The aperture of entry was comparatively small, since to take so direct and lengthy a course through the skull the impact of the bullet needed to be at nearly an exact right angle to the surface of the bone. Any disposition to assume the oval form, therefore, depended mainly upon the degree of slope of the actual area of the skull implicated. In size the aperture of entry did not greatly exceed the calibre of the bullet; in outline it was seldom exactly circular, but rather roughly four-sided, with rounded angles, slightly oval, or pear-shaped. The margin of the opening consisted of outer table alone, the inner being always considerably comminuted. Fragments of the latter, together with the majority of those corresponding to the loss of substance of the outer table, were driven through the dura mater and embedded in the brain. These bony fragments were more or less widely distributed over an area of a square inch or more, and not confined to a narrow track. [Illustration: FIG. 61.--Diagram of Aperture of Entry in Occipital Bone, showing radiating fissures exact length. The exit in the frontal region was of typical explosive character. Range '100 yards'.] The amount of fissuring at the aperture of entry was often not so extensive as I had been led to expect. Fig. 61 is a diagram illustrating a fairly typical instance; in some cases no fissuring existed. As a rule the nearer to the base, the greater was the amount of fissuring observed. The fissures were sometimes very extensive in this position, probably as a result of the lesser degree of elasticity in this region of the skull. Again, when the aperture of entry was near the parts of the vertex where sudden bends take place, considerable fissuring of the same nature as that seen in the superficial tracks (fig. 68) was produced in the flat portion of the skull above the point of entrance. Radial fissuring around the aperture of entry in the skull scarcely corresponds in degree with that seen when the shafts of the long bones are struck, and is far less marked and regular than when one of these small bullets strikes a thick sheet of glass set in a frame. I saw several apertures in the thick glass of the windows of the waterworks building at Bloemfontein produced by Mauser bullets. They differed little from the opening seen in an ordinary plate-glass window resulting from a blow from a stone, except perhaps in the regularity and multiplicity of the radial fissures. As in the skull, the opening was a little larger than the calibre of the bullet, and the loss of substance on the inner aspect considerably exceeded that on the outer.