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Surgical Technique

SURGICAL TECHNIQUE.

Asepsis is the method of rendering the free surfaces and the deeper tissues of the body, the hands of the operator, the instruments, sponges or swabs, and the suture and dressing material he is going to use in an operation in a sterile condition; that is, free from obnoxious micro-organisms which, if they gain entrance into wounds, multiply, produce toxins, and cause inflammation and its consequences, such as suppuration, necrosis, or septicaemia. It also includes keeping the operation wound free from pathogenic microbes and the removal of the media for their development until the tissues have undergone complete repair. It implies not only that bacteria must be destroyed on the free surfaces, but they must not be intro duced into the wounded tissues by the surgeon's hands, instruments, sponges or swabs, sutures or dressings.

Asepsis is carried out by sterilization of the tissues and the surgical appliances and materials by means of heat and with the aid of chemical agents that have the reputation of destroying bacteria or retarding or preventing their develop ment.

Although the process cannot be carried out successfully in veterinary surgery, owing to the unfavourable surroundings of our patients and the lack of trained assistants, it may be partially adopted as regards instruments, dressings, water, and certain of the suture materials, which can be sterilized by boiling them for twenty to thirty minutes. It is, in fact, a valuable adjuvant to the antiseptic method, which is more applicable in operations carried out on our animals.

Antisepsis is the method of preventing infection of wounds and the mitigation and destruction of infection, should it arise, by means of antiseptics or those chemical agents endowed with the properties of retarding the development of micro-organisms which set up suppuration, gangrene, septiccemia, and other wound infections.

It was instituted in 1865 by Lister, who, in spired by the labours of Pasteur on fermentation, established the germ theory of wound in fections. By this antiseptic system he was able to reduce the mortality of major operation and other wounds from 50, 60, and more per cent to 6 and even 4 per cent. Until this era a great number of surgeons believed that the bad nature of wounds was due to a vitiated state of the atmosphere in hospitals, which they considered was charged with the miasmata of putrefaction. The work of Pasteur and of Tyndall seemed to confirm the correctness of this view by demonstrating that it was not the air itself, as many surgeons of former times thought, but the germs which floated in it that were endowed with injurious properties. Lister himself was at first a believer in the danger of aerial micro-organisms gaining entrance into wounds, and to obviate their obnoxiousness he introduced the disinfecting spray, which he ultimately abandoned. Although Lister was not the first to use antiseptics in the treatment of wounds, he was the pioneer of using them in a methodical manner with a definite object in view—that of destroying the micro-organisms which cause wound infection.

In 1870, A. Guerin introduced cotton-wool with the object of excluding germs from wounds, paying little attention to infection of instru ments, dressings, and the hands. Nevertheless he always washed his hands and cleansed the site with soap and spirit of camphor before commencing an operation. He applied several layers of cotton-wool and firmly maintained them in position by means of a bandage, which he thought checked secretion and thus pre vented infection. If the secretions were so profuse that they saturated the bandage, he added fresh layers of cotton - wool to those already in position.

Lister's practice was to destroy the aerial micro-organisms by spraying the air with a strong solution of carbolic acid in the neigh bourhood of the wound—those deposited on the wound, on the surgeon's and assistant's hands, on instruments, sponges, compresses, ligatures, and dressings. After the wound had been freed from infective germs it was covered with a pro tective dressing, impregnated with carbolic acid or some other antiseptic agent, and precautions were taken against the accumulation of serosity from the divided tissues. As germicides Lister chiefly used a 5 per cent solution of carbolic acid or a weaker one of 2i per cent. With the former he disinfected the instruments, sponges, and the operation area, and also, after finishing the operation, the crevices of the wound. The weaker solution he used for washing his hands and those of his assistants, soaking the sponges and cleansing them during the operation. Before and during the operation and until all haemorrhage had been arrested by ligaturing with catgut cut close to the knot, the lips of the wound approximated by sutures of the same material, drains fixed to allow the escape of serous discharge and dressings applied, the spray containing a 5 per cent solution of carbolic acid was allowed to play on the operation area. This area was then covered with a fine layer of oiled silk with the object of protecting the skin and wound against the irritating effect of car bolic acid; above this were placed eight double layers of carbolized gauze, the two last layers of which were separated by a layer of mack intosh to prevent the evaporation of the carbolic acid and to cause the serosity from the wound to permeate the whole extent of the dressing before reaching the outside layers. At the end of twenty-four to forty-eight hours, if this protective dressing became saturated with an abundance of serosity resulting from the irrita tion set up by the intense chemical action of carbolic acid, it was removed so as to examine the wound and the state of the sutures and drains and, if necessary, to replace it with fresh dressing after the wound had been irrigated with the strong (5 per cent) solution of carbolic acid—all performed under the carbolic spray.

Recent wounds with more or less spaces in them were washed with a 10 per cent solution of carbolic acid before the protective dressing was applied. Suppurative wounds, cavities, or sinuses were curetted and then cleansed with a 10 per cent solution of chloride of zinc, but no protective dressing was applied to them. Such were the earlier methods adopted by Lister in carrying out his antiseptic system; but as time went on these were modified by him and his followers, so that now the spray is dispensed with and wounds are no longer submitted to the irritating effects of strong antiseptics, but in their place weaker solutions are used with the object of retarding the development of bacteria when it is not possible to exclude them altogether by surgical cleanliness and a well maintained protective dressing.

Although the strict antiseptic method in com bination with the aseptic is capable of realiza tion in human surgery, especially when carried out in large institutions with all the necessary appliances, it is difficult to carry out in veterinary practice because of the lack of suit able surroundings and of skilled assistants, and owing to the refractoriness of our patients and the conditions under which they live. On the other hand, it is not so necessary, because under the majority of conditions our patients are less subject to those influences which in man increase the chances of becoming infected with virulent micro-organisms derived from other infected wounds. Also, the majority of operations are carried out on young and vigorous animals whose wounds, as those of castration, are left unprotected with a wide dependent orifice which affords efficient drainage. The danger of infection of wounds in animals mostly is dependent on the wounds getting infected from the soil, such as gangrenous or gaseous septi caemia and tetanus rather than from infection derived from other infected wounds.

Nevertheless asepsis and antisepsis should be carried out as rigidly as is possible in general practice, more especially when dealing with wounds penetrating the chest, abdomen, joints, tendons or their sheaths, cartilage and bone in the horse and wounds in general in sheep and in the cat, the three animals most susceptible to the bad influences of wound infection. The pig, ox, goat, dog, and fowl are more immune to infection, but notwithstanding this fact surgical cleanliness and antisepsis should be carried out as a matter of routine in these animals as in the more susceptible species.

The Choice of an Antiseptic.

An antiseptic should be chosen on account of its sterilizing influence on micro-organisms suspended in blood-serum, pus, exudations, and devitalized tissues; its power of penetration and its com parative harmlessness to the living tissues. It also should be relatively non-toxic if by chance some of it should be absorbed into the system. It by no means follows that because a certain chemical agent will destroy microbes suspended in water in a test-tube it will have the same effect when it comes in contact with them when immersed in the exudates and discharges of a wound. On the other hand, some chemical agents have very little neutralizing effect on bacteria in a culture medium in a glass tube, but have great influence on them when living in the animal body, as, for instance, the action of iodide of potassium in actinomycosis and of quinine in malaria.

The results obtained by the use of anti septics in the treatment of wounds depend rather upon the method with which they are used than on the agent selected.

Antiseptics are chemical agents which have the property of preventing or retarding the development of microbes. Some microbes, although they may not be destroyed by such agents, are so altered in physiological action that they become quite harmless. In minute quantities disinfectants and germicides may act as antiseptics, but many antiseptics have very little if any germicidal action, and in con sequence they are either unreliable or useless as disinfectants.

Carbolic acid

is one of the best-known anti septics, and although used in rather a hap hazard manner by certain surgeons before Lister employed it in a methodical manner and with a definite object, the credit of demon strating its properties is due to Lister. Although it may not be one of the most powerful anti septics it still holds its position in practical surgery, especially in the treatment of operative wounds, for sterilization of the hands of the operator and those of his assistants and of the operation zone, and also for the disinfection of instruments, ligatures, and dressings. For these purposes the pure crystallized acid, which should be rendered liquid by the aid of heat and the addition of about 2? th of its bulk of water, should be used, diluted with 20, 40, or 50 times its bulk of water, to which may be added 1 to 2 per cent of methylated spirit. The 1 in 20 or 5 per cent solution should not be used on recent operative wounds, on which it would have too much of an irritative effect; nor should the hands of the operator be immersed in it, as it produces a numbing sensation, which impairs the sense of touch. It should be reserved for the immersion of instruments, sponges, swabs, ligatures, and dressings, for the cleansing of the operation area before the skin is incised, and for the cleansing of wounds that have been exposed to the air or become foul. It is also used to set up a slight adhesive inflammation in the close vicinity of the sutures in abdominal surgery. It should not be kept long in contact with those parts of the skin which are very sensitive, as it is liable to cause vesication. If it should cause too much irritation it should be speedily removed by washing with methyl ated spirit. The 1 in 40 or 2i per cent solution is suitable for sponges or tampons, with which the wounds are freed of blood by gently wiping it away from the tissues. Before these are used for such purposes they should be well squeezed so as to remove as much of the anti septic fluid as possible, as too much irrigation, washing or wetting of recent wounds sets up irritation in the tissues, producing much serum and preventing union by first intention. It is also useful for rinsing the hands, instruments, etc., from time to time during an operation. The 1 in 50 or 2 per cent solution is antiseptic in action, but beyond this dilution it loses this power.

Carbolic acid is a solvent for iodine, and in this combination acts as a powerful but pain less escharotic on new growths with ulcerating surfaces, chronic sinuses, especially those on the coronet and in actinomycosis. When used pure and highly concentrated it is not only escharotic but is also haemostatic, sealing small blood-vessels and lymphatics, hence its absorp tion does not take place and intoxication is thereby prevented. Mixed with 10 to 20 parts of olive oil it forms carbolized oil, which is useful for smearing on painful superficial wounds and burns and also on the arms and hands in difficult cases of parturition.

In canine and feline practice, carbolic lotions must not be applied too freely nor over too large a surface, for fear of intoxication by absorption, to which dogs and especially cats are very prone. Should such a deleterious effect be produced, sulphate and carbonate of sodium or magnesium should be administered.

Lysol, as well as many of its imitations sold under various names, is a preparation obtained by the saponification of one of the tar oils with an alkali, and is said to contain about 50 per cent of cresols. Adam, of Alfort, recommends a similar preparation which is made by adding 1 part of cresol to 1 part of soda lye of 30 per cent and having a density of 1332, this readily dissolving without heat. It is a dark brownish syrupy liquid, which forms with distilled water a clear solution without leaving any deposit, but with ordinary water it forms a solution which after some time becomes turbid and eventually throws down a sediment. In vete rinary practice it is almost an ideal anti septic, as it is not only cheap but is also effica cious. In consequence of its saponaceous quali ties it forms an excellent detergent for the hands, preparing the greasy skin for an opera tion, and for loosening adherent dressings from wounds. It is also a reliable agent for the dis infection of instruments, sutures, dressings, and infected wounds. Instruments submerged in it for several weeks keep free from tarnish.

For operative wounds a 1 per cent solution is an efficient antiseptic; beyond this strength it is liable to set up irritation and cause the outpouring of serum, which is inimical to reparation by first intention. It is advisable not to irrigate freshly incised wounds with this, but use a sponge or a piece of lint or a tampon of cotton-wool encased in a coating of gauze which has been immersed in the solution and then well squeezed out to wipe gently away the blood from the wound cavity. In a strength of 0.5 per cent it forms a reliable antiseptic for irrigation of the uterus of the larger animals after difficult parturition or after abortion, care being taken that the retained solution is syphoned off from the uterine cavity. Instru ments, suture material, and surgical dressings, after they have been sterilized by boiling, should be immersed in a 5 per cent solution until they are required for use, when they should be trans ferred to a 2.5 per cent solution, into which the hands and instruments should be plunged from time to time during the operation. The 5 per cent solution has a benumbing action on the hands; it is a reliable detergent and disinfectant for foul wounds and for the feet. It is an excellent agent to remove blood from the skin and coat after an operation, and for shepherds to wash their hands in during the lambing season, to apply to the navel and, in the castra tion and docking season, to the scrotal and tail wounds.

Although it is relatively less poisonous than carbolic acid it should not be used as a uterine irrigant nor applied over too large a surface of the skin in canine and feline practice. Adam's preparation is used 1 in 100 to 400 of water as a disinfectant and antiseptic.

Cofectant,according to the Lancet Commis sion, has the highest carbolic acid coefficient. It is composed of phenols, phenoloids 66.27, resins with fatty acids 24.66, water 6.4, potash 2.67 per cent. It is an efficient disinfectant even in 1 per cent solutions, and is particularly useful in foul wounds in the larger animals. Creolin and Izal are cheap and reliable dis infectants and antiseptics. The only objection to these three agents in veterinary practice is that they form, with water, emulsions which hide instruments and dressings immersed in them from the view of the operator. As they are relatively cheap they are suitable for surgical operations on the feet and for the disinfection of foul wounds in farm animals.

Mercury perchloride

or sublimate is a power ful antiseptic. The researches of Koch and others have demonstrated that 1 in 1000 solu tion kills the spores of anthrax in fifteen minutes, and the bacilli themselves are killed by 1 in 15,000 in one minute. The development of the same bacilli is prevented by 1 in 500,000. Solutions of 1 in 10,000, 2000 or 1000 have been used in general and ophthalmic surgery, and for cleansing the operation zone of skin or mucous membrane and for washing freshly incised wounds and the hands. It may also be used for irrigating abscess cavities. To get the best results it should be freshly prepared and used hot, as it is more active in a weaker solu tion when used hot than when used in a stronger but cold solution. Concerning the treatment of suppurating wounds, the wound must be washed daily with a warm 1 in 2000 solution and the part dressed with as much care as if non-infected, when in a short time the discharge of pus will gradually cease and the wound remain clean and sweet. It should not be injected into cavities nor into the uterus, as it is rapidly absorbed and likely to set up intoxication.

It is used for the sterilization of the hands, catgut, and other organic suture material, and dressing. It is unsuitable for the disinfection of instruments, as it destroys the metal and blunts the cutting edge.

One of the objections to its use is that it forms an albuminate with the albumin of the tissues and fluids of the body with which it comes in contact, and is therefore rendered inert as an antiseptic. This is, however, obviated by adding tartaric acid, sodium chloride, ammonium chloride or hydrochloric acid to the solution containing it. It will not act efficiently on a greasy skin and is incom patible with alkalies and their carbonates, soap, iodine, and some metallic salts. On some people it causes irritation of the hands. It is also liable to produce irritation of wounds and there by hinder the reparative process.

Some authorities use alcohol instead of water as a solvent. One part of sublimate in 500 parts of alcohol 90 per cent is used as a dis infectant for the hands and skin, but there are many safer and just as effectual agents for this purpose with fewer drawbacks. Lister and Watson Cheyne recommend 1 in 500 sublimate with 5 per cent of carbolic acid added for cleansing the field of operation, a foul wound, and the hands. Mercury perchloride is used in its pure state in the form of a pencil for plugging sinuses of the coronet, poll, and withers, with the object of destroying the wall of the sinus and setting up repair by granula tion. It is also used in the form of a liquor (sublimate 1 part, camphor 1 part, and spirit 10 parts) for injection into quittors, and as a paint for the skin covering articular and peri osteal exostoses, as in spavin and splint.

Lint, absorbent wool, gauze, and wood-wool are impregnated with 0.5 per cent of corrosive sublimate and coloured with methyl blue and used as absorbent or protective dressings in the antiseptic treatment of wounds.

cyanide gauze containing 3 per cent of mercuro - zinc cyanide was introduced by Lord Lister as a dressing applied direct to wounds. It has the advantage over other mercurial dressings of being less irritating and keeping well without becoming reduced by the cottons. Wood-wool and gauze bandages con taining 3 per cent of the same material are also prepared.

Mercury biniodide

has more powerful anti septic properties than sublimate and is less irritating. When used as a solvent, potassium iodide forms with it a double iodide of mercury and potassium—potassio-mercuric iodide. It does not coagulate albumin and therefore does not cause precipitation of the blood. Besides being less irritating to wounds it is less irritat ing to the hands and is far more penetrating and less toxic. It- may, when iodide of potassium is added as a solvent, be incorporated with soap, either in a liquid or solid form, as a disinfectant for washing the hands and the operation zone.

For wounds 1 in 2000-4000, and as an anti septic for irrigating the conjunctival sac 1 in 10,000, may be used.

Zinc chloride is a very powerful antiseptic and deodorant, but unless used in a very weak solution is only suitable for neglected or necrotic wounds on the lower part of the limbs of the horse. In these cases it is superior to any other agent, and when used as a 10 per cent solution to treads and other necrotic areas, usually at the front or sides of the skin cover ing the coronary region, it not only destroys the fcetor of such wounds but prevents the necrotic process extending to the deeper tissues. It thus renders a septic wound aseptic. In this strength it is useful as an injection for quittors and other chronic sinuses. Applied as a lotion of 1 in 20 to recent and also chronic collar and saddle abrasions or ulcers it acts not only as an antiseptic but also as an astringent.

It should not be used as an irrigant in deep wounds in soft tissues, as by having a very powerful astringent effect, even when applied in a very weak solution, it hinders the reparative process.

Burnett's Fluid (an impure concentrated solution of zinc chloride) diluted with five to twenty times its bulk of water is a very effica cious antiseptic deodorant, and astringent in the treatment of grease. It should be applied with brisk friction every two or three days until the desired effect is obtained.

Potassium permanganate,

besides being a dis infectant and one of the best deodorants, is also a very good antiseptic. In a one or two per thousand solution it forms a useful disinfectant and antiseptic for the hands, and mucous mem branes .of the mouth, nostrils, uterus, and rectum. It is also a good antiseptic for cleans ing the skin prior to an operation and for dis infecting septic wounds and cavities. A 1 per cent solution injected thoroughly into the depth of a snake- bite as soon as possible after its infliction is a certain antidote. Injected into the uterus after a bad parturition or in prolonged retention of the afterbirth, a solution 1 in 500 1000 destroys all bad odours. It should be injected at a temperature of 100° to 105° F. at least. This or a weaker strength is also suitable for disinfecting the conjunctival sac prior to an operation on the eyelids or eyeball. In a powdered form it may be used as a power ful disinfectant in necrotic wounds due to the bacillus necrosis on the limbs of horses.

Hydrogen peroxide

is a feeble germicide and only a moderate antiseptic even against anaerobic microbes. It has no effect on the Bacillus per fringens. It acts more as a detergent than as an antiseptic, and in consequence it is suitable for cleansing the mouth, rectum, vagina, con junctival sacs, nasal channels and sinuses, and the external ear. It has been used as an aid in determining the extent of an open abscess cavity by distending the lumen in order to enable one to find a safe place for making a counter-opening for drainage purposes. It is useful for loosening adherent bandages and dressings. Injected into sinuses, abscess cavi ties, and deep wounds it loosens the discharges and cleanses the cavities of debris. It does not precipitate albumin. It acts as an astringent in nasal haemorrhage and a styptic in removal of polypi. It relieves wasp and hornet stings. Gauze in form of sheet or ribbon saturated with 5 per cent solution is useful for plugging cavities and wounds.

Aluminium acetate

in the form of liquor aluminii acetici is known as Burow's Solution. One drachm of this liquor to the ounce of water forms an approximate 1 per cent solution, which is a good non-toxic, non-irritant, and astringent antiseptic for the prevention of the develop ment of pus-forming bacteria. It is a valuable agent in the treatment of burns, infected wounds, and in cases where continuous irrigation of wounded parts is required for days or weeks. It is very good in the form of a fomentation for phlegmonous inflammation. It is a suitable antiseptic in canine practice. It is injurious to instruments and roughens the hands.

Lead subacetate and acetate

are useful as sedative antiseptics in superficial inflammatory conditions and abrasions: they allay inflam mation and check secretion. They may be used in conjunction with spirit. The writer has never observed by their use on dogs any injurious effects.

Formalin.This is generally reputed to con tain by weight 40 per cent of formaldehyde, but in consequence of evaporation during storage it rarely contains more than 35 per cent. In a 5 to JO per cent solution it is invaluable in the treatment of grease, and in a 30 to 60 per cent solution, of canker. For this latter complaint it has been used in an undiluted state, but in consequence of its mummifying and penetrating action it has been known to dry up and destroy the whole of the soft tissues underlying the pedal bone so as to necessitate destruction of the animal. In its undiluted state, when care fully brushed on warts and ringworm patches, so commonly seen in young horses and cattle, it causes them to shrivel up or disappear. It has also been used for injecting into the centre of tumours and in the preparation of catgut.

Lysoform.This is a liquid formaldehyde potash soap. It does not coagulate albumin and is miscible with water and alcohol in all proportions. It is used for the sterilization of surgical instruments, of the hands of the operator, and of the hoof and surrounding skin of the larger animals. For these purposes a 2 to 5 per cent solution, which does not produce numb ness or irritation of the hands, is used. In 0.5 to 1 per cent warm solution not exceeding a temperature of 106° F. it may be used for irrigating the vagina, uterus, abscess cavities, and septic wounds. A 2 per cent solution has a styptic effect on wounds, and allays pain caused by bites, stings, and burns. In con sequence of its powerful germicidal properties and of being practically odourless it is used for washing the udders of cows before milking, a process which sensibly reduces the number of germs in milk.

Methylated Spirit.

The mineralized or de naturalized methylated spirit is 90 per cent alcohol or rectified spirit, to which are added 10 per cent by volume of wood naphtha and iths per cent of mineral naphtha or petroleum oil. Industrial methylated spirit is rectified spirit with 5 per cent its volume of wood naphtha.

It has long been used by many surgeons as an antiseptic to wounds. More recently it has been employed for cleansing the skin after it has been disinfected prior to an operation. Probably the good effects of spirit of camphor, friar's balsam, and the tinctures of iodine and calendula on wounds are partly due to the spirit they contain. Spirit is also used to remove an excess of carbolic acid from the skin before it has had time to produce a caustic effect, and in the cleansing of surgical instruments.

In pre-antiseptic days, spirit, especially cam phorated spirit, was applied to wounds by means of lint saturated with it. Several layers were used, kept wet either by frequent douching or by covering with an overlapping layer of im permeable tissue, or by changing the dressing twice daily. It was also used as a lotion com posed of 6 parts of absolute alcohol, part of liquor plumbi subacetatis, and 16 parts of dis tilled water. By itself, or containing 1 in 2000 parts of corrosive sublimate, it acts as a haemo static when applied locally by causing contrac tion of the capillaries. It is aseptic in itself.

Bismuth Subnitrate.

This is used in the formulae of Beck's bismuth paste for injection into fistulous tracts, sinuses, and abscess cavities for X-ray examination and for cura tive effect. As a preliminary injection for diagnosis and early treatment 1 part of bismuth subnitrate is added to 2 parts of hot vaseline. This is injected by means of a glass syringe under aseptic precautions. The syringe is sterilized by dry heat, and the plunger dipped in sterile oil. For late treatment bismuth sub nitrate 6 parts, white wax 1 part, soft paraffin 1 part, and vaseline 12 parts, and sometimes 1 per cent of formalin are mixed during boiling and injected with gentle pressure. As a pre caution, no water but spirit 90 per cent must be used for washing the skin and orifice of the sinus. Bacteria are diminished in number after the injection, which acts partly as a bactericide, chemiotactic, and astringent, and partly by its mechanical action. The diseased walls of the sinuses separate by the stimulating action of the injected substance, which does not cause pain.

with double its weight of iodoform (16 ounces), and worked into the form of a paste with liquid paraffin (8 ounces or more according to require ments). This formula has been named"Bipp."It is well rubbed by means of dry gauze into the surface wall of a recently infected wound after this has been mopped out with methylated spirit. The superfluous paste is removed, and the wound is then sutured and covered with sterilized gauze and an absorbent pad. The dressing should be renewed if the wound does not progress favourably.

Chinosol is largely used as a mild anti septic in veterinary practice. It may be used (1 in 1000 of water) for the hands, irrigating cavities such as the uterus, conjunctival sac, orbit after removal of the eyeball; wounds after the removal of necrotic tissue, as in those neglected wounds in dogs due to bites about the neck and shoulder. It is also a useful anti septic for washing the conjunctival membrane before an operation on the eyeball.

Gauze impregnated with a 1 per cent solution forms an excellent material for plugging cavities. The powder mixed with kaolin or charcoal makes an effectual dry dressing for granular surfaces where the skin has been destroyed by necrosis.

Salicylic acid is a powerful antiseptic, but in consequence of its insolubility in water it is not used for the irrigation of wounds. It is chiefly used in the preparation of salicylic wool and gauze and sometimes silk. For superficial abrasions or granular surface wounds it makes an efficient dry dressing when mixed with kaolin and zinc oxide—a combination far superior in effect to that of iodoform. It is especially valuable in superficial wounds about the knees and coronets in the horse and in chronic auricular catarrh in the dog.

Boracic acid

is an over - estimated anti septic. Its reputed good effects are due rather to the hot water in which it is dissolved and applied than to the acid itself. It is suitable when used hot for irrigation of the bladder, conjunctival sac, nasal channels, and other mucous surfaces. It is used in the form of powder as a desiccant for granular wounds, and in catarrhal inflammation of the external ear. In the form of an ointment it is applied to ulcers.

It is used in the preparation of Dakin's Solution, and in the following paste: boracic acid 11 ounces, French chalk 1 ounce, liquid paraffin 8 fluid ounces, brilliant green 17 grams. The boracic acid and chalk must be well mixed in a mortar and then the paraffin is incorporated. Afterwards the brilliant green is dissolved in spirit and worked up in the paste.

It is said to have given good results when thoroughly applied to every recess in a recently infected wound after the damaged tissues have been excised and the surface dried with a 1 per cent spirituous solution of picric acid.

Friar's balsam or the compound tincture of benzoin had long been used as an antiseptic before the advent of Listerism in the treatment of wounds, especially those complicating frac tures of bones. It is useful in superficial wounds, and when applied sufficiently thick it makes a good protective. In compound frac tures it is applied on a piece of lint which covers the wound; also to close the punctures in the skin after tenotomy. Evaporated to dryness over a water-bath and then mixed with collodion it forms a valuable means of retaining dressings on small wounds, such as those over the eyelids, face, knees, and on those caused by laparotomy in the dog and cat. It may be fortified by applying a finely-teased-out layer of cotton wool, and then covering it with a second coating. It is a useful application to wounds in the mouth, or in the vagina, and as a hemostatic, and when applied on gauze in the packing of cavities. It is used to mask the odour of iodoform. Tincture of iodine added to it increases its embalming or antiseptic qualities.

oil of turpentine, oil of eucalyptus, and other essential oils, when mixed with a fatty oil to which carbolic acid or creosote is added, are very powerful and efficacious germicides and antiseptics when applied to putrid and suppurating wounds. They also repel flies and thus prevent maggots developing in such condi tions in hot weather. They form a useful sedative and antiseptic application for burns.

Oil of cloves is a powerful antiseptic and germicide with local anesthetic properties. It is used chiefly on wounds in the vicinity of joints as a styptic.

Iodineis one of the more powerful antiseptics, and has been in use for such purposes for up wards of a century in the treatment of septic wounds, fistulae, and other surgical conditions. As a lotion in the form of 1 to 2 drachms of the tincture in a pint of water it has been used for irrigating operative wounds and the uterus after parturition and in metritis. Its specific action in the treatment of actinomycosis has long been established. In more recent years it has re placed washing of the skin and disinfection of the hands before an operation. For this pur pose a 2 per cent alcoholic or petrol solution has been advised, but the B.P. tincture is equally good. Tincture of iodine made with methylated spirit causes irritation to the eyes of the operator and his assistants. For the disinfection of the skin, after the hair has been closely clipped off the operation area, the tincture of iodine is brushed over a wide surface and allowed to dry in before making the incision. It has also in many directions displaced the rather laborious preparations in the sterilization of the operator's hands, the tincture being painted or well rubbed in all over the hands so as to penetrate into every crevice in the epidermis, and under the skin covering the matrix and under the free edge of the nails, and then allowed to dry into the epidermis. Although this may be found to be a safe method when adopted by surgeons, who usually pay great attention to their hands and keep them clean, it would be safer still if the usual precautions of cleanliness by scrubbing with soap and hot water and paring of the nails were carried out as a preliminary. After com pleting the suturing of a cutaneous wound, good results are obtained by painting a coat of tincture of iodine along the course of the wound and sutures, and, provided the deeper tissues are free from infection, union by first intention is obtained. If a coating is painted on the wound daily stitch suppuration is prevented. But this daily painting is not necessary if the wound as soon as it has been sutured is covered with a fortified layer of collodion. On delicate skin such as that covering the scrotum the applica tion of tincture of iodine should not be repeated, except after an interval of several days, or a painful dermatitis is likely to be set up. It acts equally well on the horse, ox, sheep, and pig as on the cat, dog, rabbit, and bird. In conse quence of its coagulating proteins irritating the tissues, and low penetrating power, it gives less satisfactory results when used with the object of sterilizing deep wounds, which still continue suppurating during its use.

The application of tincture of iodine to the navel immediately after birth is largely adopted to prevent navel-ill and other infections gaining entrance through the umbilicus. It is frequently injected into sinuous wounds in soft tissues, into bursal cysts, hematomata after the evacua tion of the clotted blood, hydrocele, and similar conditions. The ammoniated tincture or so called colourless tincture of iodine injected into the sac of bog-spavin in order to set up irritation and ultimately absorption has, in the hands of Deans, given good results.

Iodine in the form of glycerine of iodine is an excellent antiseptic for chronic auricular catarrh with thickening of the investing membrane of the external ear in dogs and cats; it is the best agent for parasitic canker, and as an anodyne for auricular irritation in all species from the horse, ox, sheep, goat, pig, down to the dog, cat, ferret, and rabbit. In the form of an ointment with vaseline, either with or without the addition of oleic acid or any other organic acid, or as a liniment with oleic acid or liquid paraffin, it makes an excellent stainless absorbent applica tion for the reduction of chronic inflammatory swellings and glandular enlargements, and to promote absorption from serous cavities. Mixed with vegetable tar and sifted tan or peat it forms a useful topical treatment for"capped elbow"and"capped hock."Mixed with 3 to 10 parts of pure carbolic acid to 1 of the iodine and injected into sinuous wounds, especially those on the coronary region and those found in botriomycotic and actinomycotic lesions, it acts as a painless escharotic, destroys the secreting surface, and sets up healthy granu lative, and hence reparative, action. Iodine dissolved in carbon tetrachloride has been used for sterilization of the hands and skin.

Iodoform is inferior to iodine as an antiseptic, and it has very little germicidal action in vitro. It does not destroy pathogenic bacteria, but it inhibits the growth of putrefactive organisms. It acts by its effect in reducing secretion from wounded surfaces by hindering emigration of leucocytes from the blood-vessels, and by the fact that iodine is liberated by contact of iodoform with the organic material of the tissues and secretions. It enters at once into combina tion with the proteins, acting as a stimulant and facilitating absorption of the exudate. It is chiefly used as a dusting-powder, which not only acts as an antiseptic but also as a sedative and anaesthetic to wounds. Dissolved in ether and brushed on the surface of wounds it leaves a very fine granular layer of the drug; in collodion, as a protective dressing for small incised wounds. In both cases it should be freshly prepared, as the iodoform undergoes decomposition if kept for a time in such solutions and forms an irritat ing compound. It may also be used as an ointment for painful wounds and ulcers, and as an oil or emulsion for fistulae and sinuses. Forced into a narrow cylindrical glass tube the powder may be pressed from this by means of a probe into fistulae and sinuses. As an insuffla tion it may be forced into the nasal channels in chronic nasal catarrh. As a dusting-powder it is inferior to a mixture of iodine and starch.

Silver nitrate

has a bactericidal action superior to that of mercuric chloride. It is a powerful antiseptic, and in 1 in 1000 to 1 in 500 of dis tilled water is invaluable for the washing of the conjunctival sac or urethral canal and also the canal of the sheath of the penis, and the nasal channels and the nasal duct. In a pure state, formed into the shape of a hard or toughened pencil, it is the best - known potential caustic or cautery and an excellent haemostatic for small haemorrhages on surface wounds.

Sodium

has long been known as possessing antiseptic properties, and when 7 parts are boiled in 1000 of water it forms a safe irrigant for operation wounds and for washing away extravasated blood from contused wounds. Afters the application of nitrate of silver it may be used for irrigating the conjunctival sac, to wash away the precipitate and to counteract its over-effects; the uterus, after extraction of the foetus; the vagina and nasal channels, to remove tenacious mucus and bacteria; and in septic wounds, to wash away the discharges.

In the form of normal saline solution (7 parts in 1000 of boiled water) it is invaluable when injected into a vein, the peritoneal cavity or the rectum, or infused under the skin by hydro static pressure to make up for the loss of fluid from the circulation resulting from profuse haemorrhage following parturition, operation, or accident. It forms a safe irrigant for the thoracic and peritoneal cavities. In shock, it is indicated to overcome the fall of blood press ure. It is contra-indicated in wounds where there is much oozing of blood from small vessels, as it prevents the formation of fibrin and hence delays coagulation. It may be permitted to remain in contact with living tissue without any injurious effect. It is more suitable for the mechanical cleansing of clean wounds than it is for infected wounds, as probably when kept in too long contact with the infected material it may set up general infection or intoxication. It should not be allowed to remain in an infected cavity. Saline solution is isotonic with the tears and blood. Holding one's hands in a warm solution enables one to taste the salt on one's tongue within a few moments, thus showing how rapidly it is absorbed by the normal skin.

This physiological salt solution, also termed normal saline solution or isotonic salt solution, contains 0.91 per cent of sodium chloride. It is isotonic since it has about the same equivalent as blood-serum and the lachrymal fluid. When higher molecular concentrations are used they are spoken of as hypertonic and lower as hypo tonic.

Ringer's solution, which is composed of sodium chloride 0.91, potassium chloride 0.025, calcium chloride 0.02, sodium bicarbonate 0.015, with sufficient water to produce 100, is some times preferred to the normal saline solution.

Soap is an antiseptic and detergent as well as a solvent of fatty and horny material. It is used for cleansing the hands of the operator as well as the skin covering the operation area. In a 2.5 to 5, per cent solution of either hard yellow soap or soft soap it has a bactericidal action and is used for irrigating the natural channels prior to operative interference; it has a beneficial action in septic wounds by washing away the discharges, stimulating the separation of necrosed parts and rendering the surface sterile.

Cocoa-nut oil soap is said to have the highest bactericidal action. Those made from castor and olive oils have only bactericidal properties when used in a 5 per cent solution. It increases the bactericidal action of creosol, formalin, and coal-tar.

The green soft soap may be converted into a liquid soap by the addition of one or more times its weight of methylated spirit or half to one of ether. Such soaps may have added to them to increase their antiseptic properties oil of turpentine or eucalyptus, creolin, creosote, izal, or oil of lavender. Some ethereal soaps have as much as 1 per cent of mercuric iodide added to them and hard soaps as much as 3 per cent. Methylated ether added to spirit soaps lessens their viscidity. A liquid soap without spirit may be prepared by boiling olein with soda-lye. A turpentine soap is made of one part each of oil of turpentine to two parts of soft soap. The soap and glycerine are heated together and when cool the turpentine is added. Pumice and marble soaps are prepared for cleansing the hands and removing coarse epidermis.

Tincture of saponine or quillaia is

a powerful antiseptic for wounds. It was used as far back as 1850 by Le Bceuf for the saponification of coal-tar (1 part tar to 2-4 tincture of saponine). Lemaire, in 1860, used 1 part of this mixture to 4 of water for the disinfection of wounds. The same authority in 1863 introduced carbolic acid for the same object. It is interesting to note that Lemaire was the first to realize the truth of Pasteur's work in its application to wounds.

Copper sulphate

in 1 in 1000 is an astringent antiseptic suitable for the irrigation of infected mucous membranes and certain accidental wounds. It has been used for irrigating the genital passages after epizootic abortion, specific urethritis, and the nasal channels affected with chronic catarrh. Used in a 5 to 10 per cent solution it is useful in grease and exuberating granular surfaces, as it constricts the blood vessels and lessens the blood supply to the part. In the form of a very fine powder it is dusted on for the repression of that exuberant granu lation tissue so often found following lacerated wounds of the skin covering the metacarpal and metatarsal regions. After it has been applied the part must be firmly bandaged. In the form of a pencil it is used to touch up granular lids, or as a crystal to verrucose granu lations found in the vagina or on the penis of dogs affected with infective granuloma.

Sodium hypochlorite,

prepared by the action of sodium carbonate on a solution of chloride of lime, was first introduced by Berthollet as a disinfectant and deodorant. The B.P. solution is composed of chloride of lime 10, sodium car bonate 15, water 100. Labarraque's Solution is about one-fourth the strength of this.

Labarraque's

Solution and Eau de Javelle, which is a solution of chlorinated potash con taining 2.5 per cent of chlorine, have long been used as disinfectants and antiseptics for infected and gangrenous wounds. In 1840 Renault, of Alfort, published a memoir on the treatment of wounds, and recommended chlorinated soda as a valuable disinfectant for gangrenous and other wounds. Both Blaine and Youatt spoke highly of its virtues as an antiseptic and deodorant for foetid ulcers in the mouth, gangrenous wounds, and phagedenic ulcers. As time went on and fresh men came along with new ideas and remedies this valuable agent became no longer the correct thing to use, and so it was discarded and practically lost sight of until Dakin quite recently reintroduced it in a less caustic or irritating form.

Although the chlorinated solutions mentioned above are valuable germicides, disinfectants, and deodorants, they are very irritating and often cause grave injury to the tissues. This is due to the fact that they always contain free alkali, which may also be increased when brought into contact with the proteins in the discharges and tissues. They have also a hydro lytic or dissolving action on the tissues.

In order to overcome these objections to its use in the sterilization of infected wounds, Dakin introduced boric acid in the chlorinated soda solution and thus rendered it almost neutral under all conditions and deprived of its irri tating properties. Dakin's Solution contains a mixture of hypochlorite and polyborate of soda and small quantities of free hypochlorous acid and boric acid. Should any alkali be formed it would be immediately neutralized by the boric acid and the acid borates found in the solution.

Dakin's original solution was composed of: anhydrous carbonate of soda, 140 grammes (or crystallized soda carbonate, 400 grammes), chloride cf lime of good quality, 200 grammes, ordinary water 10 litres, boric acid 40 grammes. The carbonate of soda is dissolved in the water, to which is then added the chloride of lime. After being well shaken and allowed to stand for half an hour to become clear, the liquid is syphoned off and filtered through cotton. To the filtrate the boric acid is added, so that the solution may be used at once.

As there were several drawbacks to this solution, Daufresne endeavoured to remove them by preparing it in the following manner: chloride of lime (having 25 per cent active chlorine) 200 grammes, carbonate of soda anhy drous 92 grammes (or crystallized carbonate of soda 262 grammes), bicarbonate of soda 76 grammes.

Into a 12-litre carboy 200 grammes of chloride of lime and 5 litres of tap water are placed and shaken vigorously two or three times and left for twenty-four hours. The carbonate and bi carbonate of soda are dissolved in 5 litres of cold water. This is poured in the chloride of lime solution and shaken for a minute and then set aside for the carbonate of lime to settle. At the end of half an hour the clear liquid is syphoned off and filtered through double paper in order to obtain a perfectly clear product, which should be kept in a cool and dark place, preferably in a black carboy. The solution, which should contain 0475 per cent of hypo chlorite of soda, with small quantities of neutral salts of soda, is then ready for surgical use.

It is isotonic with the blood serum. There is no danger when it is accurately prepared and used in fresh solution. No water must be added, as its bactericidal potency would become reduced.

The co-workers of Carrel have shown that below 045 per cent of hypochlorite of soda content the solution is insufficiently active, whilst above 0.50 per cent it is too irritating.

In order to obtain specific results with Dakin's Solution, Carrel has laid it down that it must be used under special conditions. For the chemical sterilization of infected wounds, as those of warfare, the solution is brought into all the recesses of the wounded surfaces by continuous or intermittent instillation by means of small rubber tubes. The tubes inserted into the wounds are perforated and fed by long con ducting or instillation tubes supplied from a pear-shaped ampoule or flask suspended at a certain height from the patient. The out flowing tube attached to the nozzle at the bottom of the flask or container may be pro vided or not with a drop-counting contrivance and a stop-cock, so as to allow a continuous or an intermittent instillation.

The tubes are disposed in the wound in such manner that the liquid may readily spread direct over the whole surface. No gauze or other dressing must intervene between them and the wound. The tubes are arranged accord ing to the shape of the wound, and as soon as they are in position gauze compresses soaked in Dakin's Solution as modified by Daufresne are applied so as to help to fix the tubes on the surface of the wound. The perforated part of the tube must be buried wholly in the wound in order to prevent the liquid escaping and possibly doing harm. The surrounding skin is protected by squares of gauze sterilized in vaseline. The dressing is completed by a sheet of cotton-wool protected on either side by one thickness of gauze.

Continuous instillation gives better results than intermittent instillation. But it is only suited to wounds where the liquid can remain in quantity. Intermittent instillation is used for extensive and irregular wounds having several openings. It is carried out by releasing for a few seconds every two hours the pinch cock which is placed on the irrigating tube just below the reservoir. The wound should be kept constantly moist. The instillation con tinues until all microbes have disappeared from the"smears."So long as a focus of infection, however so small, remains on the surface of the wound; total reinfection is possible. If the instillations be stopped or their frequency lessened, when the microbial curve shows only one or two microbes per field of the microscope, rapid reinfection may be brought about. By suppressing the microbes the hypochlorite solution does not lessen repair but accelerates it. In general, from three to four days are needed to sterilize a wound in the soft parts, and fifteen days or more for a compound fracture. These figures are those observed when the wound is sterilized before the suppurative stage. But if the treatment is com menced after the wound has already suppurated the duration of the in stillation period is usually much longer. Bacterio logical examination alone can indicate the time when the instillation may be discontinued. As soon as the wound no longer contains any mi crobes it may be closed.

grenous material dissolve. It destroys toxins in pus and microbes.

It therefore acts on the microbes, free ana tomical elements, and necrosed tissue. It does not injure tissues provided with circulation. It has a profound effect on the process of repair.

_ Such are the salient facts concerning Dakin's Solution and its application in practice by Carrel and his co-workers. For a fuller and more detailed account the reader is referred to Child's translation of the little work on The Treatment of Infected Wounds, by A. Carrel and G. Dehelly, 1917.

Eau de Javelle, when used as a 15 per 1000 solution, acts similarly to Dakin's Solution.

Chloramine or para-toluene sodium-sulpho chloramide, is manufactured from para-toluene sulphochlorate, a by-product in the manu facture of saccharine, and has been introduced by Dakin for practical use in the sterilization of wounds. It has a high germicidal power. It is very soluble in water and is stable. It does not coagulate proteid matters in the ordinary treat ment of wounds. It is used 1 in 500 to 1 in 1000 solution and acts in a manner similar to that of Dakin's Solution.

Antiformin is a trade name given to a solution of chlorinated soda which is said to contain 5 per cent of available chlorine and 7.5 per cent of sodium hydroxide. A 1 in 20 solution will destroy most germs in five minutes, but not the acid-fast bacilli such as those of tuberculosis and Johne's disease.

Eusol is composed of equal parts of chloride of lime and boracic acid. To this combination in a dry state has been given the name Eupad.

Of this 25 grammes are added to 1 litre of water and filtered. This solution is said to contain 0.5 per cent of hypochlorous acid or 0.27 grammes of hypochlorous acid in 100 c.c. of the solution. It is used for infected wounds. It has an irritating action on the living tissues.

The same objections to Labarraque's Solution and Eau de Javelle apply equally to this pre paration. It is, however, very efficacious in recently highly-infected wounds which cannot be properly treated by the Carrel method.

Fresh chloride of lime 1 part, with 9 parts of dry powdered boracic acid, is recommended by Vincent as a highly - powerful antiseptic or germicide dry dressing for infected wounds.

Flavin (acriflavine), proflavine, brilliant green and other aniline dyes, either 1 in 500 to 1000 aqueous, spirituous, or normal saline solution, have been recommended as powerful bacteri cides and promoters of epithelial regeneration in infected wounds, but, according to certain reliable observers, they are inferior to some of the well-recognized antiseptics and germicides.

Acetozone is a powerful bactericide, but its price precludes its use in general veterinary

wounds, solution, cent, antiseptic and acid