Incisions are made in such a manner that the diverticula of the wound are laid open as freely as possible. The liquid should penetrate everywhere, and remain in contact with the infected area as long as needful. As gravity plays an important part in the distribution of a liquid, those wounds which can be filled up like a cup are the most favourably qualified for sterilisation. That is the reason why wounds on the anterior surface of limbs are preferred to dependent counter-openings. Liquid is thus retained in the wound and its walls bathed more completely. Very large incisions need not be objected to, because they allow the topography of the wound to be studied and diverticula dealt with.
Once the wound has been thus freely laid open and all foreign bodies removed, the best possible conditions for contact between the liquid and the surfaces of the wound are obtained. It only remains to make arrangements for the application of the antiseptic to the whole of the infected surface.
It is indispensable to place the liquid in direct contact with the tissues in the deepest regions of the wound. Distribution of a liquid over the whole extent of an irregular surface is difficult to accomplish.
The simplest method, which at once occurs to every one, is to use absorbent gauze or other fabric, or strands of cotton-wick, conducting by capillary action the liquid from an external reservoir over the whole surface of the wound. This arrangement has been adopted by Sir Almroth Wright in his dressings of hypertonic saline solution. At the outset of our researches on the sterilisation of wounds we employed a similar method. Layers of absorbent tissue were applied to the surface of the wound, a rubber tube led the liquid to the tissue to which was entrusted equal distribution to all parts of the wound. Experience was not slow in making clear to us that procedures based on this principle were incapable of producing efficient contact of the antiseptic with the surfaces of the wound. In fact, at the end of a few hours the deepest part of the conducting tissue became impregnated with plasma or pus, and impermeable to the antiseptic liquid. On casual examination, the apparatus appeared to be working well, but the liquid went into the tissue without moistening the raw surfaces. This method of conducting the liquid was abandoned entirely. It has only been retained to distribute liquid on the surface of a rubber tube pierced with small holes. These tubes covered with tissue are sometimes used during the first few hours following the infliction of a wound, because at this period secretion is slight. In all other cases we use absorbent tissue compresses, which by a special arrangement cause the liquid to flow between themselves and the wound.
The procedure which has been adopted consists in distributing the liquid to all parts of the wound by means of rubber tubes, utilising the force of gravity of the liquid. The disposal of these tubes varies with the shape and situation of the wound. In wounds which have only a single opening so situated that they can be filled up like a cup, permanent contact between the antiseptic and the surfaces is assured by introducing a rubber tube to the bottom of the cavity (Fig. 31). If the patient reclines in a suitable position, the wound remains full of antiseptic liquid. But in dealing with surface wounds (Fig. 32)- large, irregular wounds, and those with several wide openings (Fig. 33)- it becomes more difficult to distribute the liquid over the whole surface. The most practical method consists in allowing small rubber tubes perforated with minute holes to lie on the tissues. The holes number fifty to each tube, and have a diameter of about 0.5 millimetre. When these tubes are charged with liquid under pressure, the surface of the wound is moistened, by the fluid which issues from all the orifices. This procedure has been adopted, in the first place, because it is successful, and next, because it can be carried out by means of articles readily obtainable commercially. The tubes should be tied up at one end and the perforations made with an ordinary-punch.
Fig. 31. - Wound with superior opening which can be filled like a cup.
Fig. 32. - Surface wound receiving liquid from a tube perforated by small holes.
Fig. 33. - Irregular wound with several perforated tubes in its diverticula.
But this manner of distribution is far from ideal, because, the holes being too large and not sufficiently numerous, the liquid spurts out too profusely over a space too limited. So it is not made the best use of. Probably a tiny hose, pierced with a great number of microscopic holes, or rather rubber membranes, whence the antiseptic could ooze out, would bring about more intimate relations between liquid and microbes. A totally different arrangement might be conceived, by which the liquid could be distributed over the surface of the wound without using tubes at all. If the antiseptic were incorporated with a substance which had the property of melting very slowly in contact with the tissues, and which at the same time could be moulded to fit all the irregularities of the wound, a more perfect distribution of the antiseptic would be attained.