ANATOMY OF THE HORSE. 
319 
The Horny Sole is a production from the villi of the sen¬ 
sitive sole ; after the same process as that by which the horny 
frog is secreted from the villi of the sensitive frog. 
In a state of health of the foot, the secretion of horn is un¬ 
ceasingly going on. Disease or injury of the glandular parts may 
diminish, or altogether suspend the process; disease, under certain 
other forms, is said also to have the effect of increasing it; but 
whether we have any artificial means of effecting this, seems 
questionable. The wall grows from above dowmvards. If a 
mark is made in any part of the wall, it will remain until it 
grows out, or becomes cut off below, at the inferior border; 
and by observations made on the gradual descent and disappear¬ 
ance of these marks, calculations may be formed of the period of 
time required for the renewal or restoration of the wall. 
Properties of Horn. 
Horn is a tough, flexible, elastic substance, consisting of tubu¬ 
lar fibres, more or less intimately connected together, taking the 
direction from the surface of the body on which it grows. Its 
property of toughness or resistance much depends on its con¬ 
dition in regard to moisture; for if it is exposed to a degree 
of heat sufficient to abstract much of its natural juice or imbibed 
moisture, it loses its flexibility and toughness,and becomes brittle. 
On the other hand, saturated with moisture, it is converted into 
a soft and highly flexible substance, but at the same time becomes 
weak and unresisting. This known effect aids us to account for 
the flat-footedness of horses reared in low, fenny, or marshy situ¬ 
ations ; the hoof being constantly in a state of saturation with 
moisture, the wall and sole yield to the superincumbent burthen 
of the body, and the latter grows flat (instead of remaining con¬ 
cave or arched), and even in some instances bulges. If oily or 
unctuous applications have any effect in softening the hoof, they 
appear to do so by filling the crevices and interstices be¬ 
tween the fibres on the surface, and in this manner checking or 
suppressing evaporation. Horn takes a high and beautiful polish. 
Although much inferior in transparency to tortoise-shell, it may be 
worked up to bear so near a resemblance to it as to be often, in 
manufactures, substituted for it, as in combs, See. The hoof admits 
of an elegant polish ; and in that altered and improved state has 
been manufactured into articles no less useful than valuable and 
ornamental : even the hoofs of the living animal may, by being 
kept clean, and when dry rubbed with linseed oil, be numbered 
among the beauties or ornaments Nature has bestowed upon 
quadrupeds. 
