NAVICULAE-JOIKT LAMENESS. 



789 



ary light driving on mud roads, but when subjected to such 

 severe and continued concussion, they became a direct cause of 

 irritation and disease. As a good iUustration of this cause of 

 danger, I copy the remarks of a very excellent author fWhite) on 

 the danger of lowering the 

 heels too suddenly and subject- 

 ing them to severe strain: " It 

 has appeared in a great num- 

 ber of dissections of the feet of 

 horses affected with chronic 

 lameness, that the small bone 

 of the foot, called navicular or 

 nut-bone, is diseased either on 

 the surface over which the 

 great tendon of the foot passes, 

 or on that which articulates 

 with the small pastern and 

 coffin bones." In speaking of 

 the cause, he says: "I once 

 knew an excellent trotting- 

 horse that had won several 

 matches. Thin-heeled shoes 

 were put on his feet, but it 

 was soon found that he could 

 no longer trot; that when 

 urged he would go into a can- 



FiG. 695. — Excellent view of perforans 

 tendon. From photograph of 

 manikin of the foot. 



And this, I have no doubt^ was 



ter. The shoes were therefore 

 taken off, and a common shoe 

 applied, but it was too late. 

 He was no longer able to trot, 

 caused by inflammation of the coffin -joint, or of the pai'ts con- 

 nected with it, in consequence of lowering tlie heels and throw- 

 ing so much stress on the tendon and navicular bone." 



In talking with an intelligent veterinary surgeon on this sub- 

 ject, he referred to a case in his own practice that had strained 

 the perforans tendon. The owner called him in to treat it, and 

 by proper management soon relieved the lameness; but in conse- 

 quence of the horse's being driven and speeded too soon, there was 

 a return of the lameness, which he again treated with success. 



