cted to the parts in question, the
sand-crack goes undiscovered, until of greater dimensions.

Further, the fissure may be hidden, either accidentally or of set purpose.
It may be covered by the hair, filled in and covered over with mud, or
intentionally concealed by being 'stopped' with an artificial horn, with
wax, or with gutta-percha, or, as is more common, be hidden by the lavish
application of a greasy hoof-dressing.

In this latter connection it is well to warn the veterinary surgeon,
especially the beginner, when examining for soundness, to be keenly
critical before passing an animal who is presented with feet smothered with
tar and grease or any other dressing. More especially should this warning
be heeded when examining any of the heavier breeds of animal with an
abundance of hair about the coronet.

Referring again to the search for the crack, it is well to know that with
toe-crack the fissure is the more readily seen when the foot is lifted from
the ground. With quarter-crack, on the other hand, the fissure is wider,
and consequently the easier detected with the foot bearing weight.

Although commencing in the insidious manner we have described, the lesion
is not thus often seen by the veterinary surgeon. Usually, the animal with
sand-crack is brought for his inspection when lameness has arisen from it.
In this case the cause for the lameness will reveal itself in the crack,
which is now too large to escape observation. The coronet is hot and tender
to the touch, and a sensation of warmth is sometimes conveyed to the hand
by the horn of the surrounding parts of the wall. It is hardly necessary to
say that, with accompanying conditions such as these, the sand-crack is a
_deep_ one.

Where the lameness is but slight, we may attribute it almost solely to the
pain occasioned by the mere wounding of the keratogenous membrane, and to
no very extensive inflammatory changes therein. By some authorities this
is said to be due to the pinching of the sensitive structures between
the edges of the fissure in the horny covering. In our opinion, however,
pinching does not occur unless inflammatory exudation into the sensitive
structures adjoining the crack has led to sufficient swelling to cause them
to protrude. In other words, the movements of the horny box, communicating
themselves to the structures beneath, and so occasioning movement in the
wounded keratogenous membrane, are quite sufficient to give rise to the
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