ly, for it follows as a matter of course that these
tissues, themselves in a diseased condition, must naturally produce a horn
of a greatly altered and inferior quality.

When following the _subacute_ form of laminitis, the changes characterizing
pumiced-foot are slow in making their appearance. The animal at first goes
short, and the lameness thus indicated gradually becomes more severe, until
the animal is no longer able to work. The feet become hot and dry, the
hoof loses its circular form, and the growth of horn at the heels becomes
excessive. At this stage the appearance of bulging at the sole begins to
make itself seen. Later, the outer surface of the wall becomes 'ringed' or
'ribbed,' the rings being somewhat closely approximated in the region of
the toe, and the distance between them gradually widening towards the
heels. The wall too, especially in the region of the toe, instead of
running in a straight line from the coronary margin to the shoe, becomes
concave. It is this change, together with the appearance of the rings, that
indicates the loosening of the attachment of the os pedis to the wall, and
its afterwards backward and downward direction (see Fig. 124).

[Illustration: FIG. 81.--HOOF WITH THE RIBS OR RINGS CAUSED BY CHRONIC
LAMINITIS.]

As a sequel of _acute_ laminitis, these changes make their appearance with
more or less suddenness, and are generally complicated in that they owe
their occurrence to the formation of pus within the horny box.

_Treatment_.--Pumiced-foot is always a serious condition. The animal is
useless for work upon hard roads or town pavings, and is of only limited
utility for slow work upon soft lands. The more serious form, that
following acute laminitis, and complicated by the presence of pus, we may
regard as beyond hope of treatment.

With the more simple form of the condition, we may do much to render
greater the animal's usefulness. The same principles as were applied to the
shoeing of flat feet will have to be observed here. Trimming or paring
of any kind, save 'straightening up' of the wall, must be severely
discountenanced. A broad-webbed shoe, one that will give a certain amount
of cover to the sole, is indicated. As in the treatment of flat-foot,
however, direct pressure upon the sole must be avoided, and the shoe
'seated.' The 'seating,' however, should not commence from the absolute
outer margin of the shoe's upper surface. A _flat_ bearing should be given
to the