Part 74

Definition. Causes: wet impermeable soil, clay, river bottoms, deep valleys, inundations, enclosing forests, damp air, lack of sunshine, rank fodders, wet seasons, damp, cold, basement stables, heating constipating fodder (corn, buckwheat, wheat), dentition, training, age of domestication, sale, etc., spring, shedding coat, heredity, debility, ill health, worms, debilitating infectious diseases, over work, insufficient, indigestible food, local irritants. Microbes. Rheumatism. Parasitism. Symptoms: fever variable, lack of vigor, sudden attack, irritation, photophobia, lachrymation, closed lids, contracted pupils, retracted eye, redness, swelling of lids, conjunctiva, haw, sclera, slight corneal opacity, with vascularity, aqueous turbid, flocculent, iris of dull color, sluggish, pupil contracted, hypopion, posterior chamber yellowish green, intraocular tension, crisis seventh to tenth day, convalescence fifteenth day. Recurrence. Obscurity of vision. Eye between attack: blue zone around cornea, eye seems smaller, retracted, prominent haw, angle in upper lid, dull iris, tint lighter, contracted pupil, cataract, alert ears. Lesions: exudates back of cornea, narrowed anterior chamber, sizy aqueous, thickened iris, adhesions of lens capsule, or iris, torn iris, lens opaque, fibroid, calcareous, atrophied, black cataract, vitreous opaque, yellow, black, shrunken, choroid uneven, discolored, detached, retina with exudate, detached, posterior chamber contracted. Prevention: drainage, mature horses for damp lands, liming soil, get fodder from dry locality, don’t breed in cloudy regions, good diet and regimen, avoid corn, wheat and buckwheat, Glauber salts, pure dry stable, exclude debilitating diseases and parasites, keep in hard muscular condition, change to dry locality, don’t breed from blind stock, legislation. Treatment: remove causes, cure rheumatism or other morbid factor, darkness, antiphlogistics, laxative, diuretic, local bleeding, cupping, blister, seton, locally atropine, cocaine, pyoktannin, sublimate, lead, puncture, tonics, treat corneal opacities. Jurisprudence: return a newly bought horse in 30 days, (France) or more: extend the time if suspected.

Definition. This is an inflammatory affection of the interior of the eye, intimately related to certain constitutions, soils, climates, and systems of management, showing a strong tendency to recur again and again, and usually ending in blindness from cataract or other destructive lesion.

Causes. A =wet, impermeable, swampy or undrained soil= is a potent cause of this disease. Heavy clays, which absorb and retain moisture, river bottoms and deltas which are frequently overflowed and constantly wet, hollow basins where no effective drainage has been secured, and the coasts of seas and lakes which scarcely rise above the level of the water and are submerged at intervals, are the especial homes of the affection. In time past the disease was very prevalent in the low districts of France (Reynal), Belgium, Alsace-Loraine (Zundel, Miltenberger,) Germany, Holland (Möller), the English fen country and above all the damp lands of Ireland. Lafosse mentions a whole family of horses in South Western France which were characterized by blindness. Reynal records the terrible devastation which it caused in former times in the government studs at Limousin and Pompadour. It also prevails on the low banks of the Guadalquivir near Seville (Hurtrel d’Arboval), around Ostend, Cassel and Frankfort (Hofgeismar). Wet soils surrounded by forests or hills, which hinder free circulation of air, are especially injurious (Reynal). At Schlestadt, Alsace, at the beginning of this century, Miltenberger found 75 per cent. of the horses of the environs affected, whereas after great drainage works and the removal of all stagnant water Zundel found in 1870 not more than 2 per cent. In many localities in England, Ireland, France, Belgium and Germany the disease has greatly diminished in connection with land drainage and improved methods of culture. Harmon tells how in different parts of Brittany, drainage supplemented by the free use of marl and lime on the soil has caused a striking decrease in the prevalence of the malady. In the department of Ain a ratio of 333 per 1000 was thus reduced to 100 per 1000 (Reynal). On the contrary in the absence of such drying of the soil the previous high ratio of attacks was maintained. This has been notorious in the damp lands of Northern France and Belgium (Picardy, Artois, Flanders, where it often reaches 40 to 70 per cent. Reynal): Alsace-Loraine, Holland, Hanover, Mecklenberg, North and East Prussia, Lithuania, the low parts of Austria and Hungary and the Danubian Principalities—Moldavia and Walachia.

Reynal further shows that dealers are in the habit of taking young horses, which have so far escaped, or which have suffered but one moderate attack, away from the low damp soils of the low Pyrenees or of the Jura Valley in France to the dry elevated lands of Dauphiny, Provence and Languedoc in France, or to the mountainous regions of Catalonia in Spain in the well justified confidence that few of them will suffer a second attack.

As a direct test the French Government sent ten yearling foals from the affected depot at Limousin to the healthy depot at Tarbes, retaining an equal number at home as test animals: it also sent ten yearlings from Tarbes to Limousin, retaining an equal number at Tarbes as test cases. Then the twenty yearlings at Limousin were divided, five of the home bred and five drawn from Tarbes having been sent into a very low wet country at Lariviere, and the rest were sent to a high dry location at Maraval. The result was that but one of the ten yearlings sent from Limousin to Tarbes contracted the disease, while on the damp land at Lariviere one Limousin-bred and four Tarbes-bred colts suffered; and finally on the dry soil at Maraval not a single colt, from either Limousin or Tarbes was attacked.

The other conditions that usually attach to a low, damp soil are important factors. =Damp air and a cloudy, rainy climate= are potent accessory causes. Hence the great prevalence of the disease formerly in Ireland, on the west coast and in the fen country in England, in Belgium, in the Low Pyrenees, in the valleys of the Loire, Jura, Meuse, Moselle, the Guadalquivir, etc., (Reynal). Such an atmosphere relaxes the system, induces a heavy lymphatic temperament, with coarse bones and muscles, an excess of connective tissue, thick hide and hair, and thick, shaggy and often gummy legs. All this implies a low tone of health which will less effectually withstand inimical influences.

The =rank, aqueous fodders= grown on such damp localities have a similar effect. These are more bulky and less nutritive and fail to maintain the highest tone and vigor. The animals must overload the stomach and intestines in order to obtain the requisite amount of nutriment, so that with a large, pendent belly they are still in poor condition. The case is even aggravated when they go on the succulent grasses of early spring, as they continue to gorge and may even make fat, but they lack in muscle and tone and in this condition even the rapid formation of blood seems to favor the attack. Möller records the great prevalence of the disease in Central Germany in 1884, in connection with excessive rainfall, inundations, and spoiled fodder.

Dard records that a low, overflowed meadow in the Soane bottom near Chalons, caused blindness in nearly all horses put upon it. Bouin quotes a case of a sewage irrigated meadow in Vendée which almost infallibly produced recurrent ophthalmia in the horses fed on its products. On the other hand, oats and hay from a dry, rich soil and well harvested, are the most trustworthy food when the disease is to be dreaded.

=Damp night air on wet, impermeable soils= is to be especially feared as not only relaxing the system and lowering its power of resistance, but also producing a chill and thereby increasing the susceptibility.

=Damp, cold basement stables= are concurrent causes acting like the wet soils, the damp air, and the attendant relaxing conditions. Thierry long ago noticed that improved stable hygiene around Strassburg led to a notable decrease of recurrent ophthalmia. In 1807 horses were blind to the extent of 16.5 per cent., in 1821 to 8.5 per cent., and in 1870 Zundel found but 1.79 per cent., and few of the latter from recurrent ophthalmia.

Again the ventilation, lighting and drying of close, low, dark damp stables where the disease had previously prevailed has often practically banished the affection. Hofgeismar states that during the prevalence of the disease in a detachment of the German army in Alsace, out of 84 attacks in 700 horses 52 appeared in February and March, the period of severe weather and close stabling.

=Fodders of a heating, or starchy nature=, like =Indian corn=, =buckwheat=, or =wheat= strongly predispose to the disease, probably by inducing costiveness, slight impactions and indigestions, and in bad, frequently recurring cases the writer rarely fails to find that the animal is being fed on corn. Beans, peas, vetches and other leguminous fodders are less injurious and when grown on high, dry soils and fed judiciously they are as a rule harmless. When grown rank, badly harvested, and used to excess they become distinctly hurtful. Any fodder which has been allowed to become musty is to be avoided, since any condition which lowers the general tone of health strongly predisposes to an attack. The same remark applies to irregularities and faults in feeding. The best food and the most abundant supply will fail under such circumstances to maintain the condition, and the horse that is losing condition is becoming increasingly susceptible to this malady.

The period of =dentition= and =training= is the most common occasion for the attack, partly because this is the time when the colt is taken from the pure air and exercise of the field, into the hot, close, impure atmosphere of the stable, partly because he is made to exchange the cooling succulent grass for the stimulating ration of hay and grain, partly because he is subjected to severe constraint and much excitement in the hands of the trainer, and partly because of the irritation of the gums, the jaws and the whole head in connection with the shedding and eruption of the teeth. When injudicious biting is resorted to, to give a special curve to the neck, the consequent obstruction of the jugulars and capillary congestion in the head is another potent cause. Heavy draught and overdriving have a similar effect. In 53 cases Schmidt found that 3 occurred under one year old, 5 in the 2d year, 10 in the 3d year, 16 in the 4th, 15 in the 5th, and 4 from the 5th to the 9th years.

=Influence of Season.= Mayer gives a statement of the percentages seen in the various months of the year as follows: January 4.9%, February 4.7%, March 10.1%, April 15.1%, May 13.4%, June 9.9%, July 11.9%, August 6.4%, September 4.9%, October 6.2%, November 6.7%, December 5.2%. The high rate in March, April and May may have a significance in connection with the debility connected with shedding the coat, and the resumption of more active work, when somewhat out of condition, it must also be noted that this is in Germany the season of the most active trade in horses and consequent change of ownership, stabling, feeding, work and management.

=Heredity= must be accepted as one of the most potent accessory causes. The lymphatic constitution is of course transmitted and with it the special susceptibility. This is notorious in the case of both parents, and is of course more potent if both sire and dam were predisposed, and have themselves suffered. In the latter case the heredity of the lymphatic temperament, and of the impaired organ of vision combine to render transmission more certain. A mare may have borne a number of sound foals before suffering from the malady and then have offspring that do contract the disease. So with the stallion. Möller quotes the case of the eastern horse Turk-Mayn-Atty which served for a length of time in Prussian Studs and left a great stock of blind progeny. Lafosse records the existence of a family of horses in Southern France all of which went blind. The same cause has greatly extended the disease among fast American horses in which the great strain of the track served to intensify the tendency. The writer has seen a colt which was born blind, by a blind dam and got by a sire with diseased eyes, but still held at $300 for service. Mangin, Marimpocy and Hamon record congenital cases from parents with affected eyes.

This hereditary susceptibility is so strong and pernicious that intelligent horsemen everywhere refuse to breed from either horse or mare that has once suffered from recurrent ophthalmia, and at the Government studs in France not only is every unsound stallion rejected but the service of the healthy stallion is refused to any mare which has suffered from disease of the eyes. A consideration for the future of our horses would demand that no stallion shall stand for the public service of mares unless he has been examined and licensed as a sound animal.

Yet, as already stated, heredity is not the one controlling factor, since the offspring of the victims of this disease will often escape when brought up in a high, dry locality.

Reynal records the appearance of the disease in =alternate generations=, the stallion offspring of blind parents remaining sound himself but producing foals which became victims of the disease in large numbers. A partial explanation may be found in the better conditions under which the stud horse was kept, while under less favorable surroundings his offspring developed the disease.

It must be added that every condition which induces =debility= or =ill health= is favorable to the development of the malady. The presence of =worms in the bowels= is a familiar example. Any debilitating disease like =strangles=, =influenza=, =contagious pneumonia=, =indigestion=, etc., and overwork or insufficient or indigestible food act in the same manner.

Again, =local irritants= may rouse the latent tendency. Street or stable dust, sand, hay seeds, chaff, blows on the eye with whip or other object, wounds, irritant gases, smoke, fierce light, cold draughts, storms, and whatever determines inflammation of the eye may be the occasion of an outbreak of recurrent ophthalmia.

=Microbiology.= It will be recognized that none of these causes fully account for the specific and recurrent nature of this affection, and it is felt that something more is wanted to furnish a full and satisfactory explanation of the malady. This explanation is sought in a direct infection, but in spite of extended investigations by many observers no specific microbe has been demonstrated as uniformly present in all cases.

Potapenke found in the blood of the affected horses a plasmodium like that of ague. This agrees with the damp regions in which the malady prevails and no less with its intermittent or periodic character.

Vigezzi found in the aqueous and tissues a micrococcus (ophthalmo-coccus) which, cultivated on gelatin agar and inoculated in the anterior chamber or under the conjunctiva, produced an affection which he recognized as recurrent ophthalmia.

Trinchera found in the aqueous of the affected animals a bacillus and cocci. Drawing this aqueous into a sterilized syringe and injecting it into the anterior chamber of sound horses produced in 12 to 48 hours characteristic periodic ophthalmia. This was repeated by Schütz and Schwartznecker.

Robert Koch found in the affected aqueous, cocci, singly or in chains and bacilli with rounded ends. Injection of the latter into a sound horse’s eye led to characteristic inflammation and loss of vision. In the cornea of the rabbit it had no effect.

Richter found in the eyes of a foal born with recurrent ophthalmia, of sound parents, diplococci and triplococci.

These observations do not demonstrate the constant presence of one definite microbe, nor that the disease is invariably due to any one particular organism, yet they may be held as strongly suggestive that any one of a variety of microörganisms may prove an exciting etiological factor in a susceptible system, or that, along with the organisms heretofore demonstrated, there exists an essential microbian cause which has up to the present eluded detection.

Other points which give circumstantial support to the microbian theory may be shortly stated: