LAMENESS IN HORSES. 
543 
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, 
and consequently thin and fragile. Quickly, it extends down- 
wards, through the thickest part of the wall, stopping as it does 
in some instances, at least for a time, half way down, and after- 
wards 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. 
Lameness is the usual Accompaniment of penetrant 
sandcrack ; but not the invariable one. When penetrant, it is 
said to arise from the sensitive laminae getting pinched between 
the sides of the crack. However this may be, inflammation 
following the lesion has certainly its share in causing tenderness 
or pain during action. In general the lameness does not amount 
to 3 much, nor is it of long duration, providing the sandcrack 
receive proper and timely attention ; but if the crack is not 
heeded, action of the foot will much aggravate the malady, and 
end in lameness increased so much as to forbid further use being 
made of the animal. 
Toe Sandcrack. 
Occurring in the hind foot — as this crack almost invariably 
does — occupying a different situation in the hoof, and arising 
altogether from a different cause, toe sandcrack may be regarded 
as almost a distinct affection. 
The SUBJECT of IT is not the light horse, but the heavy 
one. The cart and waggon horse, the dray horse, the latter 
especially, and in particular, I believe, in paved towns such 
