[Footnote A:  Veterinarian, vol. lxi., p. 141.]

Still a further useful clamp is that of Koster.  This is considerably broader than the clamp of Vachette, and its gripping edges are provided with teeth (see Fig. 89).

As with the clamp of Vachette so with this, a groove is burned into the wall on each side of the crack for the accommodation of the jaws of the instrument, and the clamp itself pressed home by means of a special pair of forceps.  This form of clamp holds well, and has the advantage of securing a wider area of horn than that of Vachette or McGill.

[Illustration:  FIG. 89.—­KOSTER’S SAND-CRACK CLAMP.]

Clamping by any method should be advised or undertaken only under certain conditions.  The horn should be moderately strong, and the wall should be thick.  This practically restricts the use of the clamp to cracks of the toe, and it is there, as a fact, they are found of most benefit.  While burning the grooves for the clamp, and while tightening the clamp itself, the animal’s foot should be on the ground and bearing weight at the heels, thus insuring the greatest possible approximation of the edges of the crack.

With all methods of clamping an untoward result is sometimes the formation of a fresh crack at the point of insertion of the clamps.

(c) By the Use of Thin Metal Plates.—­These are of use when the horn of the wall is too thin to allow of clamping, and are therefore of especial use in cracks of the quarters.  The plates are made so as to cover the greater part of the length of the lesion, and are fastened to the wall by two or more screws on either side of the crack.  It is an advantage to slightly let the plate into the wall by means of fitting it hot.  In a complicated crack the plate serves the further useful purpose of holding in position antiseptic pledgets, and so keeping the lesion free from dirt and grit.

(d) By Various Methods of bandaging the whole Circumference of the Wall.—­In our opinion this method of attempting to secure immobility of the crack, and so prevent its extension, is not often followed by success.  The main objection to the method is that it subjects the whole of the wall to the same pressure, and does not restrict the operation to the point at which it is required.  As in the case of the metal plate, however, this method has the advantage that antiseptic dressings may be kept in position in the case of a complicated crack.

[Illustration:  FIG. 90.—­SAND-CRACK BELT.]

The binding of the wall may be accomplished in two ways.  The simpler of the two is to merely apply the sand-crack belt depicted in Fig. 90.  Beneath this should be applied a compress of tar and tow or other material, and the whole tightened up and kept in position by means of the buckle and strap.  This method of binding admits of after-tightening should it unfortunately work loose.