Similar remarks may be made respecting Boyer’s apparatus for making permanent extension in oblique fractures of the os femoris. It is much more complex and difficult to be constructed than that of Desault. Nor does it possess a single advantage over it as improved by Drs. Physick and Hutchinson. In a word, the forms of apparatus of Boyer may answer well enough in hospitals and in cities, where the expence of such articles is not much regarded, and where workmen to make them can be readily procured. But, as the practitioner in the country is generally obliged to be himself the constructor of the forms of apparatus which he uses, and as he is not at all times prepared to meet heavy expenses, it is to those recommended and employed by Desault that he must necessarily have recourse. With these remarks the translator submits to the good sense and candour of his countrymen the following sheets, as the offspring of some of his hours of leisure throughout the winter. He hopes that the appendix subjoined by himself will not be regarded as either an useless or an unpleasing addition. Every native of the United States, whose bosom glows as it ought, with that noblest of passions, the _amor patriæ_, will witness with pride and exultation the improvements that are daily making in the arts and sciences, by the industry and enterprize of his enlightened countrymen. Such a mind will enjoy in anticipation the glory of his country, at that period, when she will be able to reflect back, with increased splendour, the light which she has so long been borrowing from the countries of Europe. The translator does not plead the want of time as an apology for any imperfections or errors which his translation may exhibit. Yet he believes it to be true, that had he had more time to bestow on it, he could probably have rendered it more worthy of public patronage. A TREATISE ON FRACTURES, DISLOCATIONS, &c. MEMOIR I. ON THE FRACTURE OF THE CONDYLES OF THE LOWER JAW. §I. 1. The lower jaw, a kind of moveable hammer, destined, to use the words of a certain physiologist, to triturate the aliments against the almost immoveable anvil of the upper jaw, is more exposed to the action of external bodies, and consequently to fractures, than most of the other bones of the face. But all parts of it are not alike subject to such accidents. Common in its body, but less frequent in its branches or sides, fractures sometimes occur in the two processes in which its branches terminate. One of these processes, concealed by the zygoma, embosomed in the temporal muscle, and covered by the masseter, is less liable to fractures than the other, which serves as the centre of the motions performed by the bone, and is protected externally only by the parotid gland. §II.