11. Previously to the application of these, it is necessary, according to the precept of Hippocrates, to place the fore-arm in a middle state between pronation and supination, flexion and extension. This position is highly favourable to the relaxation of the muscles, and is that, above all others, as the father of medicine observes, which those who have sustained a fracture naturally assume, and which alone they can, for a long time, retain, without experiencing any inconvenience. 12. The fore-arm being thus placed, an assistant makes extension, by taking hold of the four fingers; a mode to be adopted in preference to that of Petit, who directs us to make extension at the wrist; for the real momentum or force of a power is in the inverse ratio of its distance from the place of resistance. At the same time, another assistant makes counter-extension on the humerus, which he grasps with both his hands, in such a manner, that his thumbs correspond to the back part of it, while his fingers cross each other anteriorly. 13. It further follows, from what was said (8 and 9), that the process of conformation, so often useless and even injurious, in other fractures of bones, is necessary here, to restore to the fragments that exact contact which they have lost, in a transverse direction. If the displacement be forward, the surgeon pushes both fragments backward, while the assistants maintain the extension. If the bones project backwards, they must be pushed in the contrary direction. As to a lateral displacement (8) in which the broken ends approach each other, it is not altogether useless, as Petit observes, to endeavour to remove it, by forcing the muscles into the space between the bones. This is done by making a moderate pressure on the anterior and posterior surfaces of the fore-arm, in order that the bones, being thus removed from each other, may come in contact with their broken ends. If this be done, when the apparatus is first applied, the reduction is attended with but little difficulty, and the ends of the fragments are easily retained in apposition. § VI. OF THE MEANS OF MAINTAINING THE REDUCTION.