374 DISEASES OF THE FEET. 



more or less tender, and requires careful shoeing, in order that 

 no undue weight be thrown upon the weakened portion. 



Causes. — Anything that destroys the integrity of the coronary 

 substance, such as treads, quitters, &c. 



The treatment, if there be a wound, must be directed to the 

 diseased coronet ; removing all ragged edges, making the wound 

 as level as possible, and moulding the parts into their natural 

 condition, as nearly as can be done, by firm pressure ; bringing 

 the edges of the wound together, and inducing it to heal by 

 secondary adhesion. If the case be an old one, the gap in the 

 coronet healed up, and filled with fibrous tissue, but little can 

 be done, except filling the fissure with gutta-percha from time 

 to time as occasion may require, and applying a bar shoe, so as 

 to throw the bearing from the weak part. Blisters to the 

 coronet are sometimes useful. 



Tricks are played upon feet of this kind ; false-quarters, sand- 

 cracks, and seedy-toes are filled with gutta-percha, moulded to 

 the part whilst warm, nicely filed or rasped when cold, and the 

 whole surface of the foot blackened with lamp-black and oil, or 

 covered with tar. 



Caution. — Never examine a horse as to soundness if the feet 

 are dirty, without having them washed. 



SAND-CRACK. 



A sand-crack consists of a fissure of greater or lesser extent 

 in any part of the foot, commencing at the coronet, and generally 

 found in the inner quarters of the fore and the toes of tlie 

 hind feet, very rarely in the outer quarters. 



Professor Dick taught that " a sand-crack may happen in 

 an instant, from a false step ; and hence a horse, though he may 

 spring a sand-crack within an hour after purchase, cannot be 

 returned on that account to the seller." This opinion is held 

 by many other writers and teachers ; but it is incorrect, except 

 in very rare instances. A sand-crack proceeds by slow degrees. 

 Prior to its appearance, the horn is imperfectly secreted ; it is 

 dry and brittle. Horn is built up of tubes matted together. 

 These tubes are similar to hair, and are secreted by the same 

 kind of cells. And " the same cell which forms the scaly 

 epithelium, epidermis, and hair is utilized in building up the 



