SAND-CRACK. 323 



ministration of laxatives, alteratives, etc., a run at grass 

 for a time will be found to have a beneficial effect. 



SAND-CRACK. 



A sand-crack consists of a fissure, or solution of con- 

 tinuity in the horny material of the wall of the hoof. The 

 fissure extends through the wall, and in a direction 

 parallel to that of the fibres of the horn. These fissures 

 may exist in any part of the wall, and according to 

 their situation do they receive various names. Thus, a 

 crack in the wall on its anterior asjDect is known as a 

 centre-crack, while one occurring on the quarter is called a 

 quarter-crack. This latter form or variety is the most 

 common, the inner quarter of a fore-foot being the most 

 usual situation of sand-crack. The general name of 

 sand-crack is applied to the condition because it is more 

 common amongst horses kept upon a hot sandy soil, such a 

 soil being supposed to exert some influence in the pro- 

 duction of cracks in the horn. Sand-cracks are said to be 

 complete when they extend from the coronary band down 

 to the plantar border, and are designated as incomplete 

 when they extend onl}' a portion of the distance between 

 the two points named. Occasionally sand-crack exists on 

 the outside quarter of the wall. When in the hind-foot 

 they are usually of the variety designated as centre-crack, 

 or toe-crack. 



Causes. — Certain breeds and strains of horses are pre- 

 disposed to sand-cracks, those having thin and brittle feet 

 being especially liable to cracks in the hoof. In many cases 

 it is unquestionably due to an hereditary predisposition. 

 Improper shoeing also tends to produce the condition, the 

 exciting cause being hard and fast work. Sand-cracks are 

 very common amongst running and trotting horses, owing 

 to the nature of their work, and the fact that they are usually, 



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