[31] A case of luxation of the head of the os femoris in a forward direction, but differing in some respects from the above, occurred lately in the Pennsylvania hospital under the care of Dr. Physick. The doctor reduced this luxation in the amphitheatre, in the presence of his class, by a process which was also somewhat different from that adopted by Desault. In the case of Desault’s patient the luxated limb was shorter than the sound one: in that of Dr. Physick’s it was evidently longer. This was no doubt owing to the head of the os femoris having, in the former case, passed farther up towards the superior rim of the os pubis than it had in the latter. In both cases the protuberance formed by the head of the bone in the groin could be readily felt. For the purpose of making counter-extension, Desault passed a strap between the scrotum and the thigh of the sound side: Dr. Physick, for the same purpose, passed the strap between the scrotum and the affected thigh. He conceived that by this mode he could act with more effect on the pelvis, and more effectually prevent the acetabulum of the affected side from being drawn in any measure downward by the extending forces. It would seem, that by making counter-extension, in such a case, on the sound side, the pelvis is made to rotate, so to speak, on its own axis, in the direction in which the counter-extension is made. The necessary effect of this rotation must be, a slight descent of the acetabulum of the affected side. But to retain the acetabulum firmly up is the true and only end of counter-extension. Dr. Physick appears therefore to have availed himself of the greatest mechanical advantage of which the situation of the parts admitted. Again: Desault placed the strap on which extension was made just above the ancle: Dr. Physick placed the strap intended for the same purpose above the knee. His object in this was, to have the leg free and unincumbered, in order that he might be able to use the limb with more advantage, as a lever of the first kind, to assist in moving the head of the os femoris towards the acetabulum. The fulcrum of the lever into which the limb was thus converted, was a strap passed round the affected thigh a few inches below the groin, and drawn laterally with great force in a direction opposite to that in which the bone was displaced.