24. As the union of the humerus to the clavicle, by means of the scapula, communicates to the one the movements of the other, it is easy, by placing the ball used by Paul of Egina, under the arm-pit, to convert the arm into a lever of the first kind.[2] [2] That form of lever, where the weight to be raised or the resistance to be overcome, is at one end, the force at the other, and the fulcrum or prop between them. This form is well represented by the handle of a pump, where the piston is the weight or resistance, the hand of the drawer of water the force, and the iron pin, on which the handle works, the fulcrum or prop. TRANS. The lower extremity of the arm being then pressed towards the body, the upper end is separated from it, and becomes, with regard to the clavicle, what the efforts of an assistant who makes the extension, in a fracture of the leg, are to the foot of the patient. The mode of reduction being established, it was necessary, in the next place, to invent a bandage, calculated to retain the broken ends of the bone in contact. Desault thought it practicable to unite these two points of treatment, in the same process, that is to say, to reduce, and at the same time to retain the fracture. Here the art is indebted to him for an improvement, which, I will venture to say, carries it near to perfection. To judge of this, it will be necessary only to take a hasty survey of the different kinds of apparatus proposed by different writers. § VII. OF THE MEANS OF RETAINING A REDUCTION. 25. Here all authors seem to have been directed by the same principle. This is to keep the shoulder of the affected side, 1st, drawn forcibly backwards, 2dly, approximated towards the shoulder of the sound side. Such was the practice of the Greek physicians, whom we have seen in common with Hippocrates, Celsus, and Paul of Egina, employing a kind of bandage, varied in its form, according to the displacement it was intended to remedy. Above all others, we find an application of this principle, in the figure of 8 bandage, a particular form, which was employed in practice by Albulasis, an Arabian, and afterwards by his countrymen, as well as by Lanfranc, Guy of Chauliac, and their contemporaries. The use of this bandage was continued by Pare and his successors, and has been lately modified by several authors, such as Heister, Petit, Brunninghausen, &c. 26. But under whatever form it shows itself, its action is always the same, and always insufficient. On comparing its effect with the general principle, on which every apparatus for the clavicle should be constructed (20), we perceive, that it by no means answers the threefold indication, of retaining the shoulder backward, outward, and upward.