frame about seven feet in length, three in width, and four in height, made to separate across the middle. By turning this wheel crank at the side, the two sections are caused to move in opposite directions at an equal rate of speed, and with extreme steadiness and precision. It is furnished with head and axilla strings and gaiters for the feet, both of which are made fast by a fine rope to cleats at the head and foot of the frame. On either side, at the point of separation, is inserted a metallic measure, graduated to the sixteenth of an inch, by which the amount of extension is accurately indicated, and by means of which a record of progress can be kept from day to day. The bed upon which the patient lies consists of a series of movable narrow, transverse cushions, which rest upon a shoulder inside the frame. The lower portion of the frame is divided into inches along this shoulder, the two sides being numbered exactly to correspond.

The upper section of the table is surmounted by a four-post canopy, which carries a belt, upon which, under certain circumstances, to which allusion will be made later, the body of the patient is supported, the head at the same time resting upon a similar adjustable belt at the upper end of the couch. The ease with which extension of the spinal column can thus be produced, the extreme delicacy as well as tremendous power of the extending force, and its self-registering capacity, combine to render this apparatus what the French call an "instrument of precision." And it must be confessed that the operation is performed with the least possible discomfort to the patient. The entire absence of all jerk or jar in its action enables extension to be made, to a very considerable degree, almost without his consciousness.

Having thus briefly indicated some of the more important of the means at our disposal for practising the various modes of spinal extension, it remains for me to speak of the motives with which this operation is performed. Its objects are twofold: First, direct or immediate; Second, indirect or mediate.

Its direct object is the overcoming of muscular and ligamentous contraction, with a view, first, of reducing fractures or dislocations of the vertebræ; secondly, of overcoming spinal curvatures and deformities; and, thirdly, by frequent repetition, of enabling the muscles of the spine at length to maintain it in a position of normal rectitude. For the first-mentioned purpose, namely, the reduction of fractures and dislocations of the ver

tebræ, “Johnstone's Extension" or, as he prefers to call it, "Surgical Table," is certainly most admirably adapted. The difficulty is, that such cases are usually of an extremely critical nature, not admitting of delay, and that this apparatus is not likely to be at hand in case of accident. If, however, every large hospital were provided with one, it might occasionally happen that a case would be brought in, demanding its use, which could be saved in no other way. I cannot urge too strongly the importance of the immediate and persistent, and, if need be, heroie employment of extension in every traumatic lesion of the spine of a paralyzing character. The cases are fast multiplying in our journals in which it has been used with the happiest effects in both dislocations and fractures. Either suspension or horizontal extension may be employed. The plan of Hippocrates, which you see represented in the plate to which I point, by means of traction on fillets around the chest and loins, by two assistants, while the surgeon himself endeavors to press the parts into their normal relations, will often prove entirely successful, and the means for it will generally be at hand. Where the almost inevitable conditions, in the event of the failure to give relief, are those of a horrible, lingering death, continuing it may be through weary months of agony, surely the surgeon is justified in assuming any risk. But, fortunately, the risk is not nearly so great as is usually imagined. Hippocrates shows us what we may safely venture to do.

When, however, the correction of deformity by means of daily repeated extension is the desired end, self-suspension by means of the spinal swing must suggest itself as the superior method, from the fact that the muscles of the spine are thus brought into voluntary action, and stimulated to increased development and tone. There is besides a degree of freedom and variety of movement in the latter which render its daily employment less irksome to the patient than the close restraint of the couch and the entirely passive character of its movement.

The indirect or mediate object of spinal extension is the overcoming or redressing of a curvature and the concomitant deformity of the trunk for a brief space of time, during which a fixed dressing can be applied, or a cast taken from which a removable jacket can be made. With the former of these plans, namely, the application of the plaster-of-Paris jacket, the name of our distinguished president is associated the world over, and

will be indissolubly connected as long as medical science shall continue to bless humanity. In a paper which I had the honor to read before the Medical Society of the State of Pennsylvania, a year ago, on the subject of "Horizontal Extension for the purpose of applying the l'orous Felt Jacket for Curvatures of the Spine," I gave my reasons for considering that this mode was preferable to vertical extension or suspension for the purpose of taking a cast or applying a jacket. These were, briefly, diminution of pain inflicted upon the patient, and hence diminution of anxiety and of necessity for haste on the part of the operator, and greater ease of manipulation. The plan which I adopted was to saturate short strips of crinoline with liquid plaster, lay them in order upon the extending couch in two or three layers, transversely, place the patient upon them and double them over the trunk after the manner of the bandage of Scultetus.

The table before me dispenses with the bandage altogether, in taking a cast for merely temporary purposes. It is provided, as you see, with a large pan, which sets into the upper part of the frame, and in which two smaller pans, open at both ends, are laid. These smaller pans can be telescoped, one inside the other, and thus adapted to the length of the trunk. The process of taking the plaster cast with this table is as follows: The patient, having been first thoroughly greased over the entire body, is laid upon his face upon the table, the plaster troughs or pans being in position. He rests with his forehead supported by one broad strap, and his trunk by a second, while the legs lie upon so many of the movable couch pieces below, as it is found convenient to leave in position. The head and feet being then properly secured, gradual extension is made. When it has reached such a point that the patient becomes conscious of pain in the back, it is to be very slightly relaxed. The chest band is now to be removed, and the forehead band placed at such a height that the most dependent part of the chest shall lack about a fourth of an inch of touching the bottom of the plaster pan. The movable inner pans are now adjusted to the length of the trunk, and their open ends are quickly filled up with moist plastic clay, fitting accurately to the body. Plaster of the consistence of cream is now poured into the pan, and a fine cord or soft wire is laid along each side of the patient, close to the skin, from the axilla to the trochanter, for the purpose of cutting the cast. This done, the patient's back and sides are quickly coated with a thick plaster

solution, until he is firmly incased in a shell of about threefourths of an inch in thickness. The wires will now be ready to be drawn. This must be done carefully, drawing directly outward from each end with steady force. The upper section of the cast is then gently removed, the lower section remaining in the pans, until the patient is lifted off. He should be raised out of it by elevating the forehead strap before relaxing the extension, in order not to injure the fine surface of the cast. The two segments can be cemented together with a little liquid plaster, at leisure, and the cast is then complete. Inside of this form is cast a plaster mould, which is of course a complete reproduction of the trunk of the patient; and on this mould the felt, in a state of the utmost plasticity, is accurately stretched, being adapted to every minute inequality of the surface. A jacket is thus obtained which is as perfect in fit as the plaster, but which is pervious to the air, and removable at pleasure for purposes of cleanliness.

I may be pardoned for calling your attention, in conclusion, to the fact that spinal extension is, however, only one of several important uses to which such a table can be put. Its applicability to the reduction of fractures of the lower extremities, of dislocations, and even to the performance of operations in which immobility of the limb is a prime desideratum, needs only to be mentioned to be appreciated. The movable and sectional character of the bed enables us to get at any part of a limb without subjecting the patient to the pain of lifting it, while at the same time it is held much more firmly than could be done by an assistant. For irrigation and drainage, it will afford marked facilities.

It has also features which make it very serviceable as a convalescent bed, of after operations or accidents, or for the hopelessly bedridden, in the way of mechanism for altering the position of the body, with great ease and comfort to the patient for the purpose of defecation and for maintaining cleanliness. In a large hospital I am confident that it would be called into almost daily requisition.