The older method of binding the wall, and one now often practised by the smith, is to use a quantity of so-called ‘tar-band’ or other stout cord.  With this the foot is neatly bound after the manner of a cricket-bat handle, and all movement of the crack apparently restricted.  There is always a tendency, however, for such a dressing to work loose, and in the case of a complicated crack it has the disadvantage of permanently hiding from view the changes taking place in the discharge from the fissure.

(e) By wedging the Crack.—­This is the exact opposite of clamping.  Whereas in clamping we obtain immobility of the crack by keeping it fixed in the position of greatest approximation of its edges, in wedging, the crack is rendered free from movement by maintaining it in that position where its edges are most widely separated.  In this case the edges of the crack are pared smooth, the cavity thoroughly cleansed, and a wedge of hard wood firmly driven in so as to fit exactly the fissure.

On the face of it it appears that this procedure would really tend to force open and so lengthen the crack, especially at its coronary extremity.  What one should really remember, however, is that the crack is not made wider than before, but that it is simply maintained in a position occurring with every contraction of the heels of the foot, when it is normally at its widest.  Movement of the edges is thereby stopped, the immediately surrounding structures are rested, and a new growth of horn, free from crack, induced to grow down from the coronet.

This method of treatment only serves to emphasize the fact that, with a sand-crack once formed, it is the constant movement of the parts that tends most to keep it in existence, and not any particularly marked exertion of force.

Some practitioners, with the wedge, apply also a clamp, thus assuring additional firmness and solidity to that portion of the wall under treatment.

The method of wedging is undoubtedly successful, if neatly performed.

(f) By Surgical Shoeing.—­A partial rest is given to the affected parts by easing the bearing of the shoe at the point required.  This may be done either by removal of part of the wall at the spot indicated, or by thinning the web of the shoe in the same position.  The former is the method usually practised.  Cessation of movement given in this way is, as we have already said, only partial; for, while the effects of pressure and concussion from below are minimized, the crack is still able to suffer from the movements of expansion and contraction of the foot.  Still, as an auxiliary to other treatments, ‘easing’ of the wall under the affected part should always be practised.

[Illustration:  FIG. 91.—–­THE BEARING ‘EASED’ BY REMOVAL OF THE WALL.]

[Illustration:  FIG. 92.—­THE BEARING ‘EASED’ BY THINNING THE WEB OF THE SHOE.]

Figs. 91 and 92 show respectively the manner of ‘easing’ by removal of the wall, and by thinning the web of the shoe.  In this connection it is necessary to point out that on no account should ‘springing’ of the heels of the shoe be allowed.  Fig. 93 illustrates the ill-practice.