Part 66

The cavity should be thoroughly washed with stimulating antiseptic solutions, such as 3 per cent solution of carbolic acid, 3 per cent solution of compound cresol, 1 to 1,000 bichlorid of mercury, or 1 per cent permanganate of potash solution. If the abscesses are foul and bad smelling, their cavities should first be syringed with 1 part of hydrogen peroxid to 2 parts of water and then followed by the injection of any of the above-mentioned antiseptics.

COLD ABSCESSES.

Cold abscess is the term applied to those large, indolent swellings that are the result of a low or chronic form of inflammation, in the center of which there is a small collection of pus. They are often seen near the point of the shoulder, forming the so-called breast boil. The swelling is diffuse and of enormous extent, but slightly hotter than surrounding parts, and not very painful upon pressure. A pronounced stiffness, rather than pain, is evinced upon moving the animal. Such abscesses have the appearance of a hard tumor, surrounded by a softer edematous swelling, involving the tissues to the extent of a foot or more in all directions from the tumor. This diffused swelling gradually subsides and leaves the large, hardened mass somewhat well defined. One of the characteristics of cold abscesses is their tendency to remain in the same condition for a great length of time. There is neither heat nor soreness; no increase nor lessening in the size of the tumor; it remains in statu quo. If, however, the animal should be put to work for a short time the irritation of the collar causes the surrounding tissues to assume again an edematous condition, which after a few days' rest disappears, leaving the tumor as before or but slightly larger. Upon careful manipulation we may discover what appears to be a fluid deep seated in the center of the mass. The quantity of matter so contained is very small—often not more than a tablespoonful—and for this reason it can not, in all cases, be detected.

Cold abscesses are mostly, if not always, caused by the long-continued irritation of a loose and badly fitting collar. There is a slow inflammatory action going on, which results in the formation of a small quantity of matter inclosed in very thick and but partially organized walls that are not so well defined as is the circumference of fibrous tumors, which they most resemble.

Treatment.—The means recommended to bring the acute abscess "to a head" are but rarely effectual with this variety; or, if successful, too much time has been occupied in the cure. We must look for other and more rapid methods of treatment. These consist, first of all, in carefully exploring the tumor for the presence of pus. The incisions must be made over the softest part and carried deep into the tumor—to its very bottom, if necessary—and the matter allowed to escape. After this, and whether we have found matter or not, we must induce an active inflammation of the tumor, in order to promote solution of the thick walls of the abscess. This may be done by inserting well into the incision a piece of oakum or cotton saturated with turpentine, carbolic acid, tincture of iodin, etc., or we may pack the incision with powdered sulphate of zinc and keep the orifice plugged for 24 hours. These agents set up a destructive inflammation of the walls. Suppuration follows, and this should now be encouraged by hot fomentations and poultices. The orifice must be kept open, and should it be disposed to heal we must again introduce some of the agents above described. A favored treatment with many, and it is probably the best, is to plunge a red-hot iron to the bottom of the incision and thoroughly sear all parts of the walls of the abscess. This is to be repeated after the first slough has taken place if the walls remain thickened and indurated.

It is useless to waste time with fomentations, poultices, or blisters in the treatment of cold abscesses, since though apparently removed by such methods, they almost invariably return when the horse is put to work. Extirpation by the knife is not practicable, as the walls of the tumor are not sufficiently defined. If treated as above directed, and properly fitted with a good collar after healing, there will not remain any track or trace of the large, unsightly mass.

FISTULAS.

Definition.—The word fistula is applied to any ulcerous lesion upon the external surface of the body which is connected by ducts, or passages, with some internal cavity. Because of this particular formation the term fistulous tract is often used synonymously with the word fistula. Fistulas may exist in any part of the body, but the name has come to be commonly accepted as applicable only to such lesions when found upon the withers. Poll evil is a fistula upon the poll, and in no sense differs from fistulous withers except in location. The description of fistula will apply, then, in the main, to poll evil equally well. Quittor presents the characteristic tubular passages of a fistula and may, therefore, be considered and treated as fistula of the foot. Fistulous passages may also be developed upon the sides of the face, through which saliva is discharged instead of flowing into the mouth, and are called salivary fistulas. A dental fistula may arise from the necrosis of the root of a tooth. Again, a fistula is sometimes noted at the umbilicus associated with hernia, and recto-vaginal fistulas have been developed in mares, following difficult parturition. Fistulas may arise from wounds of glandular organs or their ducts, and thus we have the so-called mammary or lacrimal fistulas.

Fistulous tracts are lined with a false, or adventitious, membrane and show no disposition to heal. They constantly afford means of exit to the pus or ichorous material discharged by the unhealthy parts below. They are particularly liable to develop at the withers or poll because of the exposed positions which these parts occupy, and, having once become located there, they usually assert a tendency to further extension, because the vertical and laminated formation of the muscles and tendons of these parts allows the forces of gravitation to assist the pus in gaining the deeper-lying structures and also favors its retention among them.

Causes.—Fistulas follow as a result of abscesses, bruises, wounds, or long-continued irritation by the harness. Among the more common causes of fistula of the poll (poll evil) are chafing by the halter or heavy bridle; blows from the butt end of the whip; the horse striking his head against the hayrack, beams of the ceiling, low doors, etc. Fistulous withers are seen mostly in those horses that have thick necks as well as those that are very high in the withers; or, among saddle horses, those that are very low in the withers, the saddle here riding forward and bruising the parts. In either of these locations ulcers of the skin, or simple abscesses, if not properly and punctually treated, may become fistulas. They are often caused by bad-fitting collars or saddles, by direct injuries from blows, and from the horse rolling upon rough or sharp stones. The pus burrows and finds lodgment deep down between the muscles, and escapes only when the sinus becomes surcharged or when, during motion of the parts, the matter is forced to the surface.

Symptoms.—These, of course, will vary according to the progress made by the fistula. Following an injury we may often notice soreness or stiffness of the front legs, and upon careful examination of the withers we see small tortuous lines running from the point of irritation downward and backward over the region of the shoulder. These are superficial lymphatics, and are swollen and painful to the touch. In a day or two a swelling is noticed on one or both sides of the dorsal vertebrae, which is hot, painful, and rapidly enlarging. The stiffness of the limbs may disappear at this time, and the heat and soreness of the parts may become less noticeable, but the swelling remains and continues to enlarge.

A fistulous ulcer of the poll may be first indicated by the opposition which the animal offers to the application of stable brush or bridle. At this time the parts are so sore and sensitive that there is some danger that unless handled with the greatest care the patient will acquire disagreeable stable habits. The disease in its early stages may be recognized as a soft, fluctuating tumor surrounded by inflammatory swelling, with the presence of enlarged lymphatic vessels and stiffness of the neck. Later the inflammation of the surrounding tissues may disappear, leaving a prominent tumor. The swelling, whether situated upon the head or the withers, may open and form a running ulcer, or its contents may dry up and leave a tumor which gradually develops the common characteristics of a fibrous tumor. When the enlargement has opened we should carefully examine its cavity, as upon its condition will wholly depend our treatment.

Treatment.—In the earliest stage, when there is soreness, enlarged lymphatics, but no well-marked swelling, the trouble may frequently be aborted. To do this requires both general and local treatment. A physic should be given, and the horse receive 1 ounce of powdered saltpeter three times a day in his water or feed. If the fever runs high, 20-drop doses of tincture of aconite root every two hours may be administered. The local application of cold water to the inflamed spot for an hour at a time three or four times a day has often proved very beneficial, and has afforded great relief.

Cooling lotions, muriate of ammonia, or saltpeter and water; sedative washes, such as tincture of opium and aconite, chloroform liniment, or camphorated oil, are also to be frequently applied. Should this treatment fail to check the progress of the trouble, the formation of pus should be hastened as rapidly as possible. Hot fomentations and poultices are to be constantly used, and as soon as the presence of pus can be detected, the abscess wall is to be opened at its lowest point. In this procedure lies our hope of a speedy cure. As with any simple abscess, if drainage can be so provided that the pus will run off as fast as formed without remaining within the interstices of the tissues, the healing will be rapid and satisfactory.

Attention is again called to the directions given above as to the necessity of probing the cavity when opened. If upon a careful examination with the probe we find that there are no pockets, no sinuses, but a simple, regular abscess wall, the indication for treatment is to make an opening from below so that all the matter must escape. Rarely is anything more needed than to keep the orifice open and to bathe or inject the parts with some simple antiseptic wash that is not irritant or caustic. A low opening and cleanliness constitute the essential and rational treatment.

If the abscess has already opened, giving vent to a quantity of purulent matter, and the pipes and tubes leading from the opening are found to be extensive and surrounded with thick fungoid membranes, there is considerable danger that the internal ligaments or even some of the bones have become affected, in which case the condition has assumed a serious aspect. Or, on the other hand, if the abscess has existed for some time without a rupture, its contents will frequently be found to consist of dried purulent matter, firm and dense, and the walls surrounding the mass will be found greatly thickened. In such a case we must generally have recourse to the application of caustics which will cause a sloughing of all of the unhealthy tissue, and will also stimulate a rapid increase of healthy organized material to replace that destroyed in the course of the development and treatment of the disease. Threads or cords soaked in gum-arabic solution and rolled in powdered corrosive sublimate may be introduced into the canal and allowed to remain. The skin on all parts of the shoulder and leg beneath the fistula should be carefully greased with lard or oil, as this will prevent the discharge that comes from the opening after the caustic is introduced from irritating or blistering the skin over which it flows. In obstinate cases a piece of caustic potash (fused) 1 to 2 inches in length may be introduced into the opening and should be covered with oakum or cotton. The horse should then be secured so that he can not reach the part with his teeth. After the caustic plug has been in place for 24 hours, it may be removed and hot fomentations applied. As soon as the discharge has become again established the abscess should be opened from its lowest extremity, and the passage thus formed may be kept open by the introduction of a seton. If the pipes become established in the deep tissues beneath the shoulder blade or among the spines of the vertebral column, it will often be found impossible to provide proper drainage for the abscess from below, and treatment must consist of caustic solutions carefully injected into all parts of the suppurating sinuses. A very effective remedy for this purpose consists of 1 ounce of chlorid of zinc in half a pint of water, injected three times during a week, after which a weak solution of the same may be occasionally injected. Injections of Villate's solution or alcoholic solution of corrosive sublimate, strong carbolic acid, or possibly oil of turpentine will also prove beneficial. Pressure should be applied from below, and endeavors made to heal the various pipes from the bottom.

Should the swelling become general, without forming a well-defined tumor, the placing of 20 to 30 grains of arsenious acid, wrapped in a single layer of tissue paper, in a shallow incision beneath the skin, will often produce a sloughing of the affected parts in a week or 10 days, after which the formation of healthy tissue follows. The surrounding parts of the skin should be protected from any damage from escaping caustics by the application of lard or oil, as previously suggested.

Although the successful treatment of fistulas requires time and patience, the majority of cases are curable. The sinuses must be opened at their lowest extremity and kept open. Caustic applications must be thoroughly used once or twice, after which mild astringent antiseptic washes should be persistently used until a cure is reached.

It sometimes happens that the erosions have burrowed so deeply or in such a direction that the opening of a drainage passage becomes impracticable. In other cases the bones may be attacked in some inaccessible location, or the joints may be affected, and in these cases it is often best to destroy the horse at once.

The reappearance of the fistula after it has apparently healed is not uncommon. The secondary attack in these cases is seldom serious. The lesion should be carefully cleaned and afterwards injected with a solution of zinc sulphate, 20 grains to the ounce of water, every second or third day until a cure is effected.

In fistula of the foot we see the same tendency toward the burrowing of pus downward to lower structures, or in some cases upward toward the coronet. Prior to the development of a quittor there is always swelling at the coronet, accompanied with heat and pain. Every effort should now be made to prevent the formation of an abscess at the point of injury. Wounds caused by nails, gravel, or any other foreign body which may have lodged in the sole of the foot should be opened at once from below, so as to allow free exit to all purulent discharges. Should the injury have occurred directly to the coronet the application of cold fomentations may prove efficient in preventing the formation of an abscess.

When a quittor becomes fully established it should be treated precisely as a fistula situated in any other part of the body; that is, the sinuses should all be opened from their lowest extremities, so as to afford constant drainage. All fragments of diseased tissue should be trimmed away, antiseptic solutions injected, and, after covering the wound with a pad of oakum saturated with some good antiseptic wash, the whole foot may be carefully covered with clean bandages, which will afford valuable assistance to the healing process by excluding all dirt from the affected part.

Another form of treatment for this class of infections consists in the use of bacterial vaccines. Such treatment appears to be well adapted for the purpose, and according to current veterinary literature has met with success. These vaccines are composed of several strains of the organisms usually found in these pustular infections of the horse. Two kinds of vaccines are used: First, autogenic vaccines, which consist of heated (killed) cultures of the organism or organisms which are causing the trouble and which have been isolated from the lesions; second, stock vaccines, consisting of dead organisms of certain species generally found in these lesions and which are used in diseased conditions caused by one or the other of these germs. The vaccine is administered subcutaneously by means of a syringe, but the quantity of the vaccine to be injected and the number of doses to be used should be left to the judgment of a competent veterinarian.

INFECTIOUS DISEASES.

By RUSH SHIPPEN HUIDEKOPER, M. D., Vet.

[Revised by A. Eichhorn, D. V. S.]

GENERAL DISCUSSION.

An infectious disease may be defined as any malady caused by the introduction into the body of minute organisms of the vegetable or animal kingdom which have the power to multiply indefinitely and set free certain peculiar poisons which are chiefly responsible for morbid changes. Nearly all diseases of animals for which a definite cause may be attributed are caused by bacteria; such are tuberculosis, anthrax, blackleg, lockjaw, and others. There are some diseases, as, for instance, Texas fever and rabies, which are caused by a minute animal parasite known as protozoa, while others again, like lumpy jaw and aspergillosis, are caused by fungi. Besides there are infectious diseases in which the causative agents have never been successfully isolated, as they are so small that they can not be detected by the aid of the most powerful microscope, and accordingly they are termed as ultravisible viruses. Hog cholera, foot-and-mouth disease, smallpox, and others belong to this group.

Bacteria may be defined as very minute unicellular organisms of plantlike character. They multiply either by simple division or by spore formation, the latter usually taking place when the conditions pertaining to the growth of the bacteria become unfavorable. The spores are much more resistant to destruction than the bacteria which produce them.

Another group of parasites producing disease is known as protozoa. These are more complex than bacteria, and their artificial cultivation is also much more difficult than is the case with the bacterial parasites. Of the representatives of this group, causing disease in animals, are the trypanosomes, which are the causative factors of dourine and surra, and the piroplasma, which induce Texas fever in cattle and malaria or biliary fever of horses. There are also disease-producing fungi which are responsible for certain affections in horses; among these the most important are mycotic lymphangitis, or sporotrichosis, and streptotrichosis.

The introduction of the infection may take place in various ways. The most frequent method is by ingestion. Further, the entrance of the germs may occur by inhalation, skin abrasions, wounds of any kind, through the genital organs, and at times also through the milk ducts of the teats. As a general rule infectious diseases have a period of incubation which comprises the time elapsing between the exposure to the infection and the actual appearance of the disease. This period varies in the different diseases.

The treatment of infectious diseases is, as a rule, unsatisfactory. When the symptoms have once appeared a disease is liable to run its course in spite of treatment, and if it is one from which animals usually recover, all that can be done is to put them into the most favorable surroundings. Many infectious diseases lead sooner or later to death; treatment is useless so far as the sick animals are concerned, and it may be worse than useless for those not yet affected. All animals suffering with infectious diseases are more or less directly a menace to all others. They represent for the time being manufactories of disease germs, and they are giving them off more or less abundantly during the period of disease. They may infect others directly or they may scatter the virus about and the surroundings may become the future source of infection.

Therefore, in the control of infectious diseases prevention is the most important procedure. The isolation or segregation of healthy animals from infected ones should be primarily considered, and if at any time an animal manifests the symptoms of an infectious disease it is essential to protect the others from such a source of danger. In some of the infectious diseases it may become advisable to kill the infected animals in order to avoid the spread of the disease. This is especially important in diseases which are slow in their course, such as tuberculosis. At times when diseases appear in a country where they have not been prevalent it becomes advisable and necessary to protect the healthy herds by the slaughter of all the infected animals. Pursuance of this policy has resulted in control of the foot-and-mouth disease, and has proved to be a very satisfactory method of eradication.