Contents

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SECTION I

GENERAL SURGERY

CHAPTER I

HELMETS AND BODY ARMOR-THE MEDICAL VIEWPOINT ^a

The nature of a projectile determines in no little degree the character and treatment of a wound. Bullets or fragments of shell of high velocity are less serious sources of infection than those of low velocity. A ball which mushrooms is eminently destructive-to such a degree, indeed, that bullets designed to mushroom have been forbidden in warfare. It follows that abreastplate of metal which tends to mushroom any impinging hall (fig. 1)
   
 FIG.1.- Mushrooming of bullets upon impact with armor. The missile on the left is a copper-jacketed bullet of 230 grains; the one in the middle is a similar missile deformed upon contact with armor at a velocity of 800 foot-seconds; the remaining missile is a similar one mushroomed upon impact with armor at about 1,500 foot-seconds

would be justly regarded as a source of considerable bodily danger to its wearer. Hence, from the general viewpoint, the use of armor would be sanctioned only when, on broad averages, the soldiers who wear it would be able to take a more effective part in warfare. In a word, any army could afford to lose one soldier, if by means of armor two soldiers were able to remain in active service.

To discuss the nature of wounds produced by projectiles which had pierced a helmet or body defense is not the purpose of the present chapter; their nature and fate is considered in Chapter II of this volume. It is rather to show the findings of departments of war of various countries as to the use of armor asa practical means of saving "effectives". It has been shown a that: (1) Helmets and body armor were found, on broad averages, of distinct advantage to the wearers. (2) A steel helmet became part of the regular military equipment of many nations; at the front its use was obligatory. (3) Body armor
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^a The statements of fact appearing herein are based on "Helmets and Body Armor in Modern Warfare," by Bash-ford Dean, Ph. D., New Haven, Yale University Press, 1920.

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was used only for special service, e. g., for bombing parties, or for machine gunners. (4) Its employment was limited partly or largely by the inconvenience which its weight caused its wearers, who on the first opportunity, disregarding the protection it afforded, were apt to throw it aside.

Experiments to determine the protective qualities of helmets were first carried out by the Intendant General Adrian (1914-15) of the French Bureau of Inventions, whose faith in his work led to the arming of soldiers in great numbers with the newly devised defense, half a million helmets having been placed in the field in the initial experiments. Had these been carried out on small groups, as an economical measure, a true result might not have been forthcoming, for it will be seen (1) that an innovation of this kind would have been resisted firmly by already overequipped soldiers, whose neighbors were notthus additionally burdened, and (2) that the results of a small experiment would have failed to impress experts, medical and technical-who regarded the use of armor as "dead as Queen Anne." In fact, shortly after the experiment of General Adrian, many critical reports were filed showing that hospitals were crowded with head-wound casualties in helmet-wearing soldiers. It was only the more careful analysis of the data which showed that these men, although wounded, were men who were saved, for without their helmets most of them would have succumbed to cranial injuries.

Effort was made by the writer to tabulate the practical results in the use of the helmet on different fronts, but no detailed statistics were to be had. Hospitals were usually crowded with cases, and their personnel could give little time or effort to determining the cause and the condition of the wounding. Of the French, however, the hospital records show that in 1915 (before the introduction of helmets) about one head wound in four proved fatal. After the introduction of the helmet, however, statistics in the same hospitals show that in head wounds, at the worst, but one case in four and a half proved fatal, and at the best one case in seven--a perceptible betterment of conditions. Evidence is abundant which shows that the same shrapnel helmet saved its wearer many times. In any event, the results in this direction were convincing--the shrapnel helmet had come to stay.

HELMETS OF VARIOUS NATIONS
    
The merits, from the medical viewpoint, of three types of helmets may be considered: (1) The French, adopted also by Belgians, Italians, and Slavs.(2) The British, which was adopted also, but provisionally, by the American Army. (3) The helmet of the Central Allies.

The French helmet was a response to the need of producing quickly a metal head defense which would be reasonably strong and not so heavy as to cause serious discomfort to its wearer. It weighed 27 ounces, was manufactured of a mild steel with medium resistance and was built up; the parts often were separated by the shock of the projectile. Impact tests a demonstrated that the French helmet was perforated at a point pressure of from 674 to 756 pounds, indenting to a depth of from one-fourth to one-fifth inch. Such metal was easily penetrated by the Browning revolver of .25 caliber at
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a  Conducted by Dr. E. Dupuy, of the Chemical Laboratory of the Sorbonne.

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6-foot distance, the ball then penetrating “hardwood”' behind it to a depth of from 3 ½ to 5 ½ inches. The French helmet is therefore weak; it has, in fact, but half the strength of the British helmet. The wonder is only that the French helmet proved so great a success; it demonstrated, at least, that the soldier of 1915 was subject to injury from splintered missiles of low velocity, spent shrapnel, and the like.

The British helmet, weighing 35 ounces, made practically of a single piece of 12 percent manganese alloy, ruptured only, according to Dupuy's results, after a blow equivalent to 1,580 pounds had been given, the rupture following a point indentation of 0.28 inch--an indentation not extreme when it is recalled that the French helmet indented to 0.25 inch at half the pressure. The American helmet, of similar model, was slightly heavier than the British, averaging about 1 ounce. It was made of a somewhat different manganese alloy, and was on the average from 12 to 15 percent stronger (Dean's experiments).An improved steel (manganese-nickel alloy of Baker) produced a helmet withthe same resistance to rupture as the German one at a saving of from 4 to 9 ounces in weight. Improvement in steel alloy which could be pressed into helmets was here noteworthy.

The German helmet, weighing from 40 to 48 ounces, was admirably pressed in a silicon nickel steel; it was about 30 percent stronger than the English helmet, but its greater weight a distinct disadvantage.

 FIG. 2.- Diagram showing larger degree of protection of Model 2A, contrasted with standard British model (less heavy line), the thinner cranial wall indicated by shading. The new model protects the sides and base of the cranium

From the medical viewpoint, the matter of the form of a helmet proved of considerable moment. Strong recommendations were made that an American helmet should be introducted which cover in greater degree the back of the cranium, its sides and base. For it was clear that the British helmet was seated too high up on the head. Its brim, it is true, was a strong defense from missiles approaching from above, but it was of no value as a protection from splinters or shrapnel from lower levels. The form of the helmet finally recommended to the American Army is shown in Figure 2. This protected in best degree the region of collected nerve fibers, the thinner part of the cranial wall, and proximal cranial nerves.

THE FREQUENCY OF INJURY FROM MISSILES OF LOW VELOCITY, WITH RESPECT TO THE WEARING OF ARMOR

The statistics of European hospitals compiled through the year 1916 (later figures not accessible) demonstrate that three-quarters of the casualties were due to missiles of low velocity-roundly, those traveling at a rate of less than a thousand feet per second--to which the lightest type of helmets and

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armor used in the World War would have been proof. a And from French statistics there are similar results, 60 to 80 percent of the cases having been wounded by missiles of low velocity. The American statistics obtained from the assistant director, surgical service, A. E. F., show that wounds caused by missiles of middle and low velocity constitute about 80 percent of all.

The results of a review of the French hospital records (summer, 1918)show the following percentages:

CHART

A more careful analysis of these cases would probably show that as many as three-quarters were due to missiles included under the limit of velocity noted above--that is, the equivalent physically of a 230-grain bullet traveling less than 1,000 feet a second. In this connection the American surgeon, Dr.Walter Martin, who traveled on a special mission for the American Army, found on the Western Front (1916-17) a "large proportion of the wounds examined were due to missiles of low and middle velocity." And surgeons agree that it is nearly always possible to determine from the nature of a fresh lesion whether it was caused bv a missile of this character.

Summarizing the situation, it may be stated that the proportion of wounds due to middle and low velocity projectiles is not less than 60 percent of all cases. This, in fact, is the least estimate the writer has been able to gather from medical experts in various services, some of whom declared emphatically that this percentage is entirely too small; that as many as 95 percent of the wounds would usually fall within the limits given above. It is pointed out, for example, by Col. Joseph A. Blake, director of one of the largest American military hospitals (April 30, 1918) that the statistics as given above deal only with one class of wounded, for "a large number whose injuries are not infected are returned at the front and are not entered in the statistics of the hospitals." It is clear, therefore, that had armor been worn generally in the war a large number of the wounded would have been by its use; consequently its importance as a practical means of life-saving deserves full recognition. Moreover in numerous cases armor might have saved its wearers from missiles of high velocity which impinged obliquely, and were capable, therefore, of being deflected-an important consideration, since only a smaller proportion of missiles would be apt to impinge upon an object in a direct axial line.

FREQUENCY IN THE LOCATION OF WOUNDS AND ITS BEARING ON THE ARMOR PROBLEM

If it could definitely be established that a certain region of the body is particularly susceptible to injury, it is that region obviously which should be protected by armor. A curve of frequency in wounds with respect to their
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^a Two hundred and thirty data from English hospitals. obtained through the courtesy of Capt. I. S. St. C. Rose and of Captain Leeming, of the Trench Warfare Division, Ministry of Munitions, London.

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location is to be examined, therefore in order to detemine the proprable usefulness of body defenses. The study of hospital statistics in this connection might a furnish practical hints, and from this viewpoint the hospital records have been studied, especially of the French front. From an examination of the records of the French. Medical Department (report from Col. Walter D.McCaw, M. C., United States Army, June 30, 1918), wounds have been classified according to their anatomical situation and percentage of their occurrence as follows:

                                                                  percent
Head.........................................................11.90
Thorax....................................................... 7.25
Spine......................................................... 2.20
Abdomen.................................................. .3.97
Arm......................................................... 14.07
Forearm................................................... 10.75
Thigh........................................................ 15.62
Leg...........................................................17.84
Foot.......................................................... 7.45

This indicates that 41 percent of the casualties suffered from leg wounds, 34 percent from arm wounds, and head and trunk each about 12 percent.

A comparison of data obtained from various specialists has led to the belief that the following percentage tabulation of wounds with respect to their anatomical situation (hospital cases only) is not far wrong (up to 1918):
                                                                percent
Lowr extremities........................................35
Upper extremities..................................... 25
Head and trunk........................................ 20
Trunk....................................................... 20

In a word, over 50 percent of the hospital cases suffered from wounded extremities, and rarely more than a fifth of the patients were wounded in the head. The number of patients wounded in the abdomen is usually small, at first sight unexpectedly so. Abadie (d'Oran) in his studies of wounds of the abdomen, offers the following table:

Abdominal wounds.....................................cases..479
Due to low-velocity projectiles.................... do.....332
Due to high-velocity projectiles................... do.....147

Thorax.................................................lung cases..15
Due to low-velocity projectiles.....................do......13
Due to high-velocity projectiles.....................do...... 2

Extracted................................................................72
Bullets.....................................................................33
Shrapnel fragments..................................................39

To describe the various forms of body defenses classified as to their protective merits seems hardly the function of the present discussion. Their use was special. Not more than 2 percent of the British soldiers at the front were provided with body armor. The French wore armor hardly in greater degree; the Germans on a scale of two suits of armor per company. At danger points this armor was used in considerably greater numbers. In this connection reference is made, however, to the work carried on by the British hospital service as suggested in the following diagrams, tabulating documents gathered toward the close of the war. b They indicate “areas of danger"
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^a But these statistics become readily controversial; our figures are based upon hospital cases only, the 1ocation of wounds on the dead of the battle field can not be determined.
b These were furnished the writer by the Trench warfare Division, Ministry of Munitions, London (Captain Bose).

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which would, of course, govern in a degree the wearing of armor, from the frequency of entry wounds. The first diagram (fig. 3) gives the topographical areas. The second (fig. 4), showing the anterior portion of the chest, indicates by dots actual entry wounds in 163 cases. In the last figure (fig. 5) there are shown by small dots entry wounds in chest and abdomen as recorded

FIG. 3.- Diagram showing areas of danger. This and Figures 4 and 5 were made available through the courtesy of Capt. I. S. St. C. Rose, Trench Warfare Division, Ministry of Munitions, London

in about a thousand cases (163 thoracic, 834 abdominal), the deeper shading indicating the points of greatest danger.

A final word should be said about the degree of protection furnished by defenses (a) of metal and (b) of textile. It has long been known that various fibers, notably silk, show high ballistic resistance. In fact, much "soft armor"made its appearance during the war. To this end the munitions bureaus of various countries made exhaustive experiments with silk, hemp, sisal, cotton,

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hair, flax, kopak, balata, etc., with the result that the silk fiber was demonstrated to be the most effective. According to Captain Ley of the munitions board in London, the experiments conducted at Wembley in "fragmentation huts" showed that sample pads of silks gave even better results than plates of helmet steel of even twice their weight, keeping out 74 degrees of “medium shrapnel bullets at 600 foot-seconds." A British expert in this field (Mr.William A. Taylor) declares that pure woven silk gives "materially better

FIG.4.- Diagram showing anterior portion of chest. Heart and roots of large vessels are indicated

results than manganese steel against shrapnel bullets up to a velocity of 900-1,000 foot-seconds, weight for weight." Also, “ that silk weighing 10.8 ounces per square foot is proof against shrapnel at 800 foot-seconds, whereas steel to give the same resistance would weigh about 20 ounces. The relative advantages and disadvantages of silk as compared with steel for body armor may be summarized as follows: Silk does not give nearly the same resistance as steel against high velocity pointed projectiles (e. g., rifle bullets) or bayonet thrusts, but, on the other hand, it does not deform the bullet which perforates it. The bullet which passes through steel is always deformed and causes the

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more serious wound. Against low-velocity blunt projectiles (e. g., shrapnel shell, splinters, bomb fragments) up to a certain velocity, silk is superior to steel, weight for weight." In general, however, the results of the English were by no means convincing to American observers. The latter declare that the " fragmentation hut tests " of the English do not furnish accurate data. The object thus tested is, or is not, struck, directly or indirectly, as the hazard of

FIG. 5.- Diagram indicating by small dots entry wounds in chest and abdomen as recorded in about 1,000 cases (163 thoracic, 834 abdominal) The deeper the shading as here indicated, the greater the danger

the exploding bomb of shrapnel dictates. American tests, on the other hand were made with ball of uniform weight which was shot directly at the object to be tested, with an explosive so graduated as to insure a definite impact. Hence we are firmer in our faith that the textiles are by no means better body defenses than plates of metal, weight for weight. We admit, however, that textiles have a definite value in preventing injuries from splash of lead or from ,smaller fragments produced by a crumbling projectile.