abdomen; but if any impediment to the reduction still remain, the cause, in all probability, arises either from the neck of the sac having become strongly adherent to the crural ring, or from the bowel being bound by bands of false membrane to the sac. In either case, it will be necessary to open the sac, and examine its contents. The neck of the sac is then to be exposed by an incision carried through the integument across the upper end of the first incision, and parallel with Poupart's ligament. The neck is then to be divided on its inner side, and the exposed intestine may now be restored to the abdomen. [Footnote: The finger is the safest director; for at the same time that it guides the knife it feels the stricture and protects the bowel. As all the structures which are liable to become the seat of stricture--viz., the falciform process, Gimbernat's ligament, and the conjoined tendon, lie in very close apposition, a very short incision made upwards and inwards is all that is required.] [Illustration: Abdomen, showing bone, blood vessels and other internal organs.] Plate 46--Figure 3 [Illustration: Abdomen, showing bone, blood vessels and other internal organs.] Plate 46--Figure 4 [Illustration: Abdomen, showing bone, blood vessels and other internal organs.] Plate 46--Figure 5 COMMENTARY ON PLATE 47. THE SURGICAL DISSECTION OF THE PRINCIPAL BLOODVESSELS AND NERVES OF THE ILIAC AND FEMORAL REGIONS. Through the groin, as through the axilla, the principal blood vessels and nerves are transmitted to, the corresponding limb. The main artery of the lower limb frequently becomes the subject of a surgical operation. The vessel is usually described as divisible into parts, according to the regions which it traverses. But, as in examining any one of those parts irrespective of the others, many facts of chief surgical importance are thereby obscured and overlooked, I propose to consider the vessel as a whole, continuous from the aorta to where it enters the popliteal space. The general course and position of the main artery may be described as follows:--The abdominal aorta, A, bifurcates on the body of the fourth lumbar vertebra. The level of the aortic bifurcation corresponds with the situation of the navel in front, and the crista ilii laterally. The aorta is in this situation borne so far forwards by the lumbar spine as to occupy an almost central position in the cavity of the abdomen. If the abdomen were pierced by two lines, one extending from a little to the left side of the navel, horizontally backwards to the fourth lumbar vertebra, and the other from immediately over the middle of one crista ilii, transversely to a corresponding point in the opposite side, these lines would intersect at the aortic bifurcation. The two arteries, G G,* into which the aorta divides symmetrically at the median line, diverge from one another in their descent towards the two groins. As both vessels correspond in form and