Chapter XXVIII: Part 28

_Complication of the intestines._--When any cause acts as an irritant to the intestinal tract during the course of this specific fever it may produce inflammation of the organs belonging to it. This cause may be constipation, which can find relief only in a congestion which offers to increase the function of the glands and relieve the inertia caused by a temporary cessation of activity; or irritant medicines, especially any increased use of antimony, turpentine, or the more active remedies; the taking of indigestible feed, or of feed in too great quantities, or that has been altered in any way by fungus or other injurious alterations; the swallowing of too cold water; or any other irritant may cause congestion. This complication is ushered in by colics. The animal paws with the fore feet and evinces a great sensibility of the belly; it looks with the head from side to side, and may lie down and get up, not with violence, but with care for itself, perfectly protecting the surface of the belly from any violence. At first we find a decided constipation; the droppings if passed are small and hard, coated with a viscous varnish or even with false membranes. In from 36 to 40 hours the constipation is followed by diarrhea. The alimentary discharge becomes mixed with a sero-mucous exudation, which is followed by a certain amount of suppurative matter. The animal becomes rapidly exhausted and unstable, staggers on movement, losing the little appetite which may have remained, and has exacerbations of fever. The pulse becomes softer and weaker, the respiration becomes gradually more rapid, the temperature is about 1 deg. to 1.5 deg. F. higher. If a fatal result is not produced by the extensive diarrhea the discharge is arrested in from 5 to 10 days and a rapid recovery takes place.

_Complication of the lungs._--If at any time during the course of the fever the animal is exposed to cold or drafts of air, or in any other way to the causes of repercussion, the lungs may become affected. In the majority of cases, however, after three, four, or five days of the fever, congestion of the lungs commences without any exposure or apparent exciting cause. Unless this congestion of the lungs is soon relieved it is followed by an inflammation constituting pneumonia. This pneumonia, while it is in its essence the same, differs from an ordinary pneumonia at the commencement by an insidious course. The animal commences to breathe heavily, which is distinctly visible in the heaving of the flanks, the dilatation of the nostrils, and frequently in the swaying movement of the unsteady body. The respirations increase in number, what little appetite remained is lost, the temperature increases from 1 deg. to 2 deg., the pulse becomes more rapid, and at times, for a short period, more tense and full, but the previous poisoning of the specific disease has so weakened the tissues that it never becomes the characteristic full, tense pulse of a simple pneumonia.

On percussion of the chest dullness is found over the inflamed areas; on auscultation at the base of the neck over the trachea a tubular murmur is heard. The crepitant rales and tubular murmurs of pneumonia are heard on the sides of the chest if the pneumonia is peripheral, but in pneumonia complicating influenza the inflamed portions are frequently disseminated in islands of variable size and are sometimes deep-seated, in which case the characteristic auscultory symptoms are sometimes wanting. From this time on the symptoms of the animal are those of an ordinary grave pneumonia, rendered more severe by occurring in a debilitated animal. The cough is at first hacky and aborted; later, more full and moist. There is discharge from the nostrils, which may be mucopurulent, purulent, or hemorrhagic. As in simple pneumonia, in the outset this discharge may be "rusty," owing to capillary hemorrhages. We find that the blood is thoroughly mixed with the matter, staining it evenly, instead of being mixed with it in the form of clots. At the commencement of the complication the animal may be subject to chills, which may again occur in the course of the disease, in which case, if severe, an unfavorable termination by gangrene may be looked for. If gangrene occurs it is shown by preliminary chills, a rapid elevation of temperature, a tumultuous heart, a flaky discharge from the nostrils, and a fetid breath; the symptoms are identical with those which occur in gangrene complicating other diseases.

_Complication of the brain._--At any time during the course of the disease congestion of the brain may occur; at an early period if the fever has been intense from the outset, but in ordinary cases more frequently after three or four days. The animal, which has been stupid and immobile, becomes suddenly restless, walks forward in the stall until it fastens its head in the corner. If in a box stall and it becomes displaced from its position, it follows the wall with the nose and eyes, rubbing it along until it reaches the corner and again fastens itself. It may become more violent and rear and plunge. If disturbed by the entrance of the attendant or any loud noise or bright light, it will stamp with its fore feet and strike with its hind feet, but is not definite in fixing the object which it is resisting, which is a diagnostic point between meningitis and rabies and which renders the animal with the former disease less dangerous to handle. If fastened by a rope to a stake or post, the animal will wander in a circle at the end of the rope. It wanders almost invariably in one direction. The pupils may be dilated or contracted, or we may find one condition in one eye and the opposite in the other.

The period of excitement is followed by one of profound coma, in which the animal is immobile, the head hanging and placed against the corner of the stall, the body limp, and the motion, if demanded of the animal, unsteady. Little or no attention is paid to the surrounding noises, the crack of a whip, or even a blow on the surface of the body. The respiration becomes slower, the pulsations are diminished, the coma lasts for variable time, to be followed by excesses of violence, after which the two alternate, but if severe the period of coma becomes longer and longer until the animal dies of spasms of the lungs or of heart failure. It may die from injuries which occur in the ungovernable attacks of violence.

_Complication of the feet._--The feet are the organs which are next in frequency predisposed to congestion. This congestion takes place in the laminae (podophyllous structures) of the feet. The stupefied animal is roused from its condition by excessive pain in the feet and assumes the position of a foundered horse; that is, if the fore feet alone are affected, they are carried forward until they rest on the heels; and if the hind feet are affected, all the feet are carried forward, resting on their heels, the hind ones as near the center of gravity as possible. In some cases the stupor of the animal is so great that the pain is not felt, and little or no change of the position of the animal is noticeable. The foot is found hot to the touch, and after a given time the depressed convex sole of typical founder is recognized.

_Pleurisy._--This is a rare complication, but when it does occur it is ushered in by the usual symptoms of depression, rapid pulse, small respiration, elevation of the temperature, subcutaneous edema of the legs and under surface of the belly, and we find a line of dullness on either side of the chest and an abscess of respiratory murmur at the lower part. If it is severe, there may be an effusion filling one-fourth to one-third of the thoracic cavity in from 36 to 48 hours.

_Pericarditis_ is an occasional complication of influenza. It is ushered in by chills, elevation of the temperature; the pulse becomes rapid, thready, and imperceptible. The heart murmurs become indistinct or can not be heard. A venous pulse is seen on the line of the jugular veins along the neck. Respiration becomes more difficult and rapid. If the animal is moved the symptoms become more marked or it may drop suddenly dead from heart failure.

_Peritonitis_, or inflammation of the membranes lining the belly and covering the organs contained in it, sometimes takes place. The general symptoms are similar to those of a commencing pericarditis. The local symptoms are those of pain, especially to pressure on side of the flanks and belly, distention of the latter, and sometimes the formation of flatus, or gas, and constipation.

Other occasional complications are nephritis, hepatitis, inflammation of the flexor tendons and rupture of them, and abscesses.

_Diagnosis._--The diagnosis of influenza is based upon continued fever, with great depression and symptoms of stupor and coma; the rapidly developing, dark-saffron, ocher, yellowish discoloration of the mucous membranes, swelling of the legs and soft tissues of the genitals. When these symptoms have become manifested the diagnosis of a local complication is based upon the same symptoms that are produced in the local diseases from other causes, but in influenza the local symptoms are frequently masked or even entirely hidden by the intense stupor of the animal, which renders it insensible to pain. The evidence of colic and congestion, which is followed by diarrhea, indicates enteritis. The rapid breathing or difficulty of respiration points to a complication of the lungs, but, as we have seen in the study of the symptoms, the local evidences of lung lesions are frequently hidden. Again, we have seen that inflammation of the feet, or founder, complicating influenza is frequently not shown on account of the insensibility to pain on the part of the animal, which indicates the importance of running the hand daily over the hoofs to detect any sudden elevation of temperature on their surface.

The diagnosis of brain trouble is based upon the excessive violence which occurs in the course of the disease, for during the intervening period or coma there is no means of determining that it is due to this complication. Severe cases of influenza may simulate anthrax in the horse. In both we have stupor, the intense coloration of the mucous membranes of the eyes, and a certain amount of swelling of the legs and under surface of the belly. The diagnosis here can be made only by microscopic examination of the blood. In strangles, equine variola, and scalma we have an intensely red, rosy coloration of the mucous membranes, full, tense pulse, and although in these diseases we may have depression, we do not have the stupor and coma except in severe cases which have lasted for several days. In influenza we have no evidence of the formation of pus on the mucous membranes as in the other diseases, except sometimes in the conjunctivae.

In severe pneumonia (lung fever) we may find profound coma, dark-yellowish coloration of the mucous membranes, and swelling of the under surface of the belly and legs; but in pneumonia we have the history of the difficulty of breathing and an acute fever of a sthenic type from the outset, and the other symptoms do not occur for several days, while in influenza we have the history of characteristic symptoms for several days before the rapid breathing and difficulty of respiration indicate the appearance of the complication. Without the history it is frequently difficult to diagnose a case of influenza of several days' standing, complicated by pneumonia, from a case of severe pneumonia of five or six days' standing, but from a prognostic point of view it is immaterial, as the treatment of both are identical. The fact that other horses in the same stable or neighborhood have influenza may aid in the diagnosis.

_Prognosis._--Influenza is a serious disease chiefly on account of its numerous complications. Uncomplicated influenza is a comparatively simple malady, and is fatal in but 1 to 5 per cent of all cases. In some outbreaks, however, complications of one kind or another preponderate; in such instances the rate of mortality is much increased.

_Alterations._--The chief alteration of influenza occurs in the digestive tract, and consists in hyperemia, infiltration, and swelling of the mucous membrane, and especially of the Peyer's patches near the ileocecal valve. The tissues throughout the body are found stained, and of a more or less yellowish hue. There is always found a congested condition of all the organs, muscles, and interstitial tissues of the body. The coverings of the brain and spinal cord partake in the congested and discolored condition of the rest of the tissues.

Other alterations are dependent entirely upon the complications. If the lungs have been affected, we find effusions identical in their intimate nature with those of simple pneumonia, but they differ somewhat in their general appearance in not being so circumscribed in their area of invasion. The alterations of meningitis and laminitis are identical with those of sporadic cases of founder and inflammation of the brain.

_Treatment._--While the appetite remains the patient should have a moderate quantity of sound hay, good oats, and bran; or even a little fresh clover, if obtainable, can be given in small quantities. It is not so important that a special diet shall be observed as that the horse shall eat a moderate quantity of nourishing feed, and he may be tempted with any feed of good quality that he relishes. He should be placed in a well-ventilated box stall away from other horses. Grass, roots, apples, and milk may be offered and, if relished, allowed freely. To reduce the temperature the safest simple plan is to inject large quantities of cold water into the rectum. Antipyrene may be used with alcohol or strychnia. Derivatives in the form of essential oils and mustard poultices, baths of alcohol, turpentine, and hot water, after which the animal must be immediately dried and blanketed, serve to waken the animal from the stupor and relieve the congestion of the internal organs. This treatment is especially indicated when complication by congestion of the lungs, intestines, or of the brain is threatened. Quinin and salicylic acid in 1-dram doses will lower the temperature, but too continuous use of the former in some cases increases the depression. Iodid of potash reduces the excessive nutrition of the congested organs and thereby reduces the temperature; again, this drug in moderate quantities is a stimulant to the digestive tract and acts as a diuretic, causing the elimination of waste matter by the kidneys. Small doses of Glauber's salt and bicarbonate of soda, used from the outset, stimulate the digestive tract and prevent constipation and its evil results.

In cases of severe depression and weakness of the heart digitalis can be used with advantage. At the end of the fever, and when convalescence is established, alcohol in one-half pint doses and good ale in 1-pint doses may be given as stimulants. To these may be added 1-dram doses of turpentine.

In complications of the intestines camphor and asafetida are most frequently used to relieve the pain causing the colics; diarrhea is also relieved by the use of bicarbonate of soda, nitrate of potash, and drinks made from boiled rice or starch, to which may be added small doses of laudanum.

In complication of the lungs iodid of potash and digitalis are most frequently indicated, in addition to the remedies used for the disease itself.

Founder occurring as a complication of influenza is difficult to treat. It is, unfortunately, frequently not recognized until inflammatory changes have gone on for several days. If recognized at once, local bleeding and the use of hot or cold water, as the condition of the animal may permit, are most useful, but in the majority of cases the stupefied animal is unable to be moved satisfactorily or to have one foot lifted for local treatment; the only treatment consists in local bleeding above the coronary bands and the application of poultices.

During convalescence small doses of alkalines may be kept up for a short time, but the greatest care must be used, while furnishing the animal with plenty of nutritious, easily digestible feed, not to over-load the intestinal tract, causing constipation and consequent diarrhea. Special care must be taken for several weeks not to expose the animal to cold.

_Prevention._--In order to prevent the introduction of the disease it is advisable to isolate newly purchased animals for at least a week. Further, the stabling of healthy horses in sales and feed stables should also be guarded against. At the beginning of an outbreak the disease may be checked by immediate isolation of the affected horses, by taking the temperatures of the healthy animals, and by the segregation of those showing a marked elevation.

Bacterial vaccines are now being prepared for the prevention of this disease and also for its cure, but to date the results are not convincing as to the beneficial action of these products. Since the cause of the disease has not yet been satisfactorily determined it is difficult to conceive how immunity could be produced with the aid of the germs which enter into the preparation of these products. The reports would indicate, however, that vaccines exert a favorable influence upon the course of the disease, probably preventing severe complications which under ordinary conditions are the principal factors in determining the severity of the outbreak.

CONTAGIOUS PNEUMONIA.

_Synonyms._--Edematous pneumonia; stable pneumonia; equine
pleuropneumonia; influenza pectoralis equorum; pleuropneumonia;
influenzal pneumonia; Brustseuche (German).

Contagious pleuropneumonia is an acute contagious disease of horses manifesting itself either as a croupous pneumonia or a pleuropneumonia with complications in the form of serous infiltrations of the subcutaneous tissues and tendons.

_Etiology._--Investigators of this disease incriminated various kinds of microorganisms as the cause of this affection. Transmission experiments were usually negative with these organisms. This was also the case in attempts to transmit the disease by feeding with affected parts of the lungs, intestinal contents, and nasal discharge; likewise by intravenous or subcutaneous injections of blood and of emulsions made from nasal discharge, urine, the lung, and other organs.

The most recent experimental results of Gaffky and Lueber proved that at least at the beginning of the disease the bronchial secretion contains the infection. Upon killing horses affected with the typical forms of the disease on the third or fourth day of the affection the air passages are usually found to be filled with a yellowish, tenacious, germ-free secretion with which they succeeded in infecting healthy colts. The virus has not been isolated. The possibility of its being a protozoan is suggested by the above-named investigators through their observations of round or rod-shaped bodies in the round cells of the secretions.

Two organisms were formerly especially considered to play an important part in the cause of the disease, the _Streptococcus pyogenes equi_, which has been isolated from most cases of the disease, and the _Bacillus equisepticus_, which by some investigators was considered to be the cause of contagious pleuropneumonia. Although there is no doubt as to the presence of these microorganisms in most of the cases, their association with the cause of this disease, however, is now doubted, especially since attempts to transmit the disease with pure cultures of these germs failed to reproduce the typical form of the disease. They, however, are of great significance in connection with the pathological changes occurring in connection with the infection and probably are the determining factor in the course of the disease. They exert their action after the animal has already been attacked by the true virus, and then produce the inflammatory changes attributed to these secondary invaders.

This disease is the adynamic pneumonia of the older veterinarians, who did not recognize any essential difference in its nature from an ordinary inflammation of the lungs, except in the profound sedation of the force of the animal affected with it, which is a prominent symptom from the outset of the disease. Again, this same prostration of the vital force of the animal, combined with the staggering movement and want of coordination of the muscles, caused it for a long time to be confounded with influenza, with which at certain periods it certainly has a strong analogy of symptoms, but from which, as from sporadic pneumonia, it can be separated very readily if the case can be followed throughout its whole course.

Infectious pneumonia is a specific inflammation of the lungs, accompanied with interstitial edema and inflammation of the tissues of these organs and a constitutional disturbance and fever. It causes a profound sedation of the nervous system, which may be so great as to cause death. It is sometimes attended with pleurisy, inflammation of the heart or septic complications, which also prove fatal.

Old, cold, damp, foul, unclean, and badly drained and ventilated stables allow rapid dissemination of the disease to other horses in the same stable and act as rich reservoirs for preserving the contagion, which may be retained for over a year.

The virus is but moderately volatile, and in a stable seems rather to follow the lines of the walls and irregular courses than the direct currents of air and the tracts of ventilation. Prof. Dieckerhoff found that the contagion of influenza was readily diffusible throughout an entire stable and through any opening to other buildings, but he also found that the contagion of infectious pneumonia is not transmissible at any great distance, nor is it very diffusible in the atmosphere. A brick wall 8 feet in height served, in one instance, to prevent the infection of other animals placed on the opposite side from a horse ill with the disease, while others placed on the same side and separated from the focus of contagion only by open bars in the stall were infected and developed the disease in its typical form.

_Symptoms._--The symptoms differ slightly from those of a frank, fibrinous pneumonia, but not so much by the introduction of new symptoms as by the want of or absence of the distinct evidences of local lesions which are found in the latter disease. All the pneumonias throughout the whole course of the trouble are less marked and less clearly defined.

The symptoms may develop slowly or rapidly. If slowly, there is fever and the animal gives a rare cough which resembles that of a heavy horse affected with a slight chronic bronchitis; it becomes somewhat dejected and dull, at times somnolent, and has a diminished appetite. This condition lasts for several days, or the disease may begin with high fever, and the symptoms described below are severe and develop in rapid sequence. The respiration increases to 24, 30, or 36 to the minute, and a small, running, soft pulse attains a rhythm of 50, 70, or even more beats in the sixty seconds. The heart, however, contrary to the debilitated condition of the pulse, is found beating violently and tumultuously, as it does in anthrax and septic intoxication. The mucous membranes of the eyes and mouth and of the genital organs are found somewhat edematous, and they rapidly assume a dirty, saffron color, at times approaching an ocher, but distinguishable from the similar coloration in influenza by the want of the luster belonging to the latter and by the muddy, dull tint, which is characteristic throughout the disease.

Suddenly, without the preliminary rales which precede grave lesions of the lungs in other diseases, the blowing murmur of pneumonia is heard over a variable area of the chest, usually, however, much more distinctly over the trachea at the base of the neck and directly behind the shoulder on each side of the chest. In some cases the evidence of lung lesion can be detected only over the trachea. The lesions of the lungs may be scattered throughout both lungs, involving numerous small areas, or they may be confined to and more or less fully occupy one or two lobes. Occasionally there is a general involvement of both lungs. The body temperature has now reached 104 deg. or 105 deg. F., or in extreme cases even a degree higher. The debility of the animal is great without the stupefaction or evidence of cerebral trouble, which is constant with such grave constitutional phenomena in influenza or severe pneumonia. The animal is subject to occasional chills, and staggers in its gait. The yellow coloration of the visible mucous membrane is rendered pale by infiltration of the liquid of the blood into the tissues; the pulse may become so soft as to be almost imperceptible, the heart movement and sounds being at the same time exaggerated. The animal loses flesh rapidly, and dropsies of the extremities, of the under surface of the belly, or of the internal organs may show themselves.

_Terminations._--These symptoms may gradually subside after five to eight days, with an improved appetite the inanition may cease and the animal commence to nourish its impoverished blood and tissues; the pulse becomes stronger and the heart more regular and less tumultuous; the mucous membranes assume a brighter and more distinct color; the difficulty of respiration is removed, and the animal may make a recovery. When death occurs it is usually directly due to heart failure; in some cases it is caused by asphyxia, owing to the great amount of exudation into the lung tissue, rendering its further function impossible.

_Complications._--The pulmonary complications of infectious pneumonia are secondary inflammatory or necrotic changes in the lungs themselves. Suppuration at times takes place in the bronchi and may extend to the lung tissue. In this case mucous rales develop which are most distinctly heard over the trachea and on the sides of the chest directly behind the shoulders. With the development of the mucous rales, to be heard on auscultation, we have a more purulent discharge from the nostrils, similar to that of a chronic or subacute bronchitis. If the inflammation has been of some standing, cavernous rales may be heard, indicating the destruction of a considerable portion of lung tissue and the formation of a cavity. The effects of this more acute inflammatory process are not appreciable in the general condition of the animal, except to weaken it still further and add to its debilitated and emaciated cachexia. Gangrene sometimes occurs. A sudden rise of the body temperature of 1 deg. or 2 deg., with a more enfeebled pulse and a still more tumultous heart, develop simultaneously with the appearance of a discharge from the nostrils. This discharge is gray in color, serous or watery in consistency, mixed with the detritus of broken-down lung tissue, and sometimes contains clots of blood, or in more serious cases may be marked by a quantity of fluid blood from a hemorrhage, which proves fatal. The discharge is fetid to the smell. The animal emaciates rapidly. On examination of the lungs mucous rales are heard in the larger bronchi, cavities may be found at any part of these organs, and points of lobular pneumonia may be detected.

A very serious complication is an inflammation of the heart muscle. This is shown by a very weak and rapid pulse, great prostration, some filling of the lungs. This complication nearly always terminates in death. Other complications which may be mentioned are inflammation of the kidneys, blood poisoning, congestion of the brain, and inflammation of the tendinous sheaths and the tendons of the legs.

_Diagnosis._--As fever is the first symptom of infectious pneumonia, it is useful during an outbreak of this disease to make daily temperature measurements of the exposed horses, so that the first indication of disease may be discovered and the horse removed from contact with those that are sound.

_Prognosis._--The mortality in this disease may be as high as 25 per cent, but it is usually not more than 10 per cent. If there is a special tendency to complications of some sort, the mortality is increased.

_Alterations._--At the time of death from infectious pneumonia we frequently find septic changes and the evidences of putrefaction. The solidification of the lung tissue is found irregular in shape and high around the root of the lungs and the large bronchi, and is generally covered by sound lung tissue. The anterior lobes of the lungs are usually entirely affected. The diseased portion appears of a gray-yellowish color, somewhat watery, and tears readily. Matter is found in the air tubes which form gutters through the jellylike mass of the diseased lung. Abscesses from the size of a nut to larger masses may be found throughout the lungs. The blood is dark in color, fluid, or only clotted into soft, jellylike masses. Masses of gangrenous or dead-black tissue may be present.

_Treatment._--Bleeding is not to be used, because it would only still further weaken an already enfeebled animal; antimony or the alterants would increase the depression of a too-depraved constitution. There is in this disease no acute congestion of a particular organ to draw off by depletive measures, nor any violent blood current to be retarded, for fear of hypernutrition of any special part.

Revulsives do good, as they excite the nervous system and awaken the torpor of the weakened blood vessels, which aid in the reestablishment of the functions. As in other diseases, mustard poultices may be applied over the belly and sides of the chest, but caution must be used in the employment of blisters, as ugly ulcers may result from their action on a tissue of weakened vitality. Setons are dangerous from the great tendency in this disease to septic complications. Repeated friction of the legs by hand-rubbing and warmth by bandaging and by rubbing the surface of the body with turpentine and alcohol, which is immediately to be dried by rough towels, will excite the circulation and stimulate the emunctories of the skin.

Stimulants are given internally from the outset of the disease. Turpentine in 1-dram doses regulates the heart and excites the kidneys to carry off waste matter, but if repeated too frequently may disturb the already delicate digestive system. Alcohol rectifies the latter danger, and is a useful stimulant to the heart and digestive system, if given with care in small doses. It is an antiputrid, and is especially indicated when septic complications and gangrene are present. The aromatics and bitter tonics are useful; gentian and tea in warm decoction form a useful menstruum for other remedies. Digitalis is a useful remedy. Strychnin and quinin may be given throughout almost the whole course of the disease. The various preparations of iron are astringents and excitants to the digestive system. Carbolic acid is an antiputrid which is of marked benefit in edematous pneumonia; it should be given in small doses diluted in alcohol.

Salicylic acid may be given in 1 or 2 dram doses every few hours. It is much used for troubles of the serous membranes, lowers the temperature, and is of value in this disease in preventing the exudation into the tissue of the lungs. The alkalines, as the sulphate and bicarbonate of soda, the nitrate of potash, and very small doses of the iodid of potash, should be employed to regulate the digestive tract, the kidneys, and the other excreting glands, and to stimulate absorption of the waste matter.

The biological products enumerated under the treatment of the catarrhal form of influenza are also recommended for this disease. The bacterial vaccines in particular are being employed to a great extent, but the results are not uniformly satisfactory, especially with regard to prevention. They might, however, exert a beneficial influence against an attack of the secondary invaders and complications. A serum is also being prepared especially for the treatment of this disease, and since this is obtained from animals which have been highly immunized against the various organisms found in association with influenza it no doubt is beneficial, especially when the life of the animal is threatened. Such serum, however, should be used in sufficiently large doses, as repeated experience has proved that small doses have no beneficial action on the disease.

More recently salvarsan is being highly recommended for the treatment of the pneumonic form of influenza, and by many investigators it is considered as a specific for this affection. A single injection of this preparation is supposed to result in a rapid clearing of the lungs and the recovery of the animal is hastened. The cost of this product, however, at the present time, is exorbitant, and it should be considered only in the treatment of very valuable animals.

The same procedure as given for influenza should be carried out in the prevention of this affection.

The diet demands the strictest attention from the outset. In many of the fevers the feed has to be diminished in quantity and regulated in the quality of its heat-producing components during the acute part of the disease, so as to lessen the material for combustion in the inflamed organs. In edematous pneumonia, on the contrary, all the feed that can possibly be digested and assimilated must be given. Choice must be made of the richest material which can be handled by the weakened stomach and intestines without fatiguing them. Good, sound hay should be chopped short and dampened or partly boiled; in the latter case the hay tea can be reserved to use as a drink. Oats may be preferred dry or in other cases are taken better scalded; in most cases, however, it is better to give slops of oatmeal, to which may be added a little bran, barley flour, or boiled milk and wheat flour. Pure cow's milk, not too rich in fatty matter, may be given alone or with beaten eggs; frequently the horse has to be coaxed with the milk diluted with several parts of water at first, but will soon learn to drink the pure milk. Apples and carrots cut up raw or boiled are useful, and fresh clover in small quantities will frequently stimulate the appetite. In other words, various feeds and combinations should be given to the horse. Throughout the course of the disease and during convalescence the greatest attention must be taken to cleaning the coat thoroughly so as to keep the glands of the skin in working order, and light, warm covering must be used to protect the animal from cold or drafts of air.

STRANGLES.

_Synonyms._--Distemper; colt-ill; catarrhal fever; one form of
shipping fever; febris pyogenica.

_Definition._--Strangles is an infectious disease of the horse, mule, and ass, seen most frequently in young animals, and usually leaving them immune from future trouble of the same kind.

It appears as a fever lasting for a few days, and is usually associated with an abscess formation of lymph glands, especially those under the jaw, which have a tendency to break on the outside. It usually leaves the animal after convalescence perfectly healthy and as good as it was before, but sometimes leaves it a roarer or is followed by the development of deep-seated abscesses which may prove fatal.

_Causes._--The cause of strangles is infection by direct contact with an animal suffering from the disease, or indirectly through contact with the discharges from an infected animal, or by means of the atmosphere in which an infected animal has been. There are many predisposing causes which render some animals much more subject to contract the disease than others. Early age, which has given it the popular name of colt-ill, offers many more subjects than the later periods of life do, for the animal can contract the disease but once, and the large majority of adult and old animals have derived an immunity from previous attacks. At 3, 4, or 5 years of age the colt, which has been at home, safe on a meadow or in a cozy barnyard, far from all intercourse with other animals or sources of contagion, is first put to work and driven to the market town or county fairs to be exposed to an atmosphere or to stables contaminated by other horses suffering from disease and serving as infecting agents. If it fails to contract it there, it is sold and shipped in foul, undisinfected railway cars to dealers' stables, equally unclean, where it meets many opportunities of infection. If it escapes so far, it reaches the time for heavier work and daily contact on the streets of towns or large cities, with numerous other horses and mules, some of which are sure to be the bearers of the germs of this or some other infectious disease, and at last it succumbs.

The period of the eruption of the last permanent teeth, or the end of the period of development from the colt to an adult horse, at which time the animals usually have a tendency to fatten and be excessively full-blooded, also seems to be a predisposing period for the contraction of this as well as of the other infectious diseases. Thoroughbred colts are very susceptible, and frequently contract strangles at a somewhat earlier age than those of more humble origin. Mules and asses are much less susceptible and are but rarely affected. Other animals are not subject to this disease, but there is a certain analogy between it and distemper in dogs. After exposure to infection there is a period of incubation of the disease, lasting from two to four days, during which the animal enjoys its ordinary health.

_Symptoms._--The horse at first is a little sluggish if used, or when placed in its stable is somewhat dejected, paying but moderate attention to the various disturbing surroundings. Its appetite is somewhat diminished in many cases, while in some cases the animal eats well throughout. Thirst is increased, but not a great deal of water is taken at one time. If a bucket of water is placed in the manger the patient will dip its nose into it and swallow a few mouthfuls, allowing some of it to drip back and then stop, to return to it in a short time. The coat becomes dry and the hairs stand on end. At times the horse will have chills of one or the other leg, the fore quarters, or hind quarters, or in severe cases of the whole body, with trembling of the muscles and dryness of the skin.

If the eyes and mouth are examined the membranes are found reddened to a bright rosy color. The pulse is quickened and the breathing may be slightly accelerated. At the end of two days a cough is heard and a discharge begins to come from the nostrils. This discharge is at first watery; it then becomes thicker, somewhat bluish in color, and sticky, and finally it assumes the yellowish color of matter and increases greatly in quantity.

At the outset the colt may sneeze occasionally and a cough is heard. The cough is at first repeated and harsh, but soon becomes softer and moist as the discharge increases. Again, the cough varies according to the source of the discharge, for in light cases this may be only a catarrh of the nasal canals, or it may be from the throat, the windpipe, or the air tubes of the lungs, or even from the lungs themselves. According to the organ affected the symptoms and character of cough are similar to those of a laryngitis, bronchitis, or lung fever caused by ordinary cold.

Shortly after the discharge is seen a swelling takes place under the jaw, or in the intermaxillary space. This is at first puffy, somewhat hot and tender, and finally becomes distinctly so, and an abscess is felt, or having broken itself the discharge is seen dripping from a small opening. When the discharge from the nostrils has fully developed the fever usually disappears and the animal regains its appetite, unless the swelling is sufficient to interfere with the function of the throat, causing pain on any attempt to swallow. At the end of four or six days the discharge lessens, the soreness around the throat diminishes, the horse regains its appetite, and in two weeks has regained its usual condition. Old and strong horses may have the disease in so light a form that the fever is not noticeable; they may continue to eat and perform their ordinary work as usual and no symptom may be seen beyond a slight discharge from the nose and a rare cough, which is not sufficient to worry any but the most particular owner. But, on the other hand, the disease may assume a malignant form or become complicated so as to become a most serious disease, and even prove fatal in many cases. Inflammation of the larynx and bronchi, if excessive, produce violent, harsh coughing, which may almost asphyxiate the animal. The large amount of discharge may be mixed with air by the difficult breathing, and the nostrils, the front of the animal, manger, and surrounding objects become covered with a white foam. The inflammation may be in the lung itself (lobular pneumonia) and cause the animal to breathe heavily, heave at the flanks, and show great distress. In this condition marked symptoms of fever are seen, the appetite is lost, the coat is dry, the horse stands back in its stall at the end of the halter strap with its neck extended and its legs propped apart to favor breathing. This condition may end by resolution, leaving the horse for some time with a severe cough, or the animal may die from choking up of the lungs (asphyxia).

The swelling under the jaw may be excessive, and if the abscess is not opened it burrows toward the throat or to the side and causes inflammation of the parotid glands and breaks in annoying fistulas at the sides of the throat and even up as high as the ears. Roaring may occur either during a moderately severe attack from inflammation of the throat (larynx), or at a later period as the result of continued lung trouble. Abscesses may develop in other parts of the body, in the poll, in the withers, or in the spaces of loose tissue under the arms, in the fold of the thigh, and, in entire horses, in the testicles.

During the course of the disease, or later, when the animal seems to be on the road to perfect recovery, abscesses may form in the internal organs and produce symptoms characteristic of disease of those parts.

Roaring, plunging, wandering in a circle, or standing with the head wedged in a corner of the stall indicate the collection of matter in the brain. Sudden and severe lung symptoms, without previous discharge, point to an abscess between the lungs, in the mediastinum; colic, which is often continuous for days, is the result of the formation of an abscess in some part of the abdominal cavity, usually in the mesentery.

_Pathology._--The lesions of strangles are found on the surface of the mucous membranes, essentially of the respiratory system, and in the loose connective tissue fibers of the internal organs and glands, and consist of acute inflammatory changes, tending to the formation of matter. The blood is unaltered, though it is rich in fibrin, and if the animal has died of asphyxia it is found dark colored and uncoagulated when the body is first opened. If the animal has died while suffering from high fever the ordinary alterations throughout the body, which are produced by any fever not attended by alteration of blood, are found.

_Prevention._--Healthy horses should be separated from the infected animals, and the stables in which the disease has occurred should be thoroughly disinfected. Since the disease frequently occurs annually on infected premises, systematic disinfection should be practiced after an outbreak. The stables, as well as all utensils which might have come in contact with the infection, should be thoroughly disinfected. By such practices recurrences of the disease may be prevented.

_Treatment._--Ordinary light cases require but little treatment beyond diet, warm washes, moistened hay, warm coverings, and protection from exposure to cold. The latter is urgently called for, as lung complications, severe bronchitis, and laryngitis are often the results of neglect of this precaution. If the fever is excessive, the horse may receive small quantities of Glauber's salt (handful three times a day) as a laxative, bicarbonate of soda or niter in one-dram doses every few hours, and small doses of antimony, iodid of potash, aconite, or quinin. Steaming the head with the vapor of warm water poured over a bucket of bran and hay, in which belladonna leaves or tar have been placed, will allay the inflammation of the mucous membranes and greatly ease the cough.

The swelling of the glands should be promptly treated by flaxseed poultices and bathing with warm water, and as soon as there is any evidence of the formation of matter it should be opened. Prompt action in this will often save serious complications. Blisters and irritating liniments should _not_ be applied to the throat. When lung complications show themselves the horse should have mustard applied to the belly and to the sides of the chest. When convalescence begins great care must be taken not to expose the animal to cold, which may bring on relapses, and while exercise is of great advantage it must not be turned into work until the animal has entirely regained its strength.

Bacterial vaccines are now being extensively used for the prevention and treatment of this disease. They are prepared from the specific germ of the disease and frequently exert a very beneficial influence. A serum is also being prepared from horses, which is injected with gradually increasing doses of this germ. This serum possesses considerable curative value and may prove especially valuable in cases in which the animals have failed to respond to other forms of treatment, or when valuable animals are affected with the disease.

PURPURA HEMORRHAGICA.

_Synonyms._--Anasarca; petechial fever; morbus maculosus.

_Definition._--This disease is a septic bacterial intoxication, acute and infectious in character, and is manifested by edematous swellings of the subcutaneous connective tissue, and hemorrhages on the mucous membrane and in the internal organs.

A previous attack of influenza is a common predisposing cause of this disease, which appears most frequently a few weeks after convalescence is established. It occurs more frequently in those animals which have made a rapid convalescence and are apparently perfectly well than it does in those which have made a slower recovery.

Anasarca commences by symptoms which are excessively variable. The local lesions may be confined to a small portion of the animal's body and the constitutional phenomena be nil. The appearance and gravity of the local lesions may be so unlike, from difference of location, that they seem to belong to a separate disease, and complications may completely mask the original trouble.

In the simplest form the first symptom noticed is a swelling, or several swellings, occurring on the surface of the body--on the forearm, the leg, the under surface of the belly, or the side of the head. The tumefaction is at first the size of a hen's egg; not hot, little sensitive, and distinctly circumscribed by a marked line from the surrounding healthy tissue. These tumors gradually extend until they coalesce, and in a few hours we have swelling of the legs, legs and belly, or the head, to an enormous size; they have always the characteristic constricted border, which looks as if it had been tied with a cord. In the nostrils are found small reddish spots, or petechiae, which gradually assume a brownish and frequently a black color. Examination of the mouth will frequently reveal similar lesions on the surface of the tongue, along the lingual gutter, and on the fraenum. If the external swelling has been on the head, the petechiae of the mucous membranes are liable to be more numerous and to coalesce into patches of larger size than when the dropsy is confined to the legs. The animal may be rendered stiff by the swelling of the legs, or be annoyed by an awkward swollen head, which at times may be so enormous as to resemble that of a hippopotamus rather than that of a horse. During this period the temperature remains normal; the pulse, if altered at all, is only a little weaker; the respiration is only hurried if the swelling of the head infringes on the caliber of the nostrils. The appetite remains normal. The animal is attentive to all that is going on, and, except for the swelling, apparently in perfect health.

In from two to four days, in severe cases, the tissues can no longer resist the pressure of the exuded fluid. Over the surface of the skin which covers the dropsy we find a slight serous sweating, which loosens the epidermis and dries so as to simulate the eruption of some cutaneous disease. If this is excessive we may see irritated spots which are suppurating. In the nasal fossae the hemorrhagic spots have acted as irritants, and, inviting an increased amount of blood to the Schneiderian membrane, produce a coryza or even a catarrh. We may now find some enlargement and peripheral edema of the lymphatic glands, which are fed from the affected part. The thermometer indicates a slight rise in the body temperature, while the pulse and respiration are somewhat accelerated. The appetite usually remains good. In the course of a few days the temperature may have reached 102 deg., 103 deg., or 104 deg. F.

Fever is established, not an essential or specific fever in any way, but a simple secondary fever produced by the dead material from the surface or superficial suppuration, and by the oxidization and absorption of the colloid mass contained in the tissues. The skin may suppurate or slough more or less over the areas of greatest tension or where it is irritated by blows or pressure. The great swelling about the head may by closure of the nostrils interfere seriously with breathing. Internal edema may occur in the throat, lungs, or intestines. Septicemia, or blood poisoning, may result from anasarca.

_Terminations._--The simple form of the disease most frequently terminates favorably on the eighth or tenth day by resolution or absorption of the effusion, with usually a profuse diuresis, and with or without diarrhea. The appetite remains good or is at times capricious.

Death may occur from mechanical asphyxia, produced by closure of the nostrils or closure of the glottis. Metastasis to the lungs is almost invariably fatal, causing death by asphyxia, Metastasis to the intestines may cause death from pain, enteritis, or hemorrhage.

Excessive suppuration, lymphangitis, and gangrene are causes of a fatal termination by exhaustion. Mortal exhaustion is again produced by inability to swallow in cases of excessive swelling of the head.

Peritonitis may arise secondary to the enteric edema, or by perforation of the stomach or intestines by a gangrenous spot. Septicemia terminates fatally with its usual train of symptoms.

_Alterations._--The essential alterations of anasarca are exceedingly simple; the capillaries are dilated, the lymphatic spaces between the fibers of the connective tissue are filled with serum, and the coagulable portion of the blood presents a yellowish or citrine mass, jellylike in consistency, which has stretched out the tissue like the meshes of a sponge. Where the effusion has occurred between the muscles, as in the head, these are found dissected and separated from each other like those of a hog's head by the masses of fat. The surface of the skin is desquamated and frequently denuded of the hair. Frequently there are traces of suppuration and of ulceration. The mucous membrane of the nose is found studded with small, hemorrhagic spots, sometimes red, more frequently brown or black, often coalesced with each other in irregular-sized patches and surrounded by a reddish zone, the product of irritation. If edema of the intestines has occurred, the membrane is found four or five times its normal thickness, reddish in color, with hemorrhages on the free surface. Edema of the lungs leaves these organs distended. The secondary alterations vary according to the complications. There are frequently the lesions of asphyxia; externally we find ulcers, abscesses, and gangrenous spots and the deep ulcers resulting from the latter. The lymphatic cords and glands are found with all the lesions of lymphangitis. Again are found the traces of excessive emaciation, or the lesions of septicemia. Except from the complications the blood is not altered in anasarca.

_Diagnosis._--The diagnosis of anasarca must principally be made from farcy or glanders. In anasarca the swelling is nonsensitive, while sensitive in the acute swelling of farcy. The nodes of farcy are distinct and hard and never circumscribed, as in the other disease. The eruption of glanders on the mucous membranes is nodular, hard, and pelletlike. The redness disappears on pressure. In case of excessive swelling of the head in anasarca, there may occur an extensive sero-fibrinous exudation from the mucous membranes of the nose, poured out as a semifluid mass or as a cast of the nasal fossae, never having the appearance or typical oily character which it has in glanders. The inflammation of the lymphatic cords and glands in anasarca does not produce the indurated character which is found in farcy.

_Prognosis._--While anasarca is not an excessively fatal disease, the prognosis must always be guarded. The majority of cases run a simple course and terminate favorably at the end of 8 or 10 days, or possibly, after one to two relapses, requiring several weeks for complete recovery. Effusion into the head renders the prognosis much more grave from the possible danger of mechanical asphyxia. Threatened mechanical asphyxia is especially dangerous on account of the risk of blood poisoning after an operation of tracheotomy. Edema of the viscera is a most serious complication. The prognosis is based on the complications, their extent, and their individual gravity, existing, as they do here, in an already debilitated subject.