method of examination is required. If otherwise, however, the animal’s head may be held still and some object which will attract his attention is moved before the eyes, outward and inward, when the affected eye moving in the direction of the paralytic muscle will lag visibly behind its fellow. These conditions are usually due to lesions in the respective nerves or their cerebral ganglia.

=Spasmodic or Spastic Squint= is the exact antithesis of the above, the eye turning toward the muscle which is the seat of spasm. It may be seen in certain cases of rabies and is always due to disorder of the central nervous ganglia.

In some cases squinting is associated with over-fatigue, or debility, and then usually partakes of the paralytic character.

In the lower animals convergent strabismus has been most frequently observed. Brouwer records a case in the horse and Koch a congenital one in the cow. Zschokke reports a case in the cow connected with an angioma at the base of the brain. Other forms are noted by Peters, Barrier, Bayer and others. Stockfleth quotes a case in the dog following prolapsus bulbi and doubtless connected with injury to ocular muscles or nerves, sustained in the accident.

_Treatment_ will vary with the ascertained cause. As a rule cases that depend on structural changes in the brain are hopeless. Those that depend on temporary congestion or other transient disorder of that organ may recover when that has been overcome. In cases in which debility is a prominent feature, tonics, moderate exercise in the open air and general hygienic care are demanded. The final resort in bad cases is tenotomy of the rectus on the side toward which the eye turns. In man when this is found to be insufficient the opposing weak or paretic muscle is also advanced. The tendon close to its sclerotic attachment is laid bare by incision, and a silk or catgut thread is passed through each border, upper and lower. The tendon is now cut through with scissors on the corneal side of the sutures and, by means of their needles, the latter are passed through the conjunctiva and capsule of Tenon, from within outward and close to the margin of the cornea. The sutures are now tied somewhat tighter than is absolutely necessary to properly balance the eye so as to allow some room for relaxation in healing. We are not aware that this measure of advancement has been employed in the domestic animals.

NYSTAGMUS. OSCILLATORY MOVEMENT OF THE EYE.

This consists in spasmodic involuntary oscillation of the eyeball in a horizontal, lateral, oblique or rotary direction. In animals it has been seen in connection with poisoning and brain diseases. Johné has observed it in horses in cerebro-spinal meningitis, Wenderhold in epilepsy, and Möller in chloroform anæsthesia. Möller has further seen it in puppies with congenital microphthalmos, and Siedamgrotzky in swine which had been poisoned by herring brine.

Slight cases of functional disturbance may improve under good hygiene, open air life and tonics, cases due to poisons may recover spontaneously when such poisons have been eliminated, but those which depend on structural disorder of the brain are beyond remedy.

DISEASES OF THE SKIN.

Ultimate skin lesions in man and animals similar. Masked by thick
cuticle, pigment, hair, fur, feathers. White, hairless skin. Lesions
and deranged functions: Maculæ, erythema, papules, nodules, blisters,
blebs, pustules, boils, carbuncles, scales, crusts, sitfasts, horny
growths, erosions, abrasions, chaps, fissures, ulcers, excrescences,
cicatrices, neuroses, morbid secretions, changes in glands, hairs, in
derma. Scleroderma. Elephantiasis. Vegetable and animal parasites.

In cutaneous diseases in man and animals the actual lesions are largely of the same nature, yet in the animal covered with hair, fur or feathers, and with the cuticle deeply pigmented, the diagnosis of the different affections becomes much more difficult. On white-skinned animals and on parts with little or no hair, the identification of the different forms is usually possible. The following list may serve to indicate the nature of the different lesions, but these must not be accepted as indicating distinct diseases, as two or more of these forms often coexist or succeed each other in the same affection:—

1st. =Maculæ: Spots: Discolorations.= Examples: Black, melanotic spots in skins of white horses: white spots in dourine, after pustules, etc.: ecchymosis after contusions, stings, insect bites, etc.: petechial spots in anthrax, rouget, hog cholera, rinderpest, canine distemper, swine plague, scurvy, etc.

2d. =Erythema: Rash: Flush.= Congestive redness usually disappearing under pressure. _Physiological_ in blush or glow of exercise, _pathological_ from insolation, friction, deranged innervation, etc.

3d. =Papulæ: Papules: Pimples.= Small, red, hard, conical elevations, not forming blister nor pustule. Due to exudation and the accumulation of leucocytes at given points, having a local or general cause, (psoriasis, intertrigo, etc.).

4th. =Tuberculæ: Nodules.= Larger but still circumscribed thickening of the entire skin from exudation and cell growth, from ½ inch to 2 or more inches in diameter and sometimes becoming confluent. Examples: Urticaria (surfeit) in solipeds, and cattle; petechial fever, farcy, etc. Sometimes chronic.

5th. =Vesiculæ: Blisters.= Rounded or conical elevations the size of a millet seed to a pea, and having a small liquid exudation under the cuticle in the centre. In inflammations of the papillary layer, of a sufficiently acute type the tendency is to the formation of vesicles. These lesions are, therefore, often present in very different forms of skin disease from those due to simple thermic irritation, to constitutional diseases like eczema, or contagious ones like sheep pox. May merge into pustules or other advanced lesions.

6th. =Phlyctenæ: Bullæ: Blebs.= In these the individual lesion is larger than in vesicles. They are of any size from a pea upward. The most striking example is in cantharides, blisters, scalds and burns, but in other cases it depends on a constitutional condition or a specially exudative dermatitis.

7th. =Pustulæ: Pustules.= These differ from vesicles in that the central exudate becomes the seat of suppuration and a limited collection of pus, at first central, though later involving, it may be the whole area of the exudate. It is often merely an advanced stage of the papule or vesicle. We find examples in the different forms of variola, in lesions caused by tartar emetic or croton oil, and in several forms of dermatitis. It is essentially microbian.

8th. =Furunculus: Furuncle: Boil.= Inflammatory nodosity of the derma, resulting in a necrotic central core and suppuration. Is bacteridian and common on the coronet and lower parts of the limbs in solipeds.

9th. =Carbunculus: Carbuncle.= An inflammatory nodosity or cluster of nodes of much greater extent, tending to necrotic change and sloughing over a much more extending area. Microbian.

10th. =Squama: Scales: Dandruff.= Exudation products and cells dessicate and exfoliate as branlike scales or thicker coherent laminæ. Examples are found in psoriasis, pityriasis, eczema, variola, rinderpest, etc.

11th. =Crustæ: Crusts: Scabs.= Hard, solidified masses of epidermis, blood, pus and serous exudate.

12th. =Callositas: Callosity.= Abnormal thickening of the epidermis, as a physiological protective cell growth. Examples: pads on the knees of camels, cows and even horses from kneeling on a hard, uneven surface.

13th. =Sitfasts: Necrotic Callosities.= Combination of dried up exudate of horny consistency, and a thickened, fibroid and partially necrotic portion of the subjacent derma with little or no disposition to spontaneous detachment.

14th. =Cornu Cutaneum: Keracele: Horny Growth.= Abnormal horny growth from keratogenous tissue, or from the derma in its vicinity or at some other point of the skin.

15th. =Erosions: Abrasions.= Lesions of the cuticle exposing the true skin, and the result of itching, scratching, friction, biting or other mechanical or thermic injury.

16th. =Rimæ: Cracks: Chaps.= These are linear breaches often confined to the epidermis in the bends of joints, under congestion and suppression of sebaceous secretion, in elephantiasis, dropsy, petechial fever, etc. Unless they have ulcerated they may heal without cicatrix.

17th. =Crevasses: Fissures.= These are chaps, which extend into the derma, giving rise to destruction of tissue and leaving a cicatrix on healing. Examples are found in the hollow of the pastern, behind the knee (Mallenders), in front of the hock (Sallanders), in the swellings of petechial fever, malignant catarrh, stocked legs, grease, etc.

18th. =Ulcus: Ulcer.= A sore that extends by the continual molecular breaking down of the forming granulations and of the adjacent and subjacent diseased tissue.

19th. =Excrescences: Hyperplasiæ: Phymata: Dermatomata.= These may include over luxuriant granulations which rise above the level of the skin and become organized into projecting fibro-cellular, raw or scabby masses: tumors of all kinds—warty, papillomatous, horny, epidermic, cancerous, sarcomatous, pigmentary, angeiomatous, tuberculosis, etc.

20th. =Cicatrices: Scars.= These are puckered, raised or sometimes depressed, lines or areas of condensed connective tissue with a covering of epidermis, taking the place of the normal dermis and epidermis and their appendages, which have been destroyed. They result from traumatic, ulcerous, or atrophic destruction of the skin.

21st. =Neurosis.= These may be exemplified by the intense itching of the skin without appreciable structural change. So in cutaneous anæsthesia and hyperæthesia.

22d. =Modified Secretions.= These include absence of perspiration—anidrosis, excessive perspiration—hyperidrosis, suppressed sebaceous secretion—asteatosis, excessive sebaceous secretion—steatorrhea or seborrhea, fœtid sweat—bromidrosis, colored sweat—chromidrosis, _urinous sweat_—uridrosis.

23d. =Structural alterations in glands and ducts.= Cystic ducts—hydrocystoma, blocked ducts—acne, inflamed glands—hidrosadenitis.

24th. =Abnormal conditions of the hair.= This embraces baldness, hypotrichosis, alopecia, excessive growth of hair, hypertrichosis, white patches, canities, nodular hairs, piedra, brittle hair, fragilitas crinium, felted hair, plica, trichoma.

25th. =Scleroderma.= Hard, leathery, thickened skin. Examples in old boars on shoulders, and in other animals.

26th. =Elephantiasis Pachydermia.= Enormous hypertrophy of the skin, with usually distention of the lymph plexuses and vessels (lymphangiectasis: see Vol. I).

26th. =Vegetable parasites.= Trichophyton, achorion, microsporon, actinomyces, etc. (See parasites).

27th. =Animal parasites.= Lice, fleas, diptera, trombidium, Acari, ixodes, cimex, filaria, coccidia, etc. (See parasites).

GENERAL CAUSES OF SKIN DISEASES.

External. Internal. Traumas, abrasions, excoriations, lacerations,
contusions, compression, radiating heat, scalding, incandescent
objects, solar heat, chemical caustics, cold, freezing, kicks, bites,
tusk horn or claw wounds, stings, venoms, envenomed bites, road dust,
sweat, excretions, sebum, mineral and vegetable poisons, essential
oils, fungi. Hyperæmia, exudation, depilation, sudation, moulting,
climatic changes, unwholesome or irritating foods, ptomaines,
alimentary fermentations, hepatic, renal or blood disorders, altered
innervation, youth, age, temperament, heredity. Experimental nervous
cases.

These may be =external= or =internal= or both.

=External Causes.= Some affections of the skin are due to external causes exclusively, while in others the local cause of irritation is accessory but no less important in maintaining the trouble. Among the more prominent external factors may be named: traumatisms, abrasions, excoriations, lacerations, contusions, compression, radiating heat, boiling water, hot or incandescent solids or liquids, solar heat, chemical caustics and irritants, cold, freezing, injuries by harness, kicks, lacerations with teeth, tusks, horns or claws, stings, bites, (leeches, snakes, etc.), venoms, (snake, toad, etc.), road dust and sweat, liquid fæces or urine, excess of sebum in sheath or vulva, mineral poisons (mercurial, iodides, bromides, arseniates, caustic alkalies, caustic salts, etc.), vegetable poisons (croton, bryonia alba and dioica, heracleum or cow parsnip, polygala or milk wort, cyclamen or sow bread, polygonum hydropiper, mustard, œnanthe, cicuta, hypericum perforatum and androsaemum, rhus toxicodendron, radicans and venenata, capsicum, pepper, radish, Indian syringa, anemone nemorosa and patens, ranunculus acris, scelerata, flammula, mericatus and bulbosus, cytisus, euphorbium and the essential oils of turpentine, origanum, lavender, etc.), fungi of musty food, ergot, etc.

=Internal Causes.= Among these are all conditions that induce stasis in the capillaries or lymph vessels, active hyperæmia, exudation, depilation, profuse perspiration, shedding the coat, exposure to cold, chill, etc., sudden access of warm weather, poor and insufficient or rich, stimulating food, cotton seed meal, indian corn, buckwheat, purple clover, animal food (in dogs), spiced food, food spoilt by wet and cryptogams, indigestions, gastric and intestinal fermentations, hepatic disorders, renal disorders with imperfect elimination, blood disorders, and nervous disorders which entail vaso-motor changes. Early age predisposes to some affections (variola, warts); old age to others (eczema). A nervous temperament in horses favors the drier eruptions (pityriasis), a lymphatic temperament the exudative (grease, canker, moist eczema). A hot, moist season favors most skin affections (eczema, acariasis, etc.), dry insolation others (erythema) and cold still others (chillblains, frost bite, chaps, etc.). Some eruptions are at first summer troubles, disappearing on the advent of cold weather, yet in time the predisposition increases, or the inflamed skin becomes less resistant and the disease becomes permanent. A marked predisposition in certain animals, appears to inhere in the constitution and proves hereditary in the family (Blain, Lafosse, Cadeac). Nervous causes have not been satisfactorily traced in the lower animals, yet the dermatitis of the face and neck caused by the experimental lesion of the cervical sympathetic or its connecting ganglia shows clearly enough how any portion must be affected by disorder of its trophic or vaso-motor nerves. Charcot found that experimental lesions causing inflammation of the spinal cord, led to trophic changes and finally gangrene of a corresponding part of the skin. Babesiu and Israï injected oil of mustard in one side of the cord, in three dogs, and found in several days a vesicular eruption and atrophy of the skin on the same side, a result they supposed of the myelitis.

DIAGNOSIS OF SKIN DISEASES.

Diagnosis. Clip or shave skin. Examine in warmth: skin and mucosæ,
where uninjured by rubbing, moisture, dryness, color, odor, discharge.
Soapy wash. Exudation into skin: pliancy: rigidity: eruption:
tenderness, itching, history, association, feeding, watering,
exposure, housing, harnessing, driving. Coincident disease. Prognosis.
Microbian dermatosis, parasitic dermatosis, external irritants,
ingested irritants, toxic systemic products, constitution, renal
disease, movement of joints, harness.

The thick hairy covering of animals, and the vicious energy with which they often rub, scratch and bite themselves, thus turning simple into extensive and severe lesions, interfere seriously with a satisfactory diagnosis. The following precautions are usually demanded:

1st. Clip the animal close to the skin to allow of careful examination. In some affections, this may be dispensed with, but as a rule it should be followed. What appears to be a circumscribed eruption may be shown to be general, or at least extensively diffused over different regions. Or what was shown only by scurf or scab may be seen in its earlier and more characteristic stage as erythema, papule or vesicle. It may even be desirable to shave the affected part, care being taken, not to slice off the characteristic papules, etc.

2d. Make the examination in a clear day in full sunshine if possible. In dark, cloudy weather, and in dimly lighted stables it is impossible to identify the different lesions. Artificial light is very unsatisfactory. Warmth, as in sunshine, or in a warm day or room, increases any itching and the cutaneous circulation and congestion, and renders more lively and active the animal parasites that may be present. These may be found in the surface scrapings taken in warmth, and not at all if taken in cold. A hand lens will assist in the discovery of the larger parasites, while for the smaller ones the microscope must be employed.

3d. Examine carefully all parts of the skin and even the visible mucosæ, estimating whether any lesions of the latter indicate extension from the skin, by proximity, or a general constitutional affection. Scrutinize particularly such parts as have not been abraded by mechanical injury—those which show the primary character of the lesion. Is the affected portion of the skin dry or moist? Some eruptions like impetigo or grease are always moist, others like pityriasis or dry eczema are habitually dry apart from mechanical injuries. Ascertain the color, odor and consistency of any discharge. It may be a limpid or reddish serum in grease, honey like in impetigo, oily in farcy, greasy in swine plague. The odor is fœtid in grease, canker and thrush of the frog, cheesy in variola, and mousy in favus.

4th. To learn the true nature of the eruption a warm, soapy wash may be essential to remove scurf, scab, and other encrustations.

5th. Note the depth and extent of the skin lesions, the thickening of the skin, its pliancy or rigidity, its adhesions to subjacent parts or free movement upon them, whether it is contracted into folds or ridges, the degree of congestion, the nature of the eruption, uniform congestive redness, papule, vesicle, pustule, squama, sore, ulcer, nodule, slough, etc. Are the individual lesions isolated or confluent?

6th. The presence of itching and its degree are important data. Pruritus is always excessive in ordinary acariasis, marked in eczema, phthiriasis, and some neuroses, and very slight in a number of skin affections (pityriasis, ringworm, grease, thrush, contagious acne). The abrasions and sores caused by rubbing, scratching, etc., will usually give a key to the degree of pruritus, and handling the part will render the condition evident.

7th. The history of the case is always important. Is it chronic or acute? Continuous or intermittent? Associated with any special conditions of proximity to other diseased animals, to special feeding, watering, exposure, housing, harnessing, driving, which might account for it? Did there coincide with its eruption any indigestion, gastric or intestinal, or any hepatic, urinary or nervous disorder on which it might be dependent?

_Prognosis._ This is subordinate to the nature, causes, course, duration and complications of the disease.

=Microbian dermatosis= (variola, aphthous fever, rouget) usually follows a rapid course and recovery is perfect with some measure of immunity.

=Parasitic dermatosis= (acariasis, phthiriasis) is liable to have serious secondary results (infection to man or animals, loss of wool, tender skin), and to run a chronic course.

=Maladies from external irritants= (chafing, caustics, traumas, vegetable, or animal irritants), do not tend to chronicity and are often promptly curable.

=Maladies due to ingested irritants= (urticaria, distillery waste eruptions), also tend to recovery when the source of irritation is cut off.

=Maladies due to toxic products of the system= will be obstinate or incurable, in ratio with the incurability of the causative factor. Those due to the absorbed products of a simple indigestion, will tend to terminate with the removal of the cause, while those dependent on chronic and perhaps irremediable disease of the digestive organs, liver, or kidneys will be correspondingly inveterate or incurable.

=Maladies due to a constitutional vice=, in sanguification, nutrition, innervation, etc., are likely to be irremovable or only temporarily curable.

=Burns and some other skin diseases= are liable to become complicated by renal embolisms, albuminuria, indigestions, etc., which may render the skin affection inveterate or incurable.

=Dermatitis= on the folds of articulations or on the seats of harness, are sustained by the local irritation, and may necessitate long rest, or abstention from work requiring the use of such harness.

All dermatites are liable to show special features of inveteracy, or amenability to treatment according to surrounding conditions—hygienic or otherwise.

GENERAL PRINCIPLES OF TREATMENT OF SKIN DISEASES.

General and local. Diet: wholesome diet following laxative:
restricted, generous, vegetable. Rest, avoiding congestion,
perspiration, friction, stretching, pressure. Cleanliness. Diuretics.
Purgatives. Tonics. Alteratives. Sulphur. Antimony. Phosphorus.
Calcium sulphide. Pilocarpin. Baths, tepid, warm, soapy, alterative.
Emollients, simple, medicated. Drying powders. Protective films.
Stimulating and antiseptic applications. Parasiticides. Caustics.
Counter-irritants. Bandages.

These must be general and local, and the first hygienic, dietetic and medicinal.

The =diet= is especially important in eruptions due to poisons such as green food, distillery refuse, silage, roots, ergoted or smutty food, musty fodder, irritant plants in hay or grain feed, buckwheat, etc. In many cases a change to sound fodder and a laxative to clear the alimentary canal of the irritant, may be all that is required. In cases where the feeding has been parsimonious, a judiciously gradual change to a generous diet may be required. Again when the feed has been unduly rich, or spiced as in the patent food for stock or the table leavings for dogs, a plainer, simpler and less exciting diet will be called for. Indigestions, urinary and hepatic disorders due to diet may be often corrected by a more judicious ration.

=Rest= is a most important element in horses and hunting dogs. When pressure of the harness keeps up the irritation, or when active movement reopens cracks in the tense rigid congested skin of the heel, carpus or tarsus of the horse, the parts must be kept quiescent. When on the other hand chaps and fissures are caused and maintained by _stocking_, the patient may do much better with exercise. In skin congestions which are aggravated by work and increased cutaneous circulation, rest is imperative.

=Cleanliness= is no less imperative. Many cases are started and maintained by filth on the skin and in the air of the stable and hence sponging, currying, brushing, rubbing, are directly therapeutic. Yet care must be taken to avoid irritation where the skin is tender. In the sensitive heels of the horse congestion, chaps, and _stocking_ are often determined by washing in ice cold water and leaving to dry uncovered, in a draught of air, or by washing with common laundry soap having alkali in excess. Even tar soap will sometimes keep up the trouble in a specially sensitive skin. Apart from such exceptional conditions, thorough grooming is commendable, not only in cleaning the skin, but in improving its circulation and nutrition.

=Diuretics= are often beneficial in eliminating from the system the irritant products generated from disorders in sanguification, digestion, urinary secretion and hepatic function, as well as those that are derived from the cutaneous disorder. They tend further to reduce any existing fever, and to cool and relieve the burning integument. The alkaline diuretics are often very useful.

=Purgatives= act in a similar way and are especially indicated in cases due to ingested irritants, and in such as depend on morbid products of gastro-intestinal or hepatic disorder. In many acute attacks these may be said to be almost specific in their action as in urticaria, and in the eruptions due to distillery products or green food.

=Tonics= are often called for to correct dyspepsias, to improve the general health and vigor, the sanguification and nutrition in weak and debilitated conditions. Iron, cod liver oil, bitters, quinia, quassia, calumba, gentian, nux, are often of value in such cases.

=Alteratives.= =Arsenic= may be said to act as a tonic with a special tendency toward the skin where it affects the epidermis and epidermic products and is applicable to many subacute and chronic disorders, as psoriasis, acne, dry eczema, and pemphigus. It has been further supposed to be most useful in superficial lesions, and in those due to a neurotic origin, from the known operation of arsenic on the nerves. It is little suited to acute skin diseases, and though often valuable is not to be trusted as universally applicable.

=Sulphur= is often useful as a laxative, but also as a stimulant to the cutaneous secretions when these are impaired.

=Antimony= is similarly a cutaneous stimulant and is sometimes useful in chronic inactive conditions.

=Phosphorus= has been found useful in obstinate cases and probably acts on the nerve centres in improving nutrition of the integument.

=Calcium sulphide= is sometimes useful with free secretion from the diseased surface, but its action is somewhat uncertain.

=Pilocarpin= operates by securing free secretion from the skin as well as from the various mucosæ, and seems to benefit by elimination, as well as by modifying the cutaneous functions and nutrition.

=Local Applications.= =Baths= may be placed foremost among these. Cleanliness is a prime necessity in treating skin disease. Tepid or warm water is especially required in acute disease in sensitive skins. In chronic cases with accumulation of scabs a soap wash following a 24 hours inunction with oil or lard may be demanded, but as a rule castile or other non-caustic soap should be used. In certain cases the baths may be advantageously medicated, as with calcium sulphide, potassium sulphide, salt, alum, tannic acid, tar, creolin, lysol, cresol, chloro-naphtholeum, arsenic, mercury, etc. The water alone is, however, of great value in soothing and moderating inflammation, softening and dissolving scabs and epidermis, and relieving the dryness and rigidity.

=Emollients= are used for the same end as calmatives, and relaxing and protective agents. Fatty bodies occupy a front rank, the bland vegetable and animal oils being not only soothing but nutritive (cod, lard, olive, cotton, almond, linseed, rape, pea nut, lanolin, neats foot and goose oil). Care should be taken that these are pure and in no sense rancid. Vaseline or petrolatum are free from the risk of rancidity, yet it should be free from contamination unless a stimulating action is wanted. Glycerine often used as an emollient has the disadvantage of drawing water from the surface and of actually irritating some sensitive skins. Glycerol made with glycerine and starch is more soothing. Glycogelatine made with glycerine 5, gelatine 3, and water 9, is very emollient and protective. This can be made the basis of astringent, sedative and antiseptic preparations by adding zinc oxide, lead acetate, chrysarobin, salicyclic acid, tannin, sulphur, oil of birch or of tar, etc. An excellent emollient paste is compounded of zinc oxide and vaseline one-half ounce of each, salicylic acid, ten grains. Oleate of lead is an excellent sedative application in irritation or pruritus.

=Drying powders= are found in starch, talc, magnesia, zinc oxide, lycopodium, bismuth oxide, boric acid, iodoform, aristol, salicylic acid, tannin, and, above all, magnesia carbonate. A slight addition of morphia sulphate will render them analgesic. Tar in zinc oxide or bismuth will secure antiseptic and stimulating qualities.

=Protective films= for irritable surfaces may be had from collodion, or from a solution of gutta percha in chloroform 1 ∶ 10 (traumaticin).

=Stimulating and antiseptic applications= are found in tar or oil of tar in suitable excipient and of a strength suited to the case, oil of white birch, oil of lavender, oil of cade, oil of cashew nut, oil of juniper, oil of hemlock, Canada balsam, balsam of Tolu or Peru, creolin, lysol, cresyl, creosote, carbolic acid, chloro-naphtholeum, etc. Ichthyol, of great value in chronic affections, may be used in oil or vaseline (5 ∶ 100), or in the form of Nuna’s varnish: Ichthyol 40, starch 40, concentrated albumen solution 1 to 1½, and water 20. Add the water to the starch, then rub in the ichthyol and finally the albumen. Resorcin is a useful stimulant, alterative, and antipruritic (1 ∶ 30 alcohol and oil).

As =antiseptics= and =parasiticides=, in addition to the above, are alpha- and beta-naphthol, iodized phenol, chloral camphor (rub together till they form a clear fluid), phenol camphor (add camphor gradually to the melted phenol crystals), mercuric chloride, cupric sulphate and silver nitrate. Potash (green) soap, medicated or not with tar or other agent, is of great use in many chronic affections. The phenol combinations are all more or less anæsthetic, and therefore sedatives and antipruritic. Quassia, Stavesacre, tobacco, etc., are of great use in parasitisms though not antiseptic. Sulphur fills both indications, and is a bland generally applicable agent.

=Caustics= (silver nitrate, antimony chloride, electric or thermocautery) are useful in luxuriant granulations, hyperplasias, and often in excessive secretion, or on infected surfaces.

=Counter-irritation= over the vaso-motor centres, is often of value, when the distribution of the eruption coincides with that of particular nerves, and indicates a nervous element in the causation.

=Bandages= of various kinds may be demanded to afford support in threatened dropsical effusion or excessive granulation or hyperplasia, to protect the surface against outside infection, to confine volatile applications to the affected part, and to prevent injury from biting, licking, scratching, or rubbing.

For the same reason it may be desirable to employ a muzzle, beads on the neck, tying to two opposite rings by short halters, hobbles, or other means of restraint.

ERYTHEMA. ERYTHEMATOUS DERMATITIS.

Definition, congestion, heat, redness, tenderness without eruption.
Sheep: swine: dogs: white horses and cattle. Causes: slight irritants.
Symptoms: congestion momentarily effaced by pressure, may go on to a
distinct irruption.

_Definition._ Congestion of the papillary and adjacent layers of the skin with heat, redness, and tenderness, or a diffuse superficial inflammation with some superadded swelling.

_Genera susceptible._ The affection is seen in sheep, swine, dogs, and in white horses and cattle or on white parts of the skin. It is not readily recognized on pigmented parts.

_Causes._ The action of any slight irritant: pressure, friction, brushing, currying, blows, vesicants, rubefacients, stings, parasitism, radiant heat, intense sunshine, cold (reaction), storm, plunging in cold streams when heated, feeding on stimulating agents, notably buckwheat.

_Symptoms._ On white skins there is a uniformly diffused redness, without papule or other eruption, and the color may be momentarily effaced leaving a perfectly white spot, made by the pressure of the finger. The affected part is warm, tender, and it may be, itchy. It may be but the first step of a distinct eruption of another kind, such as variola, vesicles, papules, pustules, but then the affection takes a different name. It has been named according to its seat, cause and nature as follows:

INTERTRIGO. INTERTRIGO OF CHAFING.

Causes: friction, inside thighs, side of scrotum or mammæ, inner side
of elbow, between digits on clipped heels, under harness. Dried sebum,
sweat, dust, clay. Pricks with stubble. Symptoms: lameness on
starting, abduction, straddling, knuckling, steps on toe. Treatment:
abate cause, cleanse, rest, dusting powders, zinc, lycopodium,
magnesia, starch, bismuth, alum, lead, morphia, surgeon’s cotton.
Carron oil, vaseline, antiseptics.

This occurs where the folds of skin come in contact and rub on each other as between the thighs or beside the scrotum, sheath or mammæ in fat horses and other animals, on inner side of the elbow, between the digits in ruminants, on clipped heels in horses, and under harness. Irritant perspiration and sebaceous matter dried on, and mixed with more or less gritty or septic road dust contribute to it. Drying of clay and mud in the cleft of the frog, or in the interdigital space of ruminants is a common cause, also pricking with stubble.

_Symptoms._ These are most marked when the animal has been standing with the raw surfaces partially dried and adherent. After moving for some time, and when the surface has been moistened by the exudate there may be little lameness. Until then he moves hesitatingly and stiffly, with the legs abducted or in case of the hind ones straddling. With intertrigo of the pastern or frog, the horse stands on the toe or with the fetlock knuckled forward, and avoids as far as possible a full extension. The same is true of cattle with interdigital intertrigo.

The affected part is hot, perhaps swollen, red, damp and exceedingly tender. Under renewed work, lameness disappears, but becomes worse on standing, and an extensive exudation may occur subcutaneously. If this becomes infected it may result in severe and even destructive lesions, but it usually remains simple and proves readily responsive to soothing and protective treatment. It is most amenable to treatment in dogs and meat producing animals of which no work is required. On the contrary the latter when travelled long distances on foot may suffer severely.

_Treatment._ First abate the cause. With castile soap wash from the affected part the dried accumulations of sweat, sebum, dust and other matters, remove clay from frog, interdigital space or heels. Rest until the congestion and tenderness subside. Drying applications in the form of dusting powders are usually best: zinc oxide, lycopodium, magnesia oxide, may be dusted in freely after the affected part has been thoroughly exposed and dried. In the absence of these use gloss starch, corn starch, farina or white bismuth. To one or other of these may be added a little alum, lead acetate or morphia. The addition of a layer of surgeons’ cotton is useful, if in a place where it will be retained. Of liquid applications the veterinarians white lotion (zinc sulphate and lead acetate, of each 1 oz. water 1 qt.) is one of the best, being at once sedative and astringent. It may be applied on cotton. Astringent preparations with glycerine are useful but glycerine has the serious drawback of attracting moisture and increasing the secretion when drying is desirable. Carron oil (equal parts of lime water and linseed oil) is most effective and free from this objection. Vaseline alone or medicated with zinc oxide, lead acetate, alum or tannic acid may be resorted to when dusting powders fail. Morphia and camphor have been added when itching is violent.

In intertrigo of the frog or interdigital space the danger of infection from the floor or road is so great that the demand for antisepsis must overcome other considerations. Calomel freely applied to the surface, previously cleansed and dried, is most successful. It may be bound in place by a pledget of cotton and bandage. In other cases alum 5 parts, copper sulphate 1 part, or carbolic acid and tar may be bound to the part.

ERYTHEMA CALORICUM: SOLAR ERYTHEMA.
WHITE FACE AND FOOT DISEASE IN HORSES.

England to Africa, on white skins, especially of face. Symptoms: local
congestion, swelling, itching, desquamation, during extreme heat: in
worst cases fever, dullness, inappetence, costiveness, diarrhœa, head
constantly moving, rubbing, vesicles, pustules, excoriations, cracks,
fissures, septic ulcers in nose and mouth, submaxillary and pharyngeal
swellings, recovery with dermal thickening and tenderness. Diagnosed
from petechial fever by the itching, and the absence of petechiæ.
Prevention: breed solid dark colors, avoid white skinned in hot
climates or work in shade, away from hot winds; sunshade; avoid
friction and wetting in sunshine. Treatment: shade, astringents, cool
irrigation, vaseline, zinc ointment, lamp black, antiseptics. Tie so
as to prevent rubbing.

This has been observed in different latitudes from the cool climate of Great Britain, to the burning suns of Africa, though it reaches its highest intensity in the hotter regions. The parts to suffer are those that are devoid of pigment, as the white star, snip or blaze on the face, the white feet or legs, the white areas in the piebald, and the whole surface in the albino. The white face, however, suffers more than the white legs, apparently because of its more constant exposure, the absence of shadow from the trunk, and the delicacy of the skin and fineness and thinness of the hair.

_Symptoms._ In slight cases there may be no constitutional disorder, only redness, itching, swelling and subsequent desquamation of epidermis on the white portion of the skin, which may prove persistent so long as hot weather lasts and recover on the advent of cold.

The more violent cases seen in warmer climes, may be heralded by febrile reaction, dullness, prostration, inappetence, constipation and sometimes diarrhœa. The head may be kept in constant movement, the itchy white parts being rubbed on any object within reach, and the limbs are stretched, the front ones forward and the hind backward, with a tendency to rub them with the nose or foot. The skin at first red, becomes later swollen, covered with vesicles which pass into pustules, burst and discharge. Meanwhile the subcutaneous connective tissue is infiltrated and gravitates toward the lowest parts, causing extensive submaxillary swellings and stocking of the limbs. In its worst forms it may go on to necrosis and sloughing, but more commonly the affected part becomes raw, excoriated, cracked and fissured. Sometimes the pituita or even the buccal membrane becomes involved, with muco-purulent discharge. In other cases the absorption of septic products causes inflammation and swelling of the submaxillary or pharyngeal lymph glands. Under favorable conditions, the secretions dry, the sores heal and the exudate is in great part absorbed, but there usually remains some thickening of the affected parts and a diminished vitality of the skin, which renders it morbidly sensitive to sources of irritation.

Severe cases might be mistaken for petechial fever, but there is much more pruritus, and there is an absence of the petechiæ, on the mucosæ, and of a tendency to the extension of the disease far beyond the patches of white.

_Treatment. Prevention._ This malady should be warded off by breeding or selecting for warm, sunny climes, animals of a solid color, and discarding all with white patches. Animals bred in a cooler climate should not be suddenly transferred to a hot one. When the animal with white face or feet is found in the hot sunny climate, it should be devoted as far as possible to work in the shade (indoors or in mines), or its white patches should be protected against the full unmitigated rays of the sun, and the hot winds. Sun shades are useful or in their absence leafy branches fastened to the bridle so as to protect the face. It is further important to avoid the friction of harness on the susceptible parts, or wetting of them when in the full glare of sunshine. Another obvious precaution is to keep the white patches well covered with lamp black.

When attacked the animal must be placed under cover and eruption treated with cooling astringents, constant irrigation with cool water, or lotions with acetate of lead, tannic acid, alum or sulphate of zinc. When the skin is dry and rigid it may be treated with vaseline, alone or with zinc oxide, lamp black or any one of the astringents above named. Open sores may be treated like ordinary wounds, tense engorgements may be drained by punctures followed by antiseptic dressings, and abscesses may be opened and evacuated.

During the treatment the patient should be tied short to two sides of the stall, and other measures taken to prevent him from rubbing or otherwise injuring the affected parts.

BUCKWHEAT ERYTHEMA: FAGOPYRISM. WHITE SKIN DISEASE.

Form of white face disease, with irritating ingesta, buckwheat, etc.,
occurs from dried products, no insects; growing potatoes; sunshine;
idiosyncrasy. Symptoms: as in white face disease: in winter itching
and rubbing: in summer may go on to nervous symptoms. Treatment: stop
feeding buckwheat. Give laxative and diuretics. Local treatment as in
white face disease.

This may be held to be but a form of the last named affection, in which, however, certain irritating ingesta (buckwheat, maize, wheat), are essential factors in addition to the white skin and strong sunshine. It is seen only on white skins or the white portions of parti-colored skins, while the blacks, browns and other colors usually escape. Black breeds of hogs (Essex) escape under the same feeding and exposure, as do solid colored horses of the darker shades. Of the different food factors, buckwheat (Polygonum fagopyrum, persicare, etc.), is the most to be feared, and the poison seems to be inherent in all the products (green vegetable, dry seeds, bran and straw) and is not destroyed by cooking. Buckwheat cakes sometime produce erythema in man. This excludes the idea of the transfer of a living cryptogam to the skin, though not the theory of pathogenic products of the fungi. The invoking of bee stings and the bites of insects, which are strongly attracted to the buckwheat, is untenable because the affection occurs from the dried seeds, bran and straw, and has been known to break out weeks after the buckwheat was withdrawn from the ration.

In addition to buckwheat, maize and even wheat when liberally fed have been known to cause erythema. Hemminger records a similar outbreak in horses working among growing potatoes.

In addition to the food, clear sunshine is essential and an individual idiosyncrasy. All animals, though equally exposed are not equally attacked.

_Symptoms._ These do not differ materially from those of the white face and foot disease already described. There are intense redness and tumefaction of the white skin or the white portions, showing prominently in the delicate parts (ears, eyelids, lips), with violent itching, rubbing and sometimes vesicles with yellowish contents, followed by sores and scabs. In the winter season there may be itching and rubbing only. In summer it may become erysipelatoid and extend to the mucosæ, of the respiratory and digestive organs, with hyperthermia, nervous excitement, vertigo, turning in a circle and even spasms and convulsions.

_Treatment._ This is essentially the same as for the white face and foot disease with this additional that the buckwheat or other offensive ingredient must be withdrawn from the ration, and what remains in the bowels must be expelled by saline or other laxative. Cooling diuretics must follow to eliminate irritant matters that may have been absorbed.

ERYTHEMA FROM IRRITANTS.

Irritant agents of all kinds, even if caustic or pustulant in concentrated forms, may be so diluted as to cause simple erythema. Among chemical agents we have ammonia, lye, caustic acids and salts, iodine, carbolic acid, the various tar products, kerosene, aniline, chloroform, ether, formaline, etc. Of thermic irritants may be named solar heat, fire heat, steam, hot water, hot air, and congelation (chillblains, freezing) the latter being especially common in the digital region when salt has been applied to snow or ice. Vegetable irritants include mustard, capsicum, moulds, euphorbium, rhus, milkwort, the volatile oils, etc. Among animal irritants must be named cantharides, mylabris, potato beetle, insect stings, venom of the irritated toad, liquid discharges from the kidneys or bowels, and discharges from open sores. Even the escape of tears upon the face will cause erythema.

The _symptoms_ in all such cases will vary with the potency of the factor and the susceptibility of the skin. Beside the common symptoms the color and odor of the skin will often yield valuable diagnostic indications. There is the white of muriatic acid, carbolic acid or zinc chloride, the black of silver salts or sulphuric acid, the yellow of iodine, chromium compounds and nitric acid, the well known odors of ammonia, iodine, chlorine, carbolic acid, tar, essential oils, chloroform, ether, formaline, kerosene, mustard, etc.

_Treatment_ is that of simple erythema after one has applied the appropriate antidote to the particular irritant. For the alkalies and carbolic acid use vinegar, for the acids oxide or carbonate of magnesia, chalk or lime water, for iodine and chlorine weak alkaline solutions, for rhus, ammonia or other alkali, or potassium permanganate, and for insect stings and animal venoms, alkalies or permanganates. The caustic salts may demand milk, white of egg, or some other albuminous solution. When no chemical antidote is available, the first step is to wash off the offending agent, and then treat the erythema.

DERMATITIS.

Under this head may be included a class of inflammations of the skin, due mainly or entirely to external causes, not essentially parasitic, and attended by distinct eruptions (papular, vesicular, pustular, etc.). Many of these are but an advance beyond the simple erythematous inflammation, and coincide with it, the one condition being present at one part of the diseased area, and the more advanced and severe lesions at another part. Bearing in mind the frequency of this connection, it will be unnecessary to dwell at length on this class of affections.

=Dermatitis Traumatica. Dermatitis from Mechanical Injury.= Besides the veritant factors already named as causing traumatic erythema, we must here recognize contusions, over-reaching, treads, interfering, bruising and chafing by harness, girths, circingles, hobbles, ropes, traces, twists, and blows with whip, club, chain or rope. Here the source of injury must be removed, by attention to shoeing, harness, etc., and the lesions treated according to their gravity as simple wounds.

=Dermatitis Venenata: Dermatitis Calorica.= These, like the corresponding erythema, come from contact with irritant plants or animals or their products, from excessive heat or cold, and may show any grade of eruption or even gangrene and sloughing. Apart from the washing off of the irritant or venomous matter and the application of alkalies or permanganates in the case of the latter, these must be treated like ordinary sores. In burns, especial value attaches to solutions of sodium bicarbonate, and preparations that will exclude the air. Vesicles may be emptied by puncture and the part covered with cotton soaked in carbolated sweet oil and lime water, or carron oil (linseed oil and lime water) may be freely applied, or a resorcin solution (2:100 water), or a thick varnish of linseed oil and litharge, equal parts, with 5 per cent. of salicylic acid, melted and painted over the surface. A layer of surgeon’s cotton covered by a rubber bandage where admissible, will complete the dressing. In the process of healing, skin grafting may be required. Thin slices of cuticle are placed in the center of the granulating surface, or at intervals and carefully bound in place.

When a part has been frozen the usual method is to recover circulation slowly by rubbing with cold water or snow. The parts are then treated by astringent and antiseptic dressings. If the skin sloughs use antiseptics until it separates, and then treat like an ordinary sore.

Chillblains may be treated with a mixture of sweet oil, 5 ozs., oil of turpentine ½ oz., Aqua Ammonia ½ oz., oil of peppermint 1 dr., or powdered camphor 10 grs., Peru balsam 20 drops, linseed oil 2 ozs. Nourishing food and a course of iron should be given.

=Dermatitis Medicamentosa.= Medicines given by the mouth sometimes cause inveterate skin eruptions. Among these are arsenic, belladonna, bromides, iodides, mercurials, salicylates, tansy, turpentine, tar, and the carminative seeds and oils. The latter are chargeable with many eruptions in live stock fed on patent foods. In cattle treated with iodides for actinomycosis, an universal eruption and desquamation is a common condition. In all such cases the drug must be withheld, the bowels cleared out by a purgative and the elimination of any remaining irritant products favored by gentle diuretics.

ECZEMA. A BOILING OUT. A PUSTULE.

General method of eruption. Successive advancing lesions. Definition.
Causes: usual factors and special susceptibility.