driven in behind, and a little below the trochanter, and this position may have prevented the descent of the thigh.

Ten minutes

Experiment IV.-May 10, 1860.-On the right hip of the same subject as the last, placed upon its back upon the table; all rigor mortis was overcome by forcible flexion, &c., of the thigh. A measuring tape was fastened by a flat-headed nail to the last spine in the sacrum, so that it would be carried round the ilium, including the trochanter, to a needle in the symphysis pubis: this measurement was exactly twenty and a half inches. At the edge of the measuring tape, another needle was knocked into the trochanter, which was to serve not only as an index, but also as a means of securing the same position of the tape at the next measurement. Needles were fastened into the inferior anterior spine of the ilium, and in the lower part of the femur as before. Incisions were made down to the bone previous to inserting each needle, so as to leave them free on all sides. A strap, fastened round the ankle, held a ring which permitted a system of pulleys to be hooked upon the limb. Counter extension was made by a rope passed under the perinæum. When all things were ready, and the measurement by staff accurately procured, a system of three pairs of pulleys was hooked upon the limb, and upon its rope a weight of 28 lbs. was fastened; this procured an extending force of 756 lbs., or 64 cwt. There was a gentle crackling in the whole limb, but the measurements were precisely the same. were now allowed to elapse, and the weight was seen gradually to sink down towards the floor; at last the stretching of some part of the extension and counter-extension (either limb or rope) was so great, that it was necessary to fasten the weight higher on the cord. The measurement between the needle in the ilium and that in the femur was now again taken, and no difference was found; thus the weight had in no degree lengthened the thigh, i. e. it had not increased the space between knee and pelvis. The cotyloid cavity was now pierced from the pelvis: measurement still showed no difference in the distance of the two needles. A considerable portion of the inner wall of the acetabulum was gouged away, as in the last experiment, and a wedge, three quarters of an inch in breadth, was driven in above, and a little behind, the head of the femur. This caused the trochanter visibly to project: the measurement round that side of the pelvis and great trochanter was within a fraction of twentyone inches. There was found, in the distance between the needle in the great trochanter and that in the symphysis pubis, a decrease of nearly two lines; this was attributable to rotation inwards; but between the needle in the inferior spine of the ilium, and that above the knee, no difference in length could be detected. A wedge, just one inch broad, was now driven in directly

behind the head of the femur; when it had got nearly home, considerable power was used, and the trochanter was seen to project further at each blow of the mallet, and the needle which had been driven into it, turned like an index more and more towards the ilium. At last the trochanter projected so much, that the iliac fossa and belly of the gluteus medius, formed a deep hollow; the measurement round the ilium and trochanter was now 22 inches; the needle in the trochanter was a fraction of a line nearer to the one in the symphysis pubis, showing how great rotation inwards must have been. The measurement between the needle in the anterior spinous process of the ilium, and that in the lower part of the femur, remained precisely the same.

The wedge was withdrawn.

The head of the bone did not return to its old place. The weight was removed from the cord. The head of the bone fell back-not suddenly, but still pretty quicklyinto the socket, producing a remarkable sound precisely like that of disarticulation. The measurement in length, of the femur, was found precisely the same as before and during the trial.

These experiments set at rest the supposition of any real lengthening of the thigh being possible, without dislocation. Such results are consonant with reason; but I should hardly have conceived, that a separation of an inch, with such great projection of the trochanter, could have made absolutely no difference in length, although I expected to find that difference very small. We must then look entirely to position, as the cause of this important symptom.*

*This last experiment was referred to in Chapter I., p. 18, by an error, as Experiment III.

CHAPTER XV.

ON AFFECTIONS OF SYNOVIAL SHEATHES AND BURSE IN THE NEIGHBOURHOOD OF JOINTS.

THE synovial membranes which line tendons and their sheathes, or which form fluid pads between the skin and bony points exposed to friction, also between tendons and the subjacent bone, in every case where the former passes over a tuberosity to be inserted at its further side, are all subject to inflammation.

The Bursa, as these latter bags of synovial membrane are called, are thus to be found in certain points of the body in a normal condition. Some are superficial, others deep. To the former class belong the sac between the skin and olecranon process, and that between the same structure and the patella with its ligament, &c., &c.; to the latter, the bursa between the biceps tendon and tuberosity of the radius, between the ligamentum patellæ and tuberosity of the tibia, between the tendo Achilles and os calcis, &c. &c. But if, from deformity or other cause, any point be exposed to unusual friction insufficient to produce ulceration of the skin, a bursa in that point will be formed. Thus, one will arise on the outside of the foot in talipes varus, if the person walk about; in angular curvature of the spine, a bursa is developed between each projecting spinous process and the skin; and many other such instances might be given. The various facts and investigations upon this production of new bursæ show that they are formed from the common areolar tissue; that there is no structural difference between them and the bursa normally found in the body; and, therefore, it may well be assumed that normal bursæ are produced by the friction which they are developed to prevent.

The inner lining of these sacs is not smooth, but covered by fringes, like, but smaller than, those in joints; moreover, fibrous bands, running along the wall, project into the cavity. The outer part is simply condensed areolar tissue, and is continuous with that structure on all sides. If the bursa be subject to

considerable pressure, its outer portions will become more condensed, till they assume a fascia-like appearance and hardness.

Any bursa of the body is liable to become inflamed, and the attack may be either acute or chronic; even the acute disease may be simply one which causes increase of normal secretion and thickening, or it may be suppurative. Fortunately, suppuration of a synovial bursa does not often arise spontaneously, except in the subcutaneous sacs. I have never been able clearly to ascertain such action in any deep bursa, although in certain cases of deep-seated diffuse suppuration I have considered a synovial sac the probable birthplace of the disease. The purulent inflammation is usually produced by a blow, or some external violence, acting upon a much-debilitated constitution. The action is not confined to the bursa itself, but is of a diffuse form, and attacks the areolar tissue continuous with the bursal walls. The general symptoms are precisely those of the "diffuse inflammation of the cellular tissue "—of what used to be called "phlegmonous inflammation," viz., a brown, dry tongue, heat of skin, sleeplessness, and a weak, quick pulse. The local symptoms differ only in this, that in the phlegmonous inflammation the pus can only be diffused into the areolar meshes; in bursal suppuration a cavity exists wherein a good deal of the pus is always collected, and thus we have the local symptoms of a circumscribed abscess combined with those of a diffused one. The skin at the inflamed part is of a dusky red; the colour has no sharp boundary, but fades gradually into the normal hue of the surrounding skin. The swelling is more or less conspicuous, according to the size of the bursa, its superficial position, and the stage of the inflammation. The heat is very considerable, and the pain is great, as long as tumefaction continues and tension be not relieved. If the case be suffered to go on, as sometimes happens, without any adequate treatment, typhoid symptoms develope themselves, and the state of the patient may become critical, absorbent inflammation, greater and greater debility, ultimately prostration, with low, muttering delirium, will shortly be followed by death from exhaustion or purulent infection.

Free incisions through the whole reddened portion of the skin, profound enough to include the deep side of the bursa; poultices, mixed with charcoal or yeast, or chlorinated soda, is the

fit local management. The general treatment should be stimulant and tonic. Bark and ammonia, quinine with æther, chlorate of potash, or other such medicine, combined with opium and camphor, or opium and chloric æther, at night; wine, brandy, or, in those accustomed to it, gin, may all, in the worst cases, be needed. It is generally advisable to give, before resorting to any of the above means, a brisk purge; but this is certainly not always desirable. Our power over the intestinal mucous membranes is often very much abused, and in few ways more than in first attacking all patients with a drench. A little judgment in considering the condition of the tongue, the aspect of the conjunctiva, and the state of the abdomen, will guard us against such errors. To purge a patient with bursal suppuration, who does not need such treatment, is to inflict upon him an absolute injury, by weakening his powers of resistance to disease.

When the patient recovers from the depressed condition, the wound made into the skin and the walls of the abscess begins to granulate, and to throw off any sloughs that may have formed. Among these must be included the whole bursa. It comes away in white soaked shreds of dead material, not one portion retaining any life, and remaining behind. After a time, even before all the sloughs have separated, the poultices may, if the skin and wound look sodden and inactive, be changed for a dressing of dilute nitro-hydrochloric acid; and when the sloughs have entirely separated, lint dipped in cold water; or if the granulations be flabby, and the discharge considerable, a solution of alum (from ten to twenty grains in the ounce) may be advantageously employed. As the bursa, particularly when swollen, occupied considerable space beneath the skin, a cavity will be left, in which matter will collect, unless its sides be kept together. It is, therefore, necessary to apply some pressure by means of pads, with a bandage or strapping plaister.

Subacute, or chronic and non-suppurative inflammation, may attack either a superficial or a deep bursa, and though the disease will not lead to such violent symptoms as the pus-producing malady, it causes frequently considerable pain and inconvenience. When the bursa thus affected is superficial the nature of the disease is easily discovered, and its treatment, if the attack be recent, by blisters, or iodine, or other form of