Part 57 (2/2)
WOUNDS OF THE SKIN.
Wounds of the skin are fully discussed in the next chapter.
FOOTNOTES:
[3] An outbreak of quittor near Cheyenne, Wyo., which came under the author's observation, was caused by the mud through which the horses had to wade to reach the watering troughs. These troughs were furnished with water by windmills, and the mudholes were caused by the waste water.
More than 50 cases developed inside of two months, or during September and October. In these 50 cases all forms of the disease and all possible complications were presented. During the rainy season at Leadville, Colo., outbreaks of quittor are common, and the disease is so virulent that it has long been known as the ”Leadville foot rot.” The soil being rich in mineral matters is no doubt the cause of the outbreaks. In the city of Montreal quittor is said to be very common in the early springtime, when the streets are muddy from the melting snow and ice.
[4] Descazeaux has shown that the worms found in these summer sores are probably larval forms of the stomach worms of the horse, _Habronema megastoma_, _H. microstoma_, and _H. muscae_. Ransom has shown that the larval stage of _H. muscae_ develops in the common housefly, the fly becoming infested as a maggot in horse manure. Infestation with the adult worms in the stomach of the horse (Pl. V, fig. 4) may take place through the ingestion of such infested flies, or by the escape of the larva from the proboscis of the fly as it feeds on the moist lips of the horse. In view of this it may be surmised that summer sores may arise as the result of flies so infested feeding on the moisture on the skin of the horse. In some forms of summer sores along the abdomen there are found immature stages of _Habronema_ which apparently have just escaped from the egg and which are younger than some of the stages found in the fly. In this case it is surmised that these embryos from the manure enter the soiled skin of the horse, as it lies down on dirty bedding and manure, and develop in the skin as they would ordinarily in the fly.
Descazeaux calls these summer sores cutaneous habronemiasis.
Preventive measures consist in the removal of the adult worms from the stomach of the horse by the use of anthelmintics, the destruction of the embryos in the manure, fly-control measures, and the use of clean bedding.--M. C. HALL.
[5] Descazeaux recommends the application and injection of 2 to 3 per cent trypanblue, though he states that the only truly efficacious treatment is the early and complete ablation of the invaded tissue.--M.
C. H.
[6] Revised by M. C. Hall.
WOUNDS AND THEIR TREATMENT.
By CH. B. MICHENER, V. S.
[Revised by John R. Mohler, V. M. D., A. M.]
DESCRIPTION OF WOUNDS.
A wound is an injury to any part of the body involving a solution of continuity or disruption of the affected parts and is caused by violence, with or without laceration of the skin. In accordance with this definition we have the following varieties of wounds: Incised, punctured, contused, lacerated, gunshot, and poisoned. They may further be cla.s.sified as superficial, deep, or penetrating, and also as unclean, if hair, dirt, or splinters of wood are present; as infected when contaminated with germs, and as aseptic if the wound does not contain germs.
An incised wound is a simple cut made with a sharp body, like a knife, producing merely a division of the tissues. The duller the body the more force is required, the more tissues destroyed, and a greater time will be required for healing. In a cut wound the edges are even and definite, while those of a lacerated wound are irregular and torn. Three conditions are present as a result of an incised wound: (1) Pain, (2) hemorrhage, (3) gaping of the wound. The first pain is due to the crus.h.i.+ng and tearing of the nerve fibers. In using a sharp knife and by cutting quickly, the animal suffers less pain and healing occurs more rapidly. The secondary pain is usually due to the action of the air and inflammatory processes. When air is kept from the wound pain ceases soon after the lesion is produced. Hemorrhage is absent only in wounds of nonvascular tissues, as the cornea of the eye, the cartilage of joints, and other similar structures. Bleeding may be from the arteries, veins, or capillaries. In the last form of bleeding the blood oozes from the part in drops. Hemorrhage from the veins is dark red and issues in a steady stream without spurting. In arterial bleeding the blood is bright red and spurts with each heart beat. This latter variety of hemorrhage is the most dangerous, and should be stopped at once before attempting any further treatment. Bleeding from small veins and capillaries ceases in a short time spontaneously, while larger vessels, especially arteries, require some form of treatment to cause complete stoppage of the hemorrhage.
HEMOSTASIA.
By this term is meant the checking of the flow of blood. It may be accomplished by several methods, such as compress bandages, torsion, hot iron, and ligatures. The heat from a hot iron will cause the immediate clotting of the blood in the vessels, and this clot is further supported by the production of a scab, or crust, over the portion seared. The iron should be at a red heat. If at a white heat, the tissue is charred, which makes it brittle and the bleeding is liable to be renewed. If the iron is at a black heat, the tissue will stick to the iron and will pull away from the surface of the wound. Cold water and ice bags quickly stop capillary bleeding, while hot water is preferable in more excessive hemorrhages. Some drugs, called styptics, possess the power of contracting the walls of blood vessels and also of clotting the blood. A solution of the chlorid of iron placed on a wound alone or by means of cotton drenched in the liquid produces a rapid and hard clot. Tannic acid, alum, acetic acid, alcohol, and oil of turpentine are all more or less active in this respect. To check bleeding from large vessels compression may be adopted. When it is rapid and dangerous and from an artery, the fingers may be used for pressing between the wound and the heart (digital compression), but if from a vein, the pressure should be exerted on the other side of the wound. Tourniquet may also be used by pa.s.sing a strap around the part and tightening after placing a pad over the hemorrhage. The rubber ligature has now replaced the tourniquet and is bound tightly around the limb to arrest the bleeding. Tampons, such as cotton, tow, or oak.u.m, may be packed tightly in the wound and then sewed up. After remaining there for twenty-four or forty-eight hours they are removed. Bleeding may sometimes be easily checked by pa.s.sing a pin under the vessel and by taking a horsehair and forming a figure 8 by running it above and below the pin, thus causing pressure on the vessel.
Torsion is the twisting of the blood vessel until the walls come together and form a barrier to the flow of blood. It may be accomplished by the fingers, forceps, or by running a pin through the vessel, turning it several times, and then running the point into the tissue to keep it in a fixed position.
Ligation is the third method for stopping a hemorrhage. The blood vessel should be seized with the artery forceps, a clean thread of silk pa.s.sed around it, and tied about one-half inch from its end. The silk should be sterilized by placing it in an antiseptic solution so as not to impede the healing process or cause blood poisoning or lockjaw, which often follows the ligation of a vein with unsterilized material. Sometimes it will be impossible to reach the bleeding vessel, so it is necessary to pa.s.s the ligature around a ma.s.s of tissue which includes the blood vessel. Ligation is the most useful method of arresting hemorrhage, since it disturbs healing least and gives the greatest security against secondary hemorrhage.
SUTURES.
After the bleeding has been controlled and all foreign bodies removed from the wound, the gaping of the wound is noticeable. It is caused by the contraction of the muscles and elastic fibers, and its degree depends on the extent, direction, and nature of the cut. This gaping will hinder the healing process so that it must be overcome by bringing the edges together by some sort of sutures or pins or by a bandage applied from below upward. As suture material, ordinary cotton thread is good, if well sterilized, as are also horsehair, catgut, silk, and various kinds of wire. If the suture is made too tight the subsequent swelling may cause the st.i.tch to tear out. In order to make a firm suture the depth of the st.i.tch should be the same as the distance the st.i.tch is from the edge of the wound. The deeper the suture the more tissue is embraced and the fewer the number of st.i.tches required. In tying a suture the square or reef knot should be used. Closure of wounds by means of adhesive plaster, collodion, and metal clamps is not practiced to any great extent in veterinary practice.
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