The healing of open incised wounds may be accomplished, according to the high sur gical authority from whom we have already quoted, in five different ways, if we include those in which the process is assisted by treatment—viz., (1) by immediate union, or (in surgical language) by union by the first intention; (2) by primary adhesion, or union by the adhesive inflammation; (3) by granulation, or by the second intention; (4) by sec ondary adhesion, or the third intention—i.e., by the union of granulations; and (5; by scarring under a scab, the so-called subcutaneous cieatrization. healing by immediate union takes place when the wounded parts being placed and maintained in contact, first stick together, and then become continuous, without the formation of any new material as a connecting medium. For example, a flap of skin is raised by dissection in the removal of a tumor or a mammary gland, and is then replaced on the subjacent parts. In three days at most, the union may be complete, without any indication of inflamma tion, there being no evident efflux of blood, no exudation of reparative material, and no soar. In healing by primary adhesion, lymph exudes from both cut surfaces, becomes organized, gradually connects the cut surfaces, and at length forms between them a Srm layer of connective tissue, covered with a thin shining cuticle. These steps are well seen after the operation for hare-lip, for example. Iu healing by grannlation, the wound becomes coated over with the white film, containing colorless blood-cells, as already described. If these glazed surfaces are brought and kept together, they will probably unite, the film becoming organized, and contributing to form a bond of union; but if the wound be left open, the film increases, and takes part in the formation of granulations (q. v.). We cannot enter into the life history of these granulations, and can only remark, that they are finally developed into a scar, consisting of fibro-cellular or connective tis sue, with a superficial layer of epidermis. The completion of the healing is accom plished by the gradual improvement of the scar, in which the connective tissue becomes more perfect in its character, and the cuticle becomes thicker and more opaque. Heal ing by secondary adhesion, or by third intention, " is accomplished by the union of two granulating surfaces (e.g.. those of two flaps after amputation) placed and maintained in contact. In this state the two surfaces simply unite, or else new material, produced from either or both surfaces, adheres to both, is organized into continuity with both, and then unites them."—Paget, op. cit., p. 586. Healing by scabbing, or under a scab, is, according to the same authority, the most natural, and in some cases the best of all the healing processes. In animals, it is often observed that if a wound be left wide open, the blood and other exudations dry on its surface, and form an air-tight covering, under which scarring takes place, and which is cast off when the healing is complete. In man, this process is less frequent, because, in the first place, exudations seem to be more often produced under the scab, which detach it, and prevent the healing; and secondly, sur gical interference seldom allows this method to have a fair trial.
Such are the several modes of healing of simple, incised, and all open wounds. We have now to consider the nature of the processes therein concerned. Every wound is followed by more or less tendency to an inflammatory process. This tendency may not proceed beyond an increased sensibility of the part and a slight efflux of blood, and there may be no inflammatory exudation; and this is the best condition for healing by immediate union in which no new material is required; or the inflammatory process may go on to the production of lymph, and then cease—a condition essential to healing by adhesion. In healing by granulation, a very low degree of inflammation (such as is requisite for the effusion of the first materials for granulation) is best; while for healing by secondary adhesion or by scabbing, inflammation must be altogether absent. The due understanding of these relations of inflammation and the healing processes of open. wounds, affords important aid•as to the mode of treatment. Nothing should be done to excite or increase inflammation. So much as may be necessary for some of the
modes of healing, is sure to occur spontaneously, and more will only do harm; on the other hand, the inflammation excited by the wound does not require special treatment, except in the case of organs (such as the eye. the peritoneum, the lungs, the large joints, etc.), in which serious mischief may be very rapidly induced by inflammation. The position of the wounded part is a subject of considerable importance. " When comfort has, as far as possible, been secured, the next object should be that the wounded part should be relaxed, so that the edges of the wound may come near or• together; that no part, and especially no muscle, should be on the stretch, and that the direction of the wound may be such as will allow fluids to flow away from some part of it." In the great majority of cases, healing by immediate union, or by primary adhesion, is most desirable, and should be aimed at—the exceptional cases being wounds through many structures, and exposing considerable surfaces of deep-seated bone; deep wounds whose depth far exceeds their length; wounds of which the deeper portions of the sides cannot be kept in good contact; wounds through parts in a very inflamed or otherwise disordered state; and those which are likely to be troublesome from secondary hemorrhage—in all of which there is a fear of the collec tion of blood and other fluids under the closed integuments. In attempting to induce healing by either of these modes, the points to be attended to are—the arrest of the bleeding, the cleaning of the wound, the exact apposition of its edges, and their main tenance in this position, and the exclusion of the whole wound from the air. If the bleeding arise from vessels of considerable size, they must be tied, twisted, and pressed (according to Simpson's plan) or crushed at their ends; but all these means, and espe cially ligature, should be avoided if possible, because they are impediments to exact union; and spontaneous closure of the vessels by the action of cold air or water, and pressure with dry lint, is preferable. The cleanirig of the wound is best effected by allowing a gentle stream of water to over it. Soft sponges are sometimes useful for this pur pose; but they must be used as dabbing (not as scrubbing) agents, and the greatest atten tion must be paid to their cleanness: the sponge used for the wounds or sores of one patient should never be applied to those of another. Apposition is effected by padding and bandaging, sutures (q.v.), and adhesive plasters—the former being useful in deep wounds, while the latter two serve for more superficial wounds. Although a simple incised wound, after its sides have been thus brought into complete contact, may be left exposed to the air, some covering to exclude the air is deemed preferable. Whatever is used should be light, not adhesive, and not prone to decomposition—its object being to protect the wound probably from a deleterious action of the air, and more certainly from sudden change of temperature, friction, and dust. Nothing is better for this pur pose than lint soaked in oil, or simple cerate on perforated linen. The following remarks on the dressing of wounds are condensed from Mr. Paget's memoir. No general rule can be laid down regarding the time at which any or the whole of the dressings should be removed. In small wounds about the face, union may be complete in two days; but it is not so firm as to be safe from probable accidents, and metallic sutures possess the advantage of exciting so little irritation, that they may be left in their places for any length of time till union is perfectly secure. They should therefore not be removed for four days, or, in the case of large wounds, for a week, or longer. They should not all be removed at once, and those that are removed should be replaced by strips of adhesive plaster; the union or scar must be cleaned most gently, and protected from the plaster with oiled lint. If, on the first dressing, the union or adhesion of the wound is pro gressing favorably, then it will usually be sufficient to dress it subsequently on every second day; and if all goes well, the union of small wounds may be regarded as safe at the end of a week, and that of larger ones at the end of ten days or a fortnight.