6. _Perforations._--Although these were common in cancellous bone, they were comparatively rare in the compact shafts. I saw, however, complete pure perforations of the shafts of the tibia, femur, clavicle, and other bones. These perforations were, I believe, always the result of low degrees of velocity, and they took the place of simple transverse fractures of the 'cut' variety. The apertures of entry and exit in the bones resembled in character those seen in the soft parts, or in the bones of the skull in low-velocity injuries (see figs. 71 and 72, p. 261). The entry was more or less cleanly cut, while at the exit a plate of bone was raised, and either separated or turned back on a hinge by the bullet (fig. 52), (plate XVII.) Such a projecting hinged fragment was sometimes a source of some trouble; thus in a case of postero-anterior perforation of the lower third of the shaft of the femur, the long exit fragment projected into the substance of the quadriceps extensor muscle, and interfered with flexion of the knee-joint. Fig. 57 of a superficial tunnel of the lower third of the tibia is especially interesting as bringing such injuries of the long bones into line with fractures of the flat bones of the skull, such as are illustrated in fig. 68, p. 259. Plate XXI. affords an excellent example of perforation of the shaft of the tibia, although complicated by the secondary fissure. Plates XXIII., VIII., and III., of the fibula, humerus, and clavicle, exhibit examples of what may be called spurious perforations of the shafts of bones, since comminution or loss of continuity accompanies all three. Subsequently to writing the above paragraphs, I took the opportunity of re-examining the magnificent series of gunshot fractures collected during the Franco-German campaign by Sir William MacCormac, and afterwards presented by him to the museum of St. Thomas's Hospital. The close approximation in type between the main features in these and those in the fractures produced by the modern bullet is very striking. In the case of the shafts of the long bones, the same stellate, oblique, wedge-shaped, and even perforating injuries are illustrated on a coarser scale. In a specimen of a patella, a perforation of the lower half, implicating also the tendon of the quadriceps muscle is, though large, almost as pure as a Mauser perforation. The difference in the nature of the lesions of the bones is seen to be, firstly, one of pure magnitude, corresponding to the size of the large Snider bullet by which they were produced. Thus the fragments generally are larger, and occupy a wider area of the shafts, the first character depending on the lesser degree of velocity of the bullet, the latter on its volume and weight. Fine comminution, however, the most striking feature of the modern injury, is throughout absent.