Another mode in which the effects of pyæmia may be occasionally exhibited in military hospitals is the following. A case of gunshot fracture of the shaft of a bone may have been progressing favourably, a considerable quantity of callus may have been thrown out and consolidation to a great extent effected, when suddenly pyæmia supervenes, and all this advance towards union recedes, the ends of the broken bone again become detached and loose, and a fatal result follows. A striking instance of this retrograde action, consequent upon a sub-acute form of pyæmia, came under my notice in the Crimea.

Corporal B., 19th Regiment, aged 19 years, of good health and strong frame, had his left thigh-bone comminuted at the attack on the Redan on the 8th September 1855 by a rifle bullet. The missile struck the shaft near its centre. The bone was much split, and amputation, if performed, would have had to be done close to the trochanters. In consequence of the very unfavourable results which had attended amputations in this situation, and considering the youth and good constitution of the patient, I determined to try and save the limb. The case progressed favourably for some time. Some dependent incisions had to be made to facilitate the escape of pus and to effect the removal of detached splinters. At the end of October consolidation had so far advanced that the patient was able unassisted to raise the limb a short distance up from his bed. On the 2nd November, however, without any apparent cause, he was seized with rigors and vomiting; profuse bilious diarrhoea followed, and, though checked for a time, continued to recur at intervals up to the date of his death. The discharge from the wound became excessive in quantity, of thin consistence, dark colour, and offensive; there was the peculiar odour of pyæmia; the ends of the bone at the seat of fracture became loose and movable; the patient very despondent; he had a quick, small pulse, and suffered from chills, followed by fever and profuse night-sweats, as if he were suffering from a complication of ague, of which, however, there was no previous history. Then great cedema of the injured extremity appeared, with excessive general prostration, and the patient expired on the 1st of December.

Attempts were made, by the free use of stimulants and appropriate medicines, to bring the patient's constitution into a state offering a favourable prospect for secondary amputation of the limb, but without success. At the post-mortem examination, all the muscles of the thigh presented a peculiarly pale, oedematous, almost gelatinous aspect; the structures around the seat of fracture, and for some distance from it, upwards and downwards, were in a semi-sloughy, softened condition; and the connective tissue of the whole limb was infiltrated with ill-conditioned purulent fluid, without any apparent effort to circumscribe it.

Dr. Femarch records an acute case very similar in its results. A Schleswig-Holstein soldier had both his left femur and left humerus shattered by musket bullets. At first the case proceeded favourably, and the humerus was consolidated in the third week without the removal of a single sequestrum. The femur also seemed inclined to heal, although the bullet remained in the wound; but, in the fourth week, the discharge became sanious. Pyæmia developed itself from this time, and soon proved fatal. During the last few days the fracture of the humerus again gave way. At the autopsy, it was found that this bone, in its middle. was in eight large splinters, of which five were already firmly united to the lower, and three to the upper fragment, by means of a considerable mass of callus. This callus was evidently reabsorbed at the spot where the splinters had been mutually united, and thus the continuity had been again broken.

Modes of death in pyæmia.-When pyæmia runs on to a fatal termination, and this is its usual result within a period of four to eight days, death may occur in several ways. It may either happen from cerebral excitement, succeeded by coma; or the patient may sink under the effects of various visceral disorders. In some instances fatal pneumonia, gangrene of the lungs, or empyema have supervened. Death may take place rapidly by paralysis of the nervous centres, or under symptoms of fever of a typhoid character; or, where the pyæmic abscesses are so placed as not to interfere seriously with the more important vital functions, the patient may sink more slowly from general exhaustion, or the effects of excessive diarrhoea.

Nature of pyæmia. The complex symptoms which characterise pyæmia have led to a great variety of theories for their explanation. The term pyæmia, or pus-poisoning of the blood, sufliciently shows the opinion which originally dictated it. No one now believes that true pus, in its uncorrupted state, can be absorbed into the circulation and be the source of the symptoms which accompany pyæmia. Like the doctrine of metastasis, or change of seat of pus from place to place, as once held, the notion of pus circulating through the circulatory system in this disease is now abandoned. By most pathologists the disease is attributed to the invasion and growth of pyogenic microbes. The manner in which pyæmia may be communicated from patient to patient by using the same sponges or materials of dressings, its tendency to prevail in buildings which have been previously for some time in use as hospitals for the treatment of wounded, and many other such circumstances, favour the idea of infection by some form of septic poison or nosogenic micro-organisms.

One of the most frequent phenomena accompanying pyæmic disease is the formation of clots or thrombi, probably septic, in some of the veins. The detachment of fragments of these clots,

carriage of them into the general circulation, and their subsequent impaction at some parts of the circulatory system where the arteries become too small to admit the clots to pass on, lead to the phenomena of embolism. The obstruction of the vessel by the clot or embolus leads to the deprivation of a particular part of the body of some of its normal supply of blood; inflammation of a low type or septic character is excited, a pyæmic abscess is formed, or occasionally gangrene results. Thrombosis and embolism thus together become leading causes in the production of the purulent collections which constitute some of the most remarkable features in the pathology of pyæmia.

But the purulent collections which are met with in pyæmia cannot always be traced to the origins just named. Sometimes they take place with a rapidity and in such a diffuse way as to exclude embolism from being concerned in their production. Several joints remote from each other may become tender and swollen together, or may become enlarged without attracting early attention, proving there has not been much pain, and in a few days may be filled with fluid of a purulent character. Diffused collections of sero-purulent fluid may with almost equal suddenness spread through the connective tissue of one or more limbs, or may accumulate in one or both of the pleural cavities. Multiple abscesses may form in the liver or lungs, and yet no signs of embolic mischief be traceable in these organs. The fact than an embolic source is not discoverable is not of course a sufficient proof that no such origin has existed; but the absence of the appearances of embolism that are occasionally found elsewhere, and particularly the rapidity with which these collections sometimes form, certainly favours the supposition that they are occasionally formed independent of any such origin. In some of these instances the infection appears so suddenly, and is so general in its nature, that those who regard microscopic germs as the essential cause of the disease, attribute it to the action of certain microbes that are able to penetrate all the living tissues, to grow and multiply in them as well as in the blood, and so to give these pyæmic cases their virulent character. Judging, however, from clinical observation of them, it seems impossible to exclude at the same time the existence of special degrees of receptivity in different individuals, traceable either to constitutional peculiarities, previous habits of life, the extent to which men have been subjected to unhygienic surroundings, to excessive fatigue from prolonged marches or other military operations in which they have been engaged, or to some other such causes giving various degrees of predisposition to the disease.

Association of pyæmia with gunshot wounds of bones.There appear to be several reasons why pyæmic action is more likely to follow gunshot wounds of bones than injuries of other

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parts. The prolonged duration of the suppurative action while sequestra are being detached, and the formation of new bone is proceeding; the long period of confinement in a hospital atmosphere to which the patient is necessarily subjected; the frequency with which an extension of the suppurating action takes place along the medullary canal; the obstructions which are apt to cause imprisonment of the pus, so that its constant free escape is not permitted, as in wounds of the softer parts; the facility which is gradually acquired for the pus to burrow along and between the inactive muscles, so leading to its being retained among them for long periods; the readiness with which pus becomes the subject of putrefactive changes when air, particularly foul air, has access to it; these seem to constitute a sufficient set of causes leading to pyæmic poisoning after such injuries. The peculiar circumstances of the venous system in bones, especially the situation of the vessels in unyielding hard canals, so that their extremities after division are apt to remain patulous, seem also to favour its occurrence. Septic puriform fluid, detached particles of disintegrating tissues, and putrefactive discharges are more likely to pass along them into the general circulation, than they are along veins of the soft parts, which may collapse, or become closed by pressure from surrounding structures, after similar gunshot injuries. But in all such cases clots are usually found in veins in varying states of firmness or partial disintegration. After wounds of the head in which the vascular system of the diploë is involved, the formation of thrombi in the sinuses of the dura mater may be expected; and in case of this occurring, as the thrombi soften down, or as portions of them become detached, the particles would readily pass to the right side of the heart, and so to the finer ramifications of the pulmonary arteries. The stretched condition of the sinuses between the membranous laminæ of the inelastic dura mater causes them to correspond with veins of bones in respect to their persistent patulous condition. When pyæmia follows injuries of the head, the pyæmic foci are almost invariably found in the structure of the lungs, and this would seem to be a result of the facts just mentioned.

Prevalence of pyæmia in military hospitals.—There is this peculiarity connected with gunshot wounds in military hospitals in time of war, that usually many such wounds (and a large proportion of them are always complicated with fractured bones) occur at the same time. Hence a ward may be filled with cases in all of which suppurative action is proceeding. Under such circumstances a condition of atmosphere is easily produced that must tend to poison the constitutions of the patients. Septicæmia, varying in degree according to the amount of concentration of the putrid emanations in the atmosphere, is the result. The depraved state of the patient's blood causes the pus of a suppurating wound to

contain within itself the elements of more speedy decay. Its proneness to putrefaction is increased. This disposition of the discharges to take on the process of decomposition at once finds agents ready to set it in action in the micro-organisms abounding in the impure atmosphere if the wounds are allowed to be brought into contact with it. It has been well established that if one patient suffering from pyæmia is placed in a ward where there are many other patients with suppurating wounds, a considerable proportion of the latter will almost certainly become infected with the disease. It has also been remarked that when patients with fresh wounds are admitted into hospitals which had been used for the wounded from previous battles, especially if any patients with suppurating wounds still remain in them, the new-comers become much more than ordinarily exposed to an invasion of pyæmia. This can only be accounted for by supposing the hospital to be tainted by matters in a more or less advanced state of decomposition, concealed in the walls, floors, and ward furniture, or, according to present views, by the special forms of bacteria which belong to pyæmic infection. It must also be remembered that any circumstances tending to irritate a suppurating wound (and suppurating wounds. in which the jagged ends or splinters of broken bones are implicated are particularly liable to be so irritated) have long been supposed to assist in inducing the development of pyæmia. Irritation of this kind is sure to occur when wounded men have to be transported long distances, as must often happen in time of war.

It is indeed almost impracticable, under the ordinary circumstances of warfare, to procure the absolute rest necessary for patients with fractured bones; or, with deficient numbers of surgeons and attendants in proportion to the numbers of patients, to obtain that perfection in sanitary arrangements which is essential for averting the causes which tend to the development of pyæmia. No one who is familiar with the usual state of hospitals, especially of the temporary field hospitals, and with the difficulties in the way of ensuring the requisite cleanliness of patients, attendants, and hospital surroundings, in a country where military operations are in progress, can be surprised at the frequent occurrence of septic disease among men under treatment for suppurating gunshot wounds.

Conclusions regarding pyæmia in military practice. To judge from observation in military practice, it would seem as if, as a general rule, it were necessary for two conditions to co-exist for the development of pyæmia-viz., the process of suppuration in the patient, and the presence of an agent such as a septic poison in the atmosphere in which the patient is placed. If a patient suffering from an ailment or injury unattended with suppuration be placed in a ward in which many suppurating wounds