=Toe-crack= occurs most often in draught horses and most frequently in the hind feet. In shod hoofs it starts at the coronary border, and unless proper treatment is instituted soon reaches the plantar border. Long toes and low quarters and excessive dryness of the horn are predisposing causes. The exciting cause is usually forward pressure of the upper end of the short pastern against the thin upper edge of the wall of the toe. In the last part of the phase of contact of hoof with ground the pasterns are upright, or may even incline downward and backward (foot-axis broken strongly backward), the short pastern presses the coronary band firmly against the upper thin edge of the toe, when if brittle through dryness it is unable to stretch and tears asunder. Thus, under the effort of starting a heavy load, when a horse with all four legs flexed has risen upon the points of his toes, a short quick slip followed by a catch, will frequently start a crack at the coronet. The hoof should be so dressed and shod that the foot-axis shall be straight when seen from the side. In hind feet it is admissible to break the foot-axis slightly forward. Therefore, shorten the toe and spare the quarters. If the latter are deficient in length, raise them by swelling the branches or by low heel-calks. [Illustration: FIG. 217. Toe-crack immobilized by lateral toe-clips: _a_, bearing-surface left free from pressure; _b_, heads of the rivets (nails) driven through holes previously drilled.] The shoe may be open, or a bar-shoe, or a short shoe with a rubber frog- and buttress-pad. Whatever expands the quarters closes a toe-crack. The Defay’s shoe (Fig. 206), or the Chadwick spring beneath a rubber pad, or beneath a bar-shoe with leather sole, if the frog be much shrunken, will be of service. The shoe should fit air-tight, except for an inch or so on both sides of the crack. Two lateral toe-clips (Fig. 217) are drawn up, and the wall between these clips is cut down from a twelfth to an eighth of an inch. [Illustration: FIG. 218. Spiral drill for boring the hole into which a round wire nail is driven to fasten a toe-crack: (_a_) three sided point of drill (similar to the point of a stilet of a cæcal trocar).]