FAULTY CONFOEMATION 147 



When following the subacute form of laminitis, the 

 changes characterizing pumiced-foot are slow in making 

 their appearance. The animal at first goes short, and the 

 lameness thus indicated gradually becomes more severe, 

 until the animal is no longer able to work. The feet 

 become hot and dry, the hoof loses its circular form, and 

 the growth of horn at the heels becomes excessive. At 

 this stage the appearance of bulging at the sole begins to 

 make itself seen. Later, the outer surface of the wall 

 becomes 'ringed' or 'ribbed,' the rings being somewhat 

 closely approximated in the region of the toe, and the 



Fig. 81, — Hoof with the Ribs or Rings caused by Chronic 

 Laminitis. 



distance between them gradually widening towards the heels. 

 The wall too, especially in the region of the toe, instead of 

 running in a straight line from the coronary margin to the 

 shoe, becomes concave. It is this change, together with 

 the appearance of the rings, that indicates the loosening 

 of the attachment of the os pedis to the wall, and its after- 

 wards backward and downward direction (see Fig. 124). 



As a sequel of acute laminitis, these changes make their 

 appearance with more or less suddenness, and are generally 

 complicated in that they owe their occurrence to the forma 

 tion of pus within the horny box. 



Treatment. — Pumiced-foot is always a serious condition. 

 The animal is useless for work upon hard roads or town 



10—2 



