QUARTER SANDCRx\CK. 475 



likewise accounts for the comparative infrequency of quarter 

 sandcrack at the present day among our nag and cavalry 

 horses, since that which has tended to diminish the frequency 

 of contraction has had the same effect in regard to the occurrence 

 of sandcrack. Greater attention to shoeing, and increased care 

 about the condition of the hoof itself, has no doubt had very 

 beneficial effect in the prevention both of contraction and sand- 

 crack. 



The Origin of Sandcrack is usually sudden, both 

 in the fore and hind feet ; though in the former case, from its 

 situation in the inner quarter, a part not exposed to transient 

 view, it is possible for a crack to exist for some time, unless 

 lameness happens to arise from it, without being discovered. 

 The crack first takes place through the superior or coronary 

 border of the hoof, that being composed of new-formed horn, 

 which is thin and fragile. Quickly, it extends downwards, 

 through the thickest part of the wall, stopping, as it does in some 

 instances, at least for a time, half way down, and afterwards 

 reaching nearly or quite to the bottom. 



Sandcrack is either penetrant or non-penetrant. 

 It is usually penetrant; by which we mean, the crack extends 

 completely through the thickness of the hoof, and produces 

 lesion of the sensitive parts underneath the horn, giving rise 

 to some little hemorrhage in the first instance, and subsequently 

 to more or less inflammation ; occasionally, even to suppuration ; 

 depending, of course, on the extent and nature and duration of 

 the lesion, as well as on any treatment, or aggravation from 

 non-treatment, it may have received since being occasioned. 

 When the crack does not extend through the substance of the 

 wall — which it sometimes does not at first, though it may do so 

 afterwards — it may be said to be non-'penetrant. And this, 

 when it happens, seems to be referrible to a sort of natural 

 fusion there certainly exists between the solid horn, as it 

 descends from its secreting gland, the coronet — and the horny 

 laminae, which become glued to it in its course downwards. It 

 is in this uniting horny medium that seedy toe commences and 

 progresses. 



