Chapter III: General Characters of Wounds Produced by Bullets of Small Calibre (1)

The effects of injuries inflicted by bullets of small calibre may be divided into two classes:

1. Direct or immediate destruction of tissue.

2. Remote changes induced by the transmission of vibratory force from the passing projectile to neighbouring tissues or organs.

Those of the first class will be mainly considered in this chapter; the remote effects will be dealt with under the headings devoted to special regions.

In dealing with the wounds as a whole I shall first describe those of uncomplicated character as type injuries, and deal with those possessing special or irregular characters separately.

TYPE WOUNDS

1. _Nature of the external apertures._--The apertures of entry and exit in uncomplicated cases are very insignificant, but the size naturally varies slightly with that of the special form of bullet concerned. As will be shown moreover, the difference in size is the only real distinguishing characteristic in many cases between wounds produced by the modern bullet of small calibre and those resulting from the use of the older and larger projectiles of conical form. I have been very much struck on looking over my diagrams of entry, and especially exit, wounds to find that they reproduce in miniature most of those figured in the History of the War of the Rebellion; some of these diagrams are reproduced in this chapter.

_Aperture of entry._--The typical wound of entry with a normal undeformed bullet varies in appearance according to whether the projectile has impinged at a right angle or at increasing degrees of obliquity, or again, to whether the skin is supported by soft tissues alone, or on those of a more resistent nature such as bone or cartilage.

When the bullet impinges at a right angle the wound is circular, with more or less depressed margins, and of a diameter, corresponding to the size of the bullet occasioning it, from a quarter to a third of an inch. The description 'punched out' has been sometimes applied to it, but it would be more correct to reverse the term to 'punched in,' since the appearance is really most nearly simulated by a hole resulting from the driving of a solid punch into a soft structure enveloped in a denser covering. The loss of substance, moreover, in the primary stage is not actually so great as appears to be the case, fragments of contused tissue from the margin being turned into the opening of the wound track. The true margin therefore is not sharp cut, and the nature of the line differs somewhat according to the structure of the skin in the locality impinged upon. Thus the granular scalp and the comparatively homogeneous skin of the anterior abdominal wall will furnish good examples of the nature of the slight difference in appearance. From the first the margin is also often somewhat discoloured by a metallic stain, similar to that seen when a bullet is fired through a paper book. This ring is, however, narrow, and not likely to be noticeable when the bullet has passed through the clothing. In any case it is subsequently obscured by the development of a narrow ring of discoloration due to the contusion. This latter varies in width, and still later a halo of ecchymosis half an inch or more in diameter surrounds the original wound.

With increasing degrees of obliquity of impact more and more pronounced oval openings of entry result, culminating in an actual gutter such as is seen in fig. 17.

In all oval openings the loss of substance is more pronounced at the proximal margin, while the wound is liable to undergo secondary enlargement at the distal margin, since in the former the epidermis is mainly affected, while in the latter the epidermis is spared as an ill-nourished bridge, the deeper layers of the skin suffering the more severely. When the wound occurs in regions, such as the chest-wall or over the sacrum, where the skin is firmly supported, the oval openings are often very considerable in size, reaching a diameter at least double that of the circular ones. In the case of the oval openings the depression of the margins is not such a well-marked feature as in wounds resulting from rectangular impact of the bullet, since the distal margin is really lifted.

_Aperture of exit._--The wound of exit in normal cases offers far more variation in appearance than that of entry, this variation depending on several circumstances: first, the want of support to the skin from without, and such other factors as the degree of velocity retained by the travelling bullet, the locality of the opening, and the density, tension, and resistance offered by the particular area of skin implicated.

When the range has been short and the velocity high, it is often difficult to discriminate between the two apertures. Both may be circular and of approximately the same size, and the only distinguishing characteristic, the slight depression of the margin of the wound of entrance, may be absent if any time has elapsed between the infliction of the injury and examination by the surgeon. One very strong characteristic if present is the general tendency of the margins, and even the area surrounding the exit wound itself, to be somewhat prominent. Fig. 16 shows this point, although the wound from which it was drawn had been produced thirty-six hours before death. The specimen was then hardened in formalin and still preserves its original aspect. This character is, however, more frequently displayed in wounds received at mean, or longer, ranges. In wounds produced by bullets travelling at the highest degrees of velocity it is often absent.

When the range of fire has been greater and the velocity retained by the bullet lower, slit wounds are common, or some of the slighter degrees of starring. Actual starring I never saw, but reference to figs. 20 and 21 will show a tendency in this direction, also a close resemblance to the starred wounds resulting from perforations by large leaden bullets. Such wounds, I believe, are usually the result of a somewhat low degree of velocity.

Slit exit wounds may be vertical or transverse (fig. 20) in direction, and the production of these is dependent on the locality in which they are situated, the thickness, density, and tension of the skin, and the nature of the connection of the latter with the subcutaneous fascia in the locality. Thus in wounds of different parts of the hairy scalp, so little variation exists in the relative density and structure of the skin, that, in spite of the want of external support at the aperture of exit, it is often difficult to discriminate offhand the two apertures, if neither bone nor brain débris occupies that of exit.

If, however, a wound crosses from side to side a region such as the thigh where well-marked differences exist in the subjacent support, thickness, and elasticity of the skin implicated in the apertures, the wound of entry, if in the thick skin of the outer aspect, was usually circular, while the exit in the thin elastic skin of the inner aspect was either slit-like or starred. The difficulty in laying down any general rule as to the occurrence of circular or slit apertures of exit in any definite region is, however, great, as may be seen by reference to the accompanying diagrams taken from two patients wounded at Paardeberg (figs. 22 and 23).

In fig. 22 the bullet entered the outer and posterior aspect of the left buttock, crossed the limb behind the femur, and emerged at the inner aspect by a vertical slit: the bullet then entered the scrotum by a vertical slit, and emerged by a typical circular aperture; re-entered the right thigh by a transverse slit aperture, and, striking the femur in its further course, underwent deformation, and finally escaped by an irregular aperture 3/4 of an inch in diameter. The occurrence of exit slits in the adductor region is common, and to be explained by the tendency of the comparatively thin elastic skin to be carried before the bullet; the slit entry in this position must, I suppose, be explained by the comparatively slight support afforded by the underlying structures, which are often in a condition of hollow tension. The scrotal wounds are perhaps more difficult to account for, but in this case the fact of the distal aperture being directly supported by the right thigh is a ready explanation of the circular exit, while the skin corresponding to the slit entry was no doubt carried before the bullet, and finally gave way in the line of a normal crease.

In fig. 23 all the wounds are circular except the final exit, which was irregular as a result of the bullet in this case also having struck the femur in the second thigh. Considerable variation also exists in the size of the circular apertures; this illustrates the secondary enlargement often occurring in such wounds, and most marked at the apertures of entry, as the more contused. Both diagrams were made from patients eight days after the reception of the wounds.

This diagram is of considerable interest when compared with fig. 22. I believe the comparative regularity in the wounds to have been due to a higher degree of velocity of flight on the part of the bullet]

Lastly, vertical or transverse slits may be looked for with considerable confidence in situations in which transverse oblique or vertical folds or creases normally exist in the skin, and depend on the lines of tension maintained by the connection of the skin in these situations to the underlying fascia. Thus I saw well-marked transverse and vertical slits in the forehead corresponding with the creases normally found there, and in this situation I noted some slit entries. Transverse slits were common in the folds of the neck, the flexures of the joints (fig. 20), and the anterior abdominal wall either in the mid line or in creases like those stretching across from the anterior superior iliac spines. Again they were seen in the palms and soles, but here more readily tended to assume the stellate forms. Vertical slits are less common; they occurred with the greatest frequency in the posterior axillary folds.

Oval apertures of exit are far less common than those of entry, since the most common factor for the production of an oval opening, bony support, is never present. In long subcutaneous tracks, or very superficial wounds, they are however sometimes met with and may terminate in a pointed gutter (see figs. 18 and 24).

The greatest modifications in the appearance and nature of the apertures of entry are dependent on previous deformation of the bullet, when all special characteristics are lost, and it becomes impossible to form any opinion as to the type of bullet concerned. These modifications are naturally far more common in the aperture of exit, since the bullet so often acquires deformity in the body as the result of impact with the bones. Further remarks on this subject will be found with the description and comparison of the various bullets on p. 81.

2. _Direct course taken by the wound track._--This character primarily depends on the velocity with which bullets of small calibre are made to travel, and on the small area of the tissues upon which they operate. In this relation the degree of velocity retained by the bullet is often of minor importance, provided it be sufficient to penetrate the body. Fired within a distance of 2,500 yards there is little doubt that a bullet of the Lee-Metford, Mauser, or Krag-Jörgensen types, passes straight between the apertures of entry and exit when these are of the type outline, even when the bones are implicated. By reason of the small size of the projectiles, their shape, and the spin and velocity transmitted to them, there is no reason why at a sufficiently short range they should not traverse the body from the crown of the head to the sole of the foot. The necessary conditions of position and distance for such an injury are obviously not often obtained, but it may be pointed out that the Belgian Mauser rifle at a distance of five yards is capable of driving a bullet 55 inches or nearly five feet into a log of pine-wood. Many examples of long tracks will be referred to later, but the following instances may be of interest in this relation. A bullet entering at the occipital protuberance traversed the muscles of the neck, passed through the thoracic cavity, fractured the bodies of the third and fourth and grooved the seventh and eighth dorsal vertebræ, grooved the seventh and eighth and fractured the ninth and tenth ribs, traversed the muscles of the back and finally lodged against the ilium; the whole length of this track measured some 25 inches. Again, at the battle of Belmont a Mauser bullet entered the pelvis of a horse just below the anus, and traversed the entire trunk before emerging from the front of the chest: it may be of interest to mention that this animal was alive and moving about the next day, but I am sorry I can give no further information regarding his fate.

The possibility of contour tracks travelling around the walls of the chest or abdomen has therefore rarely to be considered, except in occasional instances where the bullet fired from a long range has impinged against a bone and is retained in the body. The small volume of the bullets, however, allows the production of very prolonged direct subcutaneous tracks in the body wall, in positions where they would be manifestly impossible with projectiles of larger calibre.

Figs. 24 and 25 illustrate wounds of this nature. In the case figured in fig. 24 the bullet entered over the third rib in a vertical line above the right nipple; it then coursed obliquely down, crossing the seventh costal cartilage, and finally emerged 3 inches above the umbilicus. Where the track crossed the prominence of the thoracic margin the skin was so thinned as to undergo subsequent discoloration, while a distinct groove was evident there on palpation. In some similar cases I have seen the central part of the track secondarily laid open as a result of the thinning of the skin and consequent sloughing due to the interference with its vitality.

Short of sloughing, the skin may show signs of alteration of vitality for a long period after the injury; thus fig. 25 depicts the condition seen in a superficial wound of the thigh five weeks after the injury. The line of passage of the bullet between the two openings was still clearly visible as a dark red coloured streak. Grooves in such cases are generally readily palpable in the early stages, while later the want of resistance is replaced by the readily felt firm cord representing the cicatrix. These points are of much importance in discriminating between perforating and non-perforating wounds of the abdomen, and are again referred to in that connection.

The direction of the tracks obviously depends on the attitude assumed by the patient at the moment of impact of the bullet and the direction whence the firing has proceeded. The frequent assumption of the prone position during the campaign led to the occurrence of a large proportion of longitudinal tracks in the trunk, or trunk and head, which will be referred to later. Certain battles were in fact strongly characterised by the nature of the wounds sustained by the men. Thus at Belmont and Graspan, where some rapid advances were made in the erect attitude, fractured thighs were proportionately numerous, while at Modder River, where many of the men lay for a great part of the day in the prone position, glancing wounds of the uplifted head, of the occipital region, or longitudinal tracks in the trunk and limbs were particularly frequent. I very much regret that the material at my disposal does not allow me to add some remarks as to variation in the nature of the wounds according to whether they were received from an enemy firing from a height or from below, but it is possible that some information on this subject may be forthcoming when the returns of the Service are made up, since it is naturally of great importance as to the effect of trajectory in the proportionate occurrence of hits.

3. _Multiple character of the wounds._--The same conditions responsible for the length and directness of the tracks, account for the frequently multiple character of the wounds implicating either the limbs or viscera--thus, lung, stomach, liver; neck, thorax, abdomen; abdomen, pelvis, thigh. Also for the frequent infliction of two or more separate tracks by the same bullet--thus, arm and forearm with the elbow in the flexed position; both lower extremities; both lower extremities, penis or scrotum; leg, thigh, and abdomen, with a flexed knee; upper extremity and trunk, and more rarely one upper and one lower extremity. Again, it was remarkable how often the same bullet would inflict injuries on two or more separate men, not unfrequently dealing lightly with the first and inflicting a fatal injury on the second, or vice versâ. The small calibre of the bullet, moreover, allows of the neatest and most exact multiple injuries. Thus in a patient who was crawling up a kopje on all fours, the flexed middle digit of the hand was struck. The bullet entered at the base of the nail, first emerged at the distal interphalangeal flexor fold, re-entered the metacarpo-phalangeal fold, and finally emerged from the back of the hand between the third and fourth metacarpal bones.

4. _Small 'bore' of the tracks, and tendency of the injury to be localised to individual structures of importance._--Here we meet with the most striking characteristic of the injuries, and evidence that reduction of calibre affects more strongly the nature of the lesion than does any other element in the structure of the modern rifle. The diameter of the track slightly exceeds that of the external apertures, probably as a result of the more ready separability of the elements of the structures perforated than exists in the skin. The calibre, moreover, tends to be fairly even throughout when soft structures only are implicated, though local enlargements result wherever increased resistance is met with. Thus a strong fascia may offer such resistance as to increase locally the bore of the track, and in this particular the state of tension of the fascia when struck will affect the degree of the enlargement. The most striking instances of local enlargement of the track are of course seen when a bone lies in the course of the bullet, but we must here bear in mind the introduction of a new element--the propulsion of comminuted fragments together with the bullet itself. In cases of fracture the distal portion of the track is in consequence many times larger than the proximal. The most striking examples of small even tracks are seen, on the other hand, in punctures of the elastic and practically homogeneous lung tissue, where the wounds are extremely small.

On transverse section of the track the gross amount of actual tissue destruction occupies a lesser area than that corresponding to the diameter of the bullet. The destructive action of the projectile is in fact exerted mainly on the tissues directly lying in its course, the track being opened up during the rush of the passage of the bullet, partly as a result of its wedge-like shape and partly as a result of the throwing off of the tissues forming the walls of the track by a diversion of a portion of the force in the form of spiral vibrations dependent on the revolution of the bullet. Again, the opening out of the tissues may be aided by the direction taken by the first and strongest as well as the simplest series of vibrations transmitted, which would assume the shape of a cone of which the point of impact forms the apex.

The escape from actual destruction by structures lying in the immediate neighbourhood of the track is indeed often surprising, but not perhaps so astonishing as the perforation of long narrow structures such as the peripheral nerves and vessels, without irreparable damage to the parts remaining, and this although the structures themselves may be of a diameter not exceeding that of the bullet itself. The capacity of these projectiles to split such structures as tendons was already well known before our experience in this campaign, but the injuries to the nerves and vessels of the same character came as a surprise to most of us. The lateral displacement of tissues seems to bear a strong resemblance to what is seen on the passage of an express train, when solid bodies of considerable weight are displaced by the draught created without ever coming into contact with the train itself. The tendency to lateral displacement is still more strongly exhibited when dense hard structures such as bone are implicated. Here the fragments at the actual points of impact on the proximal and distal surfaces of a shaft are driven forwards, while the lateral walls of the track in the bone are simply comminuted and pushed on one side without loss of continuity with their covering periosteum.

The extension of this form of displacement to a degree amounting to a so-called explosive character in the case of the soft tissues, even when the bullet passed at the highest degrees of velocity, was, however, never witnessed by me, and I very much doubt the existence of a so-called 'explosive zone' so far as wounds of the soft parts are concerned. On the contrary, I am inclined to believe that the highest degrees of velocity are favourable to clean-cut neat injuries of the soft tissues. I saw a large number of type wounds of entry and exit inflicted at a range of under fifty yards.

5. _Clinical course of the wounds._--The tendency of simple wounds such as are above described to run an aseptic course was very marked, and, given satisfactory conditions, deep suppuration and cellulitis were distinctly rare. It may also be confidently affirmed that when suppuration did occur, with apertures of entry and exit of the normal small type, this was always the result of infection from the skin, or infection subsequent to the actual infliction of the wound. The infrequency of suppuration depended on the aseptic nature of the injury, the smallness of the openings, the small tendency of the track to weep and furnish serous discharge in any abundance, the comparative rarity of the inclusion of fragments of clothing or other foreign bodies, and possibly in some degree on the purity and dryness of the atmosphere, which favoured a firm dry clotting of the blood in the apertures of entry and exit, and consequent safe 'sealing of the wound.'

As to the aseptic nature of the injury, it will be well to first consider the question of the sterility of the bullet. Putting laboratory experiments on one side, the large experience of this campaign seems to prove to absolute demonstration that, bearing in mind the very large proportion of instances of primary union in simple tracks, the surgeon has nothing to fear on the part of the bullet itself. This is the more striking when we remember that these bullets shortly before their employment were carried in a dirty bandolier, and freely handled by men whose opportunities of rendering either their hands or implements aseptic were as bad as it is possible to conceive.

Several explanations are to hand, but none of them conclusive. Two must, however, be shortly considered. First, the surface of the bullet, except its tip and base, is practically renewed by passage through the barrel. Secondly, there is the question of the heat to which it is subjected. As far as cauterisation of the tissues is concerned, this question has been practically settled in the negative, since actual determinations of the heat immediately after the moment of impact have been made, and again it has been shown that butter is not melted, and that neither gunpowder nor dynamite is exploded, by firing bullets through small quantities of those materials. Again, the absence of any sign of scorching of the clothes of the wounded is strong evidence against the possibility of any considerable heat being applied to the tissues of the body; while another observation, although of less importance as affecting spent bullets only, that bullets, which have perforated the body but lie between the skin and the clothing, leave no sign of cauterising action on either, may be mentioned. None the less, the sources of heating while the bullet is passing from the barrel are many and obvious. Thus there is the heat consequent on explosion of the powder, the warm state of the barrel itself when the rifle has been fired a few times consecutively, and the heat resulting from the force and friction essential to the propulsion of the bullet through the barrel. Again, bullets covered with wax before their introduction into the barrel retain no trace of this when they have been fired, although at any rate the portion covering the tip is not exposed to friction on the part of the rifle, and lastly the base of the bullet has no other explicable reason for its innocuousness than subjection to a certain degree of heat. While not claiming any cauterising action on the tissues by the bullet, I should therefore still be inclined to allow the probability of the heat to which the surface of the bullet is exposed exerting a cleansing action on the projectile. In regard to this point it is interesting to bear in mind that shots from an ordinary gun seldom or never give rise to infection.

Foreign bodies were rarely carried into the wounds with the bullet. I saw several instances in which portions of the metal of cigarette cases and of cartridge cases when the bullet had perforated cartridges in the wounded man's bandolier, and in one instance small pieces of glass from a pocket mirror, must have been carried in without any obvious ill effect. Fragments of clothing, on the other hand, in every case caused suppuration: clothing was not often carried in, the khaki linen was perforated with a clean aperture, most commonly a slit; but the thick woollen kilts of the Highlanders, and thick flannel shirts, occasionally furnished fragments. The introduction of large pieces of clothing is a sure proof of irregularity of impact on the part of the bullet. The frequency with which portions of cloth were introduced from the kilt was one of the strongest surgical objections to its retention as a part of the uniform on active service.

Retained bullets themselves remained as foreign bodies in a certain number of cases. I cannot say that suppuration never followed the retention of a bullet, since in two of the instances where I saw such removed they lay in a small cavity containing at any rate a 'purulent fluid.' In one of these the bullet was a Martini-Henry, and in both the bullet had been imbedded for some weeks, and had certainly not occasioned a primary suppuration of the wound.

The favourable influence of the pure and dry nature of the atmosphere in this campaign must certainly not be underrated, and in support of this influence I think I may say, from the experience of cases that I saw coming from Natal where the climate and surroundings were not so favourable as on the western side, that suppuration was more common and more severe in the moister atmosphere.

Putting aside all the above remarks, however, I am inclined to think that a general tendency to primary union and the absence of suppuration will always be a feature of wounds from bullets of small calibre, and that this favourable tendency is attributable to certain inherent characters of the injuries. Of these the nature and small size of the openings, the dry character of the lining of the track due to superficial destruction and condensation of the tissue forming its wall, the small disposition to prolonged primary hæmorrhage, and the absence of any great amount of serous exudation during the early stages of healing are the most important.

A mechanical factor of great importance also exists in the spontaneous collapse and automatic apposition of the walls of the track. This closure is rendered additionally effective in many cases by the interruption of the continuous line in the wounded tissues consequent on alteration in the position of the parts traversed when an attitude of rest is assumed by the injured part. The indisposition to suppuration and the apparent unsuitability of the tissue lining the track for the development and spread of infecting organisms are well illustrated by several observations. Thus, even if the bullet be thoroughly aseptic, the fragments of destroyed skin driven into the track by the bullet can scarcely be free from organisms; yet these seldom give rise to trouble. Again, if for any reason a deep portion of a track becomes infected and suppurates, there is no tendency for the spread of infection along the line of wounded tissue, but rather for the development of a local abscess, pointing in the ordinary direction of least resistance, irrespective of the course originally taken by the bullet.

Engraved and Printed by Bale and Danielsson, Ltd.

G. L. CHEATLE.

Mauser Wound of Entrance, a little more than 48 hours after infliction. About 12/1.

Section of the entry segment of an aseptic Mauser wound removed a little over forty-eight hours after its infliction. Magnified twelve diameters.

The margins of the opening are still sloping and depressed, indicating the originally 'punched-in' nature of the aperture. A thin stratified layer of epidermis completely closes it. No scab remains.

The wound track is occluded by an effusion of lymph, commencing organisation of which is shown under a higher magnifying power by the presence of leucocytes near the margin of the bounding tissue, and some giant cells. The effusion of lymph occupies a slightly wider area immediately beneath the papillary layer of the skin, then narrows, and broadens again as the subcutaneous fascia is reached, indicating the effect of resistance in widening the area of damage.

The subcutaneous connective tissue bounding the track shows little sign of alteration beyond a general slight tendency of the lines of structure to deviate in the direction of the passage of the bullet.

No hæmorrhage is apparent beyond a small collection of blood situated immediately beneath the new layer of epidermis at the left-hand corner of the opening.

Range probably within 800 yards. Seat of wound, abdominal wall a highest point of iliac crest.]

Fig. 25 (_a_), A (plate I.) represents a section carried across an aseptic aperture of entry. The specimen was removed by Mr. Cheatle from a patient who died forty-eight hours after reception of the injury. It shows well the small amount of gross destruction suffered by the subcutaneous tissue, and the rapid repair which follows, since macroscopically the track is scarcely discernible. Reference to plate I. shows the remarkable fact that even at this early date considerable progress towards definite healing has occurred, and a thin layer of stratified epidermis covers the original opening. The question may be raised whether the origin of this epidermal layer is not in part a floating up of the margins of the main aperture.

During the course of healing some variation takes place in the appearance of the apertures, especially that of entry. This, at first contracted, later becomes somewhat relaxed, while in many cases a small halo of ecchymosis develops around it. The blood-clot occupying its centre now contracts, the margins rapidly become approximated centripetally, and a small circular dark spot only remains, which is later replaced by a small red cicatrix. The dark central spot under these circumstances consists of the contused margin of the wound in the skin, and a small proportion of blood-clot which finally comes away as a small dry scab. When slight local infection occurs in place of simple contraction and dry scabbing, the process is prolonged, the contused margin separates by granulation, the clot in the opening breaks down, and a small ulcer of somewhat larger proportions than the original wound remains and takes some days to heal.

The aperture of exit in simple wounds of the soft parts sometimes heals even more rapidly than that of entry, and if of the slit form may be almost invisible at the end of ten days or a fortnight, actual primary union having taken place as after a simple small incision. Larger or irregular exit apertures, however, take a longer period to close than entry wounds, and this is most often observed when the bullet has undergone deformation within the body, or bone fragments have been driven out with the bullet.

Fig. 25 (_a_), B (plate II.) represents a section of an infected exit aperture from a patient who died seven and a half days after its infliction. Two main points of interest are at once apparent: 1. The carrying forwards of the subcutaneous fat into the lips of the skin wound by the bullet. This illustrates the manner in which lightly supported structures are carried forward by the bullet, and throws some light on the mode by which vessels and nerves may escape by a process of displacement. This figure may be compared with fig. 25 (_b_) which shows a tag of omentum similarly carried forward by a bullet crossing the abdominal cavity and plugging the exit wound. 2. The second feature of interest is the amount of hæmorrhage into the subcutaneous tissue. In this respect the contrast between the exit and entry apertures is marked, since in the latter hæmorrhage is scarcely apparent. The presence of such hæmorrhages is explained by the same dragging action as the extrusion of the fat, and is of course dependent on consequent rupture of small vessels. It is of importance as predisposing the exit wound to more easy infection, and it accounts for the persisting subcutaneous induration more often detected beneath healed exit than entry apertures. Again, it suggests that the presence of blood in the deeper parts of the tracks may be the determining cause of the indurated cords often replacing them.

Engraved and Printed by Bale and Danielsson, Ltd.

G. L. CHEATLE.

Mauser Wound of Exit, 7-1/2 days after infliction. Healing delayed by Infection. About 12/1.

Section of the exit segment of a Mauser wound, removed seven and a half days after infliction. Magnified twelve diameters.

The healing process has been delayed by infection.

There is no attempt at closure by a layer of epidermis, and the margins are not depressed.

The wound track is narrower than that seen in the entry wound plate I., and completely occluded by a plug of the subcutaneous fat which has been carried forward by the bullet in its passage. A small wedge-shaped plug of lymph indicates the position of the actual track at its termination.

Dragging on the surrounding tissue consequent on the extrusion of the plug of fat has ruptured some capillaries, and given rise to considerable extravasation of blood, which is seen as a darker layer in the deepest portion of the wound.

Comparison of this plate with the exit wound depicted in fig. 16, p. 56, explains the nature of the tags of tissue there seen to protrude from the convex opening.

Range 800 yards. Seat of wound, abdominal wall below 9th costal cartilage.]

_Pari passu_ with the closure of the external openings, healing of the track takes place, but this is not always so rapid a process as is apparently the case. In many instances the closure, and even definite healing, of the external wounds is complete long before the track has actually healed, even though it be contracted up to complete closure as far as any cavity is concerned. This is well seen in many cases in which the exit opening is large as a result of deformation of the bullet, or the passage of bone splinters in conjunction with it; here, in spite of absence of all suppuration, the track may remain patent for many weeks. This may point to infection, but the tardiness in actual consolidation corresponds with what we are well acquainted with in the case of all aseptic wounds when a slough has to separate or become absorbed, and it is therefore only what might be reasonably expected when we remember that every such bullet track is lined by a thin layer of damaged tissue.

When fully healed, the points of entry and exit are so insignificant as to be less obvious than ordinary acne scars, and later are often hardly visible, but for a considerable period they are often more palpable than apparent. This depends upon the induration of the line of cicatrix corresponding to the course of the original track which is adherent to the two points. The induration is indeed so marked as to occasionally give rise to the suspicion that a foreign body such as a fragment of lead or of the mantle of the bullet has been enclosed during the healing of the wound.

In the deeper portions of the tracks the extreme density of the cicatrix is a factor of great prognostic importance, since if it implicates muscles, tendons, vessels, or nerves, impairment of movement, circulatory disturbance, or signs of neuritis or nerve pressure are often witnessed. Thus, for instance, a track traversing the calf, will more or less tie the whole thickness of the structures perforated at one spot, and the apertures of entry and exit may be visibly retracted when the muscles are put in action with consequent pain and stiffness to the patient. Such pain and stiffness form some of the most troublesome after-consequences of many simple wounds. It is remarkable for how long a period after the healing of the wound and resumption of active duty the patients suffer from pain in and radiating from the locality of the wound, when fatigued or suffering from stiffness from the prolonged retention of one attitude or exposure to cold. The cords, however, eventually completely disappear, and the cicatrices become moveable. The effects of secondary pressure on the vessels and nerves are considered under the headings devoted to those structures.

_Suppuration._--While the occurrence of deep suppuration or septic phlegmon was rare, local suppuration of the apertures of entry and exit was seen in a considerable proportion of the wounds. This was referable to infection from the skin itself, or to infection from without subsequent to the infliction of the injury. Infection from the skin, difficult to obviate at all times, is especially likely to occur in wounds the first dressing of which is often delayed, and which happen to men sweating freely into clothes the condition of which is at least undesirable for contact with a recent wound. Beyond this, the first dressing materials, removed from a soiled tunic by possibly a comrade or a stretcher-bearer, are scarcely above reproach of the probability of containing septic organisms themselves. Again, once applied, the exigencies of the situation often necessitate an amount of movement fatal to the retention of the dressing over the wound, and a second opportunity of infection arises before the patient comes into the hands of the surgeon in the Field hospital.

The general tendency of such suppurations when they occurred in uncomplicated flesh wounds was to remain superficial, either involving the contused margin of the cutaneous opening and the plug of blood-clot occupying it, and resulting in a slight enlargement of the wound only, or at most involving the subcutaneous tissue and not extending into the deep planes of the trunk or limbs. In either case a slight delay in healing was the most serious result, while constitutional signs of infection were either absent or of the slightest nature. The same indisposition to spread by the track was equally noted when a deep portion became infected from, for instance, the intestine in a belly wound.

Wounds of irregular type, however, such as those caused by ricochet bullets, or accompanying severe fractures, or those caused by fragments of larger projectiles, often suppurated freely in spite of exposure to no more unsatisfactory surrounding conditions than the wounds of small bore. This appears to show conclusively that the first element in the general slight consequences of small-bore wounds is their calibre, and, secondly, that increase of velocity on the part of the bullet, while it in some measure compensates for the loss of volume in the projectile, on the other hand reacts in favour of the wounded in so far as the injuries it effects on the soft tissues are ill suited to the development of septic organisms in the parts.

_Retained bullets._--These were met with more frequently than might have been expected, but I can give no idea as to their proportional occurrence, since so many of the slighter injuries never came under my observation. Experience, however, showed that the bullets of large calibre and low velocity employed during the campaign were far more commonly lodged in proportion to the frequency of their use. Thus I saw a considerable number of Martini-Henry, Snider, large leaden sporting bullets, and shrapnel retained. Again, among the bullets of smaller calibre, the Guedes 8-mm. bullet, which travels at a comparatively low rate of velocity and with moderate spin, was far more frequently lodged than the Lee-Metford or Mauser in comparison with the number of Guedes rifles in use.

Bullets of small calibre were, however, also retained with some degree of frequency, either as the result of striking at a long range, or in such a direction as to need to traverse a large segment of the body before escaping, or as striking large or several bones, or making some irregular form of impact: the last was a not infrequent explanation of lodgment, especially when a bone lay in the course of the track. Ricochet bullets naturally were especially likely to be retained, both on account of the low velocity with which they often travel and the irregularity of their surface with consequent loss of penetrating power.

WOUNDS OF IRREGULAR TYPE

Many of the wounds met with deviated so greatly in appearance and general characters from what has been described above as to afford little or no evidence of having been inflicted by small-calibre bullets, and before describing these it is necessary to give a short account of the circumstances which are responsible for such departures from the common type. In the case of the wound of entry, the simplest explanations are lateral impact on the part of the cylindro-conoidal projectile, due to the position of the part struck or the direction in which the bullet has been fired, wobbling on the part of the bullet due simply to loss of velocity and force in flight, or to turning of the bullet by impact with an obstacle to its course (ricochet) which may amount to actual reversal of the striking end. As a rule, in such cases the size of the aperture of entry exceeds that of exit, and in a large proportion the bullet is retained within the body.

Of these explanations that of the 'wobble' needs some passing notice. In its simplest form it depends merely on loss of velocity of flight on the part of the bullet, the centre of gravity of which lies behind its middle; hence a tendency to turn over and over is acquired. As a result of this, either the side of the tip, the side of the bullet, the side of the base, or the base itself may form the portion of the projectile which comes into contact with the body. The tendency to wobble is naturally greatly increased in ricochet bullets, since the contact, if lateral, serves to check the spin on which the bullet depends for its flight on an axis parallel to its long diameter. The first effect of wobbling is to increase the size and interfere with the regularity of outline of the wound of entry; but it also acts in a more serious manner, since the increase of the area of impact augments the resistance offered by the body; therefore the degree of damage to the tissues is accentuated and becomes greater than it would be from a bullet travelling at the same rate on its normal axis. Hence the wounds are both large and severe, or if the velocity is very low, the projectile is especially likely to be retained.

Actual reversal of the bullet usually only slightly enlarges the aperture of entry, but injuries to cancellous bone are apt to be more severe when the bullet enters in this manner, or again it is often retained. I saw several such cases during the campaign.

Another form of wobble is suggested by Nimier and Laval,[9] of which I can offer no experience. They suggest that, as rotation slows, the bullet may on impact wobble like a top before it ceases to spin. Probably the power of penetration possessed by a bullet wobbling in this manner would not be very great, but its effect would mainly be altered in the direction of an abnormal increase in the size of the aperture of entry, or possibly in the degree of comminution in fractures.

It is probable that some of the more serious wounds observed were merely the result of unusual forms of impact with normal flight on the part of the bullet. The majority, however, depended, in the case of the wound of exit, on deformation of the bullet within the body, or the propulsion of bone fragments with it, and, when both apertures were affected, to previous ricochet on the part of the projectile.

It is here necessary to give a short account of the more common deformities met with, and to refer to the special characters possessed by different types of bullet of small calibre which may affect the ease with which deformity is produced, and the degree to which it is commonly carried. The effect of ricochet is to lower the velocity of flight, and at the same time to effect certain alterations of form in the bullet. These with rectangular impact in the case of bullets travelling at a low degree of velocity consist in a bending and deformation of the tip; in the higher degrees, of bending, shortening, extensive destruction, or complete fragmentation. If the bullet makes lateral impact, only widening and flattening result, often with the escape of the lead core from the mantle. That a ricochet bullet may travel a considerable distance is shown by the following observations quoted from Nimier and Laval.[10]

From left to right: 1. Guedes; regular dome-shaped tip; mild steel mantle; thickness at tip 0.8 mm.; at sides of body 0.3 mm. 2. Lee-Metford; ogival tip; cupro-nickel mantle; thickness at tip 0.8 mm.; gradual decrease at sides to 0.4 mm. 3. Mauser; pointed dome tip, steel mantle plated with copper alloy; thickness at tip 0.8 mm.; gradual decrease at sides to 0.4 mm. 4. Krag-Jörgensen; ogival tip as in Lee-Metford; steel mantle plated with cupro-nickel; thickness at tip 0.6 mm.; gradual decrease at sides to 0.4 mm. The measurements of the sides are taken 2.5 cm. from the tip. Note the more gradual thinning in the Lee-Metford mantle.]

Up to a distance of 1,700 to 1,800 metres the bullet may make several ricochet bounds. When the bullet strikes first at short distances (as 600 metres), it may make several bounds of from 300 to 400 metres: at moderate distances (as from 600 to 1,200 metres), bounds of 200 to 300 metres; and at distances above 1,200 metres, bounds of 100 to 200 metres. The length of the ricochet bounds depends on the angle of impact of the bullet with the ground, the nature of the slope of the latter, and the velocity of the bullet.

Putting aside the question of calibre and volume of the bullets we are concerned with, I believe the most important variations as serious effects of ricochet depend on the relative thickness and the composition of the mantles. Fig. 26 illustrates the relative thickness of the mantles in the Krag-Jörgensen, Mauser, Lee-Metford, and Guedes bullets. Given an equal degree of force and velocity on the part of the bullet at the moment of impact, the assumption is justifiable that the thinner mantles would tear or burst more readily in direct ratio to their relative thinness. I believe this assumption to be borne out by my own experience of the common deformities that occurred; but the great relative frequency with which Mauser bullets came under my observation, and the difficulty of forming any estimate of the velocity and force retained by any particular bullet at the moment of impact, make it impossible for me to express myself with the confidence which I should wish.

The second condition which influences the nature and degree of the deformities depends on the relative tenacity or brittleness peculiar to the metal employed in the manufacture of the mantles. In the case of the Lee-Metford this consists of an alloy of 80 parts of nickel with 20 of copper. The Krag-Jörgensen and Mauser are ensheathed in steel plated with cupro-nickel, and the Guedes has a plain steel envelope coated with wax.

Both as a result of experience in the field gained from ricochet bullets, and in the hospitals from bullets which had undergone deformation within the body, I am under the firm impression that the thin nickel-plated steel envelope of the Mauser bullet splits more readily than the thicker and more tenacious cupro-nickel envelope of the Lee-Metford, that the direction of the ruptures is more purely longitudinal, and the fissuring itself more extensive and complete.

I append below a series of deformities observed in Mauser bullets, some of which were collected on the field of battle, but all of which were familiar to me in bullets removed from the bodies of patients, except the complete disc shape shown in fig. 29. They correspond with specimens of which I made sketches at the time of removal from the body, but which I had not the heart to retain in view of the natural wish of the patients to keep them as mementoes of their wounds.

From left to right: 1. Slipper form; slight broadening and turning of tip. 2. More pronounced degree of form 1, with laceration of the mantle opposite the shoulder of the bullet. This is the weakest spot, for two reasons: the alteration in curve at this position, and the junction of the thickened point of the mantle with the thinner sides. 3. Lateral ricochet involving nearly whole length of bullet. Rupture of mantle from broadening of core opposite shoulder. 4. Similar lateral ricochet with extensive longitudinal rupture of mantle, the latter being turned out and forming a cutting 'flange.']

Slight indentations and deviations from strict symmetry of form of such degree as not seriously to influence the outline and nature of the apertures were very common. Beyond these one of the most frequent primary deformities was that we familiarly spoke of as the 'slipper form' (No. 1, fig. 28). This results from light glancing contact of the tip with a hard body: in it the mantle of the bullet is rarely fractured, and the deformity itself is of slight importance, except in so far as it may influence the direction of the wound track, which acquires a tendency to be curved. The tip of the bullet is slightly flattened and turned up, down, or to one side, according to the point struck. I saw this deformity frequently, both with Lee-Metford and Mauser bullets. Nos. 2, 3, and 4 are more pronounced degrees of the same type of deformity, accompanied by more or less extensive fissuring of the mantle. No. 4 illustrates the turning out of the longitudinally fissured mantle in such a way as to make a cutting flange. I have seen such bullets removed, and the variety is of some importance as materially increasing the cutting capabilities of the bullet, and augmenting its area of destructive action. No. 5, fig. 29, is the only form I have not seen removed, but such a bullet would account for some of the long irregular gutter wounds observed, if it retained sufficient velocity to strike with any force.

Fig. 30 illustrates complete longitudinal fissuring of the mantle. Such mantles are common, and still more so are the opened-out sheets such as is shown still attached in fig. 29. Free mantles are often very numerous on stony ground, but are of little importance, since I never saw fragments of them removed or impacted. They probably travel a very short distance after their formation, and if they did strike would possess little power of penetration. The freed leaden cores do, however, sometimes enter the body, and some of the specimens removed have been referred to the use of expanding bullets. In all the Mauser specimens the longitudinal direction of the fissuring of the mantle is striking.

Fig. 31 represents bullets removed from the body and illustrates types of deformity due to impact with the bones. The deformity resembles in some degree that of the mushroomed lead cores, and also indicates that the shoulder of the cased bullet is its weakest point. Each specimen exhibits shortening and widening without fracture of the mantle, the latter being simply thrown into folds; both bullets were lodged in the thigh after fracturing the femur. The localisation of injury to the fore part of the bullet, and the fact of expansion, allow us to infer that the degree of velocity retained on impact with the bone was comparatively low, and that neither bullet had been exposed to very severe strain.