KNBE, FETLOCK, ANKLE, AND FOOT. 215 



ease proves the inefficiency of any treatment that may have been 

 adopted and the hopelessness of the case. These patients die usually 

 between the tenth and twentieth days, either from exhaustion or pysemic 

 infections. 



Sand-crack. A longitudinal (up and down) division in the fibers of 

 the wall of the hoof, is called a sand-crack. It is usually found either 

 on the inside in the fore-feet when it is called a quarter-crack, or in 

 front in the hind-feet when it is usually named toe-crack. 



The toe-crack is most likely to be complete (that is extending from 

 the coronary band to the toe), while the quarter-crack is nearly always 

 incomplete, at least when of comparatively recent origin. Sand-cracks 

 are most serious when thej' involve the coronary band in the injury. 

 They may be complicated at any time by bleeding, inflammation of the 

 laminae, suppuration, gangrene of the lateral cartilage and of the ex- 

 tensor tendon, caries of the coffin bone, or the growth of a horny tumor 

 known as a keraphyllocele. 



Causes. Relative dryness of the horn is the principal predis- 

 posing cause of sand-cracks. Excessive dryness is perhaps not a 

 more prolific cause of cracks in the horn than alternate changes from 

 damp to dry. It is claimed that these injuries are more common in 

 mountainous countries. Animals used to running at pasture when 

 changed to hard, dry floors are more liable, especially to toe-cracks, than 

 those accustomed to stables. Small feet, with thick, hard hoofs, and 

 feet which are excessively large, are oftener ailected with sand-cracks than 

 those of better proportion. A predisposition to quarter-crack exists in 

 contracted feet, and in those where the toe turns out or the inside quarter 

 turns under. 



Heavy shoes, large nails, and nails set too far back toward the heels, 

 together with such diseases as canker, quittor, grease and suppura- 

 tive corns must be included as occasional predisposing causes of 

 sand-cracks. 



Fast work on hard roads, jumping, and blows on the coronet, together 

 with calk wounds of the feet, are accidental causes of quarter cracks in 

 particular. Toe-cracks are more likely to be caused by heavy pulling on 

 slippery roads and pavements or on steep hills. 



Sytnptoms. The fissure in the horn is ofttimes the only evidence of 

 the disease; and even this may be accidentally or purposely hidden from 

 casual view by mud, ointments, tar, wax, putty, gutta-percha, or by the 

 long hairs of the coronet. 



