ANATOMY AND PHYSIOLOGY OF THE HORSE^S FOOT. 
5 
These results are patent and visible everywhere. We can 
even trace the changes which take place from month to 
month, and observe the perfectly formed hoof, with its thick, 
beautifully polished wall, quite smooth or faintly marked by 
transverse parallel undulations equally wide from toeio heel, 
and its strong flaky sole and frog, gradually, or even rapidly, 
converted into a small, contracted, unsightly mass, with a thin, 
dry, brittle wall destitute of polish, split and chipped around 
its lower margin, and perhaps covered with powdery scales 
towards the coronet; the sole thin as paper, as hard as flint, 
and quite hot and sensitive; and the frog, diseased and 
wasted, almost lost to sight between the shrivelled-together 
heels. 
The effects of unequal pressure on the coronary cushion also 
demonstrate the imperative necessity for maintaining the 
foot perfectly aplomb in shoeing—reducing both sides of the 
wall to the same length—and attaching a shoe equally thick 
in both its branches. Upon the observance of this measure 
depends, to a great extent, the preservation or destruction of 
the natural shape of the hoof; its neglect tends incessantly 
to prevent the secretion of horn, and in time brings about the 
displacement and atrophy of the coronary cushion; for owing 
to one side of the foot being allowed to remain higher than the 
other, the cushion has to sustain undue compression in the 
portion corresponding to the lowest side; it is displaced, dis¬ 
torted, and becomes emaciated, is slow to produce born, and 
the wall secreted by it is thin, incurvated, and generally 
faulty in its texture ; at the same time the side bearing least 
weight supplies a superabundance of horn, expands, and 
thus increases the deformity of the organ. 
From this, observes M. Goyau, it will be seen that the 
influence of the volume and direction of the coronary cushion 
on the form of the hoof is of capital importance. The hoof 
is normal when this cushion is voluminous, regular, and 
rectilinear; it is defective, on the contrary, when the cushion 
is emaciated, irregular, and incurvated. The deformation of 
the cushion precedes and governs the deformities of the 
hoof. For it would appear to be well established that the 
thickness of the wall depends upon the projection of this 
cushion beyond the plane of the vascular laminae. Con¬ 
sequently it should be largest around the front of the foot and 
at the heels than elsewhere. Thus, the wall is thinnest when 
it is vertical, thicker when it has its natural inclination, and 
attains its greatest thickness when it is developed perpen¬ 
dicularly to the custion. The horn is secreted parallel to 
the direction of the laminae, and, therefore, this secretion is 
