The heart is enveloped by a fibrous sac (or bag), called the pericardium, which assumes much of the general shape of the outer surface of the heart.

The action of the heart is similar to that of a pump and its function is to keep the blood in circulation. The auricles may be considered as the reservoirs or receivers of the blood and the ventricles as the pump chambers. During the interval between contractions, the heart being in momentary repose, the blood pours into the auricles from the veins; the auriculo-ventricular orifices being widely open, the ventricles also receive blood; the auricles contract and the ventricles are filled; contraction of the ventricles follows; the auriculo-ventricular valves are forced up by the pressure of the blood and close the auriculo-ventricular openings and prevent the return of blood into the auricles; the contraction of the ventricles forces the blood from the right ventricle into the lungs through the pulmonary artery and its branches, and from the left ventricle into the aorta, thence through the arteries to all parts of the body. After the contraction of the ventricles the heart is again in momentary repose and is being filled with blood, while the valves in the aorta and pulmonary artery close to prevent the return of blood into the ventricles. (See Pl. VII.)

The average weight of the heart of an ox is said to be from 3-1/2 to 5 pounds; but, of course, owing to the many breeds and sizes of cattle, it must vary in different animals.

The vessels that convey the blood from the heart to all parts of the body are called arteries; those which return the blood to the heart are called veins. The arteries divide and subdivide (like the branches of a tree), become smaller and smaller, and ultimately ramify into every part of the body. Between the ultimate ramifications of the arteries and the beginning of the veins there is an intermediate system of very minute vessels called capillaries, which connect the arterial with the venous system of the circulation. The walls of the arteries are possessed of a certain amount of rigidity, sufficient to keep the tubes open when they are empty.

The blood leaves the left ventricle through a single vessel, the common aorta, consisting of the anterior and posterior aortas, which give off the large arteries.

The veins take the blood from the capillaries in all parts of the body. They begin in very small tubes, which unite to become larger in size and less in number as they approach the heart.

In its course an artery is usually accompanied with a vein and in many situations with a nerve. The more important arteries are placed deep within the body; when they are superficial, however, they are generally found where least exposed to injury, as, for example, on the inner side of the legs. Arteries are less numerous than veins, and their total capacity is much less than that of the veins. A great number of veins are in the tissue immediately beneath the skin and do not generally accompany arteries.

The blood, throughout its course in the heart, arteries, capillaries, and veins, is inclosed within these vessels. Except where the large lymphatics empty into the venous blood, there is no opening into the course of the blood.

All the arteries except the pulmonary and its branches carry bright-red blood, and all the veins, except the pulmonary veins, carry dark-red blood. The impure dark-red blood is collected from the capillary vessels and carried to the right auricle by the veins; it passes down into the right ventricle, and thence into the pulmonary artery and through its branches to the capillaries of the lungs, where the carbonic-acid gas and other impurities are given up to the air in the air cells of the lungs (through the thin walls between the capillaries and the air cells), and where it also absorbs from the air the oxygen gas necessary to sustain life. This gas changes it to the bright-red, pure blood. It passes from the capillaries to the branches of the pulmonary veins, which convey it to the left auricle of the heart; it then passes through the auriculo-ventricular opening into the left ventricle, the contraction of which forces it through the common aorta into the posterior and anterior aortas, and through all the arteries of the body into the capillaries, where it parts with its oxygen and nutritive elements and where it absorbs carbonic-acid gas and becomes dark colored. (See theoretical diagram of the circulation, Pl. VII.)

The branches of certain arteries in different parts unite again after subdividing. This reuniting is called anastomosing, and assures a quota of blood to a part if one of the anastomosing arteries should be tied in case of hemorrhage, or should be destroyed by accident or operation.

THE BLOOD.

The various kinds of food, after being digested in the alimentary canal, are absorbed and carried into the blood by the lymphatics, and by the blood to the places where nutrition is required. The blood takes from all parts of the body all that is no longer required, and carries it to the different organs through which it is eliminated from the body. It contains within itself all the elements which nourish the body.

The blood may be considered as a fluid holding in solution certain inorganic elements and having certain bodies suspended in it. To facilitate description, the blood may be considered as made up of the corpuscles and the liquor sanguinis. The corpuscles are of two kinds, the red and the white, the red being the more numerous. The color of the blood is caused by the coloring matter in the red corpuscles, which are the oxygen carriers. Both kinds are very minute bodies, which require the aid of the microscope to recognize them. The liquor sanguinis is composed of water containing in solution salts, albumen, and the elements of fibrin.

The lymphatics, or absorbents, are the vessels which carry the lymph and chyle in the blood. They begin as capillaries in all parts of the body, gradually uniting to form larger trunks. Placed along the course of the lymphatic vessels are glands, in some situations collected into groups; for example, in the groin. These glands are often involved in inflammation arising from the absorption of deleterious matter.

Absorption is the function of the lymphatics. The liquor sanguinis passes from the blood capillaries to supply nutrition to the tissues. All of the liquor sanguinis that is not required is absorbed by the lymphatic vessels and conveyed back to the blood by the lymphatic ducts. The lymphatics which proceed from the intestines convey the chyle into the blood during digestion. As a rule, the lymphatic vessels follow the course of the veins. All the absorbent vessels convey their contents to the thoracic duct and right great lymphatic vein, which empty into the anterior vena cava, where the lymph and chyle mix with the venous blood, and thus maintain the supply of nutritive elements in the blood.

THE PULSE.

As fully explained, the heart pumps the blood throughout the arterial system. The arteries are always full and each contraction of the ventricle pumps more blood into them; this distends their elastic walls and sends along them a wave which gradually becomes less perceptible as it nears the very small arteries. This wave constitutes the pulse, and is lost before the capillaries are reached. The sensation or impression given to the finger when placed upon the artery shows the force exerted by the heart and some important facts concerning the condition of the circulation. In adult cattle the average number of pulsations in a minute is from 50 to 60. The pulse is faster than normal after exercise, excitement, on hot days, from pain, and as a result of fullness of the stomach. In old animals it is slower than in the young and in males slightly slower than in females. In fevers and inflammations and in local diseases of the heart the pulse rate is increased. If the rate is greater than 100 or 110 to the minute the outlook for recovery is not good.

Other variations of the pulse are known as infrequent pulse, which means that the number of pulsations in a given time is less than normal. The irregular or the intermittent pulse is when the pulsations do not follow in regular order. The large pulse and the small pulse refer to the volume of the pulse, which may be larger or smaller than usual. The strong pulse and the feeble pulse refer to the strength or weakness of the pulsation. The pulse is said to be hard when the vessel feels hard and incompressible, the soft pulse being the opposite. By dicrotic pulse is meant that kind of pulsation which makes each beat seem double, and therefore it is generally called the double pulse.

The venous or "jugular pulse" is the pulsation so frequently observed in the jugular vein of cattle and is particularly noticeable while they are ruminating—"chewing the cud." It is not always associated with disease, but may be a symptom of some disease of the heart; in such cases the jugular pulse is continuous.

The place selected for feeling the pulse in cattle is where the submaxillary artery winds around the lower jawbones, just at the lower edge of the flat muscle on the side of the cheek; or, if the cow is lying down, the metacarpal artery on the back part of the fore fetlock is very convenient for the purpose.

THE EXAMINATION OF THE HEART.

Corresponding to the beats of the heart two sounds are emitted which are of a definite type in healthy animals. The first is produced by the contraction of the heart and the flow of blood out of it; the second is caused by the rebound of blood in the aorta and the closure of the valves that prevent it from flowing backward into the heart, whence it came. The first sound is the longer and louder of the two, though of low pitch. The second sound is sharper and shorter, and is not always easy to hear. There is a brief interval between them.

To distinguish these sounds, the ear is placed against the left side of the chest, a little above the point where the elbow rests when the animal is standing in a natural position, and about opposite the sixth rib. Both heart sounds are reduced in intensity when the animal is weak or when the heart is forced away from the chest wall by collections of fluid or by tubercular or other growths. Nonrhythmical heart sound is often caused by pericarditis or by disease of the valves. It may also be attributable to overfilling of the heart upon the right side, as occurs in severe congestion of the lungs and in some febrile diseases.

In pericarditis, sounds like scraping, rubbing, or splashing may be heard, entirely apart from the two normal sounds above described.

The impulse of the heart, as felt by placing the hand against the chest, is of some consequence in reaching a conclusion in respect to disease of the heart; but it must be remembered that the impulse may be very much increased by diseases other than those of the heart, as, for example, inflammation of various organs, severe pains, etc. The impulse may be increased also (when disease does not exist) by work, exercise, fright, or any cause of excitement, or, in general, by anything that causes acceleration of the pulse.

The impulse of the heart may be felt and the sounds may be heard fairly well in lean cattle, but in fat ones it is difficult and often impossible to detect either impulse or sound with any degree of satisfaction.

PALPITATION.

When the impulse of the heart is excessive—that is, when it beats more or less tumultuously—the familiar expression "palpitation of the heart" is applied; by many it is called "thumps." The hand or ear placed against the chest easily detects the unnatural beating. In some cases it is so violent that the motion may be seen at a distance. Palpitation is but a symptom, and in many instances not connected with disease of the structure of the heart or its membranes. A badly frightened animal may have palpitation. When it comes on suddenly and soon passes away, it depends on some cause other than diseases of the heart; when it is gradually manifested, however, and becomes constant, although more pronounced at one time than another, heart disease may be suspected, especially if other symptoms of heart disease are present.

INJURY TO THE HEART BY FOREIGN BODIES.

Cattle are addicted to the habit of chewing and swallowing many objects not intended as articles of food. Every veterinarian of experience has met with instances to remind him of this, and it is well known to butchers. Among the great variety of things that have thus found their way into the stomachs of cattle the following have been noticed: Finger rings, knitting needles, old shoes, table knives, wood, pieces of leather, pieces of wire, buttons, hairpins, brushes, nails, coins, etc. The more sharply pointed objects sometimes penetrate the wall of the stomach, in some cases causing gastric irritation enough to produce indigestion, gradually work their way through the diaphragm toward the heart, pierce the pericardium (bag inclosing the heart), wound the heart, and thus prove fatal to the animal. Cases are recorded in which the foreign body has actually worked its way into one of the cavities of the heart. Instances are known, however, in which the object took a different course, and finally worked its way toward the surface and was extracted from the wall of the chest. While it is possible that the foreign body may pierce the wall at different parts of the alimentary canal, as it frequently does that of the rumen (paunch), it is thought that in most cases it passes through the wall of the reticulum (smaller honeycombed compartment, or second stomach) and is drawn toward the heart by the suctionlike action of the chest. Post-mortem examinations have demonstrated the course it pursued, as adhesions and other results of the inflammation it caused were plainly to be seen. All manner of symptoms may precede those showing involvement of the heart, depending upon the location of the foreign body and the extent of inflammation caused by it. Severe indigestion may occur; stiffness and difficulty in moving about owing to the prods of the sharp body following muscular contraction; pain on pressure over the front, lower, or right side of the abdomen; coughing and difficult, quick breathing. In most cases the foreign body does not penetrate to the heart, nor even to the pericardium.

Symptoms.—The symptoms are as follows: The animal is disinclined to move actively, the step is restricted and cautious, sudden motion causes grunting, the attitude is constrained, the feet are drawn somewhat together, the back is arched, the face has an anxious expression. If the disease is of several days' standing, there is likely to be soft swelling (edema) beneath the neck, in the dewlap, and under the chest, between the fore legs. Breathing is short and difficult; it may clearly be painful. The pulse is rapid, 80 to 120 per minute. The muscles quiver as though the animal were cold. Rumination and appetite are depressed or checked. The dung is hard, and to void it appears to cause pain. These symptoms usually develop gradually, and, of course, they vary considerably in different animals, depending upon the size and location of the foreign body and the irritation it causes.

As a matter of course, in such cases treatment is useless, but when it is possible to diagnose correctly the animal could be turned over to the butcher before the flesh becomes unfit for use; that is, before there is more than a little suppuration and before there is fever. Knowing that cattle are prone to swallow such objects, ordinary care may be taken in keeping their surroundings as free of them as possible.

PERICARDITIS.

Inflammation of the pericardium (heart bag) is often associated with pneumonia and pleurisy, rheumatism, and other constitutional diseases, or with an injury. It also occurs as an independent affection, owing to causes similar to those of other chest affections, as exposure to cold or dampness and changes of the weather.

Symptoms.—It may be ushered in with a chill, followed by fever, of more or less severity; the animal stands still and dull, with head hanging low, and anxiety expressed in its countenance. The pulse may be large, perhaps hard; there is also a venous pulse. The hand against the chest will feel the beating of the heart, which is often irregular, sometimes violent, and in other instances weak, depending in part upon the quantity of fluid that has transuded into the pericardial sac. The legs are cold, the breathing quickened and usually abdominal; if the left side of the chest is pressed on or struck, the animal evinces pain. There may be spasms of the muscles in the region of the breast, neck, or hind legs. After a variable time swelling may also appear in the legs and under the chest and brisket.

In those animals in which the heart sounds may be heard somewhat distinctly, the ear applied against the chest will detect a to-and-fro friction sound, corresponding to the beats of the heart. This sound is produced by the rubbing of the internal surface of the heart bag against the external surface of the heart. During the first stages of the inflammation these surfaces are dry, and the rubbing of one against the other during the contraction and relaxation of the heart produces this sound. The dry stage is followed by the exudation of fluid into the heart sac, and the friction is not heard until the fluid is absorbed sufficiently to allow the surfaces to come in contact again. But during the time the friction sound is lost a sound which has been called a "churning noise" may take its place.

The friction sound of pericarditis can not be mistaken for the friction sound of pleurisy if the examination is a careful one, because in the heart affection the sound is made in connection with the heart beats, while in the pleuritic affection the sound is synchronous with each respiration or breath of air taken in and expelled from the lungs.

Treatment.—When pericarditis is complicated with rheumatism or other diseases the latter must be treated as directed in the description of them. The animal must be kept in a quiet, comfortable place, where it will be free from excitement. Warm clothing should be applied to the body, and the legs should be hand-rubbed until the circulation in them is reestablished, and then they should be snugly bandaged. The food should be nutritive and in moderate quantity. Bleeding should not be performed unless the case is in the hands of an expert.

At the beginning give as a purgative Epsom salt—1 pound to an average-sized cow—dissolved in about a quart of warm water and administered as a drench. When there is much pain 2 ounces of laudanum, diluted with a pint of water, may be given every three hours until the animal is better. Do not give the laudanum unless demanded by the severity of the pain, as it tends to constipate. Give one-half ounce of nitrate of potassium (saltpeter), dissolved in drinking water, four or five times a day. After the attack has abated mustard mixed with water may be rubbed well over the left side of the chest to stimulate the absorption of the fluid within the pericardium. The other medicines may be discontinued and the following administered: Sulphate of iron, 2 ounces; powdered gentian, 6 ounces; mix and make 8 powders. Give one powder every day at noon, mixed with feed, if the animal will eat it, or shaken up with water in a bottle as a drench. Also the following: Iodid of potassium, 2 ounces; nitrate of potassium, 8 ounces; mix and make 16 powders. Give one in drinking water or in drench every morning and evening. The last two prescriptions may be continued for several weeks if necessary.

In extreme cases tapping the pericardium with a trocar and cannula to draw off the fluid is resorted to, but the operation requires exact anatomical knowledge.

After death from pericarditis there is always more or less fluid found in the pericardium; the surfaces are rough and covered with a yellow-colored exudate. There are also in many cases adhesions to a greater or less extent between the heart and pericardium.

MYOCARDITIS.

Inflammation of the muscular structure of the heart occurs in limited, circumscribed areas, as evidenced by post-mortem examination, and it is probably always somewhat involved in connection with pericarditis and endocarditis. It may readily be inferred that if the whole organ were inflamed death would ensue immediately. Usually myocarditis results from the preexistence of blood poisoning or of some infectious febrile disease.

Symptoms.—The chief symptoms are those of heart weakness. The heart beat is fast, weak, and often irregular. Respiration is difficult and rapid. There is great general weakness and depression. Death comes suddenly.

Treatment.—Treatment consists in supporting the animal by the use of stimulants, such as ammonia, coffee, digitalis, camphor, etc. Complete quiet must be provided, and the general care should be as in pericarditis.

ENDOCARDITIS.

When the membrane which lines the cavities of the heart—the endocardium— suffers inflammation, the disease is called endocarditis. The cause is another disease, during which substances that irritate the lining of the heart are produced and admitted into the circulation. These substances are usually living organisms, or it is possible that in some cases they are chemical irritants. Endocarditis occurs as a complication of or sequel to pneumonia, blood poisoning, inflammation of the womb, rheumatism, or severe wounds or abscesses. The symptoms are much the same as those of pericarditis, and it is difficult to discriminate between the two affections. There is a jugular pulse, the legs may become dropsical, and there is a tendency to faint if the head is elevated suddenly. The bellowslike sound is more distinct than it is in pericarditis. It is the most fatal of heart diseases, because of the liability of the formation of clots, which may adhere to the valves, change in the structure of the valves, and often a complication with an abnormal condition of the blood. Clots may be formed in the heart, and, being carried to other parts, prove fatal by interrupting the circulation in some vital organ.

Treatment similar to that advised for myocarditis may be followed in this disease.

VALVES OF THE HEART.

The valves are subject to abnormal growths and structural changes in chronic endocarditis or as a result of acute endocarditis. Sometimes valves are torn by sudden, extreme muscular effort or a congenital abnormality. Cases are also reported in which they have been found ruptured.

Symptoms.—The general symptoms are those of heart weakness, accompanied with edema and congestion of the lungs.

Treatment.—Relief is sometimes afforded, but usually only temporarily, by the use of stimulants, especially digitalis.

RUPTURE OF THE HEART.

Sudden effort, blows, or disease may lead to rupture of the heart of the ox. The first cause does not operate so often in cattle as in horses. Tuberculosis or ulceration from other causes, such as a foreign body, is the most common source of this accident. Rupture is shown by sudden fainting, followed very shortly by death.

HYPERTROPHY AND DILATATION OF THE HEART.

This is an enlargement of the heart, and may consist of the thickening of the walls alone, or at the same time the cavities may be either enlarged or diminished. Dilatation of the cavities has been noticed as existing independently of thickened walls. In hypertrophy the sounds of the heart are loud and pronounced, may be heard on both sides of the chest distinctly, and palpitation occurs to a greater or less extent. Fortunately both conditions are very rare in cattle.

ATROPHY.

Atrophy is the technical term for wasting of the muscular tissue. Atrophy of the heart is very rare among cattle, and is usually a result of other diseases.

FATTY DEGENERATION OF THE HEART.

This condition of the heart is met with in some very fat cattle, but it must be understood that the accumulation of fat around the heart is not referred to by this designation. In fatty degeneration the elements of the muscular tissue are replaced by fatty or oily granules. The muscle becomes weak, the heart contractions are insufficient, and heart weakness is shown by general weakness, shortness of breath, and weak, rapid pulse.

CYANOSIS.

Owing to the most prominent symptoms, cyanosis is also called "blue disease," and is seen occasionally in new-born calves. It is recognized by the blue color of the mucous membrane (easily seen by looking within the mouth and nostrils), the coldness of the surface of the body, and rapid, labored breathing. It is caused by non-closure of the foramen ovale, connecting the right with the left side of the heart, and the consequent mixing of the venous with the arterial blood. Calves so affected live but a short time.

MISPLACEMENT OF THE HEART.

Cases are recorded in which the heart has been found out of its natural position, sometimes even outside the chest. This is a congenital condition for which there is no remedy. A heifer calf with the heart entirely outside the thoracic cavity and beneath the skin in the lower part of the neck was kept for two years at the veterinary hospital of the University of Pennsylvania, during which time it grew to be a well-developed cow.

WOUNDS OF ARTERIES AND VEINS.

When a blood vessel is opened a glance will tell whether it is an artery or a vein by simply remembering that bright-red blood comes from arteries and dark-red from veins. When a vein or a very small artery is severed the blood flows from the vessel in a continuous and even stream, but when one of the larger arteries is severed the blood comes in intermitting jets or spurts corresponding to the beats of the heart. It is well to call attention to the fact that the dark-red blood which flows or oozes from a wound soon becomes bright red, because it gives up its carbonic-acid gas to the air, and absorbs oxygen gas from the air, which is exactly the change it undergoes in the capillaries of the lungs.

The general treatment of wounds will be found in another section; here it is necessary only to refer briefly to some of the most practical methods used to arrest hemorrhages, as instances occur in which an animal may lose much strength from the loss of blood, or even bleed to death unless action is prompt.

BLEEDING (HEMORRHAGE).

The severity of a hemorrhage depends upon the size of the vessel from which the blood escapes, though it may be stated that it is more serious when arteries are severed. If the wound in an artery is in the direction of its length, the blood escapes more freely than if the vessel is completely severed, because in the latter instance the severed ends retract, curl in, and may aid very much in arresting the flow. When the blood merely oozes from the wound, and even when it flows in a small stream, the forming of the clot arrests the hemorrhage in a comparatively short time.

Slight hemorrhages may be checked by the continuous application of cold water, ice, or snow, to the wound, as cold causes contraction of the small vessels. Water from a hose may be thrown on a wound, or dashed on it from the hand or a cup, or folds of cotton cloths may be held on it and kept wet. Ice or snow may be held against the wound, or they may be put into a bag and conveniently secured in position.

Hot water of an average temperature of 115 deg. to 120 deg. F. injected into the vagina or womb is often efficient in arresting hemorrhages from those organs. Tow, raw cotton, lint, or sponges may be forced into a wound and held or bound there with bandages. This is an excellent method of checking the flow of blood until the arrival of an expert. If the flow persists, these articles may be saturated with tincture of iron, but it is not advisable to use it unless necessary, as it is a caustic and retards healing by causing a slough. In cases of necessity, the articles may be saturated with vinegar, or tannic acid or alum dissolved in water may be used instead. Whatever article is used should be left in the wound sufficiently long to make sure that its removal will not be followed by a renewal of the hemorrhage. Sometimes it must remain there one or two days.

An iron heated white and then pressed on the bleeding vessel for three or four seconds is occasionally used. It should not be applied longer, or else the charred tissue will come away with the iron and thus defeat the purpose of its application.

Compression may be applied in different ways, but only the most convenient will be mentioned. To many wounds bandages may easily be applied. The bandages may be made of linen, muslin, etc., sufficiently wide and long, according to the nature of the wound and the region to be bandaged. Bed sheets torn in strips the full length make excellent bandages for this purpose. Cotton batting, tow, or a piece of sponge may be placed on the wound and firmly bound there with the bandages.

Many cases require ligating, which is almost entirely confined to arteries. A ligature is a piece of thread or string tied around the vessel. Veins are not ligated unless very large (and even then only when other means are not available) on account of the danger of causing phlebitis, or inflammation of a vein. The ligature is tied around the end of the artery, but in some instances this is difficult and it is necessary to include some of the adjacent tissue, although care should be taken not to include a nerve. To apply a ligature, it is necessary to have artery forceps (tweezers or small pincers may suffice) by which to draw out the artery in order to tie the string around it. To grasp the vessel it may be necessary to sponge the blood from the wound so that the end will be exposed. In case the end of the bleeding artery has retracted, a sharp-pointed hook, called a tenaculum, is used to draw it out far enough to tie. The ligature should be drawn tightly, so that the middle and internal coats will be cut through.

Another method of checking hemorrhage is called torsion. It consists in catching the end of the bleeding vessel, drawing it out a little, and then twisting it around a few times with the forceps, which lacerates the internal coats so that a check is effected. This is very effectual in small vessels, and is to be preferred to ligatures, because it leaves no foreign body in the wound. A needle or pin may be stuck through the edges of the wound and a string passed around between the free ends and the skin (Pl. XXVII, fig. 10), or it may be passed around in the form of a figure 8, as is often done in the operation of bleeding from the jugular vein.

ANEURISM.

A circumscribed dilatation of an artery, constituting a tumor which pulsates synchronously with the beats of the heart, is called aneurism. It is caused by disease and rupture of one or two of the arterial coats. The true aneurism communicates with the interior of the artery and contains coagulated blood. It is so deeply seated in cattle that treatment is out of the question. Such abnormalities are ascribable to severe exertion, to old age, to fatty or calcareous degeneration, or to parasites in the blood vessels. Death is sudden when caused by the rupture of an aneurism of a large artery, owing to internal hemorrhage. Sometimes spontaneous recovery occurs. As a rule no symptoms are caused in cattle by the presence of deep-seated aneurisms, and their presence is not known until after death.

A false aneurism results from blood escaping from a wounded artery into the adjacent tissue, where it clots, and the wound, remaining open in the artery, causes pulsation in the tumor.

THROMBOSIS (OBSTRUCTION) OF THE ARTERIES.

Arteries become obstructed as a result of wounds and other injuries to them, as those caused by the formation of an abscess or the extension of inflammation from surrounding structures to the coats of an artery. Arteries are also obstructed by the breaking off of particles of a plug or clot, partly obstructing the aorta or other large artery. These small pieces (emboli) are floated to an artery that is too small to permit them to pass and are there securely held, producing obstruction. These obstructions are shown by loss of power in the muscles supplied by the obstructed artery and by excitation of the heart and by respiration after exercise. The loss of power may not come into evidence until after exercise.

Symptoms.—While standing still or when walking slowly the animal may appear to be normal, but after more active exercise a group of muscles, a leg, or both hind legs, may be handled with difficulty, causing lameness, and later there is practically a local paralysis. These symptoms disappear with rest. In some cases the collateral circulation develops in time, so that the parts receive sufficient blood and the symptoms disappear.

INFLAMMATION OF VEINS (PHLEBITIS).

When bleeding is performed without proper care or with an unclean lancet, inflammation of the vein may result, or it may be caused by the animal rubbing the wound against some object. When inflammation follows the operation, the coats of the vein become so much enlarged that the vessel may be felt hard and knotted beneath the skin, and pressure produces pain. A thin, watery discharge, tinged with blood, issues from the wound. The blood becomes coagulated in the vessel. In inflammation of the jugular the coagulation extends from the wound upward to the first large branch. Abscesses may form along the course of the vein. The inflammation is followed by obliteration of that part in which coagulation exists. This is of small import, as cattle have an accessory jugular vein which gradually enlarges and accommodates itself to the increased quantity of blood it must carry.

Treatment.—The treatment for inflammation of the vein is to clip the hair from along the course of the affected vessel and apply a blister, the cerate of cantharides. Abscesses should be opened as soon as they form, because there is a possibility of the pus getting into the circulation.

In the operation of bleeding the instruments should be clean and free from rust. If the skin is not sufficiently opened, or when closing the wound the skin is drawn out too much, blood may accumulate in the tissue, and if it does it should be removed by pressing absorbent cotton or a sponge on the part. Care should also be used in opening the vein, so that the instrument may not pass entirely through both sides of the vein and open the artery beneath it.

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DISEASES OF THE HEART, BLOOD VESSELS, AND LYMPHATICS.

DESCRIPTION OF PLATE.

PLATE VII:

Diagram illustrating the circulation of the blood. The arrows indicate the direction in which the blood flows. The valves of the heart, situated between the right auricle and ventricle, and left auricle and ventricle, and between the ventricles and large arteries, are represented by curved lines. These valves are intended to prevent the flow of blood in a direction contrary to that indicated by the arrows.



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NONCONTAGIOUS DISEASES OF THE ORGANS OF RESPIRATION.

By WILLIAM HERBERT LOWE, D. V. S.

DIAGNOSIS.

In the determination of disease in the human being the physician, in making his diagnosis, is aided by both subjective and objective symptoms, but the veterinary physician, in a very large majority of cases, is obliged to rely almost solely upon objective symptoms, and perhaps in no class of diseases is this more true than in the exploration of those under consideration. This condition of affairs has a strong tendency to develop observation and discernment in the veterinarian, and not infrequently do we find that the successful veterinary practitioner is a very accurate diagnostician. In order to make a differential diagnosis, however, it is not only necessary to know the structure and functions of the organs in health, but to adopt a rigid system of details of examination, without which successful results can not be reached.

History.—The history of a case should always be ascertained so far as possible. The information obtained is sometimes unsatisfactory and not to be depended upon, but even when this is the case it is advisable to weigh the evidence from every point of view.

In connection with the history of every case it is always of primary importance to ascertain the cause of illness. A knowledge of the origin and development of a disease is important, both in making a diagnosis and in formulating the treatment. Exposure to cold and dampness is frequently the exciting cause of affections of the organs of respiration.

The experienced practitioner is always sure to ascertain whether the particular animal he is called on to attend is the only one in the stable or on the premises that is similarly affected. If several animals are similarly affected, the disease may have a common cause, which may or may not be of an infectious nature.

Another thing that the experienced practitioner ascertains is what previous treatment, if any, the animal has had. Medicine given in excessive doses sometimes produces symptoms resembling those of disease.

The hygienic and sanitary conditions must always be considered in connection with the cause as well as the treatment of disease. Much of the disease which occurs in large dairies and elsewhere could be prevented if owners and those in charge of animals had proper regard for the fundamental laws of animal hygiene and modern sanitation. Disregard for these laws is the cause of most of the diseases under consideration in this chapter.

Attitude and general condition.—The feeling of pain in animals suffering from serious affections of the organs of respiration is expressed to the close observer in no uncertain language—by their flinching when the painful part is touched; by the care with which they move or lie down; by walking or standing to "favor" the part; by the general attitude and expression of the eye; by the distress and suffering apparent in the face; and by other evidences.

The general physical condition and attitude of the sick animal tell the careful observer much that aids him in making a diagnosis and prognosis. Cows suffering from affections of the organs of respiration usually assume a position or attitude that is characteristic, well known to experienced stockmen, as well as to veterinarians. When an animal has a fever or is suffering from an inflammation, the skin is one of the first parts to undergo a change that is apparent to the average observer, for it soon loses its elasticity and tone, and the hair becomes dry and staring.

From the general condition or state of nutrition one is able to judge the effect that the disease has already had upon the animal and to estimate the strength remaining available for its restoration to health; from the degree of emaciation one can approximate the length of time the animal has been ill. The age and breed of the animal, as well as its constitution and temperament, are among the things that have to be taken into account in making a diagnosis and in overcoming the disease.

The mucous membrane.—The mucous membrane should in all cases be examined. It can be readily seen by everting the eyelids or by an inspection of the lining membrane of the nostrils.

Paleness of the mucous membrane indicates weak circulation or poor blood and may result from disease, hemorrhage, or from inappropriate feed.

In healthy animals increased redness of the mucous membrane occurs from pain, excitement, or severe exertion, and in such instances is always transitory. In certain pathological conditions, such as fevers and inflammation, this condition of the mucous membrane will also be found. The increased redness of the mucous membrane lasts during the duration of the fever or inflammation.

A bluish or blue mucous membrane indicates that the blood is imperfectly oxidized and contains an excess of carbon dioxid, and is seen in serious diseases of the respiratory tract, such as pneumonia, and in heart failure.

The secretions.—The secretions may be diminished, increased, or perverted. In the early stage of an inflammation of a secretory organ its secretion is diminished. In the early stage of pleurisy the serous membrane is dry, and as the disease advances the membrane becomes unnaturally moist. The products of secretion are sometimes greatly changed in character from the secretion in health, becoming excessively irritant and yielding evidence of chemical and other alterations in the character of the secretion.

Cough.—Cough depends upon a reflex nervous action and may be primary when the irritation exists in the lungs or air passages, or secondary when caused by irritation of the stomach, intestines, or other parts having nervous communications with the respiratory apparatus. A cough is said to be dry, moist, harsh, hollow, difficult, paroxysmal, suppressed, sympathetic, etc., according to its character. It is a very important symptom, often being diagnostic in diseases of the respiratory organs, but this is a subject, however, which can be more satisfactorily treated in connection with the special diseases of the organs in question.

Respiration.—In making an examination of an animal observe the depth, frequency, quickness, facility, and the nature of the respiratory movements. They may be quick or slow, frequent or infrequent, deep or imperfect, labored, unequal, irregular, etc., each of which indications has its significance to the experienced veterinarian.

Sleep, rumination, pregnancy in cows, etc., modify the respiratory movements even in health. Respiration consists of two acts—inspiration and expiration. The function of respiration is to take in oxygen from the atmospheric air, which is essential for the maintenance of life, and to exhale the deleterious gas known as "carbon dioxid."

The frequency of the respiratory movements is determined by observing the motions of the nostrils or of the flanks. The normal rate of respiration for a healthy animal of the bovine species is from 15 to 18 times a minute. The extent of the respiratory system renders it liable to become affected by contiguity to many parts and its nervous connections are very important.

Rapid, irregular, or difficult breathing is known as dyspnea, and in all such cases the animal has difficulty in obtaining as much oxygen as it requires. Among the conditions that give rise to dyspnea may be mentioned restricted area of active lung tissue, owing to the filling of portions of the lungs with inflammatory exudate, as in pneumonia; painful movements of the chest, as in rheumatism or pleurisy; fluid in the chest cavity, as in hydrothorax; adhesions between the lungs and chest walls; compression of the lungs or loss of elasticity; excess of carbon dioxid in the blood; weakness of the respiratory passages; tumors of the nose and paralysis of the throat; swellings of the throat; foreign bodies and constriction of the air passages leading to the lungs; fevers, etc.

As already stated, it is only the careful and constant examination of animals in health that will enable one properly to appreciate abnormal conditions. One must become familiar with the frequency and character of the pulse and of the respirations and know the temperature of the animal in health, before changes in abnormal conditions can be properly appreciated.

Temperature.—The temperature should be taken in all cases of sickness. Experienced practitioners can approximate the patient's temperature with remarkable accuracy, but I strongly recommend the use of the self-registering clinical thermometer, which is a most valuable instrument in diagnosing diseases. (See Pl. III, fig. 1.) It is advisable to get a tested instrument, as some thermometers in the market are inaccurate and misleading. The proper place to insert the thermometer is in the rectum, where the instrument should be rested against the walls of the cavity for about three minutes. The normal temperature of the bovine is 101 deg. to 102 deg. F., which is higher than that of the horse. A cow breathes faster, her heart beats faster, and her internal temperature is higher than that of the horse. Ordinary physiological influences—such as exercise, digestion, etc.—give rise to slight variations of internal temperature; but if the temperature rises two or three degrees above the normal some diseased condition is indicated.

Pulse.—The pulse in a grown animal of the bovine species in a state of good health beats from 45 to 55 times a minute. Exercise, fright, fear, excitement, overfeeding, pregnancy, and other conditions aside from disease may affect the frequency and character of the pulse. It assumes various characters according to its rapidity of beat, frequency of occurrence, resistance to pressure, regularity, and perceptibility. Thus we have the quick or slow, frequent or infrequent, hard or soft, full or imperceptible, large or small pulse, the character of each of which may be determined from its name; also that known as the intermittent, either regular or irregular. We may have a dicrotic, or double, pulse; a thready pulse, which is extremely small and scarcely perceptible; the venous, or jugular, pulse; the "running down" pulse, and so on. (See p. 76.)

In cattle the pulse is conveniently felt over the submaxillary artery where it winds around the lower jawbone, just at the lower edge of the flat muscle on the side of the cheek. If the cow is lying down the pulse may be taken from the metacarpal artery on the back part of the fore fetlock. The pulsations can be felt from any superficial artery, but in order to ascertain the peculiarities it is necessary to select an artery that may be pressed against a bone.



There is a marked difference in the normal or physiological pulse of the horse and that of the cow, that of the horse being full and rather tense, while in the cow it is soft and rolling. The pulse is faster in young or old cattle than it is in those of middle age.

Auscultation.—Auscultation and percussion are the chief methods used to determine the various pathological changes that occur in the respiratory organs. Auscultation is the act of listening, and may be either mediate or immediate. Mediate auscultation is accomplished by aid of an instrument known as the stethoscope, one extremity of which is applied to the ear and the other to the chest of the animal. In immediate auscultation the ear is applied directly to the part. Immediate auscultation will answer in a large majority of cases. Auscultation is resorted to in cardiac and certain abdominal diseases, but it is mainly employed for determining the condition of the lungs and air passages. Animals can not give the various phases of respiration, as can the patients of the human practitioner. The organs themselves are less accessible than in man, owing to the greater bulk of tissue surrounding them and the pectoral position of the fore extremities, all of which render it more difficult in determining pathological conditions. (See Pl. VIII.)

The air going in and out of the lungs makes a certain soft, rustling sound, known as the vesicular murmur, which can be heard distinctly in a healthy state of the animal, especially upon inspiration. Exercise accelerates the rate of respiration and intensifies this sound. The vesicular murmur is heard only where the lung contains air and its function is active. The vesicular murmur is weakened as inflammatory infiltration takes place and when the lungs are compressed by fluids in the thoracic cavity, and disappears when the lung becomes solidified in pneumonia or the chest cavity filled with fluid as in hydrothorax. The bronchial murmur is a harsh, blowing sound, heard in normal conditions by applying the ear over the lower part of the trachea, and may be heard to a limited extent in the anterior portions of the lungs after severe exercise. The bronchial murmur when heard over other portions of the lungs generally signifies that the lung tissue has become more or less solidified or that fluid has collected in the chest cavity.

Other sounds, known as mucous rales, are heard in the lungs in pneumonia after the solidified parts begin to break down at the end of the disease and in bronchitis where there is an excess of secretion, as well as in other conditions. Mucous rales are of a gargling or bubbling nature. They are caused by air rushing through tubes containing secretions or pus. They are said to be large or small as they are distinct or indistinct, depending upon the quantity of fluid that is present and the size of the tubes in which the sound is produced. According to their character they are divided into dry and moist. The friction sound is produced by the rubbing together of roughened surfaces and is characteristic of pleurisy.

Percussion.—Percussion is that mode of examination by which we elicit sounds by striking or tapping over the part. It may be direct or indirect. If the middle finger of the left hand is placed firmly on the chest and smartly tapped or struck with the ends of the first three fingers of the right hand, the sound will be noticed to be more resonant and clear than when the same procedure is practiced on a solid part of the body. This is because the lungs are not solid, but are always, in health, well expanded with air. In certain pulmonary diseases, however, as in pneumonia, they fill up and become solid, when percussion produces a dull sound, like that on any other solid part of the animal. When fluid has collected in the lower part of the chest cavity the sound will also be dull on percussion. Where there is an excess of air in the chest cavity, as in emphysema or in pneumothorax, the percussion sound becomes abnormally loud and clear. By practice on healthy animals the character and boundaries of the sounds can be so well determined that any variation from them will be readily detected, and will sometimes disclose the presence of a diseased condition when nothing else will.

Percussion is sometimes practiced with the aid of a special percussion hammer and an object known as a pleximeter to strike upon. A percussion hammer is made of rubber or has a rubber tip, so that when the pleximeter, which is placed against the side of the animal, is struck the impact will not be accompanied with a noise. A percussion hammer and pleximeter may be purchased from any veterinary instrument maker.

CATARRH (COLD IN THE HEAD).

Nasal catarrh is an inflammation of the mucous membranes of the nostrils and upper air passages. Simple catarrh is not a serious disease in itself, but if neglected is liable to be complicated with laryngitis, bronchitis, pneumonia, plurisy, or other serious and sometimes fatal diseases of the respiratory organs. Catarrh is a common disease among cattle. It is often caused by sudden exposure to wet and cold after they have been accustomed to shelter. It may arise from inhalation of irritating gases. It is also sometimes produced by certain specific atmospheric conditions, and may assume an enzooetic form. It is very debilitating, and requires prompt and judicious treatment.

Symptoms.—Redness of the mucous membranes of the nose and redness and watering of the eyes are symptoms of nasal catarrh. The mucous membrane first becomes dry; afterwards a watery discharge appears, and later, in severe cases, the discharge becomes mucopurulent. In mild cases there is little or no fever, but in severe ones it may run high. The animal becomes dull, languid, and is not inclined to move about, and the appetite may become impaired; there is also variable temperature of the horns and ears. If in a cow giving milk the secretion diminishes, the mucus from the eyes and nose becomes thicker and yellower. Afterwards, as the symptoms increase in severity, the discharge becomes mucopurulent.

Treatment.—The animal should be housed in a well-ventilated place, with good hygienic surroundings. In cold and damp weather it should be kept warm with blanketing, and, in severe cases, hot, medicated inhalations given. If the fever is high, it may be reduced by giving nitrate of potassium, from 1 to 2 ounces, in the drinking water, three times daily. Diffusible stimulants are beneficial in most cases. Too much importance can not be attached to good nursing. There is no necessity to resort to the old system of bleeding, purging, or the use of powerful sedatives.

EPISTAXIS (BLEEDING FROM THE NOSE).

Bleeding from the nostrils is rather rare in cattle. It may arise from any one of a variety of causes, but usually results from disease or injury to the mucous membranes or to violent exertions in coughing and sneezing. It is seldom serious. It generally occurs in drops from one nostril only, accompanied with sneezing, and without frothing. Bleeding from the lungs comes from both nostrils, is bright red, frothy, and accompanied with a cough.

Treatment.—In many cases the bleeding will cease spontaneously and all that is necessary is to keep the animal quiet and bathe the head and nostrils with cold water. The cause of the bleeding should be learned and governed accordingly in the treatment. In severe and exceptional cases, when the hemorrhage is persistent and long continued, the animal's head should be tied to a high rack or beam and cold water or ice applied, or recourse to styptic injections taken. If the hemorrhage is profuse and persistent, either a drench composed of 1-1/2 drams of acetate of lead dissolved in a pint of water or 1-1/2 drams of gallic acid dissolved in a pint of water should be given.

LARYNGITIS (SORE THROAT).

An inflammation of the mucous membrane lining the larynx is known as laryngitis. It may be either a primary or a secondary disease, complicated or uncomplicated. In the majority of cases it is attributable to some form of exposure, a sudden change from warm to cold surroundings, or exposure to cold storms. It may also result from inhaling irritating gases or from external violence. In an acute attack of laryngitis there is an elevation of temperature, pain on pressure over the region of the larynx, violent paroxysms of coughing, difficult and noisy respiration. The nostrils are dilated, the nose extended, and the animal has a frightened expression. There is marked difficulty in swallowing.

Treatment.—Treatment consists of fomentations and hot applications over the throat. Stimulating liniments, mustard mixed with cold water and well rubbed in with a stiff brush, or other forms of counterirritation may be applied in severe cases. Hot inhalations should be frequently resorted to, and often afford much relief to the suffering animal. In this disease medicines should be given so far as possible in the form of electuaries (soft solid) on account of the difficulty of deglutition. Large drafts of medicines have a tendency to produce violent spells of coughing, and in this way retard recovery. The subjoined formula for an electuary will be found to answer the purpose in ordinary cases: Chlorate of potassium, pulverized, 8 ounces; fluid extract of belladonna, 2 ounces; powdered opium, 1 ounce; powdered licorice root, 8 ounces; sirup, sufficient quantity; mix. Place a small tablespoonful of the mixture frequently on the tongue or back teeth. Or the following may be used instead: Aloes, powdered opium, and gum camphor in equal parts; mix. Rub an ounce on the molar teeth every four or five hours. The bowels should be kept open and the diet should be such as the patient can easily swallow. Warm, sloppy mashes, boiled oatmeal gruel, linseed tea, and the like are the most suitable substances. If suffocation be threatened during the course of the disease, tracheotomy should be performed without delay. The details of the operation are fully described under the head of "Surgical operations." (See p. 289.)

When the disease assumes a chronic form, strong counterirritation is indicated. A cantharides blister may be applied, or the following ointment used: Biniodid of mercury 1 part, lard 6 parts; mix. In some cases it will be found necessary to repeat the application.

BRONCHITIS.

Bronchitis is an inflammation of the mucous membrane of the bronchial tubes. When a primary disease, it is generally the result of what is commonly known as "catching cold." It may be secondary to or complicated with many of the diseases of the respiratory system. It may also be caused by breathing irritating gases, or by the introduction of foreign bodies into the bronchial tubes, which sometimes results from injudicious and careless drenching when the larynx is temporarily relaxed. It may be acute or chronic, and is divided, according to the seat of the inflammation, into bronchitis proper when the large tubes are affected, or capillary bronchitis when the trouble is in the smaller ones.

Symptoms.—Loss of appetite, elevation of temperature, generally 104 deg. or 105 deg. F. The inspiration is incomplete, short, and painful, and the expiration is prolonged. The pulse is increased in frequency and is hard. A characteristic, painful cough is present, but it is paroxysmal and incomplete. Auscultation and percussion greatly aid us in a diagnosis. A normal sound is given on percussion. On auscultation, in the early stages, rhonchus rales are detected if the larger tubes are affected, and sibilant rales if the smaller ones are affected. Later mucous rales are noted, and sometimes all sounds in certain parts are absent, owing to the plugging up of the tubes. This plugging, if extensive enough, is sometimes the cause of death, or death may result from extension of the disease to the lungs or pleura.

Treatment.—The animal should be placed in a light, well-ventilated box, and the bowels kept in a soft condition by enemas, etc. Violent purgatives should not be used. The body should be kept warm by blanketing. In the early stages a draft composed as follows should be given three times daily: Extract of belladonna, 2 drams; solution of acetate of ammonium, 4 fluid ounces; water, one-half pint. In the later stage of the disease the following formula may be substituted and given twice daily: Carbonate of ammonium, 3 drams; liquor hydrochlorate of strychnin, 2 fluid drams; spirits of nitrous ether, 1 fluid ounce; water, one-half pint.

In some cases the following is preferable to either of the above, and may be given in a pint of linseed tea every four hours: Spirits of nitrous ether, 1-1/2 ounces; aromatic spirits of ammonia, 2 ounces; powdered camphor, 2 drams. The feed should be light and nutritious.

Bronchitis is liable to become chronic if not properly treated in the earliest stage. In this case remedial treatment is of little value.

PLEURISY.

Pleurisy is an inflammation of the serous membrane lining the chest cavity and enveloping the lungs. It is somewhat rare as an independent disease, but it often complicates pneumonia; indeed, it is often caused by the same germ that causes pneumonia—pneumococcus. It may arise from exposure to cold or wet or from external violence, and is usually present in some degree in cases in which the ribs have been fractured with or without a penetrated wound.

Symptoms.—In the first stage there is great pain aggravated by movement, and the animal is usually stiff as though foundered, the pulse is quick and hard, the breathing abdominal, the chest being fixed so far as possible, the inspiration short and jerky, the expiration longer. The pain is caused by the friction of the dry, inflamed pleural surfaces of the lung and chest on each other. At this stage the ear detects a dry friction murmur, resembling somewhat the sound made by rubbing two pieces of sole leather together. Pressure between the ribs gives pain and usually causes the animal to flinch and grunt. The muzzle is hot and dry, the mouth slimy, and the secretions scanty. After a day or two the severity of the symptoms is much lessened, the temperature, which during the first days may have been as high as 106 deg. F., falls to 103 deg. or 104 deg., the pain decreases, the stiffness disappears, and the patient eats a little. The pulse softens, but remains quicker than normal. Now, day by day the patient loses a little strength, the friction sound disappears as the exudation moistens the pleural surfaces; percussion now shows a horizontal line of dullness, which day by day rises higher in the chest, the respiration grows more frequent and labored, the countenance is anxious and haggard, the eyes sink somewhat in their sockets, and in unfavorable cases death occurs during the second or third week, from either asphyxia or heart failure.

In pleurisy, as in pneumonia, the elbows are usually turned outward. Care must be taken to differentiate pleurisy from traumatic pericarditis (which see). In the latter condition the area of dullness of the heart is much increased, and usually a splashing sound is heard at each beat of the heart. Another diagnostic symptom of value is that in traumatic pericarditis respiration is painful, not difficult, and the respiratory rate is very much increased on movement. In both conditions a considerable swelling of the dewlap may be noticed in the later stages.

Treatment.—Give the same general care as recommended in bronchitis or pneumonia. In the early stages give a febrifuge to reduce the fever, as directed for pneumonia. For relief of the cough give electuary formula, which will be found in the treatment of laryngitis. The bowels must be kept relaxed and the kidneys secreting freely. In the stage of effusion the following should be given three times daily: Digitalis tincture, 1 ounce; iodid of potassium, 30 to 60 grains; mix. Apply strong counterirritant to chest and put seton in dewlap. (See "Setoning," p. 293.) If collapse of the lung is threatened, a surgical operation, termed paracentesis thoracis, is sometimes performed; this consists in puncturing the chest cavity and drawing off a part of the fluid. The instruments used are a small trocar and cannula, which are introduced between the eighth and ninth ribs. The skin should be drawn forward so that the external wound may not correspond to the puncture of the chest, to prevent the entrance of air. Only a portion of the fluid should be removed. The animal gets immediate relief, but it is generally only temporary, as the fluid has a tendency to accumulate again.

PNEUMONIA.

Pneumonia is an inflammation of the lung substance, and is divided into three forms, viz, croupous, catarrhal, and interstitial. These various forms, however, can be differentiated only by the expert, and it is therefore deemed necessary for the purpose of the present work to treat the subject under the general head of pneumonia.

The causes of pneumonia in general are the same as those of the various other inflammatory diseases of the respiratory tract. The germ is known as a pneumococcus. The disease mostly follows congestion of the lungs, but may in rare cases have a parasitic origin.

Symptoms.—In the first stage, that of congestion, the disease is usually ushered in by a chill, although this may not always be observed by the attendant. This is followed by an elevation of temperature, usually 105 deg. to 106 deg. F., or it may be even higher. The respirations are quick and shallow; the nostrils are dilated; the pulse is full and hard. Cough may or may not appear in this stage. The nose is hot and dry; the tongue sometimes protrudes and is slimy; the coat is staring, and the skin dry and harsh. The urine is usually diminished in quantity, high colored, and the bowels constipated. The animal stands with the forelegs wide apart to facilitate respiration. On auscultation crepitation will be observed over the portion of the lung affected. The sounds elicited on percussion are practically normal in this stage.

In the second stage the temperature generally drops one or two degrees, and respiration is performed with much difficulty. The cough is frequent and painful. The animal still stands with the forelegs wide apart and the elbows turned outward. If it assumes the recumbent position it rests on the sternum. All secretions are more or less suspended, particularly the milk in cows. The animal has a haggard appearance, and the pulse becomes small and wiry at this period. The extremities are hot and cold alternately; the crepitation which was present in the first stage is now absent, and no sound on auscultation is heard, unless it is a slight wheezing or whistling noise. On percussion dullness over the diseased lung is manifested, indicating consolidation. The lung has now assumed a characteristic liverlike appearance.

In the third stage, if the disease is to terminate favorably, the cough becomes loose, the animal improves, the appetite returns, and the symptoms above detailed rapidly subside; if, on the other hand, resolution is not progressing, the lung substance degenerates, becomes clogged up, and ceases to function. In fatal cases the breath has a peculiar, fetid, cadaverous odor, and is taken in short gasps; the horns, ears, and extremities become cold and clammy, and the pulse is imperceptible. On auscultation, when suppuration is taking place and the lung structure is breaking down, a bubbling or gurgling crepitation, caused by the passage of air through pus, is heard.

Treatment.—Good hygienic surroundings and good nursing are essential in connection with the medical treatment. The probability of recovery depends largely on the extent of the lung tissue involved, as well as on the intensity of the inflammatory process. In the early stage, when the fever is high, febrifuges should be given. If the pulse be strong and full, aconite (Fleming's tincture, 1 to 2 drams, every four or five hours) may be given for a short time, but should be discontinued as soon as the fever begins to abate. Aconite is a valuable drug in the hands of the intelligent practitioner, but my experience leads me to believe that not infrequently animals are lost by its injudicious use, for in many febrile conditions it is positively contraindicated, owing to its action upon the heart. In a plethoric animal, with a strong, bounding pulse, bleeding may be resorted to instead of administering aconite. If the bowels are constipated, calomel, 1 to 3 drams, which acts as a cathartic and a febrifuge, is advisable. In the second stage diffusible stimulants are required, viz: Spirits of nitrous ether, 2 ounces; aromatic spirits of ammonia, 1 ounce; mix, and give in gruel three times daily. In some cases carbonate of ammonia, 2 to 5 drams, has been found beneficial. Most practitioners apply counterirritants, such as mustard plasters, turpentine, and ammonia liniment, or cantharides.

EMPHYSEMA (HEAVES).

Emphysema is a rupture of the minute air vesicles of the lung substance, and may be either interlobular or vesicular. There is an extreme interference with respiration, inspiration being short and expiration prolonged. It is a nonfebrile condition, in which the appetite is not decreased and the milk secretion is kept up. It may be caused by an attack of asthma or may result from chronic bronchitis. The disease can be diagnosed by the marked interference with respiration. The animal, as a rule, is emaciated, has a staring coat, and is hidebound. If percussion is resorted to, the animal's chest will give a tympanic, drumlike sound. The normal resonant sound is exaggerated.

Treatment.—The disease is incurable, and only a palliative form of treatment can be carried out. The destruction of the animal is often advisable, from a humane as well as from a financial point of view.

PULMONARY CONGESTION.

Cattle that are overdriven or overworked are liable to pulmonary congestion in an acute form, and sometimes to pulmonary apoplexy. In such cases they should be allowed to rest, and if the weather is hot, they should be put in a shady place. Give stimulants internally, unload the venous side of the heart by bleeding, and apply stimulating applications to the legs, and bandage.

HEMOPTYSIS.

Hemoptysis is a term used to signify bleeding from the lungs. The trouble may result from a previous congestion of the lungs or from a breaking down of the lung substance, or from specific disorders.

Bleeding from the lungs comes from both nostrils and from the mouth. The blood is bright red, frothy, and accompanied with a cough, the flow being somewhat profuse and intermingled with mucus. It may cease of its own accord. Internally hemostatics are indicated, and locally over the sides cold applications have a tendency to check the hemorrhage. A drench of 1-1/2 drams of gallic acid dissolved in a pint of water should be given.

ABSCESS OF THE LUNG.

Abscesses of the lung sometimes form during the course of or subsequent to tuberculosis or other diseases. An animal affected with abscess of the lung usually has a protracted, feeble cough and a general appearance of emaciation and anemia. The pulse is feeble and the breath foul. An offensive discharge from the lungs frequently occurs. Percussion and auscultation aid in making a diagnosis in this condition. The appetite is poor. Such animals go from bad to worse, and their prompt destruction would, as a rule, be to the interest of the owner.

HYDROTHORAX.

Hydrothorax, or dropsy of the chest, is not a disease in itself, but is simply a condition in which an effusion takes place in the chest cavity, and is the result or effect of some disease, mostly pleurisy. It can be easily diagnosed by physical signs. A loss of the respiratory murmur will be noticed on auscultation, and on percussion dullness or flatness on a line as high as the effusion has taken place. When a large amount of effusion is present, tapping with the trocar and cannula is generally resorted to. The proper method of performing this operation will be found under the head of "Pleurisy."

PNEUMOTHORAX.

An accumulation of gas in the pleural sac is known as pneumothorax. The presence of air may result from either an injury of the lung or a wound communicating from the exterior. The indications for treatment are to remove any foreign body that may have penetrated, to exclude the further entrance of the air into the cavity by the closure of the external opening, and to employ antiseptics and adhesive dressings. The air already in the cavity will in most cases be absorbed.

VERMINOUS BRONCHITIS.

This is a disease that sometimes attacks young cattle when pastured in low-lying meadows near rivers subject to flood. It is caused by a small worm, Strongylus micrurus, which lodges in large numbers in the trachea and bronchial tubes, giving rise to considerable irritation of the air passages and inflammation. Sometimes the strongyles lodge in large numbers in the windpipe, forming themselves into a ball, and thus choke the animal to death.

Symptoms.—It is liable to attack a number of animals at once, and the weakest are the first to give way. The animal has a remarkably forcible cough, distressing, and of a special hacking and paroxysmal character. A stringy mucus is sometimes expelled during the spells of coughing. This mucus contains the Strongylus micrurus, which can be detected, or their ova observed, under a low power of the microscope. The attack has a subacute character and is very exhausting. The parasites, by becoming entwined in balls, seriously impede respiration, which is always remarkably labored in this disease.

Treatment.—The affected calves should be placed in a dry stable, protected from dampness, and subjected to fumigations of sulphurous anhydrid or chlorin gas. The liberation of chlorin gas is brought about by the action of sulphuric acid, either on a mixture of chlorid of sodium and black oxid of manganese or on bleaching powder. Sulphurous anhydrid may be procured by burning sulphur. Some practitioners prescribe small doses of spirits of turpentine in linseed oil. The system requires good support, and the diet should therefore be liberal and nutritious. Equal parts of sulphate of iron, gentian, and ginger make an excellent tonic.

Prevention.—Avoid pastures notorious for generating verminous bronchitis.

PLEURODYNIA.

Pleurodynia is a term applied to rheumatism of the intercostal muscles, the apparent symptoms being very similar to those of pleurisy. The animal is stiff, is not inclined to turn around, and the ribs are kept in a fixed state as much as possible. Pleurodynia may be distinguished from pleurisy by the coexistence of rheumatism in other parts and by the comparative absence of fever, cough, the friction sound, and the effusion into the chest. The treatment for this affection is the same as that for rheumatism affecting other parts.



DISEASES OF THE NERVOUS SYSTEM.

By W. H. HARBAUGH, V. S.

[Revised by John E. Mohler, V. M. D.]

THE NERVOUS SYSTEM.

The nervous system is the distinguishing feature of animal life. Without it there can be no intelligence, no instinct, no sensibility, no perception; in fact, existence would be nothing more than vegetable life.

The senses—touch, taste, sight, hearing, smell—all depend on the nervous system. Motion depends on it. A muscle can not contract without receiving the stimulus from the nervous system. For example, if a nerve passing from a nerve center to a muscle is severed, the particular muscle that is supplied by the cut nerve is paralyzed.

The nervous system is often studied in two divisions—the cerebrospinal division and the sympathetic division.

The cerebrospinal division consists of the brain and spinal cord, nerves, and ganglia. The nerves of this division convey the impulses of motion and sensation and supply all parts which are under the control of the will. For example, the voluntary muscular tissue includes all the muscles which act as the will directs. Another example: If anything comes in contact with any part of the skin, the impression is immediately perceived. All the special senses belong to this division.

The sympathetic division consists of nerves and ganglia. The muscular tissue, which acts independently of the will—as, for example, the stomach, intestines, womb, blood vessels, ducts, etc.—is called involuntary muscular tissue, and receives nervous stimulus from the sympathetic division.

The brain, spinal cord, and the ganglia are the central organs of the nervous system. The nerves conduct the nervous influence. The nerves terminate differently according to their function. The terminations are called end organs. The terminal end organs in the skin and other parts endowed with sensation receive the impressions, which are conveyed to the brain, where they are appreciated. They are so sensitive that the most gentle zephyr is perceived. They are so abundant that the point of the finest needle can not pierce the skin without coming in contact with them, and the sensation of pain is instantly conveyed to the brain. The terminal end organs of the nerves that supply the muscles are different, as they give the impulse which is conveyed by the motor nerves to the elements which constitute the muscle, and this impulse is the excitation which causes the muscle to contract. The terminal end organs of the special senses of taste, smell, etc., receive their special impressions, and their respective nerves carry the impressions to the brain.

There are two divisions of nerves, the afferent and efferent.

The afferent nerves are those which convey the impression to the nerve centers. All the sensory nerves belong to this division.

The efferent nerves are those which convey the nervous impulse outward from the nerve centers, and they are further classified according to the function of their respective centers. For example: Motor fibers carry the impulse from the nerve center to a muscle to cause contraction. Vasomotor fibers carry the impulse to the muscular tissue in the blood vessels, which regulates their caliber. The secretory fibers convey the impulse to the cells of the glands and excite the activity of the gland, and its particular product is secreted or evolved, as, for instance, milk in the mammary gland. Inhibitory fibers control or inhibit the action of the organ to which they are distributed, as, for instance, the heart.

Nerve centers may be considered as a collection or group of nerve cells. Both the cerebrospinal and the sympathetic divisions have nerve centers. The centers derive their special names from their functions. The brain is the great center of the nervous system, as it is the center of intelligence and perception. The centers of all the special senses, as well as the centers of various functions, are located in different parts of the brain. Nerve centers also exist in the spinal cord and in connection with the sympathetic system.

A nerve is a cord consisting of a certain number of fibers of nerve tissue, inclosed in a sheath of connective tissue. Nerves divide and subdivide, sending off branches, which ramify in all parts of the body, and, as they near their terminations, they contain but one or two fibers.

The brain and spinal cord are contained within a bony canal, which forms a protective covering for them.

The spinal cord, or spinal marrow, lodged within the spinal canal, or hollow of the backbone, is continuous with the brain anteriorly, and terminates in a point in the sacrum (that part of the spinal column which immediately precedes the tail). The spinal cord gives off branches at each of the spaces between the segments of the backbone. These branches form nerve trunks which carry both sensory and motor impressions and impulses. The spinal cord is a grand nerve trunk to carry messages to or from the brain and to and from the reflex centers contained within itself.

The brain is contained within the cavity of the skull and is continuous with the spinal cord; there is nothing to mark the place where one leaves off and the other begins. The brain is the seat of reason and intelligence. Voluntary effort originates from the brain. Coordination, or harmony of movement, is controlled by the rear portion of the brain, known as the cerebellum.

The meninges are the membranes, three in number, which envelop the brain and spinal cord, and separate them from the bones which form the walls of the cranial cavity and spinal canal.

The sympathetic, also called the ganglionic, division of the nervous system consists of two chains of ganglia, reaching from the head to the tail, situated beneath the spinal column, one on either side. The presence of the ganglia or enlargements on the cords give them their chainlike appearance.

The sympathetic nerves are closely connected with the cerebrospinal nerves, but are not under the control of the will.

INFLAMMATION OF THE BRAIN AND ITS MEMBRANES (STAGGERS).

Inflammation of the brain is technically termed encephalitis and of its membranes cerebral-meningitis, but as both conditions usually occur together, and since it is practically impossible to distinguish one from the other by the symptoms shown by the diseased animal, they may as well be considered together here as varieties of the same disease. Staggers, coma, frenzy, etc., are terms that are sometimes applied to this disease in its different forms or stages.

Causes.—Severe blows on the head with a hard object, or the head coming violently in contact with the ground or other hard substance in a fall, may be followed by encephalitis. Irritation caused by tumors in the brain may produce inflammation. Feed containing deleterious matters—for example, ergot (see Pl. V) and other fungi which contain a narcotic principle—is the most frequent cause of this affection, and hence it is often called "grass staggers" and "stomach staggers." Highly nitrogenous feeds are blamed for causing this disease. Parasites, mineral and narcotic poisons, hot weather, and severe exertion or excessive excitement may cause this condition. Inflammation of the brain may occur as a complication of some infectious disease or may follow some forms of indigestion. In many localities certain plants have the reputation of causing staggers.

Symptoms.—The symptoms vary much, but a careful observer will detect a trouble connected with the nervous system without much uncertainty. The first signs may be those of frenzy, but generally at the start the animal is dull and sleepy, with little or no inclination to move about; the head may be pressed against the wall or fence and the legs kept moving, as if the animal were endeavoring to walk through the obstruction; the body, especially the hind part, may be leaned against the side of the stall or stable, as if for support. The bowels are constipated; the urine, when passed, is small in quantity and darker in color than natural. There may be trembling and even spasms of muscles in different parts. In the dull stage the animal may breathe less frequently than is natural, and each breath may be accompanied with a snoring-like sound. The pulse may be large and less frequent than normal. If suddenly aroused from the drowsy state, the animal appears startled and stares wildly. When moving about it may stagger, the hind quarters swaying from side to side.

If delirium ensues, the cow is commonly said to be mad. She may bellow, stamp her feet, run about wildly, grate the teeth, froth at the mouth. If she is confined in the stable, she rears and plunges; the convulsions are so violent in many instances that it is really dangerous for one to attempt to render aid. The body may be covered with perspiration. She may fall; the muscles twitch and jerk; often the head is raised and then dashed against the ground until blood issues from the nose and mouth; the eyes may be bloodshot and sightless; the limbs stiff and outstretched, or they may be kicked about recklessly; the head may be drawn back and the tail drawn up; the urine may be squirted out in spurts; often the "washer" (membrane nictitans) is forced over the eye. When the convulsions cease they may be followed by a period of quiet unconsciousness (coma) which is more or less prolonged, when the animal may gradually regain consciousness, get up on its feet, and perhaps quietly partake of food, if there be any within reach, while at other times it arises with much difficulty and staggers blindly about the stall or field.

It must be remembered that all the foregoing symptoms are not always seen in the same case. In those cases usually designated "sleepy staggers" the general symptoms of drowsiness are presented, while in other cases the symptoms of frenzy cause the affection to be called "mad staggers." In other cases there are symptoms of paralysis, swaying of the hind quarters, inability to rise, etc., and sometimes these symptoms of paralysis are the most striking manifestations and continue until death. Acute cases are accompanied by fever.

It is well to remark that when the disease follows injuries to the head the symptoms may not be manifested until two or three days (or longer) after the accident.

Treatment.—Recoveries are rare in spite of careful attention. To be of any service whatever the treatment must be prompt and begin with the disease. In the early stage, when the pulse is large, most cases will admit of bleeding. Eight or 9 quarts of blood should be taken from the jugular vein. This should be followed immediately by a purgative, the following for a cow of average size: Epsom salt, 24 ounces; pulverized gamboge, one-half ounce; croton oil, 20 drops; warm water, 3 quarts; mix all together and give at once as a drench. About 2 quarts of warm water or warm soapsuds should be injected with a syringe into the rectum every three or four hours. It is best to keep the animal in a quiet, sheltered place, where it will be free from noise or other cause of excitement. All the cold water the animal will drink should be allowed, but feed must be withheld, except bran slops occasionally in small quantities, or grass, if in season, which may be cut and carried fresh to the patient.

The skull must be examined, and if sign of injury is found, appropriate surgical treatment should be given.

During the convulsions all possible efforts should be made to prevent the animal injuring itself. The head should be held down on the ground and straw kept under it. Cold water may be continuously poured on the head, or bags filled with ice broken in small pieces may be applied to the head. Different authors recommend different remedies to allay the convulsions, but for two reasons it will be found extremely difficult to administer medicines during the convulsions: (1) While the animal is unconscious the power to swallow is lost, and therefore the medicine is more liable to go down the windpipe to the lungs than it is to go to the paunch; (2) the convulsions are often so violent that it would be utterly useless to attempt to drench the animal; and furthermore it must be borne in mind that during this stage the functions of digestion and absorption are suspended, and as a consequence the medicine (provided it finds its way to the paunch) is likely to remain there unabsorbed and therefore useless.

A blistering compound, composed of mustard, 1 ounce; pulverized cantharides, one-half ounce; hot water, 4 ounces, well mixed together, may be rubbed in over the loins, along the spine, and back of the head on each side of the neck. This is occasionally attended with beneficial effect, and especially so in those cases when paralysis is present.

If the purgative acts and the animal shows signs of improvement in the course of two or three days, 2 drams of iodid of potassium may be given every night and morning, dissolved in a half bucketful of drinking water, if the animal will drink it, or it may be dissolved in a half pint of water and given as a drench. Great care must be observed in regard to the food, which should be nutritive, but not coarse, and at first in small quantities, gradually increased as the patient improves. After some progress is made toward recovery 1-1/2 drams of pulverized nux vomica may be given twice a day, added to the iodid of potassium drench. This should be administered so long as a staggering gait continues.

In those rare cases when recovery takes place it is only partial as a rule, as there is generally a sequel which remains, such as partial paralysis. However, this is but a slight drawback in cattle, because when it is seen to persist the medicine should be stopped and the animal fattened for butchering.

Post-mortem examinations discover congestion of the brain and its membranes. In those cases which have exhibited much paralysis of the hind legs before death the cord may be congested in the lumbar region (loins). When the disease has been caused by injury to the head, the congestion and extravasated blood may be found inside of the cavity in the location corresponding to the place where the injury was inflicted externally. In some cases pus is also discovered. It remains to be said that in all animals that have died from this affection the lungs are found very much congested. This may lead the superficial observer to suppose that the disease was a lung affection, but in fact it is only a natural consequence when death ensues from brain disease.

APOPLEXY.

That form of congestion of the brain known as parturient apoplexy, or parturient paresis, which is so frequently associated with the period of calving is described in another part of this work. (See "Milk fever," p. 226.)

Cerebral apoplexy, not connected with parturition, is a rare disease among cattle. However, it may be due to degeneration and consequent rupture of a blood vessel in the brain.

The attack is sudden, the animal in most cases falling as if it had received a blow on the head. It may stagger and reel some time before going down. After falling, there are convulsive movements of the legs or the animal sinks into insensibility. There may be remissions in the severity of the symptoms, but the pressure from the continued escape of blood soon causes death. Rest, quiet, friction to the legs and surface, frequent turning of the animal and cold to the head are to be practiced, if treatment is attempted.

CONGESTION OF THE BRAIN.

There is a form of congestive apoplexy affecting cattle which are in a plethoric condition. The congestion, or overfilling with blood, causes pressure on the brain substance and disorganizes its function. It occurs mostly in hot weather. In this disease the symptoms are somewhat similar to those exhibited when the animal has encephalitis, but the onset is more sudden, the duration is shorter, and there is less fever. There may be frenzy or coma, or alternations one with the other. The intelligence is diminished, staring eyes, bracing with the legs, pressing against the stall partition or manger, red mucous membranes. This condition usually terminates in recovery.

In such cases bleeding should be resorted to immediately, and when the power of swallowing is not lost purgatives should be administered. Cold applications to the head and the general treatment recommended for encephalitis are indicated.

CONCUSSION OF THE BRAIN.

Severe blows on the head, striking the head against some hard object while running, or falling on the head may cause concussion of the brain. The injury may fracture bones of the cranium and produce compression of the brain.

Symptoms and treatment.—The symptoms and the treatment that is indicated differ very little from what has been said under congestion of the brain and under encephalitis. In some cases it may be necessary to operate to remove a piece of bone that is pressing on the brain or to remove a clot of blood under the area which received the blow.

EPILEPSY.

This affection is characterized by the occurrence of sudden convulsions. The animal may appear to be in a fair state of health usually, but at any time, in the stable or in the field, it may have a convulsion in which it will fall and lose consciousness. Epilepsy must not be confounded with vertigo—the fainting which is an effect of heart troubles.

The exact cause of epilepsy in the majority of cases is unknown. Post-mortem examinations in many instances have failed to discover any lesion in connection with the brain or nervous system, while in other instances disease of the brain has been found in the form of thickening of the membranes, abscesses, and tumors, and in some cases the affection has been manifested in connection with a diseased condition of the blood. The cause has also been traced to reflex irritation, due to teething, worms, and chronic indigestion.

Treatment.—When the affection is due to the last-named causes treatment may be successful if the cause is removed. If there are symptoms of worms or of indigestion, follow the general treatment advised for those troubles under their proper heads. If due to irritation caused by teething, the inflamed gums must be lanced. Examination of the mouth often develops the fact that one of the temporary teeth causes much irritation by remaining unshed, and thereby interfering with the growth of a permanent tooth. The offending tooth should be extracted. When the cause of epilepsy can not be discovered, it must be confessed that there is no prospect of a cure. However, some benefit may be expected from the occasional administration of a purgative dose of medicine. A pound of Epsom salt dissolved in a quart of warm water, for a cow of average size, may be given as a drench once or twice a month. In addition to the purgative, 4 drams of bromid of potassium, dissolved in the drinking water, three times a day, has proved very beneficial in some cases.

SUNSTROKE (PROSTRATION FROM HEAT).

Owing to the fact that cattle are seldom put to work at which they would have to undergo severe exertion, especially in collars, they are not frequently prostrated by the extreme heat of the summer months. When at pasture they select the coolest places in the shade of trees, in water, etc., when the heat becomes oppressive, and thereby avoid, as much as possible, the effects of it.

It does happen, however, that cattle that have been kept up for the purpose of fattening, when driven some distance in very hot weather, are sometimes prostrated, but it must be remembered that it is not really necessary for the animal to be exposed to the rays of the sun, as those confined in hot, close places may suffer. This often happens in shipping, when they are crowded together in cars.

Symptoms.—The premonitory signs are those of exhaustion—dullness, panting, frothing at the mouth, tongue hanging out, irregular gait, uneasiness, palpitation—when, if the circumstances which tend to the prostration are not mitigated, the animal staggers or sways from side to side, falls, struggles for a while, and then gradually becomes quiet, or the struggles may continue, with repeated but ineffectual efforts to regain a standing position. In serious cases the attack may be very sudden, unconsciousness occurring without continued or distressing premonitory symptoms.

Treatment.—At first, when not very serious, removal to a quiet, sheltered place, with a few days on a reduced diet, is all that need be done. When the animal has fallen, apply cold water or ice to the head; rub the body and limbs with cloths or wisps of straw and continue the rubbing for a considerable time. If the power of swallowing is not lost (which may be ascertained by pouring a little cold water into the mouth), give 3 drams of stronger liquor ammonia, diluted with a quart of cold water. Be very careful in drenching the animal when lying down. Repeat the drench in a half hour and an hour after the first one has been given. Instead of the ammonia, a drench composed of 3 ounces of spirits of nitrous ether in a pint of water may be given, if more convenient, but the ammonia drench is preferable. If unconsciousness continues, so that a drench can not be administered, the same quantity of ammonia and water may be injected with a syringe into the rectum. The popular aqua ammonia, commonly called "hartshorn," will do as well as the stronger liquor ammonia, but as it is weaker than the latter the dose for a cow is about 1-1/2 ounces, which should be diluted with a quart of water before it is given to the animal, either as a drench or an enema. When ammonia can not be obtained, an ounce of tincture of digitalis may be given.