judgment of the physician will interfere with the proper support of the affected structures.

At bottom, it should be made to extend several inches below the crest of the ilium, and cut off in the direction of the symphysis pubis, so that the lower part of the jacket, when the patient is seated, will not rest heavily upon the thighs, thus pushing it up and out of place, rendering the patient uncomfortable, and defeating the object intended, a perfect support. If, after cutting the jacket prior to its removal, the edges should lap when brought together, showing too much material, they should be trimmed off so as not to meet by about one inch. In trimming off the front edges, care should be taken to divide the space equally between the two sides, where the centre of the jacket is the part manipulated, otherwise it will give the apparatus a one-sided appearance.

For convenience in the further mechanical construction, I remove the jacket to my office. It is yet in a semi-plastic state, the heat of the body not being sufficient to render it as hard as it must be to answer the purpose for which it is intended.

I place it upon a table and smooth out all the folds and wrinkles on the inner surface, taking great care not to destroy the shape.

This done, it is removed and placed upon a clothier wire frame, and dried carefully at a stove. When the material is sufficiently hardened, place it over a rounding block, and with a round faced hammer pound down all the roughness and projections left upon the inner surface. I sometimes line the inside with pieces. of muslin, using as an adherent the silicated solution, and bind the arm spaces, and all other trimmed edges with pieces of muslin cut bias, not sewed on, but attached by the use of the soda. This is done to prevent the separation of the different cut edges, and render the jacket more durable. The front edges are now eyeletted or supplied with eyeletted cloth riveted on; several rows of holes about the size of a No. 16 catheter should be made in several places with a steel punch over a hard block of wood. This will allow the escape of the natural exudations of the body, and will afford all necessary ventilation. All openings should be made from the inner surface outward, in order to prevent the formation of prominences on the inside of the jacket. The instrument is now ready to be placed upon the patient.

In order to ascertain whether the curves in the jacket, particularly that of the region commonly termed "the hollow of the back," correspond with those of the body of the patient, careful measurements of the patient should be taken and compared with those of the jacket. This is most conveniently done with a common yardstick, by placing one end upon the bony prominence of the scapular region, and the other upon the nates, and measuring the are described between the straight edge and the body with a common foot rule. The anterior curve, or that of the region commonly denominated "the hollow of the back,” is ordinarily from an inch and a quarter to an inch and one half in the adult, and the jacket should be made to have this curve in order to give that support to the diseased structures which is necessary to a successful treatment.

In posterior curvatures it will be impossible to adhere to the rule laid down above, yet the patient needs support as much as any other class of cases who may apply for treatment. If any alteration in the jacket is necessary to its proper conformity, it may be accomplished by slitting the jacket at that point and removing an elliptical or wedge-shaped piece. The opening thus made is drawn together by puncturing holes in either edge and drawing together by means of a lacer or linen tape. I have now carefully and minutely described the mechanical construction of my jacket, and I feel assured that if my professional brethren will follow my process strictly, success will attend their efforts, not only in the construction of the jacket, but in affording relief to those of their unfortunate patients to whose infirmities support is rest, and rest is the natural therapeutic agent for the relief of pain. When about to adjust the jacket upon the patient finally, he or she should be extended in the manner formerly described. The jacket is then put around the body and set to its place. If too hard to adjust easily it may be softened by the application of hot water. It is now ready for lacing. Begin with a long lacer about the third or fourth hole from above down, lacing until you reach the umbilical region, there drawing it through and making a loop long enough to tie on either side, proceeding to lace tightly until the lower edge is reached, where it is fastened. The object of leaving the tie loop in the umbilical region is to draw it tightly together at that point, thus making extension and counter extension at the same time.

The bony structure of the scapular and iliac region

serves as a fulerum upon which to have the weight of the space between.

Then begin with a short lacer and lace it through the four upper holes, draw it as tightly as the patient will allow and tie. The object of this short and separate lacer is, if the patient is a female, to relieve the mammæ from undue pressure. It is my custom to protect the mammæ in females from any undue pressure by artificial breast shields made for that purpose. No dinner pad is necessary with this jacket, as the patient may find relief after a hearty meal by simply loosening the tie loop in the umbilical region, the lacer at top being sufficient to hold the jacket in place. In females who suffer from uterine displacement, this jacket has so far presented no ill effects resulting from its use.

It is lighter than any similar appliance and quite inexpensive, the quantity of the solution of the silicate of soda used being from two to four pounds, one-half being wasted in the construction of the jacket, costing about thirty-five cents, and muslin at eight or ten cents a yard will not add greatly to the cost of the whole. The silicated solution does not set near so quickly as plaster of Paris, does not crack or crumble, and is more durable. The lacing admits of its removal at any time for the purpose of cleansing the body, and after the first adjustment, no extension being required, the patient takes it off and puts it on without assistance.

The length of time one can be worn I am unable to say. I have a number of patients who have worn them constantly for two, now going on three, years, and to-day they are as firm and neatly shaped as when first put on. In fact, the only case in which I have been called upon to replace them with new ones is where the patient, being a very young person, has grown out of them, the original jacket preserving its shape and texture.

The weight of this large jacket, suited to a person weighing 140 pounds, is two pounds eight ounces, and the small one, suited to a child between one and two years old, weighs 10 ounces. The time required to mould one upon the body is from thirty to forty minutes.

A Method of Ascertaining the Extent of Curvatures.—I have found that careful measurement from the acromion process of the scapula to the symphysis pubis anteriorly, and from the same process to a central point in the sacro-vertebral region posVOL. XXXI.-58

teriorly, will give the stature of the body. If the equilibrium is at all changed, this measurement will at once show the extent, which may not be perceptible in the spinal column; if the curve be the result of spinal disease, there will be a corresponding depression of the shoulder on the opposite side of the arc. But if this curve be due to a shortened limb or a diseased hip-joint, the shoulder will not be depressed, but will remain in the natural position as in compensatory curvature of the spine. Also mensuration from the crest of the ilii to the sterno-clavicular articulation exhibits any departure from the horizontal position of the pelvis due to curvature in the lower portion of the spine or to mal-adaptation of the lower extremities.

I have only recently made these observations and present them for further investigation, hoping the profession will interest themselves in the idea advanced. It will greatly facilitate the diagnosis and prognosis in the examination and treatment of spinal disease. The advantages it possesses over others, in construction, adjustability, and symmetry, are worthy of repetition.

In construction it is light, perforated, strong, durable, simple, and of small cost. In adjustability, being eyeleted as a corset, it is removable without destruction, allows alteration for ease to deformity, yet capable of giving constant support, besides permitting the body to be cleansed and reclothed. It does not destroy symmetry, having been worn unobserved.

THE DEVELOPMENT OF THE OSSEOUS CALLUS IN FRACTURES OF THE BONES OF MAN AND ANIMALS.

BY HENRY O. MARCY, M.D.,

MASSACHUSETTS.

THE results of the investigations which I have the honor to present to you, upon the repair processes in fractures of the bones of animals and man, are quite different from the teachings which I had received, or my previous accepted conclusions.

My studies in this direction were prompted by my clinical observations upon the repair of fractures under various modes of treatment, and especially from my belief, that after careful adaptation and complete rest secured with plastic splints, there occurred, under favorable circumstances, a primary union in bone not unlike that taking place in the repair of superficial wounds.

In one or two monographs upon the treatment of fractures, published some years since, I inculcated this thought. I have availed myself of the great profit derived from the teachings of Comparative Pathology, and have selected the rabbit as the most convenient animal from which to make decalcified injected specimens. First of all, I would give full share of credit to my friend and co laborer, Dr. A. F. Holt, of Cambridge, whose painstaking and carefully prepared microscopic sections will be appreciated by all engaged in this difficult field of histological research.

A most interesting chapter in the history of medicine would. be furnished in giving the different views held in relation to the repair of bones, did the occasion permit. From the time of Galen, the fathers accepted his teaching that "the gelatinous moisture," as he called it, which surrounds the fractured extremities of a bone was the material that formed the new osseous growth called callus. Dupuytren, enlarging upon the doctrines