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the fibres become separated, and a crack or split is formed, as the result of 
the impaired secretory action of the injured part. These cracks nearly 
always come on gradually. Indeed, the writers have rarely known a crack 
to be formed suddenly. Those fissures recorded as having arisen suddenly, 
are in reality to be put down to constitutional disease of old standing. The 
brittle condition of the crust, altering the character of the horn secreted, it 
will thus be seen, is to be attributed to an unhealthy action of the membrane 
secreting the horny fibres, and of the substance binding them together. 
In some animals, the horn is more brittle and weak than it should be, 
and is more liable to crack on any unusual strain. Sucha condition of horn, 
more commonly met with in animals bred in damp, low-lying districts, 
though not unfrequently inherited, is no doubt in many instances traceable 
to badly devised methods of shoeing. When the sole and frog are made 
unduly thin by paring, and seated shoes are used, the weight of the animal 
is thrown on the crust of the wall only, instead of being more uniformly 
distributed ; and, as a consequence of this, the membrane secreting the horn 
is liable to suffer, when the crust it forms is subjected to additional strain, 
Naturally, this will be especially liable to occur when the badly-shod feet are 
subjected to continued concussion, by fast riding or driving on hard ground. 
The fissures are more likely to occur at the inner quarters of the fore feet, 
and at the toes of the hind ones; for these are the parts more especially 
subjected to strain. 
As we mentioned, the cracks, at first insignificant, lengthen and deepen, 
and thus they gradually spread through the horn to the sensitive structures, 
which become inflamed and bulge through the apertures of the wound. 
Lameness now becomes a marked feature, and the affected part becomes 
very painful. Lameness appears before the fissure is evident from the 
outside, when the crack commences beneath the outer portion of the crust, 
and then spreads outwards; and it may be added that it is in such cases as 
these, that cracks are said to be suddenly made. In reality they have been 
forming for some time past. 
Lameness is more marked when the crack is at the toe, than when in 
the quarter of the foot, and when involving the toe of the hind foot, it is still 
more aggravated. As the animal raises its foot, the walls of the fissure widen, 
and as it places its foot down again, they become approximated, thus pinching 
tightly the protruding, inflamed tissue, and causing great agony. Sand and 
mud find their way into the wound, and increase the inflammation and 
irritation, and at the same time tend to increase the extent of the fissure. 
The treatment of sandcrack varies according to the nature of the case. 
If there be no suppuration, it is our custom to make a horizontal incision 
with a firing-iron, about one eighth of an inch deep, above the upper 
extremity of the crack. The crack itself we then fill up with gutta percha, 
In simple cases, a cure is generally easily effected by these means. 
In those cases where there is lameness and inflammation, it will be 
necessary to remove the shoes and administer a dose of aloes, say four or 
five drachms, and allow total rest for several days, on a diet of warm water 
