Chapter 5

Fever is a general condition of the animal body in which there is an elevation of the animal body temperature, which may be only a degree or two or may be 10° F. The elevation of the body temperature, which represents tissue change or combustion, is accompanied with an acceleration of the heart's action, a quickening of the respiration, and an aberration in the functional activity of the various organs of the body. These organs may be stimulated to the performance of excessive work, or they may be incapacitated from carrying out their allotted tasks, or, in the course of a fever, the two conditions may both exist, the one succeeding the other. Fever as a disease is usually preceded by chills as an essential symptom.

Fevers are divided into essential fevers and symptomatic fevers. In symptomatic fever some local disease, usually of an inflammatory character, develops first, and the constitutional febrile phenomena are the result of the primary point of combustion irritating the whole body, either through the nervous system or directly by means of the waste material which is carried into the circulation and through the blood vessels, and is distributed to distal parts. Essential fevers are those in which there is from the outset a general disturbance of the whole economy. This may consist of an elementary alteration in the blood or a general change in the constitution of the tissues. Fevers of the latter class are usually due to some infecting agent and belong, therefore, to the class of infectious diseases.

Essential fevers are subdivided into ephemeral fevers, which last but a short time and terminate by critical phenomena; intermittent fevers, in which there are alterations of exacerbations of the febrile symptoms and remissions, in which the body returns to its normal condition or sometimes to a depressed condition, in which the functions of life are but badly performed; and continued fevers, which include contagious diseases, such as glanders, influenza, etc., the septic diseases, such as pyemia, septicemia, etc., and the eruptive fevers, such as variola, etc.

Whether the cause of the fever has been an injury to the tissues, such as a severe bruise, a broken bone, an inflamed lung, or excessive work, which has surcharged the blood with the waste products of the combustion of the tissues, which were destroyed to produce force, or the toxins of influenza in the blood, or the presence of irritating material, either in the form of living organisms or of their products, as in glanders or tuberculosis--the general train of symptoms are much the same, varying as the amount of the irritant differs in quantity, or when some special quality in them has a specific action on one or another tissue.

There is in fever at first a relaxation of the small blood vessels, which may have been preceded by a contraction of the same if there was a chill, and as a consequence there is an acceleration of the current of the blood. There is, then, an elevation of the peripheral temperature, followed by a lowering of tension in the arteries and an acceleration in the movement of the heart. These conditions may be produced by a primary irritation of the nerve centers of the brain from the effects of heat, as is seen in thermic fever, or sunstroke, or by the entrance into the blood stream of disease-producing organisms or their chemical products, as in anthrax, rinderpest, influenza, etc.

There are times when it is difficult to distinguish between the existence of fever as a disease and a temporary feverish condition which is the result of excessive work. Like the condition of congestion of the lungs, which is normal up to a certain degree in the lungs of a race horse after a severe race, and morbid when it produces more than temporary phenomena or when it causes distinct lesions, the temperature may rise from physiological causes as much as four degrees, so fever, or, as it is better termed, a feverish condition, may follow any work or other employment of energy in which excessive tissue change has taken place; but if the consequences are ephemeral, and no recognizable lesion is apparent, it is not considered morbid. This condition, however, may predispose to severe organic disturbance and local inflammations which will cause disease, as an animal in this condition is liable to take cold and develop lung fever or a severe enteritis, if chilled or otherwise exposed.

Fever in all animals is characterized by the same general phenomena, but we find the intensity of the symptoms modified by the species of animals affected, by the races which subdivide the species, by the families which form groups of the races, and by certain conditions in individuals themselves. For example, a pricked foot in a Thoroughbred may cause intense fever, while the same injury in the foot of a Clydesdale may scarcely cause a visible general symptom. In the horse, fever produces the following symptoms:

The normal body temperature, which varies from 99° to 100° F., is elevated from 1° to 9°. A temperature of 102° or 103° F. is moderate fever, 104° to 105° F. is high, and 106° F. and over is excessive. The temperature is accurately measured by means of a clinical thermometer inserted in the rectum.

This elevation of temperature can readily be felt by the hand placed in the mouth of the animal, or in the rectum, and in the cleft between the hind legs. It is usually appreciable at any point over the surface of the body and in the expired air emitted from the nostrils. The ears and cannons are often as hot as the rest of the body, but are sometimes cold, which denotes a debility in the circulation and irregular distribution of the blood. The pulse, which in a healthy horse is felt beating about 42 to 48 times in the minute, is increased to 60, 70, 90, or even 100. The respirations are increased from 14 or 16 to 24, 30, 36, or even more. With the commencement of a fever the horse usually has diminished appetite, or it may have total loss of appetite if the fever is excessive. There is, however, a vast difference among horses in this regard. With the same degree of elevation of temperature one horse may lose its appetite entirely, while another, usually of the more common sort, will eat at hay throughout the course of the fever, and will even continue to eat oats or other grains. Thirst is usually increased, but the animal desires only a small quantity of water at a time, and in most cases of fever a bucket of water should be kept standing before the patient, which may be allowed to drink ad libitum. The skin becomes dry and the hairs stand on end. Sweating is almost unknown in the early stage of fevers, but frequently occurs later in their course, when an outbreak of warm sweat is often a most favorable symptom. The mucous membranes, which are most easily examined in the conjunctivæ of the eyes and inside of the mouth, change color if the fever is an acute one; without alteration of blood the mucous membranes become of a rosy or deep-red color at the outset; if the fever is attended with distinct alteration of the blood, as in influenza, and at the end of two or three days in severe cases of pneumonia or other extensive inflammatory troubles the mucous membranes are tinged with yellow, which may even become a deep ocher in color, the result of the decomposition of the blood corpuscles and the freeing of their coloring matter, which acts as a stain. At the outset of a fever the various glands are checked in their secretions, the salivary glands fail to secrete the saliva, and we find the surface of the tongue and inside of the cheeks dry and covered with a brownish, bad-smelling deposit. The excretion from the liver and intestinal glands is diminished and produces an inactivity of the digestive organs which causes a constipation. If this is not remedied at an early period, the undigested material acts as an irritant, and later we may have it followed by an inflammatory process, producing a severe diarrhea.

The excretion from the kidneys is sometimes at first entirely suppressed. It is always considerably diminished, and what urine is passed is dark in color, undergoes ammoniacal change rapidly, and deposits quantities of salts. At a later period the diminished excretion may be replaced by an excessive excretion, which aids in carrying off waste products and usually indicates an amelioration of the fever.

While the ears, cannons, and hoofs of a horse suffering from fever are usually found hot, they may frequently alternate from hot to cold, or be much cooler than they normally are. This latter condition usually indicates great weakness on the part of the circulatory system.

It is of the greatest importance, as an aid in diagnosing the gravity of an attack of fever and as an indication in the selection of its mode of treatment, to recognize the exact cause of a febrile condition in the horse. In certain cases, in very nervous animals, in which fever is the result of nerve influence, a simple anodyne, or even only quiet with continued care and nursing, will sometimes be sufficient to diminish it. When fever is the result of local injury, the cure of the cause produces a cessation in the constitutional symptoms. When it is the result of a pneumonia or other severe parenchymatous inflammation, it usually lasts for a definite time, and subsides with the first improvement of the local trouble, but in these cases we constantly have exacerbations of fever due to secondary inflammatory processes, such as the formation of small abscesses, the development of secondary bronchitis, or the death of a limited quantity of tissue (gangrene).

In specific cases, such as influenza, strangles, and septicemia, there is a definite poison in the blood-vessel system and carried to the heart and to the nervous system, which produces a peculiar irritation, usually lasting for a specific period, during which the temperature can be but slightly diminished by any remedy.

In cases attended with complications, the diagnosis at times becomes still more difficult, as at the end of a case of influenza which becomes complicated with pneumonia. The high temperature of the simple inflammatory disease may be grafted on that of the specific trouble, and the determination of the cause of the fever, as between the two, is therefore frequently a difficult matter but an important one, as upon it depends the mode of treatment.

Any animal suffering from fever, whatever the cause, is much more susceptible to attacks of local inflammation, which become complications of the original disease, than are animals in sound health. In fever we have the tissues and the walls of the blood vessels weakened, we have an increased current of more or less altered blood flowing through the vessels and stagnating in the capillaries, which need but an exciting cause to transform the passive congestion of fever into an active congestion and acute inflammation. These conditions become still more distinct when the fever is accompanied with a decided deterioration in the blood itself, as is seen in influenza, septicemia, and at the termination of severe pneumonias.

Fever, with its symptoms of increased temperature, acceleration of the pulse, acceleration of respiration, dry skin, diminished secretions, etc., must be considered as an indication of organic disturbance. This organic disturbance may be the result of local inflammation or other irritants acting through the nerves on nerve centers, alterations of the blood, in which a poison is carried to the nerve centers, or direct irritants to the nerve centers themselves, as in cases of heat stroke, injury to the brain, etc.

The treatment of fever depends upon its cause. One of the important factors in treatment is absolute quiet. This may be obtained by placing a sick horse in a box stall, away from other animals and extraneous noises and sheltered from excessive light and drafts of air. Anodynes, belladonna, hyoscyamus, and opium act as antipyretics simply by quieting the nervous system. As an irritant exists in the blood in most cases of fever, any remedy which will favor the excretion of foreign elements from it will diminish this cause. We therefore use diaphoretics to stimulate the sweat and excretions from the skin; diuretics to favor the elimination of matter by the kidneys; cholagogues and laxatives to increase the action of the liver and intestines, and to drain from these important organs all the waste material which is aiding to choke up and congest their rich plexuses of blood vessels. The heart becomes stimulated to increased action at the outset of a fever, but this does not indicate increased strength; on the contrary, it indicates the action of an irritant to the heart that will soon weaken it. It is, therefore, irrational further to depress the heart by the use of such drugs as aconite. It is better to strengthen it and to favor the elimination of the substance that is irritating it. The increased blood pressure throughout the body may be diminished by lessening the quantity of blood. This is obtained in some cases with advantage when the disease is but starting and the animal is plethoric by direct abstraction of blood, as in bleeding from the jugular or other veins; or by derivatives, such as mustard, turpentine, or blisters applied to the skin; or by setons, which draw to the surface the fluid of the blood, thereby lessening its volume without having the disadvantage of impoverishing the elements of the blood found in bleeding. In many cases antipyretics given by the mouth and cold applied to the skin are most useful.

When the irritation which is the cause of fever is a specific one, either in the form of bacteria (living organisms), as in glanders, tuberculosis, influenza, septicemia, etc., or in the form of a foreign element, as in rheumatism, gout, hemaglobinuria, and other so-called diseases of nutrition, we employ remedies which have been found to have a direct specific action on them. Among the specific remedies for various diseases are counted quinin, carbolic acid, salicylic acid, antipyrene, mercury, iodin, the empyreumatic oils, tars, resins, aromatics, sulphur, and a host of other drugs, some of which are of known effect and others of which are theoretical in action. Certain remedies, like simple aromatic teas, vegetable acids, such as vinegar, lemon juice, etc., alkalines in the form of salts, sweet spirits of niter, etc., which are household remedies, are always useful, because they act on the excreting organs and ameliorate the effects of fever. Other remedies, which are to be used to influence the cause of fever, must be selected with judgment and from a thorough knowledge of the nature of the disease.

METHODS OF ADMINISTERING MEDICINES.

By CH. B. MICHENER, V. S.

[Revised by Leonard Pearson, B. S., V. M. D.]

Medicine may enter the body through any of the following designated channels: First, by the mouth; second, by the air passages; third, by the skin; fourth, by the tissue beneath the skin (hypodermic methods); fifth, by the rectum; sixth, by the genito-urinary passages; and, seventh, by the blood (intravenous injections).

BY THE MOUTH.--Medicines can be given by the mouth in the form of solids, as powders or pills; liquids, and pastes, or electuaries.

_Powders._--Solids administered as powders should be as finely pulverized as possible, in order to obtain rapid solution and absorption. Their action is in this way facilitated and intensified. Powders must be free from any irritant or caustic action upon the mouth. Those that are without any disagreeable taste or smell are readily eaten with the feed or taken in the drinking water. When placed with the feed they should first be dissolved or suspended in water and thus sprinkled on the feed. If mixed dry the horse will often leave the medicine in the bottom of his manger. Nonirritant powders may be given in capsules, as balls are given.

_Pills, or "balls"_ when properly made, are cylindrical in shape, 2 inches in length and about three-fourths of an inch in diameter. They should be fresh, but if necessary to keep them some time they should be made up with glycerin, or some such agent, to prevent their becoming too hard. Very old, hard balls are sometimes passed whole with the manure without being acted upon at all. Paper is sometimes wrapped around balls when given, if they are so sticky as to adhere to the fingers or the balling gun. Paper used for this purpose should be thin but firm, as the tougher tissue papers. Balls are preferred to drenches when the medicine is extremely disagreeable or nauseating; when the dose is not too large; when the horse is difficult to drench; or when the medicine is intended to act slowly. Certain medicines can not or should not be made into balls, as medicines requiring to be given in large doses, oils, caustic substances, unless in small dose and diluted and thoroughly mixed with the vehicle, deliquescent, or efflorescent salts. Substances suitable for balls can be made up by the addition of honey, sirup, soap, etc., when required for immediate use. Gelatin capsules of different sizes are now obtainable and are a convenient means of giving medicines in ball form.

When balls are to be given we should observe the following directions: In shape they should be cylindrical, of the size above mentioned, and soft enough to be easily compressed by the fingers. If made round or egg-shaped, if too long or too hard, they are liable to become fixed in the gullet and cause choking. Balls may be given with the "balling gun" (obtainable at any veterinary instrument maker's) or by the hand. If given by the hand a mouth speculum or gag may be used to prevent the animal from biting the hand or crushing the ball. Always loosen the horse before attempting to give a ball; if tied he may break his halter and injure himself or the one giving the ball. With a little practice it is much easier to give a ball without the mouth gag, as the horse always fights more or less against having his mouth forced open. The tongue must be firmly grasped with the left hand and gently pulled forward; the ball, slightly moistened, is then to be placed with the tips of the fingers of the right hand as far back into the mouth as possible; as the tongue is loosened it is drawn back into the mouth and carries the ball backward with it. The mouth should be kept closed for a minute or two. We should always have a pail of water at hand to offer the horse after balling. This precaution will often prevent him from coughing out the ball or its becoming lodged in the gullet.

_Pastes or electuaries_ are medicines mixed with licorice-root powder, ground flaxseed, molasses, or sirup to the consistency of honey, or a "soft solid." They are intended, chiefly, to act locally upon the mouth and throat. They are given by being spread upon the tongue, gums, or teeth with a wooden paddle or strong, long-handled spoon.

_Liquids._--It is, very often, impossible to get balls properly made, or to induce owners or attendants to attempt to give them, and for these reasons medicines by the mouth are mostly given in the form of liquids. Liquids may be given as drenches when the dose is large, or they may, when but a small quantity is administered, be injected into the mouth with a hard-rubber syringe or be poured upon the tongue from a small vial.

When medicine is to be given as a drench we must be careful to use water or oil enough to dissolve or dilute it thoroughly; more than this Wakes the drench bulky and is unnecessary. Insoluble medicines, if not irritant or corrosive, may be given simply suspended in water, the bottle to be well shaken immediately before giving the drench. The bottle used for drenching purposes should be clean, strong, and smooth about its neck; it should be without shoulders, tapering, and of a size to suit the amount to be given. A horn or tin bottle may be better, because it is not so easily broken by the teeth. If the dose is a small one the horse's head may be held up by the left hand, while the medicine is poured into the mouth by the right. The left thumb is to be placed in the angle of the lower jaw, and the fingers spread out in such manner as to support the lower lip. Should the dose be large, the horse ugly, or the attendant unable to support the head as directed above, the head is then to be held up by running the tines of a long-handled wooden fork under the noseband of the halter or the halter strap or a rope may be fastened to the noseband and thrown over a limb, beam, or through a pulley suspended from the ceiling. Another way of supporting the head is to place a loop in the end of a rope, and introduce this loop into the mouth just behind the upper front teeth or tusks of the upper jaw, the free end to be run through a pulley, as before described, and held by an assistant. It is never to be fastened, as the horse might in that case do himself serious injury. The head is to be elevated just enough to prevent the horse from throwing the liquid out of his mouth. The line of the face should be horizontal, or only the least bit higher. If the head is drawn too high the animal can not swallow with ease or even with safety. (If this is doubted, just fill your mouth with water, throw-back the head as far as possible, and then try to swallow.) The person giving the drench should stand on some object in order to reach the horse's mouth--on a level, or a little above it. The bottle or horn is then to be introduced at the side of the mouth, in front of the molar teeth, in an upward direction. This will cause the horse to open his mouth, when the base of the bottle is to be elevated, and about 4 ounces of the liquid allowed to escape on the tongue as far back as possible, care being taken not to get the neck of the bottle between the back teeth. The bottle is to be immediately removed, and if the horse does not swallow this can be encouraged by rubbing the fingers or neck of the bottle against the roof of the mouth, occasionally removing them. As soon as this is swallowed repeat the operation until he has taken all the drench. If coughing occurs, or if, by any mishap, the bottle should be crushed in the mouth, lower the head immediately.

Do not rub, pinch, or pound the throat nor draw out the tongue when giving a drench. These processes in no way aid the horse to swallow and oftener do harm than good. In drenching, swallowing may be hastened by pouring into the nose of the horse, while the head is high, a few teaspoonfuls of clean water, but _drenches must never be given through the nose_. Large quantities of medicine given by pouring into the nose are liable to strangle the animal, or, if the medicine is irritating, it sets up an inflammation of the nose, fauces, windpipe, and sometimes the lungs.

BY THE AIR PASSAGES.--Medicines are administered to the lungs and upper air passages by insufflation, inhalation, injection, and nasal douche.

_Insufflation_ consists in blowing an impalpable powder directly into the nose. It is but rarely resorted to.