HORSESHOEING. 159 



inflammation extends to the deeper layers of the pododerm, or, 

 indeed, even to the plantar cushion, and gives rise to swelling of 

 the bulb of the heel upon that side and to a well-marked lame- 

 ness, which requires treatment by a competent veterinarian. 



The bars he in the most elastic region of the hoof. The cracks 

 open and close alternately as the body-weight is thrown upon 

 and taken from the hoof. This continuous movement not only 

 renders heaUng difficult,. but, on the contrary, tends to prolong 

 the crack and to irritate and inflame the pododerm. 



Ordinarily a bar-crack is only found by a close examination 

 of the hoof after the shoe has been removed. In paring the 

 hoof the crack usually appears as a dark streak, sometimes as a 

 bloody fissure ; not infrequently grayish hoof-pus is discovered 

 in the depths of the crack. 



The treatment must be directed towards favoring the growth 

 of a continuous (unbroken) bar. This is accomplished by com- 

 pletely removing the edges of the crack, paring the horn of the 

 vicinity very thin, and preventing the least pressure upon the 

 wall of this quarter by the shoe, by lowering this quarter with the 

 rasp and applying a bar-shoe, and when necessary a leather sole. 



Following the removal of the edges of the crack there often 

 appears, especially in stumpy hoofs, a deep groove ; if the bottom 

 of this groove is moist, we should pack it with oakum wet with 

 tincture of myrrh or tincture of aloes, and cover the oakum with 

 wax (grafting wax). The cracks will return if the exciting 

 causes cannot be completely removed. 



(b) Treatment of Low Cracks {Plantar Border Cracks). — These 

 cracks, occurring principally upon the hoofs of unshod horses, 

 are the result of excessive stretching and bending of the lower 

 border of the wall. Insufficient rounding of the wall with the 

 rasp is largely responsible for them. An exciting cause in shod 

 horses is the use of too large nails in shoes that are punched too 

 fine. 



Every coronary crack becomes in time a low or plantar-border 

 crack, and this has an important bearing upon the prognosis, 



