m stones and rough roads and from the pressure
of the shoe.

The low heels, too, favour a more than due proportion of the body-weight
being thrown on to the posterior parts of the foot. Two evils, both
inclining to the production of corn, result from this. In the first
place, the sensitive structures of the posterior portions of the foot are
subjected to undue pressure from above; secondly, the posterior half of
the foot, by reason of the extra weight thrown upon it, is exposed also to
greater effects of concussion than normally it should meet. Added to this
we find that the abnormally flat condition of the sole has resulted in
a great loss of resiliency. With undue pressure above, and a loss of
resiliency and added effects of concussion below, the sensitive structures
included between the opposing pedal-bone and the horny sole are bound
to suffer more or less bruising each time the foot comes to the ground,
especially if the animal is moved at a rapid pace.

Writing here of the effects of pressure and concussion affords a fitting
occasion to mention the fact that corns occurring in feet affected with
side-bones are always worse than in feet with normal elastic cartilages.
The explanation of this is simple, for there can be no doubt that the
loss of resiliency in the diseased cartilage is only another aid to undue
pressure and concussion. The sensitive structures are pinched between
unyielding bone above and practically unyielding horn below.

Feet with high and contracted heels are also predisposed to corn. The
contraction in this case interferes with the downward movements of the os
pedis during progression, while in a state of rest there is a more or
less constant pressure upon the sensitive structures, due to the correct
downward displacement of the pedal-bone being opposed by the amount of
contraction present. In the contracted foot, too, the nutrition of the
vessels supplying the secretory apparatus of the horn is largely interfered
with. The horn loses its natural elasticity, fails to respond to the normal
movements of the parts within, and aids in the compression and laceration
of the sensitive structures.

Weak feet, with horn too thin to withstand the expansive movements
continually going on--in other words, feet with weak, spreading heels--are
also prone to suffer from corns. In this case the flatness induced by the
spreading, and the insufficient protection afforded by the thin horn,
both combine to lay t