Everything goes on as though during the first twenty-four hours, and sometimes during the early days following the receipt of the wound, the microbes dwelt on the surface of the wound; consequently, within reach of the antiseptic. However, in irregular wounds and compound fractures microbes are sometimes found to be out of reach of the liquid. After some days of treatment the secretions of certain regions become aseptic, whilst those of other regions still remain infected. These regions have not been reached by the liquid, either because the latter has not been introduced deeply into the diverticula, or because the walls are protected against the antiseptic by sphacelated tissues, blood-clots, or a compress soaked in blood. Gauze compresses, blood-clots, or dead tissues have a peculiarly harmful effect, because they protect the bacteria from the attack of the antiseptic.

2. Suppurating Wounds. - During the period of suppuration, contact between the microbes and the antiseptic was, in general, more difficult to obtain. The number of microbes had greatly increased. No longer were there topographical differences in the volume of infection, for the bacteria were found in almost equal quantities in every part of the wound. But, following the shape and character of the wound, the microbes were reached by the liquid more or less easily. In surface wounds, and in irregular wounds of the soft parts, whose walls were covered with granulations and suppurated abundantly, the antiseptic rapidly destroyed the bacteria. But when the latter were protected by necrosed tissue, tendons, or aponeuroses which were being eliminated, the liquid could not reach them, and infection persisted. Even in long-standing wounds the contact between the liquid and the microbes was so complete that, in certain cases, the latter were seen to disappear completely in forty-eight hours.

The suppression of micro-organisms in secretions, and the possibilities of sterilising the surface of a wound in such a manner that suturing becomes possible, does not mean, however, that all the microbes have been brought into contact with the antiseptic and destroyed. In fact, when by means of sutures more or less deep wounds are brought together, which have suppurated for some time before being sterilised, there is sometimes re-infection and a rise of temperature. These phenomena are not seen in wounds which have been subjected to sterilisation from the beginning. But a wound which is cicatrising at the same time that it is suppurating, is keeping in its walls microbes capable of producing re-infection at the moment of a fresh traumatism. In wounds of long standing which are suppurating, antiseptics cannot reach microbes already enclosed in granulations, but they can affect those which are at the surface of the wound. As, on the other hand, living tissues destroy or encapsule microbes withdrawn from the antiseptic, sterilisation takes place little by little.

Therefore it is important to sterilise a wound at a period as near as possible to the onset of infection. If postponed to a later period, sterilisation is effected and closure by suture may be obtained; but microbes have already become enclosed in the cicatrix, and remain alive there. We have examined, on a wound more than six months old, a thick cicatrix which had formed during that long period of suppuration. The different layers of the cicatrix presented a varied bacterial flora. Passing from the deepest part to the surface, there was first a layer containing Welch's bacillus, next a sterile layer, then a stratum containing small rod-like bodies, lastly a layer of various cocci. In wounds of long standing, the topography of infection is therefore such that the antiseptic cannot reach the microbes in every part in which they are found. But, on the other hand, the microbes are enclosed or encapsuled in the tissues, and are not in a condition to work harm until a new traumatism sets them free.

From the practical point of view, in the suppurating wounds of soft parts, contact between microbes and antiseptic sufficient to assure surgical sterilisation is possible of attainment. In deep wounds with pus burrowing along muscular interstices, where contact between antiseptic and microbe cannot be realised, results are less favourable. When suppurating wounds are accompanied by fractures, or the osseous fissures described by Policard,1 along which the micro-organisms are propagated, it becomes impossible to make the liquid penetrate into all the infected places. Similarly, when osteo-myelitis has declared itself, or when splinters have been left in the tissues, the conditions are the same. Microbes establish themselves in the sequestra at such a depth that the antiseptic cannot penetrate to them. They are protected by their situation, at the same time against the chemical agent and against the polynuclear cells coming from normal tissues. This is the reason why the infection is so extremely tenacious, when bony lesions or necrosed splinters persist at the bottom of irregular wounds.

This brief examination of the topography of infection shows that in the majority of cases it is possible to obtain intimate contact between antiseptic and microbe. Suitable preparation of the wound for the penetration of the germicide substance, and distribution of this substance over the whole of the affected surface, will enable this contact to be realised. If, up to the present, we have not succeeded in chemically sterilising wounds, it is, in part, because we have neglected to prepare them in such a manner that the antiseptic substance may reach every point where microbes exist.

1 See also Bowlby, "Wounds in War," The lancet, 1915, pp. 1388,1389.

B. Preparation Of The Wound For The Penetration Of The Antiseptic

Most important in the preparation of the wound is the mechanical cleansing of the infected regions. Free incisions in the soft parts allow this cleansing to take place even in the case of irregular torn wounds, accompanied by fracture. It is well known that shreds of clothing, projectiles, splinters lying free, blood-clots and necrosed tissues serve as shelters for microbes and protect them from the antiseptic. In consequence, every foreign body should be most carefully sought for and removed. Debris of clothing are the principal source of infection, and the antiseptic generally cannot penetrate them. Necrosed tissues are the favourite haunt of gas infection. Therefore they must be removed. Ever since the beginning of the war, Depage and the surgeons of his school have made a systematic resection of all tissues, skin, aponeuroses or muscles which were likely to mortify. This practice is excellent and ought to become general. All blood-clots are removed, and, to prevent their reoccurrence, careful haemostasis of the whole of the wound is practised. The surface of bony cavities in which projectiles are lodged, is scraped, and resected if needful. Furthermore, it is well to remember that compresses placed in wounds efficiently protect microbes against antiseptics. Therefore a wound should never be left plugged with tampons or compresses. If an open wound is desired, tubes of large calibre perforated with many wide holes are used.