5. If we attend to the signs just mentioned (3), we will perceive that they almost all result from the displacement of the fragments. But, whence arises this displacement? As far as the anterior fragment is concerned in it, it arises from, and is increased by, the flexion of the foot; and, as far as relates to the posterior one, it is to be attributed to the contraction of the muscles attached to the tendo Achillis, which is itself inserted in that fragment. Hence it follows, that the apparatus intended to prevent this displacement, ought, 1st, to keep the foot permanently extended on the leg: 2dly, to prevent the action of the muscles, by keeping them in a state of habitual relaxation by means of the constant flexion of the leg on the thigh, by making on those whose contractions are dreaded, such a regular and well directed compression as may disqualify them for contracting; and, lastly, by placing behind the posterior fragment some resisting substance, to prevent it from rising upwards. 6. If to these indications we compare Desault’s apparatus for a rupture of the tendo Achillis, as described in the preceding memoir, we will readily perceive 1st, that it perfectly fulfils that indication which relates to the anterior fragment; 2dly, that that one which relates to the posterior fragment will be equally well fulfilled by the half flexed state of the leg, by the compression made on the muscles, and by a thick compress, not very broad, laid transversely above the fragment, secured by the long roller, and afterwards by a circular bandage, which must form here, as in the case of a fractured rotula, a kind of figure of 8 around the fracture. This compress is the only modification of the apparatus requisite to accommodate it to the particular case now under consideration. 7. In applying the figure of 8 bandage here, as well as in the case of a fractured rotula, to prevent the ascent of the fragment, it is necessary to use the utmost care to free the integuments from wrinkles both above and below the fracture, lest by getting between the fragments, they might keep them asunder, and thus impede their reunion. 8. Desault used to relate in his lectures, the case of a woman whom he had formerly seen receiving a fracture of the os calcis, by falling from a great height. I cannot state the case fully, because I am not in possession of all the facts. The following one however drawn up during the first years of Desault’s practice in the Hotel-Dieu, will furnish an example of his mode of treatment. CASE. A man, likely to be arrested by some one who pursued him, leapt from a window nearly twelve feet high. In lighting, his feet struck on a beam which lay in his way, in such a manner, that the fore part of them only was supported. He made an effort to recover his equilibrium, but as the line of gravity of his body had nothing to rest on, he fell backwards, rose in order to make his escape, but fell a second time unable to rise again.