The operation by the circular incision is performed by necessity in the thick part of the leg, and the bone is usually sawn through about four inches from the patella, so that, when the stump has healed, there may be sufficient length of bone left to support with steadiness the weight of the body on the knee, and that greater facility may be given to the motion of the leg, from the preservation of the insertion of the flexor tendons. The most eligible place for the application of the tourniquet, when used, is about one-third of the length of the thigh from the knee, on the inside, where the artery perforates the tendon of the triceps muscle, and where it can be most conveniently compressed against the bone by a small firm pad, the instrument being on the outside, or opposite the pad; or the compress may be placed between the hamstring tendons, a little distance from the hollow behind the joint, the instrument itself being on the fore part of the thigh. In this method the pad must be thicker, and the compression is more painful, and not more secure. The surgeon should stand on the inside of the leg to be operated upon, that he may more readily saw the fibula at the same time as the tibia, by which the chance of splintering the fibula is diminished; for this bone is held much more steadily under the saw when the tibia is undivided, whatever pains may otherwise be taken by the assistants to secure it. The limb should be a little bent, and the circular incision made with the smaller amputating knife through the skin and integuments to the bone on the fore part, and to the muscles on the outside and back part; and as the attachment of the skin to the bone will not readily allow its retraction, it must be dissected back all round, and separated from the fascia, the division of which in the first incision would avail nothing, from its strong attachments to the parts beneath. The muscles are then to be cut through, nearly on a level with the first incision, down to the bones. The interosseous ligament between the tibia and fibula is to be divided with the catlin; and as several of the muscles cannot retract in consequence of their attachment to the bones, they are to be separated with the knife; in the same manner the inter-muscular septa, or expansions running between them, are to be divided, as they would else prevent their retraction. The retractor with three slips is now to be put on, the center slip running between the bones, by which the soft parts may be pulled back to a sufficient distance, any adhering part being divided by the point of the knife. The bones are to be sawn through with the usual precautions, and the retractor removed, when the three principal arteries should be secured: the anterior tibial, on the fore part of the interosseous ligament, between the tibia and fibula; the peroneal artery behind the fibula; and the posterior tibial near it, more inward and behind the tibia; this artery will frequently, however, contract very much, and will only show itself on the compression being taken off the artery above. It in general causes more trouble to secure it than the others, and I have two or three times seen, even in London hospitals, the needle dipped round it in despair, when merely pulling out the artery with the tenaculum, and dissecting a little round it, would have shown the small retracted bleeding vessels arising from it, and have prevented, in all probability, a secondary hemorrhage. The tourniquet, if used, being removed, the smaller vessels tied, and the stump sponged with cold water and dried, the integuments and muscles should be brought forward as much as possible, and the strips of adhesive plaster applied from side to side--that is, the wound is to be closed vertically or nearly so, that the strips of plaster may not in any way press upon the fore part of the tibia, by which its protrusion will be avoided, an occurrence which almost invariably follows when the line of approximation is horizontal and the strips of plaster press upon the bone. If the spine of the tibia be sharp, it should be removed by the saw, whether the operation be done by the circular incision or by the use of flaps.