D. CALDWELL, Clerk of the District of Pennsylvania. CONTENTS. MEMOIR I. PAGE On the Fracture of the Condyls of the lower Jaw, 1 MEMOIR II. On the Fracture of the Clavicle, 8 Explanation of the first Plate, 39 MEMOIR III. On the Luxation of the Clavicle, 41 Luxation of the Sternal extremity, 42 of the Humeral extremity, 54 MEMOIR IV. On Fractures of the Acromion, and of the lower angle of the Scapula, 57 Fracture of the Acromion, _ib._ of the lower angle of the Scapula, 63 MEMOIR V. On the Fractures of the upper end or neck of the Humerus, 67 MEMOIR VI. On the Fracture of the lower extremity of the Humerus, with a separation of the Condyls, 90 MEMOIR VII. On the Luxation of the Humerus, 102 MEMOIR VIII. On the Fracture of the bones of the Fore-arm, 146 Fracture of the Radius, 160 of the Ulna, 167 of the Olecranon, 168 MEMOIR IX. On the Luxation of the Fore-arm, 184 MEMOIR X. On the Luxations of the Radius over the Ulna, 199 Luxation of the lower extremity of the Radius, 204 MEMOIR XI. On the Fractures of the Thigh, 214 Fractures of the body of the Os Femoris, 215 of the upper end of the Os Femoris, 258 of the great Trochanter, _ib._ of the neck of the Os Femoris, 260 of the lower extremity of the Os Femoris, 280 Explanation of the second Plate, 291 Thoughts on Luxations of the Os Femoris upward and forward, 292 MEMOIR XII. On spontaneous Luxations of the Os Femoris, 299 MEMOIR XIII. On the Fracture of the Rotula, 304 MEMOIR XIV. On the formation of foreign bodies in the joint of the knee, 325 Observations and Reflections on forms of Apparatus[1] for fractures of the leg, 342