THE FOOT IN HEALTH AND DISEASE 113 



become somewhat wasted, this being apparently due to 

 diminished functional power of the muscles, owing to 

 disease in the foot. Quite a number of horses with 

 navicular disease are offered for sale and find purchasers, 

 as it is an easy matter for the inexperienced to overlook 

 a trouble so obscure, for obscure it certainly is, and it 

 renders the animal of very little commercial value. 



For the relief of the lameness, and in order to work a 

 horse thus affected, say, for a year or two longer, the 

 operation of " neurectomy," or unnerving, is practised 

 in some instances. It is not, however, a very commend- 

 able operation, and is, when performed, occasionally a 

 means towards fraud. Sometimes the operation is a 

 success, and sometimes it is not. When successful the 

 lameness is no longer observable, though of course the 

 disease pursues its slowly progressive course, and must 

 finally end either in the destruction of the animal or in 

 its becoming useless for work. 



Sand-crack 



This is a disease affecting the wall, and begins immedi- 

 ately subjacent to the coronet by making its appearance 

 in the form of a crack or split in the wall of the hoof. If 

 in the fore foot or fore feet it occurs as a rule at the inner 

 quarter, but to this there are exceptions, whereas in the 

 hind foot it occurs generally at the toe. Sand-crack may 

 begin on the inner or outer surface of the wall of the hoof, 

 and its onset may be gradual or sudden. Every class of 

 horse is equally liable to its development, but pre- 

 disposition is unquestionable in hoofs which are dry or 

 brittle, and those in which the integrity of the secreting 

 structures of the coronary band have been damaged. 

 Some hoofs are much thinner than others and this, along 

 with continued work on hard, dry roads often leads to 

 the production of sand-crack. A condition technically 

 known as " false quarter," i.e. a furrow in the wall of 

 ^ 



