ANATOMY AND PHYSIOLOGY OF THE HORSE^S FOOT. 7 
those of another scarcely at all, yet it will generally be found 
that the first has a well-formed hoof, justly proportioned in 
size to the volume of the body, and inclined in a normal 
direction around its superficies, with the horn of the wall 
thick, polished, even on its surface, and of a dark colour, the 
heels w r ell developed, a firm prominent frog, the bars sloping 
in a regular manner, and the lacunae deep and sharply 
defined; while in the second will be usually noted a hoof 
composed of thin, light-coloured horn, and too large for body 
and limb, the sole flat, heels low and weak, frog big, spongy 
and prominent, the wall uneven and ridged, destitute of 
polish, and inclined in a more or less horizontal direction. It 
has also been recognised that the abundance and rapidity of 
the hoof-growth is in relation to the thickness of the derm, 
the quantity of hair covering it, and the amount of colouring 
pigment distributed in its texture. So it is that, in general, 
horses with close-set, thick, tufty hair have the coronet 
salient and wide—an indication that the coronary cushion is 
amply developed—and the wall of the hoof is strong, and 
grows quickly; but those which have a thin fine skin, 
scantily covered by silky hair, show only a feebly prominent 
coronet and a thin wall. It is not uncommon to see light 
chestnut and white horses with thin-walled hoofs, but we 
usually expect to find them thick and strong in bay and 
other dark-coloured animals. Of course, exceptions will be 
met with, but as a rule it will be found that the above obser- 
votions are well supported by everyday experience, and that 
there is likewise a correlation between the hairs themselves 
and the horn-fibres—the coarser the hair the thicker the 
fibre. We have already explained why, in all probability, 
black hoofs should be stronger and more durable than white 
ones; possibly the same cause—the presence of pigment 
granules—may also serve to explain why the skin in proximity 
to the hoof should be less susceptible to disease when dark 
than wdien light coloured. 
Several other influences, besides those enumerated, are at 
work in modifying, accelerating, or retarding the growth of 
the hoof, and some of these have been succinctly indicated 
by M. Bouley, while others would appear to have been over¬ 
looked by him. The most general, perhaps, is that arising 
from the quantity and quality of the food the animal receives. 
When horses have experienced privations for some consider¬ 
able period, and subsequently receive a substantial ration, in 
a few weeks afterwards there may be observed a salient ring 
formed at the origin of the wall, a circumstance that suffi¬ 
ciently testifies to the increased activity of the horn-produc- 
