The principles and practice of modern surgery

The first requisite after the infliction of a wound is to arrest and control the hemorrhage. In many operations upon the extremities precautions are taken to avoid its occurrence, and the so-called bloodless method of operating, which is effected by the use of an elastic bandage of pure rubber, is frequently employed and generally gives satisfactory results. The pure-gum bandage was first introduced into surgery by Martin, of Massachusetts, and its combined use both as an elastic bandage and tourniquet was so promoted by Esmarch that it is generally known as Esmarch’s bandage, and Martin has failed to receive the credit due him.

The elastic bandage used for this purpose should be about three inches in width and five or six yards in length, and made of pure rubber. The operator begins by applying this to the tip of the extremity which is to be made bloodless. It is wound around the limb in spiral turns, with sufficient force to press out the blood from the tissues and to empty the vessels into those of the trunk. It is continued above the site of the operation, and then the limb is either constricted with a tourniquet of the old type or with one of the rubber appliances used for this purpose. A few turns of the rubber bandage may be passed more tightly about the limb at this point and secured with forceps. The rest of the bandage is then unwrapped from the limb, which will be found pale and bloodless. Operation may then be practised without the loss of more than a few drops of blood. All divided vessels should be secured before the constriction is removed and the wound closed.

In septic, tuberculous, and malignant conditions no such pressure should be made, as harmful elements might be forced into the circulation. In such cases the elastic tourniquet is applied high up and no attempt is made to force the blood out of the limb. The limb should be elevated so that its veins may empty before the bandage is applied, and a certain amount of blood will thus be saved.

Care should be taken in graduating the tightness of the constricting band, as well as its narrowness, and in preventing undue pressure upon nerve trunks. Cases are on record of temporary and even permanent paralysis, due to too vigorous application of the tourniquet, and except upon large and stout limbs it is not often necessary to apply it as tightly as is often done. Moreover even a wide rubber bandage when stretched taut becomes little better than a rubber cord or rubber tube and sinks into the tissues. A sterile towel should be folded into a strip and wound around the limb, and then a tourniquet should be applied over it so that pressure may be more equably distributed and danger of paralysis reduced.

Exigencies may require the application of the elastic tourniquet as high as it can be possibly used, either upon the shoulder or the hip. This necessity is usually observed in amputations at those joints, and the special methods required will be more fully dealt with when speaking of these procedures. (See Chapter LVII.)

The elastic bandage should have been unrolled and sterilized with the rest of the surgical equipment required, and even when so protected it would be well to cover the limb with wet sterile towels before applying the bandage, which is usually done at the last in order to avoid contamination. When this is not done the final scrubbing should not be effected until the bandage has been placed, the tourniquet applied, and the bandage again removed.

The first measure, then, in the treatment of a wound is to prevent loss of blood. This may be done in various ways, and the method should depend upon the circumstances of the case. In emergency cases it may be accomplished either by direct pressure, by constriction of the limb above the injury, or in some instances by mere position. If it be possible to make direct pressure through the medium of some clean—preferably sterile—dressing or material, this of course would be desirable. In all civilized armies soldiers are now equipped with a package of sterile dressing by which an emergency pad for this purpose can be promptly applied. Railroads and steamers are now providing emergency outfits. In injury of the arm or leg advantage may be taken of position, i. e., forced flexion, which is maintained by any measure or material which can be made available for this purpose (Fig. 60). Digital compression over a main vessel may also serve a good purpose. Mere elevation of the part, as, for example, the head, when not otherwise contra-indicated, or a hand or foot, will do much to check venous or arterial flow. Moreover, in these positions reflex contraction of arteries occurs, even in those of the head when the arms are elevated. For this reason in cases of serious nose-bleed it is often advisable to keep the arms raised high above the head.

Of other means resorted to may be mentioned:

1. Extremes of Heat and Cold.

—Water at a temperature of 130° to 160° F. is a powerful hemostatic. It stimulates contraction of the muscular coats of the vessels and produces coagulation of the albuminous portions of the blood upon the surface to which it is applied, and in this way plugs the capillaries and small arteries and so prevents oozing. Heat with pressure will be serviceable in many instances. Cold may be employed by means of ice or iced water and may be made serviceable in cavities like the mouth, the vagina, or the rectum, after patients have recovered from the anesthetic and at a time when hot water could not be borne. Cold has more of a constringing effect but less coagulating property.

2. Pressure Directly Applied.

—This may be made with a tampon in some cavity, or by a graduated absorbent dressing whose effect may be regulated by pressure of a bandage or an elastic bandage. Care should be always given that pressure be not too long nor too firmly made, and it should be released as soon as there appears edema of the part below or any evidence of insufficient circulation.

3. Styptics and Chemical Agents.

—There are many substances which contract vessels and cause more or less coagulation of blood, and at one time there were many of these in general use, but they have been supplemented by other products, i. e., cocaine, antipyrine, and adrenalin. The effect of cocaine is temporary, but sometimes is sufficient in the urethra or the nasal cavity. Antipyrine, in 5 to 10 per cent. solution, alone or with cocaine, has a similar effect, but is more lasting. Some years ago the writer stated that by mixing 10 per cent. solutions of antipyrine and tannin there was precipitated a gum-like material of extraordinary tenacity. This will check oozing from any part to which it may be applied, but it may adhere so tightly as to make it difficult to later remove the tampon. Of the hemostatic drugs, adrenalin has the most marvellous properties. It can be procured in solutions of 1 to 1000. A solution of this strength, somewhat diluted, may be spread or applied upon an oozing surface with almost instantaneous effect.

The use of gelatin in checking hemorrhage has given some satisfaction upon the Continent, but has not found much favor in this country. It consists of a solution of 2 parts of pure gelatin to 100 parts of normal salt solution, which should be thoroughly sterilized. It is injected subcutaneously to increase the coagulability of the blood, and has also been injected directly into an aneurysmal sac or its immediate vicinity to induce coagulation. It is likely that if the surgeon have a patient with the hemorrhagic diathesis the combined use of gelatin in this way and of calcium chloride internally would give satisfactory results.

A styptic has recently been introduced by Freund under the name “stypticin.” It is a product of the oxidation of narcotin, one of the opium alkaloids, and is a yellowish powder of bitter taste. Chemically it is cotarnin hydrochloride. It has been used especially in the treatment of uterine hemorrhage, with a certain degree of success, regardless of the cause of the hemorrhage. It may also be given in cases of too profuse menstruation. The average dose is 2 to 3 Gr. (0.15 to 0.20) at intervals of two or three hours. When a speedy result is desired twice the above amount in 10 per cent. solution may be given subcutaneously.

4. Destructive Methods

may include the use of the sharp spoon, chemical caustics, or the actual cautery. The curette is usually employed for removal of surfaces which have attained a spongy or easily bleeding condition, as the interior of the uterus, bleeding ulcers in other cavities, etc. When fungoid tissue is scraped to a base of healthy tissue there is usually a cessation of further hemorrhage. Occasionally there are cases of fungating cancer which bleed upon the slightest touch. The most radical way in which to deal with these for temporary purposes is to destroy the spongy tissue which bleeds so frequently. The gross part may be done with the sharp spoon and the cautery may be made to finish the work. Bleeding piles, when it is not permissible to treat them more radically, should be touched with the actual cautery, with stretching of the sphincter. The cautery knife should not be made too hot, as it may act similar to a sharp blade instead of merely searing by its heat.

5. Mechanical Means.

—When vessels of considerable size or masses of tissue containing them can be made accessible, the best means of control of hemorrhage are those which can be applied directly to the vessels. When this is not possible they should be tied en masse. A method formerly in use was acupressure. To effect this a needle was passed through the overlying skin beneath the vessel and out again, and around this a suture was tied to make pressure. Since the introduction of absorbable materials this method has been supplanted by the use of catgut sutures, which may be tied, cut short, and left to absorb.

Under the term “forcipressure” is included the method of seizing vessels before, or as they bleed, in small forceps, which are variously shaped and constructed, and grouped under the name of hemostats. Small vessels seized between the blades of such an instrument will have their walls so crushed that blood clot is so quickly entangled that the forceps can be removed in a few moments with little or no danger of subsequent bleeding. Larger vessels should be ligated.

Torsion is a substitute for ligature, especially with the smaller vessels, and denotes a twisting of the vessel end after its seizure, breaking up its inner coat, and effectually sealing its lumen. Some surgeons rely on torsion for the large vessels.

Angiotribe is the name applied to strong crushing forceps, by which a pressure of several hundred pounds can be made through a lever mechanism. In this a mass of tissue, as the broad ligament, can be secured and such tremendous pressure brought to bear that its vessels are crushed and destroyed beyond possibility of bleeding. Downes has improved upon this mechanism by adapting to it an electrocautery arrangement, by which not only pressure but also heat is brought to bear. His instrument is called an electrothermic clamp. To all of these instruments there are at least theoretical objections, in that they are more or less clumsy or unwieldy and require special equipment. They devitalize a considerable amount of tissue, all of which has subsequently to be removed either by a process of sloughing or by active phagocytosis; but they serve perhaps a useful purpose in the crushing treatment of hemorrhoidal tumors. They have been used only by a few, and have not found wide acceptance.

6. Ligatures.

—These are also mechanical means of controlling hemorrhage, but deserve to be grouped by themselves. Ligation of vessels may be preliminary or may be performed as needed during an operation.

By a preliminary ligature is meant taking such precaution as tying the carotid before operations on the face, the brain, or the femoral artery before amputation at the hip. There is also the method of temporary ligation of vessels by the application of a ligature which should not be drawn too tightly, but simply serve the purpose of gentle constriction for the half-hour or so during which it may be needed, after which the vessel is promptly released. If this ligature has not been too tightly applied the vessel walls will not have been injured and circulation is restored. Crile has effected the same purpose with the carotids by a small clamp whose pressure may be regulated by a thumb-screw.

Ligation of large trunks is made for the purpose of influencing nutrition by diminishing blood supply, as when the femoral is tied for elephantiasis of the leg, or the carotid is tied or excised, as suggested by Dawbarn, to cut off the blood supply from cancer of the face or neck.

Ligatures are usually made of absorbable material, such as catgut, chromicized or not, as may be desired, or of silk, which disappears after a time, but which is not regarded as absorbable. For special purposes other material has been used at times, such as strips of ox aorta. The surgeon has his choice of these, whether he intends to ligate the end of an artery or tie a vessel in its continuity. For the latter purpose the ligature is threaded into an artery needle, or a specially devised curved forceps known as the “Cleveland” needle. When tying the exposed end of a bleeding vessel it is desirable to tie near the cut end, so as not to leave tissue which should be absorbed, and for the same reason to not include unnecessary tissue. One of the forms of knot similar to the “reef” knot, which will not slip, should be used. Silk has the advantage over catgut in that a knot tied with it will rarely become loose, whereas catgut knots, unless carefully tied, will occasionally slip. The ligature knots should be left as short as is consistent with protection against slipping.

Fate of Ligatures.

—Silk or celluloid thread are the most unabsorbable of ligature materials ordinarily used. Even these usually disappear after the lapse of time. Absorbable ligatures of catgut disappear after a few days or weeks, according to the method of their preparation. Absorption is practically a matter of phagocytosis, the end of the vessel or tissue beyond the ligature disappearing with the latter by the process of tissue digestion.

When vessels of large size are ligated the blood supply is taken up by the collateral circulation. On the possibility or practicability of the latter will depend the success of such operations as ligation of large trunks for the cure of aneurysm. Should the collateral supply prove insufficient, gangrene, beginning at the tip of an extremity, is an assured fact.

The effects of the ligature on the vessel wall will depend upon the security with which it is tied. The damage done to the inner and middle coats by a ligature tied for permanent purposes is usually sufficient to rupture them, after which they roll up inside the outer coat, while the blood contained in that part of the vessel coagulates, the clot extending to the first vessels above and below. This quickly organizes, becomes infiltrated with cells, and brings about the complete obliteration of that part of the vessel and its transformation into a fibrous cord. This can only occur, however, when asepsis has prevailed. Should the ligature prove septic the patient is exposed to two dangers: that of secondary hemorrhage by ulceration and breaking down of the clot instead of organization, and the ordinary dangers of septic infection.

There are circumstances under which it may be well to modify the ordinary methods of ligation and not to tie knots too tightly—i. e., when the vessels are greatly weakened by extensive disease, or so stiffened by calcareous degeneration as to cause them to snap under rough handling. It has been suggested to use pieces of ox aorta to prevent these accidents.

The dangers of secondary hemorrhage pertain mostly to septic conditions. In an absolutely aseptic wound, properly cared for, secondary hemorrhage is almost impossible, but as soon as germ activity begins lymph barriers are broken down, tissues softened, and weakened vascular walls may give way.

Secondary hemorrhage may call for ligation of a main trunk not previously attacked, but in a majority of cases will demand reopening of the wound and further search for bleeding points. Should the patient’s condition be materially weakened the effects of position and of pressure may be tried in suitable cases. But the pressure which may be effective to check the hemorrhage may be sufficient to completely shut off circulation from parts beyond, and such pressure should, therefore, be judiciously practised and its effects carefully watched. The signs of secondary hemorrhage will vary with the location of its source. Occurring on or near the surface it will usually stain the dressing; occurring deeply, as in the pelvic or abdominal cavities, it will produce prompt symptoms of shock, i. e., lowered blood pressure, whose degree will indicate the extent of the blood loss. In these cases, unless the patient’s condition contra-indicate the measure, the wound should be opened under anesthesia, and the source of the bleeding sought out and mastered. The surgeon should never overlook the fact that after the gradual restoration of the force of the heart’s action, as the patient recovers from anesthesia and becomes uncontrollably restless, vessels may bleed which upon the operating table scarcely emitted a drop of blood. Experiences of this kind teach the value of hemostasis during operation, and even of absolute rest induced by an opiate, immediately after.

There are certain conditions in which the surgeon is led by experience to anticipate liability to unusual hemorrhage; such as cases of hemophilia, or anything that savors of it or of scurvy. In patients who claim to be “bleeders,” the surgeon should be extremely chary and careful during his operative work. There are, furthermore, certain toxemias, especially that of cholemia, during which the blood is slow in coagulation. When the time for preparation is afforded no cholemic patient should be operated without a few days’ previous preparation by four or five daily doses of calcium chloride, 20 to 30 grains given in plenty of water. This is known to greatly increase blood coagulability, and thereby to measurably protect the patient against the danger of an oozing of blood difficult to control.

The other measures needful in the treatment of secondary hemorrhage are those described in Chapter XVIII.

TREATMENT OF WOUNDS.

The general consideration of wounds in the previous chapters necessarily included many suggestions concerning their treatment. The first essential in the treatment of open wounds is exact hemostasis; the next is the removal of dirt and foreign material of all kinds, i. e., visible and invisible. Accidental wounds are practically never received upon surgically clean surfaces, and it may be always assumed that the possibility of infection is present. It becomes then a question to what extent the surgeon should go in removing or avoiding danger. Obviously all visible foreign material should be carefully removed and all dirt should be scrupulously washed away. Emergency treatment of a bleeding injury in a well-regulated hospital is one thing, and the exigency of a railroad accident or casualty away from civilization is quite another. The canons of antisepsis and asepsis have been elsewhere sufficiently well laid down to indicate what should be done at the time when it can be done.

The protective vitality of the human tissues permits them to bear frightful injuries or resist infection in a surprising way. But occasional escapes from severe accidents by no means justify carelessness when caution can be taken, and cannot be held as excusing the surgeon for any neglect in antisepsis.

A bruise or contusion accompanied by a slight abrasion may seem a trifling injury, and yet by virtue of the injury the resisting powers of the tissues may be rendered insufficient to protect them from infection through a break of the surface. No relatively small lesions of this kind can be safely neglected, but should be cleaned and covered with an antiseptic compress, either wet with some suitable solution or smeared with a protective ointment, or used dry with a suitable antiseptic powder, as, for example, bismuth subiodide. Injuries followed by considerable swelling should be treated according to the time which has elapsed since their reception. If, for instance, a bruise or sprain be seen early and before much swelling has occurred, ice-cold applications can be made in the hope that, by limiting the flow of blood, the outpour of fluids may be prevented. This effort should be seconded by position, and perhaps by gentle pressure. Conversely when a case is seen late, after the tissues have become waterlogged with fluids, heat should be applied in order that by stimulating the circulation reabsorption may more speedily take place. In this case, also, suitable pressure may be of service.

When there is actual hematoma, and the exuded fluid fails to disappear, an incision properly made and in the right place may permit the clot to be turned out, and then speedy recovery secured by coaptation with sutures and pressure.

Poultices are nauseous applications to make to the human body. By their indiscriminate use much harm has been done and suppuration encouraged or brought about, which but for them would not have occurred. There are occasions when a hot flaxseed poultice may be of use, but they are very few and far between. With regard to such remedies as arnica, witch-hazel, etc., the best that can be said of them is that they may be of some use by virtue of the alcohol which they contain; they serve the purpose, then, of a diluted alcohol and nothing else.

There is virtue in the use of a cold wet pack, or compress, especially in the treatment of chronic affections of the joints, and their value can be perceptibly enhanced by using solutions of sodium, or preferably ammonium chloride, and the addition of a little alcohol. Absorbent material wet in such a solution, wrapped around the part, covered with oiled silk or some impervious material, while the part is kept at rest, will render valuable service in conditions of this kind.

In regard to the relative worth of heat and cold for relief of pain, the alleviating effect of heat is more promptly manifested, but that of cold is more permanent, and especially is this true of chronic affections of the joints and bones.

In the treatment of open wounds, bleeding having been first controlled, all the surrounding parts, as well as the wound itself, should be sterilized. In a scalp wound the scalp should be shaved as well as scrubbed. All particles of visible dirt should be carefully picked out, and every particle of tissue whose vitality is so compromised that it apparently cannot live should be excised. The wound may then be irrigated or washed out with hydrogen peroxide, and not until all this is done should the operator consider how he may best close it, as well as whether he needs to provide for drainage. A ragged line of tearing will leave a jagged and more unsightly scar, especially on the face; therefore the margins of such a lacerated wound should be trimmed before coapting them.

The method of closure will depend on the degree of tension necessary for the purpose. Parts that come together easily may require but slight suturing, and with fine catgut which will loosen of itself within two or three days; the intent in such cases always being to assist the sutures by proper support of the external dressings.

Buried sutures will serve a useful purpose in many instances, and upon the face or exposed parts of the body a subcutaneous suture of fine silk or horse-hair may be so applied as to be easily removed by a single pull and leave but trifling disfigurement. Female patients will be doubly grateful if the surgeon can leave but a minimum of unsightly scar. Fasciæ will sometimes retract widely. They should be brought together by distinct separate catgut sutures. Before closure of a wound it is important to determine that no such structures as nerves or tendons have been divided, or, if such injuries have occurred, to reunite their ends by fine silk or catgut sutures. The writer prefers silk for most of these purposes, although in a nerve a fine formalin catgut suture would perhaps be the most ideal.

There are occasions when it seems impossible with the means at hand to tie or secure in any way a deep bleeding vessel which has already been seized with a hemostat. In such case the forceps may be left in situ for thirty-six to forty-eight hours. This may be done, for instance, in the groin, in the axilla, in the depths of the neck, and about the cranial sinuses. Life may be occasionally saved by this procedure which would be lost from hemorrhage without it. At other times a firm tampon of gauze may be forced into the depths of a wound for the same purpose, and maintained there by position, or by the pressure of secondary sutures, which serve the same purpose and require removal in two or three days. These measures refer rather to wounds of veins than of arteries.

If one can be absolutely sure of his asepsis, he may close even an extensive wound with little or no provision for drainage; but unless he is certain regarding it he should provide at least for escape of fluid by omitting a suture occasionally, or by drainage with a tube or a cigarette drain. In compound fractures not only must such provision be made, but the treatment of the wound may also include the introduction of wire sutures through bone ends or the use of other mechanical expedients.

The further and equally important treatment of wounds consists largely in maintaining physiological rest of the injured part, as well as the general welfare of the patient. Pain which becomes unendurable causes the patient to lose self-control and to disturb not only the dressings but apposition of wound surfaces. Pain, therefore, should be controlled by the mildest expedient that may suffice to master it. Elimination must be maintained, because the circumstances attending the injury may act to disturb it. A patient who shows no irregularity of pulse, temperature, elimination, or general comfort may be assumed to be doing as well as could be expected, and the dressings need not perhaps be changed for several days. On the other hand, with rise of temperature or pulse, increase of restlessness, swelling of the parts, or discomfort in the vicinity of the wound, the dressings should be promptly changed. It may be necessary to make such change at the end of forty-eight hours in order to permit the removal of the drain. The second dressing may then often remain a week, but any dressing which becomes saturated, even with blood, may dry and adhere to the skin, and should be removed.

It would be best to inspect the wound in all cases when the temperature and pulse are rising or when there is any disturbance in the wound. The accumulation of blood in an aseptic wound may cause much discomfort, and by its presence interfere with primary union. Should, therefore, a wound be found pouting or its edges reddened and swollen it may be safely assumed that there is something wrong, and as many sutures should be removed as may be necessary to reveal its condition and permit of its treatment.

Wounds which are foul or septic when they come under surgical observation should be treated differently. Here the first attempt should be at antisepsis. In some cases continuous immersion in warm water will give the best results. I have never found anything so prompt, however, in cleaning up a sloughing area as brewers’ yeast. When this can be obtained it should be used in sufficient abundance to get the diseased surface thoroughly wet with it. In sloughing cases moist dressings are usually preferable, and the best are the two above mentioned. This is true of those cases where part of the wound is granulating satisfactorily, while part is acting badly. Dressings in all of these cases require to be frequently changed, that they may be kept effective.

I have elsewhere called attention to the value of granulated sugar as an emergency antiseptic material of great value.

SUTURES AND KNOTS.

Sutures.

—There are many varieties of sutures which have found favor. Until the surgeon becomes expert by long practice he should confine himself to few sutures and knots. Primary sutures include continuous, interrupted, plate or modified plate, quill or modified quill, chain, and transfixion sutures, and also certain forms of suture used in intestinal surgery. The above forms are illustrated in Figs. 61 to 66. Several of them may be used in making what are known as buried sutures, i. e., those which are tied deeply, whose ends are cut off below the surface and left either permanently or for later absorption.

The purpose of a suture is to bring the parts into accurate apposition and so maintain them. It is a mistake to employ a superficial suture alone, which may leave a “dead space” beneath it. If but one suture is used, as in closing an abdominal wound, it should pass through the tissue layers of the abdomen and bring each layer into contact with the corresponding layer on the other side. Unless this can be done a series of sutures should be used uniting the tissues layer by layer. If these be made of formalin or chromic gut they will remain in situ for a length of time sufficient to serve their purpose. Some prefer silk for this purpose, but it may work out later; if sterile and freshly boiled just before using it will rarely cause this trouble. In closing a thick and fat abdominal wall four or five tiers of buried sutures may be used and their effect may be reinforced by the addition of a modified plate or quill suture, as shown in Figs. 63 and 64.

Fine wire is preferred by some operators, and horse-hair by others. Success pertains rather to the perfection of the method than to the material used. The primary feature of all wound sutures should be prevention of tension and protection against it. Further support in the same direction can be made by the use of adhesive plaster after fastening the dressing upon the wound, thus taking off strain.

Certain expedients have been resorted to in superficial wounds, some of which include the affixion of a strip of plaster on either side of the wound and then the application of the suture material through the plaster rather than through the skin. Plasters with small hooks have also been applied, and then a shoelace suture applied over the hooks, thus lacing the wound margins together. Such measures are convenient for certain cases, although they make the maintenance of strict asepsis difficult or impossible. Fine-wire clips have also been introduced, by which skin margins may be held together for three or four days, or until they have had time to unite with some firmness, after which they may be removed. These little implements can be sterilized and repeatedly used.

When an absorbable suture will serve the purpose it is desirable to use it, since the necessity of subsequent removal is thereby avoided. Inasmuch as every point through which a suture is passed will show its own minute scar, it is desirable for cosmetic purposes to use a subcutaneous suture, which may be made of chromic gut, silk, or fine wire. If of catgut it may be left to disappear spontaneously; but a silk or wire suture should be left with ends protruding from the wound so that after a few days it may be withdrawn by steady traction in the proper direction.

Secondary sutures are those which are placed at the time of the operation, but either not drawn so as to unite the wound edges, or are tied with a bow-knot, so that they may be untied and utilized later. They are useful when either hemorrhage or suppuration is anticipated, and when it is compulsory to pack a cavity with gauze.

Every suture which has failed of its purpose or ceased to be effective should be removed. Ordinarily they are left in place from four to ten days. They should be removed by dividing upon one side of the knot, which should be seized with forceps and pulled upward and to the other side. The suture should be cut at a point where it is moist, so that only its flexible portion may be drawn through the parts which it has held. Moreover the buried portion is more likely to be sterile. Secondary sutures are usually made of silkworm-gut, celluloid thread, or wire. So soon as they are found unserviceable they also should be removed.

Knots.

—The purpose of a knot is not achieved if it slips, and the “surgeon’s knot” is best for the purpose, since in the first formation one end is carried twice around the other before being tied in the opposite direction. It requires more force in making it taut, but it is safer than the ordinary reef knot (Fig. 67).

Figs. 69 and 70 illustrate the clove-hitch, which becomes firmer the tighter it is pulled. It is rarely used in ordinary sutures or ligatures, but may be made exceedingly valuable. The Staffordshire knot (Fig. 71) serves especially for securing pedicles, which are first transfixed with a double thread, the loop thus formed being slipped over the stump and secured between the two loose ends of the ligature, one end being placed over and the other under it; each is pulled tightly and secured by an ordinary knot. When properly applied it is effective. When knots are improperly applied none of them should be trusted.

When wire sutures are used it is sufficient to twist the ends, unless very fine wire is used, when it may be tied.