6. =Borders.=—The _outer border_ should usually be moderately _base-narrow_,—that is, the circumference of the ground-surface of the shoe should be less than the circumference of its hoof-surface; in other words, the entire outer border of the shoe should be bevelled under the foot. Shoes made base-narrow are not so easily loosened, and materially assist in preventing interfering. The _inner border_ should be moderately rounded. [Illustration: FIG. 110. (_a_) correct and (_b_) incorrect fullering.] 7. =The “Fullering”= (Fig. 109, _c_).—In depth it should be about two-thirds the thickness of the shoe, of uniform width, and “clean.” A fullering is not absolutely necessary, but it makes the shoe lighter in proportion to its size, facilitates a uniform placing of the nail-holes, renders the ground-surface somewhat rough, and, because it is rather difficult to make, increases the workman’s skill. [Illustration: FIG. 111. Swiss military shoe, hoof-surface.] [Illustration: FIG. 112. Swiss military shoe, ground-surface.] 8. =Nail-Holes= (Fig. 109, _d_).—=The importance of the nail-holes=, as regards their _character_, _number_, _distribution_, _depth_, and _direction_, =cannot be over-estimated=, because by the nails which are driven through them the stability of the shoe upon the hoof should be maintained without injuring the sensitive structures, splitting the horny wall, or immoderately interfering with the elasticity of the foot. Each nail-hole should taper uniformly from the ground to the hoof-surface (funnel-shaped). For a medium-weight shoe six nail-holes are sufficient, while for all heavy shoes, especially those with toe- and heel-calks, eight are indicated; however, it should by no means be said that every nail-hole should contain a nail. Hind shoes usually require one more nail-hole than front shoes, yet seldom more than eight. In front shoes the nail-holes should be placed in the anterior half of the shoe (Figs. 107 and 108), while in hind shoes they are to be placed in the anterior two-thirds of the shoe (Fig. 116), and in both cases so distributed that the toe shall be without nail-holes, except in those shoes in which it may be desirable to omit the nail-holes in an entire branch (Fig. 153). =The depth of the nail-holes=—that is, their distance from the outer edge of the shoe—will depend always upon the thickness of the wall, and =should equal the absolute= (real) =thickness of the wall= (Fig. 97). It is evident, therefore, that all nail-holes should not be placed at the same depth (for thickness of the wall, see p. 53). The =direction= in which the nail-holes should pass through the shoe depends upon the obliquity of the wall. The nail-holes around the toe, as a rule, should incline somewhat inward, the holes at the sides less so, while those at the quarters should be punched straight,—that is, should pass perpendicularly through the shoe.