Chapter XVI: Part 16

In its more virulent form it is readily inoculable on birds, mice, rats, and rabbits, while the milder cases are not easily propagated in this way.

The false membrane contains a variety of saprophytes, and among them the pathogenic bacillus, which may be obtained in pure culture by inoculating it on a rabbit or mouse. Emmerich believed this bacillus to be identical with the Klebs-Löffler bacillus of diphtheria in man, but Löffler recognizes it as essentially distinct.

The _bacillus diphtheriæ avium_ is 0.8 to 1.5μ long, by 0.8 to 1.2μ broad. The ends are oval so that short specimens seem round. In bouillon cultures they form chains or clumps. They stain in aniline dyes, most deeply at the poles. Are not stained by Gram’s method. They are non-motile, ærobic, grow in agar, and alkaline bouillon, but render the latter acid in one or two days. Do not grow on peptone gelatine, nor produce gas with sugars. Are killed in 5 minutes at 58° C. (137° F.). Are killed by dryness in 24 hours, by sulphuric acid (0.25 ∶ 100) in 10 minutes, by lime water in 1 minute, and by sulphur fumes.

_Pathogenesis._ Eight rabbits inoculated subcutaneously with 0.1 cc. of the bouillon culture died in 18 to 36 hours. Of several white and gray mice inoculated only one died. Inoculations of mature hens subcutem and on the nose had no effect. Inoculation of a six weeks old chicken caused death in 4 days with bacilli in the liver and blood (Moore). Inoculation of pigeons produced the disease (Löffler). It seems doubtful whether the milder forms part with their virulence to birds, when cultivated artificially, or whether a special susceptibility is required in order to render the inoculation effective.

_Prevention._ Besides the general conditions of good hygiene, cleanliness, pure air, and pure water, the strict exclusion of the germ is the great desideratum. New fowls should not be taken into a flock, when they show any indication of disease in the mouth, throat, nose or eyes, nor when they come from a flock in which such signs of disease can be found. When examination of the flock, from which they are sold, cannot be made, the new fowls should be placed by themselves in quarantine until proved sound. Sound flocks should not be allowed to wander at large and mingle with the birds that are unsound, or open to suspicion. Neither should they be allowed to come in contact with manure from suspected poultry yards. If disease of air passages, mouth or eyes appears, separate at once the diseased fowl, and sprinkle roost, house and yard with dilute sulphuric acid, quicklime, or other disinfectant.

_Treatment._ Beside separation and disinfection the local use of antiseptics to the surface divested of the false membrane gives the best promise. Boric acid solution (4 ∶ 100) or sublimate solution (1 ∶ 5000) may be applied to the eye. For the nose and mouth somewhat stronger applications may be made.

_Prevention of infection to man._ The essential difference of the Klebs-Löffler bacillus of diphtheria in man, and the microbe of this affection in fowls does not exclude the necessity of avoiding contagion from birds to man. Among reported cases of such infection are: (1) That at Wesselhausen, where 4 attendants on the fowls contracted the disease from the sick fowls at a time when no other cases existed in the human population: (2) That of Sebdon where 6 persons suffered and 10 fowls fed by a hospital attendant also suffered: (3) That of Tunnis in which diphtheria prevailed in fowls, and soon also in those who fed them producing an extended epidemic: (4) That of Jacksonville, Ill., where a diphtheritic chicken, conveyed the disease, with fatal effect, to a child which fondled it (Moore).

These and other similar instances seem to show that the disease of the bird may become so virulent as to be communicated to man, and the disease of man so potent as to be transmissible to the bird. Every precaution therefore should be taken to prevent infection passing from one to the other.

FOLLICULAR CONJUNCTIVITIS.

Common in dogs. Violent congestion with enlargement of lymph
follicles, or beneath the nictitans, dark red, like millet seed, also
over sclera and lids. Enlarged lymph follicles with excess of lymphoid
cells. Often chronic. Entropion. Infection. Treatment: astringent and
antiseptic lotions: lunar caustic: cocaine and crushing of follicles:
pure air: excision of nictitans.

Fröhner has drawn attention to the frequency of this affection in the dog, which according to him attacks 40 per cent. of the race. It is especially liable to begin on the inner surface of the membrana nictitans, and though it may be at first somewhat hidden by the severe congestion, yet when that subsides in part, the swollen follicles can be seen as dark red elevations, the size of a millet seed, when the nictitans has been everted. It may extend over the sclerotic and palpebræ. Microscopically these swellings are found to be enlarged lymph follicles, with an excess of lymphoid cells.

The disease tends to assume a chronic course and may cause entropion and other troublesome lesions. The diagnosis depends on the recognition of the swollen follicles, and especially in the depth of the conjunctival sac.

It is presumably infective yet all Fröhner’s inoculation gave negative results.

_Treatment._ In the earlier stages the common astringent and antiseptic lotions may be used. Sublimate, or boric acid lotions are especially valuable for their antiseptic properties. Should these fail, the eyelid and nictitans may be inverted and the individual follicles touched with a fine pencil of lunar caustic, the resulting smarting being lessened by application of cold water. In case they should still prove obstinate, the conjunctiva may be cocainized and the follicles individually crushed with ciliary forceps. Pure out door air is a prime essential in the treatment.

In extreme cases Fröhner counsels the excision of the membrana nictitans.

NEOPLASMS OF THE CONJUNCTIVA.

Pinguecula: fatty growth: Lipoma: Melanoma: Dermoid tumor in young
dogs, calves, sheep. Cocainize the part and excise. Cold water: silver
nitrate. Polypus. Pterygium.

A pale fatty looking elevation on the sclerotic at the inner side of the cornea is not unknown in the dog, resembling =pinquecula= of man. It has not been seen to prove harmful and may be safely ignored.

=Lipoma= has also been observed (Müller) and when troublesome may be removed by excision with scissors.

=Melanosis= is met with in gray horses in connection with the same disease of the skin of the lids, and usually with generalized pigment tumors. In the latter case surgical interference is useless unless it is to secure a very temporary relief.

=Dermoid Tumor of the Conjunctiva.= This consists in a cutaneous product, consisting externally of a mass of epidermic cells, beneath which are connective tissue, fat cells, and muscular fibres, glands and growing hairs. It usually extends inward from the outer portion of the sclerotic conjunctiva and may encroach on that of the cornea. It is firmly adherent to the sclera, and sometimes to the cornea by its base and deeper aspect, but the apex is free and more or less projecting. The color is yellow, or more or less blackened by pigment or even reddened by blood. It has been observed, above all, in dogs, Prince reports a case in a calf and Zundel in a sheep. The Cornell Veterinary College clinic has furnished cases in ox and dog. They have, however, nearly always been seen in young animals and are probably congenital.

These are easily removed from the eye anæsthetized by a 4 per cent. solution of chloride of cocaine. The inner projecting end of the tumor is seized by rat-tooth forceps, and carefully snipped off with sharp scissors curved on the flat. Where adherent to the cornea it must be carefully handled, but where attached to the thicker and more resistant sclerotic it can be dealt with more freely. A pencil of silver nitrate may be used to check the bleeding, or that may be effected by cold water freely applied.

=Polypus=, a small, pale, pediculated tumor of the conjunctiva is described by Lafosse and should be removed by scissors, and bleeding checked by cold, wet applications.

PTERYGIUM.

This name is employed to designate a triangular conjunctival fold broader at its sclerotic end and gradually narrowing to its corneal extremity, with loose, slightly overlapping borders, and firmly fixed to the structures beneath. It is more vascular than the surrounding conjunctiva, and its comparatively large blood-vessels have suggested the veins of an insect’s wing—hence its name. The growth may extend from either canthus toward or partly over, the cornea.

Möller and Leclainche claim its existence in dogs, though rarely to such an extent as to demand surgical interference. Dunewald operated on a case in the cow.

Unless growing, it need not be interfered with. It may be dissected up with scissors the narrow end being dragged on by forceps. Another method is to cauterize the narrow end with the electric cautery which leads to material contraction of the entire mass.

XEROSIS CORNEÆ (EPITHELIALIS). DRY KERATITIS.

This is described by Mayer as following distemper in dogs. It seems to begin in the epithelial layer of the conjunctiva, which becomes dry, lustreless, spotted, opaque and fatty so that water runs over it without wetting it. It may extend deeply into the substance of the cornea and lead to the development of a scar. When scraped and examined under the microscope the scrapings are found to consist of epithelium undergoing fatty degeneration and myriads of _xerosis bacilli_. As the disease takes occasion to attack by reason of the debility of the system, the _treatment_ is mainly corroborative and tonic, including the arrest of the affection on which the weakness depends. The early application of antiseptics is desirable (iodoform 1, vaseline 10; mercuric chloride 1, vaseline 3000). Warm compresses and a bandage may be tried.

WOUNDS OF THE CORNEA.

Causes: harness, whip, nail, hay, straw, stubble, thistles, spikes,
twigs, pine needles, cones, burdocks, stones, gravel, glass, splinters
of wood or metal, scratches, stings. Symptoms: closed lids, epiphora,
sight of lesion, soon cloudy swelling, opacity. Treatment: antiseptic
bandage and lotion, boric acid, sublimate, potassium permanganate,
avoid lead or zinc, atropia, cocaine, with perforation, bandage,
eserine, excision. For foreign body, antiseptic cotton, spud or
curette.

_Causes._ Corneal wounds are common in working animals by reason of contact with harness, canes, whips, etc., and in the stable from contact with nails or with the hard ends of hay or straw. At pasture the cornea is injured by the ends of long stubble, the sharp points of thistles, the spikes of various thorny plants, and twigs of bushes and trees. The last named factors are especially operative in hunters and horses worked in forests. Punctures with pine needles and cones, and with burdocks, are other common causes. Stones, gravel, pieces of glass, and splinters of wood or metal, produce traumas of the cornea, and, in cats and dogs, scratches and even perforations with the claws are common. In this connection the stings of insects are not to be forgotten.

_Symptoms._ There is always a prompt and complete closure of the eyelids and a profuse secretion of tears. Then on parting the eyelids with finger and thumb, the lesion of the cornea, its nature and extent should be recognizable. In case of a small, punctured wound, however, as with a smooth thorn or other conical body, the normal elasticity of the corneal tissue may lead to such a perfect coaptation of the divided edges that the lesion may escape even a close scrutiny. If the case is seen early, before time has been allowed for cloudy swelling and opacity the wound is all the more likely to escape observation. In incised, scratched and torn wounds, on the other hand, the seat and nature of the lesion are made out with the greatest ease.

_Treatment_ of a slight wound which is at once recent and free from infection, is by a simple antiseptic bandage and lotion. Boric acid (1 ∶ 100), sublimate solution (1 ∶ 5000) or potassium permanganate solution (1 ∶ 100) may be used. Lead and even zinc salts, are liable to precipitate in the abraded tissue and cause a lasting opacity. If the pain is severe it may be moderated by the addition of atropia sulphate, or a solution of 1 to 100 water may be instilled into the eye several times daily. Cocaine makes an excellent substitute. In deeper wounds, perforating the cornea and allowing the escape of aqueous humor, there may be prolapse of the iris through the wound. It may be pressed back with a flat sterilized spatula, and retained by bandage and a course of eserine. Should it still escape, it must be seized with forceps, drawn out and snipped off with a sharp pair of sterilized scissors. The greatest care must be taken to avoid infection which may cause panophthalmitis and destruction of the entire eyeball.

FOREIGN BODIES IN THE CORNEA.

In case of penetration of the cornea by thorns, thistles, glass, metal, etc., there usually follows inflammation with a red area around the offending object. If the foreign body is a piece of iron there is a brownish area caused by iron oxide. Focal or transillumination will usually reveal the object. Should both fail, a solution of fluorescin when applied will develop a greenish area around it.

_Treatment_ may be made as advised by Gould by pressing a little antiseptic cotton to the front of the eye, so as to entangle and withdraw the foreign body when the eyeball is rolled. Failing in this we may cocainize the eye and remove the offending object with a small curette or spud. A careful focal illumination of the eye will enable the operator to see and remove the smallest particles without injury. Subsequent treatment is that of wounds.

ACUTE KERATITIS. INFLAMMATION OF THE CORNEA.

Extension from conjunctivitis, wounds, foreign bodies, bites, stings,
blows, infections, filaria. Symptoms: eye tender, closed, epiphora,
red, pannus, photophobia, congested sclera, opaque or ramified red
cornea, or diffuse red, exudation, suppuration, corneal abscess,
ulcer, perforation, prolapsus iris, panophthalmia. Focal illumination.
Recovery. Permanent cicatrix or opacity. Lesions: exudates of lymph
and leucocytes into corneal layers: embryonic tissue: vascularization:
abscess: ulcer: cicatrix: opacity: staphyloma: hypopion: prolapsus
iridis: panophthalmia. Treatment: antiseptic astringents, atropine,
leeching, derivatives, blister, seton, opacities; in severe cases
antiseptic puncture, sublimate lotion, silver nitrate, potassium
permanganate, boric acid, pyoktannin: in perforations antiseptic
bandage and eserine, iridectomy: in chronic cases mercury oxide.

Keratitis occurs in all domestic animals as a primary disease, or as an extension from conjunctivitis.

_Causes._ Extension from acute, enzootic, infectious conjunctivitis in sheep and cattle has been noticed by a great number of observers. Bayer and Lohoff have studied maculated keratitis of the superficial layers in horses. Again it has followed wounds by foreign bodies, spikes of vegetables, particles of iron and glass, blows of whips, or insects, stings, etc. It also occurs in connection with the local action of particular poisons, such as variola (foot and mouth disease), canine distemper, etc., and from the local irritations caused by trichiasis or entropion or by the filariæ lachrymalis (ox) and palpebralis (horse).

_Symptoms._ The eye is extremely sensitive, and habitually closed, with a profuse flow of tears, and a disposition to resist opening of the lids. When exposed the cornea is seen to be more or less clouded and perhaps reddened by the formation of vessels proceeding from its sclerotic margin. This is known as _pannus_. If the anterior chamber is still visible the pupil is found to be contracted showing photophobia. The congestion is first visible in the sclerotic and in the absence of pigment is most intense near the margin of the cornea. Upon the cornea itself it is preceded by a deep white opacity, into which the vascularity gradually extends. The whole cornea may finally become of a bright pink hue.

The congestion of the cornea may advance to fibrinous exudation, or the formation of pus between its layers, to molecular degeneration and the formation of ulcer, or even to perforation and escape of the aqueous humor. In this case prolapsus iris, panophthalmia and destruction of the eye are likely to ensue.

Ulcer if not readily seen with unaided vision can be easily recognized by the aid of focal illumination, and abscess can be detected by the presence of a sharply circumscribed centre of intense opacity, white or yellow, and some bulging of the membrane.

The pus may be absorbed, or it may escape by rupture and discharge externally, or into the anterior chamber when the resistance is least in that direction, and when this takes place, a dangerous internal infective inflammation is the result.

In the slighter forms of keratitis the inflammation may come early to a standstill, and recede, tenderness and photophobia pass off, the eyelids may be opened, and the corneal opacities gradually disappear. If any portion of the cornea has become vascular, that portion is liable to remain opaque or even pink.

_Lesions._ Under the influence of an irritant on the cornea, the vessels in the margin of the sclerotic become actively congested and pour out lymph freely, leucocytes also escape and with the lymph pass through the lymph channels into the substance of the corneal tissue. Here they undergo active fission and increase, and the normal cells of the corneal tissue multiply in like manner, so that in a short time there is an extraordinary production of embryonic cells. Into the embryonic tissue so formed, blood escapes from forming loops of new vessels, and this goes on extending until the whole cornea may have become vascular. Degenerations in the newly formed structure may result in suppuration, (_hypopyonkeratitis_) or molecular decay and ulceration, (_ulcus corneæ_) or organization may take place into the fibrous tissue with contraction and permanent opacity, (_macula_) or a hyperplasia may form in the shape of a staphyloma.

Among the other complications may be named pus in the anterior chamber (hypopion), prolapsus of the iris, iritis and panophthalmia.

_Treatment._ In the milder form of keratitis, antiseptic astringents with atropia sulphate are often effectual: zinc sulphate, boric acid or alum (1 ∶ 100). Any direct mechanical cause of the irritation must be removed, and the eye rendered as far as possible antiseptic or aseptic. Derivatives also may be of service, and Trasbot especially advises bleeding from the angular vein of the eye but only in the very earliest stages. Cupping, leeching or setons may be employed. Excessive tension may be relieved by puncture of the cornea near its margin. The remaining opacity after the inflammation has subsided may usually be removed by touching it daily with a camel’s hair brush dipped in a solution of silver nitrate (1 ∶ 200).

In the more severe cases antiseptic lotions are even more essential, mercuric chloride (1 ∶ 5000), potassium permanganate (1 ∶ 100), boric acid (1 ∶ 100), silver nitrate (1 ∶ 200). Careful massage is of value.

Ulcers may be touched daily with a solution of silver nitrate (1 ∶ 400), or of pyoktannin (1 ∶ 100).

Perforations must be treated by antiseptic bandage, eserin, and in case of necessity, iridectomy as advised under perforating wounds.

Abscesses of the cornea should be opened with a flamed needle and treated with antiseptic lotions.

Obstinate cases are often benefited by ointment of yellow oxide of mercury 1, vaseline 10, or by the red oxide of mercury or calomel.

POISONING WITH COTTON SEED OR COTTON SEED MEAL.

Poisons in cotton plant: on man, pig, cow, stock cattle. Symptoms in
latter: Nervousness, debility, exhaustion, in-cöordination, paresis,
dyspnœa, dullness, anorexia, drooping head, trembling, lachrymation,
corneal ulcer, opacity, vesiculation; unilateral or bilateral; with
rest and change of food recover in five days except eye lesions.
Treatment: suspend cotton seed, purge, and treat eye lesions.

The cotton plant develops poisons for various genera of animals. The bark of the root is a favorite abortifacient for woman and may be used for the same purpose in the domestic animals. The seed when fed continuously to swine will destroy life with symptoms of scorbutus, and grave constitutional disorders. Cotton seed meal fed in excess to dairy cows has a bad reputation for inducing garget and mammitis. In stock cattle it has the reputation of producing diarrhœa, running from the eyes, abscess and ulceration of the cornea, staphyloma, hyperthermia (103° to 109° F.), swelled legs, congestion of the liver and spleen, and high colored urine. As described by Dr. F. C. McCurdy, of Kansas City, the southern cattle arrive in poor condition, seem nervous, weak and exhausted, move with an uncertain, staggering gait, and may fall and make convulsive but ineffectual efforts to rise. Dyspnœa, blue mucosæ, and protruded tongue are noticeable in such cases. In the slighter cases, dullness, inappetence, suspended rumination, drooping head, and trembling limbs are characteristic features, and profuse lachrymation is constant. In some eyes there is a small opaque spot around a minute ulcer containing small granules like dust or sand, and situated in the centre of the cornea on the line of approximation of the two eyelids. Larger opaque areas when present were generally confined to the corneal surface, without any areola of distended vessels, and without a vascular zone at the junction of cornea and sclera. In certain cases the whole transparent cornea stood out in the form of a vesicle, so prominently as to interfere with closure of the eyelids. The affection might attack both eyes or only one.

An important feature is that cattle coming from the cars in this condition and left at rest for five days on hay without cotton seed recovered rumination and appetite, and the weakness and nervous excitement or depression disappeared. There remained only the lesions of the eye which progress tardily according to their extent or severity.

The southern origin of the cattle, together with the congested liver and spleen and the high colored urine would have suggested the southern cattle fever, but from the promptitude of the recovery under a change of regimen and the prominence of the lesions of the eye.

The important point in connection with this subject is the prophylaxis by avoidance of the too liberal diet of cotton seed. When the disease has actually set in, the true course is to suspend this aliment, clear the bowels of any that may remain therein, and treat the lesions of the eyes according to their respective conditions.

CHRONIC KERATITIS.

Sequel of trichiasis, entropion, eczema, etc. Age. Symptoms: moderate,
lids partly closed, cilia matted together, crusted, cornea clouded,
dull, with ramifying vessels. Resolution. Fibroid degeneration,
permanent opacity. Treatment: tonic regimen, outdoor exercise, iron,
bitters, calcium sulphide, astringent antiseptic collyria, atropia,
mercury oxide.

This is especially common in dogs in warm latitudes. Trichiasis and entropion are perhaps the most common of the direct causes. Eczema and other skin eruptions affecting the lids are additional causes, while old and debilitated dogs are especially subject to the affection. It is less frequent in horses.

The _symptoms_ are much less severe than in the acute form. The lids are usually partially but rarely completely closed, lachrymation may be absent and is never excessive, the secretion usually sticks together the cilia and lids, and always forms crusts on them, the palpebræ are less sensitive than in acute keratitis, the cornea is habitually clouded of a bluish-white color, yet in the main partially transparent and without the disc opacities of the acute type of disease, and the pupil, which is usually visible in a good light or under oblique illumination, may be slightly but is not excessively contracted. The surface of the cornea seems to have lost some of its polish, and in its substance blood vessels can usually be made out.

Under favorable conditions these cases may end in resolution and especially under a change of food and environment. In less fortunate cases they result in a fibroid degeneration of the cornea and deep permanent opacity.

_Treatment._ It is usually desirable to change the regimen so as to improve the general health, and to allow a fair amount of outdoor exercise. In the very old and debilitated the case is rather hopeless. A course of iron or bitters will sometimes have a good effect. In other cases sulphide of calcium ⅒ grain thrice a day will prove useful. Eczema must be treated secundum artem.

Locally astringent and antiseptic collyria may be used as in the acute form. Atropia, 5 grs. to the oz., is a valuable adjuvant, to be instilled in drops. Ointment of yellow oxide of mercury, a piece like a pin head rubbed inside the lids once or twice a day often acts well. Finally Trasbot strongly commends liquor of Van Swieten.

OPACITY OF THE CORNEA. NEBULA. MACULA. LEUCOMA.

Nebula, macula, leucoma, pigment spots, infiltration, cicatrix,
vascular or not, result of lead, silver or cocaine. Treatment: silver
nitrate solution in young and vigorous; calomel: iodoform: avoid
mercury and iodine at the same time. Tatooing.

As a sequel of inflammation of the cornea, persistent opacities are very common occurrences. These may last only a short time after the subsidence of the inflammation, or they may be persistent and chronic. They are of all degrees of severity from a mere bluish haze to a dense white cloud, or a dark pigment spot.

The term nebula is given to the slightest form which appears as a grayish blue but still transparent blue and may be so slight as to pass without recognition except under focal or oblique illumination. It shades off gradually into the adjacent healthy cornea, and is often seen as a marginal zone when the centre of the cornea is clear.

=Macula= is more marked, requiring no special illumination to detect it, especially when the dark pupil forms a background for the affected area. It is not, however, of a clear white, but of a grayish blue tint.

=Leucoma= is a dense white spot or patch which reflects all the light falling upon it, and has usually a sharply circumscribed margin.

=Pigment spots= are usually on the membrane of Descemet and are the result of a previous adhesion of the iris and detachment of a portion of its pigment.

The white opacity may be merely a remnant of inflammatory infiltration or it may be a fibrous cicatrix with or without a remaining minute ulcer. It may be the result of an insoluble deposit of lead or silver in the tissues. Sometimes it will form as the result of the application of cocaine.

_Treatment._ A case of slight inflammatory infiltration can usually be cleared up by touching it daily with a solution of 2 grs. silver nitrate in an ounce of distilled water. This is especially satisfactory in the young and healthy, in which the power of repair is greatest. Finely powdered calomel or iodoform applied to the cornea will often prove effective. In case potassium iodide has been given by the mouth, calomel or corrosive sublimate is liable to form mercurous or mercuric iodide and cause ophthalmia. The same is true of iodoform if mercury has been given internally. As a last resort tatooing the spot has been resorted to, to hide the opacity.

ULCER OF THE CORNEA.

Infection of abrasions may cause ulcer. Age. House dogs. Puppies on
vegetable food. Exhaustion. Starvation. Improper, insufficient diet.
Specific microbes and toxins. Symptoms: Ulcer with peripheral zone of
opacity. Photophobia. In marasmus little other local trouble.
Diagnosis by oblique focal illumination or fluorescin. Granulation of
Descemete’s membrane. Escape of aqueous. Keratitis. Panophthalmia.
Staphyloma. Prognosis in debilitated, vigorous. Treatment: tonics,
fresh air, good food, sunshine, exercise, silver nitrate, mercuric
chloride, iodoform, alcohol, chlorine water, boric acid, cocaine,
eserine, atropine, warm antiseptic compress, juice of fresh cassava.

_Causes._ Wounds of the cornea making an infection entrance for pus microbes, are liable to lead to ulceration, and a corresponding destruction of the epithelium and superficial layers by inflammation, may start a similar ulcerative process. Apart from these conditions, ulceration is especially liable to occur in very old dogs, in closely confined house dogs, in puppies raised on an exclusive diet of vegetable food, and in animals worn out by disease, exhaustion, starvation, or improper and insufficient diet. Majendie’s dogs fed on sugar, starch and other imperfect diet, suffered in this way. Finally, the local action of certain specific disease poisons, enzootic purulent ophthalmia, canine distemper, dogpox (Trasbot), equine influenza (Schindelka), sheep pox, and blennorrhœa (Möller), leads to ulceration.

_Symptoms._ In keratitis there is usually a marked local opacity in the centre of which the breach of the surface may be found. The attendant photophobia with closure of the lids and pupil is strongly suggestive of ulcer. In the specific diseases, the local inflammation, the rapid progress of the lesion and the coexistence of the particular infective disease are characteristic. In cases due to debility and marasmus the disease may appear with little indication of attendant irritation, lachrymation, tenderness, photophobia, or even opacity. At one circumscribed point only is there a grayish cloud, perhaps no more than a thirtieth of an inch in diameter, and slightly projecting. This becomes soft and gelatinous and finally drops off, leaving a shallow excavation or abrasion, surrounded by a narrow grayish zone. This necrobiosis may extend inward and even penetrate the membrane, before the lesion has enlarged to more than a hemp seed in diameter. In other cases lateral extension occurs.

It is always important to recognize the ulcer at an early stage, and this may be done by oblique focal illumination and the use of a magnifying lens. In case of doubt a drop of solution of fluorescin placed on the cornea and at once washed out, will promptly reveal the lesion by the high color given to the tissues which have been denuded.

When perforation has taken place the membrane of Descemet may bulge out of the orifice and undergo granulation, or it may open and allow the escape of the aqueous humor. Active keratitis and even panophthalmia are liable to follow perforation. Again, the escape of aqueous humor tends to the approximation or contact of the iris with the cornea, where it may become adherent and staphyloma may ensue.

_Prognosis_ is unfavorable in debilitated subjects, and when the lesion is extensive and in the line of vision. In slight recent cases in good constitutions it is favorable.

_Treatment._ Debility must be met by tonics and rich diet, fresh air, sunshine and exercise. Specific diseases must be met according to their nature.

Locally the daily application of silver nitrate lotion (1 ∶ 200) is often very effective, proving an excellent antiseptic, checking the microbian proliferation, and coagulating the albumen in the wound so as to form an antiseptic barrier to further invasion. A mercuric chloride solution (1 ∶ 5000) is an excellent substitute. Iodoform powder though less antiseptic, is especially valuable in favoring the healing process. It is dusted over the cornea, and the upper lid immediately drawn down and held over the cornea for several minutes. If this is neglected the dry powder is removed by the flow of tears, and the movement of the lids and membrana nictitans. Trasbot recommends dilute alcohol (5 ∶ 100). Möller advises chlorine water reduced to one-third the standard strength, or boric acid solution (2 ∶ 100). Bouley found good results from a cocaine solution. Cadiot and Almy get the best results from creolin (.5 to 1 ∶ 1000) 5 or 6 times a day, with eserine.

In all cases great relief can be obtained from a strong atropia lotion (1 ∶ 100). Indolent cases may often be helped by warm antiseptic compresses, which seem to stimulate the circulation and nutrition of the part. The juice exuding from the scraped fresh cassava and concentrated to a syrupy consistency, is strongly antiseptic, and used with atropia or pilocarpin is the best agent known for senile ulcer (Risley).

In perforation use eserine, and antiseptic bandages and in case of prolapsus iris, excise as already advised.

CORNEAL STAPHYLOMA.

Bulging corneal scar with adherent iris: from perforation, escape of
aqueous, intraocular pressure, vascularization of cornea. Diagnosis by
central cicatrix, vascularisation, pigmentation. Oblique illumination.
Treatment: iridectomy, eserine. Suture. Enucleation.

This is a bulging forward of a corneal scar with the iris adherent to its internal surface. It may originate in perforation of the cornea and escape of the aqueous humor, or in intraocular pressure that advances the iris until it comes in contact with the cornea, which becoming adherent and receiving an abnormally large supply of blood or plasma, softens and bulges outward. It may grow out to a great length in some cases, Eck has seen it two inches in the horse, and somewhat smaller in an ox. May records a case affecting both eyes in the dog.

_Diagnosis_ is not usually difficult. The scar in the midst of a granulating projection of the cornea is nearly conclusive, but the recognition of pigmentation of the growth and the adherent iris often revealed by oblique illumination will nearly always show the true nature of the case.

_Treatment_ is by iridectomy and eserin if the disease can be recognized in its earliest stages, but it is rarely satisfactory. Later the choice may be between excision of the staphyloma and coaptation of the edges of the wound by suture, and the enucleation and removal of the eyeball. The last resort is preferable to the continued irritation of the staphyloma by the lids and cilia under the ocular movements.

ECTASIA CORNEÆ. KERATOCONUS. CONICAL CORNEA.

This consists in a thinning and protrusion of the cornea in the form of a blunt cone, without loss of transparency. It has accordingly been called _staphyloma pellucida_. There is a gradual attenuation and distension of the corneal tissue from some unknown cause. It has been seen mainly in the young and is manifestly due to a trophic defect. Stockfleth records a case in a foal and Bayer in a cow. No satisfactory treatment has been proposed, but as the trouble usually comes to a standstill without perforation, it can be left to take its course. With rapid increase and manifest tension antiseptic puncture of the cornea or even iridectomy might be tried.

KERATOGLOBUS.

This is a variety of _ectasia_ in which the clear, pellucid, protruding cornea is more globular and less conical in outline. It is seen especially with enlargement of the entire eyeball (_buphthalmus_).

TUMORS OF THE CORNEA.

Various tumors may grow from the cornea. Dermoid cysts may implicate the cornea and demand excision. Malignant growths demand extirpation of the eyeball.

WOUNDS OF THE SCLERA.

Covered as it is by the bones of the orbit, and by the palpebræ the sclera is little liable to traumatic lesions. Wounds with swords, needles, nails, splinters of wood, and other sharp pointed bodies are not unknown, however, and penetration by shot is especially common in setters. Rupture from blows of clubs, beams, poles, stumps, etc., are also met with.

The _symptoms_ are profuse lachrymation with more or less of blood, and when the eyelids are separated the wound may be discovered and its gravity estimated by protrusion of the vitreous. Slight injuries which are not infected heal readily under the treatment recommended for keratitis. Infecting and penetrating wounds are liable to cause panophthalmitis and destruction of the eye. Foreign bodies, if present, should be removed when possible. Pyoktannin is especially recommended by Stilling.

EPISCLERITIS. INFLAMMATION OF THE SCLERA.

Scleritis in man is described as a manifestation of rheumatism, gout, or tuberculosis. It occurs in animals in connection with traumatic lesions, with iritis, cyclitis and choroiditis and is manifested by more or less congestion, swelling and tenderness of the sclerotic, but is always subordinate in importance and the treatment demanded is for the more serious disease.

ECTASIA (BULGING) OF THE SCLERA.

Cases of this kind are adduced by Schleich and Mayer, in dogs, in which there was a corresponding bulging or even an absence (_coloboma_) of the choroid and retina. With a large protrusion of the sclera behind, there was a shrinkage of the front of the globe (_microphthalmos_), so that an atrophy might be suspected. The condition is irremediable.

PROLAPSE OF THE IRIS.

This has been already referred to as a complication of perforating ulcer or wound of the cornea. If it cannot be returned and maintained by a compression bandage and eserin, the only resort is to draw out the prolapsing portion and cut it off with scissors, the eye and instruments having been rendered thoroughly aseptic.

INTERNAL OPHTHALMIA.

Diagnosis of internal ophthalmias difficult. Causes: as in
conjunctivitis, extension of conjunctivitis or keratitis to iris,
choroid, ciliary circle, retina; Lymphatic constitution, damp soil,
air and stable, pit life, dentition, grain feeding, training.
Symptoms: ophthalmic symptoms generally, enlarged ciliary vessels in
sclera not movable; white zone around corneal margin; iris dull,
brownish, sluggish; intraocular tension increased: flocculi in aqueous
humor: photophobia: oblique focal illumination: sudden change from
darkness to light: synechia: ophthalmoscope. Cyclitis. Diagnosis: from
keratitis, recurrent ophthalmia. Lesions: according to chief seat of
the disease: inflammation of Descemet’s membrane, iris, choroid,
ciliary circle, lens, vitreous and retina in variable degree. Opacity
of aqueous, lens, capsules, or vitreous. Prognosis: always grave,
often vision impaired or lost. Treatment: rest, pure air, apart from
strong sunshine, removal of causes, local bleeding or cupping,
derivation, purgative, cooling diuretics: locally astringent
antiseptic lotions, cocaine, homatropine, blister, undue tension
antiseptic puncture, mercury oxide ointment; in rheumatic cases
salicin or sodium salicylate.

In the domestic animals it is not always possible to distinguish between inflammations affecting different portions of the inner and middle coats of the eye (iritis, cyclitis, choroiditis, retinitis), so that it is convenient to give in general terms the phenomena and treatment of the class known as _ophthalmia internus_. This is all the more appropriate that inflammation of one of these divisions so frequently extends to the others producing _panophthalmitis_, that the disease in one usually implies an early implication of all.

_Causes._ Many of the causes of conjunctivitis, when acting with special intensity, or for too long a time, may cause internal ophthalmia. Severe blows, bruises, punctures, lacerations, sand, cinders, dust, lime, foreign bodies inducing traumas, sudden transitions from darkness to bright sunshine, habitual exposure to sunshine or to the reflection from snow, ice or water, through a window in front of the stall, the abuse of the overdraw check rein, the glare of electric light or of lightning flashes, draughts of cold damp air between windows or doors, the beating of cold storms on the eyes and skin, a sudden chill from plunging in water or standing in a cold draught when perspiring, blows with branches, pine cones or needles in the eye, the constant irritation from entropion, trichiases, burdocks or thistles in the forelock, irritant gases, etc., are among the factors which coöperate in setting up the disease. Again diseases of the digestive organs, rheumatism, influenza, canine distemper, brust-seuche, petechial fever, variola, eczema, and aphthous fever may be direct causes. Conjunctivitis and keratitis are liable to merge into irido-choroiditis by extension, and above all when owing to perforation of the cornea a direct channel is opened for the easy entrance of infective, pathogenic microbes. A lymphatic constitution, connected with low breeding, or living in a low, damp, cloudy region, or in dark, damp, impure stables, has a strongly predisposing influence. The period of dentition, connected as it usually is with domestication, stabling, grain feeding, and training is often a potent accessory cause.

_Symptoms._ With the general phenomena of superficial or external ophthalmia there are some indications which may be called pathognomonic. These may be summarized as follows: in eyes devoid of pigment the _enlarged ciliary vessels run deeply and are not tortuous, nor mobile when rubbed; the scleral redness increases toward the margin of the cornea, but leaves a white zone in front of the penetration of the ciliary vessels; the iris has lost its clear reflection, appearing dull or brownish; the pupil is contracted and sluggish in response to light and darkness, it may be fixed or may show marked unevenness in its margin: the tension of the eye ball is often increased, flocculi of lymph may be seen in the aqueous humor settling into the lower part of the anterior chamber_. This deposit may be white or yellowish or it may even be reddened by extravasated blood especially in traumatic injuries. In traumas, too, the cornea and even the aqueous or vitreous humor may be opaque. In cases resulting from exposure to cold or from internal causes, the media of the eye are at first clear and transparent. The condition of the interior of the eye is usually to be learned by examining the patient as he stands facing the light from a dark back ground. A stable door or window will afford the requisite amount of rays falling from above and from each side upon the interior of the eye. The observer looks indirectly or obliquely and under favorable conditions can see the iris and through the pupil. If the pupil is unduly closed it may often be dilated by instilling a few drops of a 5 per cent. solution of atropia and waiting for fifteen or twenty minutes.

The examination is made more satisfactorily with a candle or other single source of light in a dark chamber. If this light is surrounded by a chimney opaque except at one side which is directed toward the eye, the results are much more satisfactory. Focal illumination with a biconvex lens, or oblique illumination will show a swollen condition of the iris with uneven bulging swellings at different points, and generally a lack of the clear dark surface which marks the healthy iris. It may be yellowish or brownish, rather than dark, or blue, or yellow, but is always duller than normal. The pupil may be contracted or dilated, but is always uneven at the margin according to the degree of congestion of the different portions. It may be quite immovable under the stimulus of light and darkness, and is always sluggish as compared with the healthy condition. To test this reflex action, the one eye may be bandaged, and the other eye covered with the palm of the hand for one or two minutes. When exposed the pupil will be found to be widely dilated, and in the healthy eye it will rapidly contract and dilate alternately until it has reached a condition of adaptation to the intensity of the light when it will remain immovable. With the inflamed iris these contractions and dilatations will be lacking altogether, or they will be sluggish and imperfect in various degrees according to the intensity of the inflammation, the degree of congestion or the tension of the liquid media of the eye. Restricted movement may also be due to adhesion to the cornea, (_synechia anterior_) or to the capsule of the lens (_synechia posterior_).

When viewed with the ophthalmoscope properly focused the choroid may show a lack of its normal lustre and an unevenness due to the formation of small rounded elevations in connection with congestion, or exudation, and patches of yellowish red or whitish discoloration together with lines of the same color following the course of the blood-vessels. It may also reveal dark spots of opacity in the lens (_cataract_) or clouds in the anterior region of the vitreous, the result of exudations. The blood-vessels may appear enlarged and tortuous.

In some cases the exudate may form a false membrane which completely closes the pupil.

A special tenderness around the margin of the cornea is suggestive of _cyclitis_. Internal ophthalmia is usually accompanied by a variable amount of fever.

_Diagnosis._ From simple keratitis, it is distinguished by the thickening, discoloration and sluggishness of the iris, by the absence, in many cases, of corneal opacity, and of free lachrymation, and in some instances by increased tension of the eyeball.

Recurring ophthalmia, which is usually also an internal inflammation, appears more abruptly and often at first with greater severity, and accompanied by more hyperthermia. There is almost always a bluish white opacity around the margin of the cornea, the eye is retracted in its sheath so as to appear smaller, and the upper lid usually shows a marked angle between its inner and middle thirds in place of the evenly curved arch of the healthy palpebra. It usually appears for the first time in the young and in those that have inherited the susceptibility and have been kept on damp soils, in cloudy districts, or dark buildings.

_Lesions._ These are necessarily varied according as the inflammation is concentrated on particular parts of the interior of the eye. The secreting membrane of the aqueous humor is nearly always inflamed giving rise to an exudate and a milky opacity of the aqueous humor. The iris is the seat of congestion exudation, thickening, cell proliferation and investment by false membranes. The capsule of the lens is early clouded, may be covered by exudate and is rendered vascular in some cases. The choroid is also the seat of congestion, exudation and discoloration with the covering up at points of its pigmentary layer. The vitreous and lens finally become the seat of exudation and opacity which is liable to prove permanent.

_Prognosis._ The internal ophthalmias are always to be dreaded. In other organs exudates may take place and become organized as permanent structures without abolishing the function or rendering the organ physiologically useless, but in the delicate and transparent tissues of the eye, any such permanent product almost infallibly causes opacity and loss, or serious impairment of vision. In the retina the displacement, derangement, or covering up of the cones and rods necessarily interferes with or abolishes sight, the opacity of the cornea, lens, capsule, or vitreous interrupts the rays of light, and the destruction, or coating over of the pigment of the choroid leads to undue reflection and destroys vision. Beside this the destruction or impairment of one part of the eye, changes the refraction and blurs the vision, or interferes with accommodation and destroys the utility of the organ. Unless therefore the disease can be cut short in its early stages and a complete resolution effected it is likely to leave the patient very much deteriorated in value. Fortunately it is only in the most violent cases or in very susceptible animals that the disease in the one eye is transmitted to the other by sympathy and leads to destruction of that eye as well.

In the _treatment_ of internal ophthalmia, rest in pure air and moderate warmth, away from a fierce glare of light is imperative. The causes should as far as possible be removed. Next, it is desirable to establish derivation. Leblanc and Trasbot attach great importance to phlebotomy from the jugular on the same side. A more direct local action with less loss of blood may be obtained from opening the angular vein of the eye or applying a leech beneath the lower lid. In most cases a sufficient derivative action can be secured by an active purgative which may be followed by daily doses of cooling diuretics. Locally astringent lotions (lead acetate or zinc sulphate 1 dr. to 1 qt. water; mercuric chloride, 1 ∶ 5000; boric acid, 2 ∶ 100; pyoktannin, 1 ∶ 1000) in combination with cocaine hydrochlorate, homatropin, atropia sulphate, duboisia or hyoscyamin (1 ∶ 1000) would be appropriate. These may be applied over the eye on a soft cloth, and in cases of infective inflammation the more antiseptic agents may be injected under the lids. When the inflammation is very severe the atropia or other sedative agent may be made of the strength of 1 ∶ 100 and a drop or two placed inside the lids with a dropper every two or three hours.

A blister of biniodide of mercury may be applied to a space the size of a dollar above the anterior end of the zygomatic ridge, or in dogs back of the ear on the side of the neck: or a seton may be passed through the skin in the same situation.

When the eyeball is unduly tense, puncture through the margin of the cornea with a fine aseptic lancet will relieve the tension and in some cases induce a more healthy action. Assiduous antisepsis is needful until the wound has healed.

In other cases benefit can be obtained from the use of an ointment of yellow oxide of mercury 1 part, in vaseline 10 parts, or of iodoform of the same strength. A small portion the size of a grain of wheat is put under the lid, and the latter manipulated with the finger to bring it in contact with all parts of the surface. In case of a rheumatic origin salicin and salicylate of soda are demanded.

SIMPLE IRITIS.

Causes. Symptoms: redness of sclera, in dogs, cats, birds, pigs, with
a narrow zone of white next the cornea, red scleral vessels immovable,
iris dull gray or brown, uneven, sluggish in response to light,
synechia anterior or posterior, lens and capsule clouded or clear,
pupillary margin uneven, myosis or midriasis, black cataract.
Treatment: rest, dark stall or covering, head elevated, midriatics,
cocaine, antiseptic puncture, purgation, leeches, seton, cooling
astringent lotions, diuretics, for tension in convalescence
iridectomy. In traumatic cases careful antisepsis.

This may come from any one or more of the _causes_ of internal ophthalmia above named. The inflammation, however, concentrates itself on the iris so as to overshadow the disease in the adjacent organs.

The more distinctive _symptoms_ are the redness of the sclerotic in unpigmented organs (swine, birds, dogs, cats), the redness increasing as it approaches the margin of the cornea but leaving a narrow white zone surrounding the edge. The red vessels on the sclerotic are not moved with the conjunctiva when the lid is moved over the front of the eye. The front of the iris is dull, grayish or brownish, it is thickened unevenly and very sluggish in response to light and darkness. Not infrequently it is adherent to the back of the cornea (synechia anterior) or to the front of the lenticular capsule (synechia posterior). The lens and its capsule may or may not be clouded, but if the interior of the vitreous can be seen it is found to be clear. The pupil is more or less uneven in outline and sometimes it is torn at its inner edge so as to form shreds and projecting tongues. Myosis (contraction of the pupil) or midriasis (dilatation) may be present. If the latter has been preceded by adhesion a portion of the uvea may remain attached to the lenticular capsule constituting =black cataract=. The lens or its capsule may become opaque, and a fibrinous membrane may form over the pupil.

_Treatment._ Rest for body and eye are essential. A dark stall, or a thick covering for the eye is desirable. The head should be kept moderately elevated to facilitate the return of blood. The pupil should be kept widely dilated to prevent adhesions to the lens. Sulphate of atropia 5 grs. to the oz. of water should be applied a few drops at a time, thrice a day, or as often as may be necessary to secure dilatation. In case the atropia fails to secure dilatation a 5 per cent. solution of cocaine should be dropped into the eye every three or four minutes for four or five times and then another application of atropia may be tried warm. Should it still fail and should there be indications of extra congestion and swelling of the iris or of excessive tension of the eyeball, relief may be obtained by puncturing the cornea. With the reduction of the tension the iris will often respond to the midriatic. Benefit may also be obtained from an active purgative, or the application of leeches in the vicinity of the eye.

Cooling astringent applications may be kept up over the eye, or warm antiseptic applications will often give great relief.

In obstinate cases the yellow oxide of mercury ointment may be applied as advised for _internal ophthalmia_.

Cooling diuretics may also be of essential advantage.

If, after a fair recovery the bulb remains unduly tense, iridectomy may be resorted to as a prophylactic measure for the future. An incision is made with a lancet close in front of the margin of the cornea, and the iris seized and withdrawn with a pair of fine forceps, and a portion snipped off with fine scissors. The eye and instruments must be rendered absolutely aseptic by carbolic acid and boiling water, and the antisepsis of the eye must be carefully maintained until the wound is healed. This tends to relieve congestion in the iris and to moderate the secretion in the anterior chamber, so that the former extreme tension does not recur. In making choice of the seat of the iridectomy a selection may be made which will do away with adhesions, or one that will expose a portion of the lens which is still transparent, and which may restore vision when obscured by a cataract.

In traumatic cases there should be extra care in maintaining a thorough antisepsis of the eye as the great danger is that of infective panophthalmitis. The injection of antiseptic liquids under the eyelids, and the covering of the eye with antiseptic cotton wool or with a soft rag wet with an antiseptic lotion are important factors in treatment.

SYMPTOMATIC OR METASTATIC IRITIS.

Complications of infectious diseases, influenza, contagious pneumonia,
strangles, tuberculosis, omphalitis. Symptoms: exudation of fibrine
and blood, with those of simple iritis. Treatment: as in iritis, plus
measures for the specific primary disease. When second eye is
threatened enucleation.