232 VETEKINAKY MEDICINE AND SUEGEKY. 



sloughing of the diseased membrane in a day or two. The animal 

 should then begin to mend, and in two or three weeks ought to be again 

 fit for work. The application of the caustic should not be repeated 

 more than once or twice. 



When the internal disease is removed, the treatment of the mere 

 sore at the coronet is easy. In fact, beyond keeping it clean, applying a 

 simple cold-water dressing, and occasionally an astringent lotion, as: 



Collodion § x. 



Carbolic acid . . . 3 i. 



Tannin 3 iv. 



little more need be done. Sometimes, however, there is a great tend- 

 ency to the growth of unhealthy granulations around the sore, which will 

 require to be checked by caustics or removed by the knife. 



Great care must in all cases be taken to prevent the external sore 

 from healing over before the internal disease is thoroughly eradicated. 

 From the great vascularity of the parts in the neighborhood of the coro- 

 net, there is always an over-tende»cy to the healing action. 



SANDCRACKS. 



Definition. — A sandcrack is a longitudinal division in the fibres of 

 the wall of the hoof, amounting to a flaw simply, or else to a cleft or 

 fissure through the substance of the horn. It is usually found on the 

 inside in the fore-feet (quarter-crack. Fig. 121) and in front in the hind 

 feet (toe-crack, Fig. 122). 



Etiology. — In most cases, the fissure is due to brittleness of the 

 crust. This brittleness may be constitutional, some horses being evidently 

 predisposed to it, but it is more often due to the evil practice of cutting 

 away the sole, and of rasping the crust. The fissure may also be a re- 

 sult of conti-action at the heels. Such contraction may arise from ' 

 natural causes, but it is certain to be aggravated, if not produced, by the 

 practice of cutting away the bars, and so-called "opening" the heels. 



Symptoms. — A sandcrack does not ordinarily cause lameness until 

 it has become suflficiently deep to expose the sensitive laminae, or until it 

 has extended to the coronary band. It is then excessively painful, and 



