142 DISEASES OF THE HORSE’S FOOT 
remember also that removal of the counter-pressure of the 
frog with the ground tended to contraction of the wall’s 
solar edge when weight was applied. Connect these two 
facts with the experience that this form of contraction more 
often than not occurs in hoofs with sloping heels, and we 
arrive at the following : 
1. The excessive slope of the heels tends to throw a more 
than usual part of the body-weight upon the posterior 
portion of the coronary margin of the wall, with a conse- 
quent expansion of that part of the coronary margin 
implicated. 
2. That the shoeing, in removing the counter-pressure 
of the frog with the ground, is at the same time tending to 
bring about contraction of the lower portions of the wall at 
the heels and quarters. 
3. That this tendency to contraction will at first appear 
in the thinner portion of the area of wall named—namely, 
in that immediately below the bulging coronary margin. 
We thus get the appearance depicted in Fig. 79—a con- 
traction (a, a) of the heels in the horn below the coronary 
margin, with the coronary margin itself bulging above, and 
a hoof of apparently normal width below. 
We say ‘apparently’ with a purpose, for, as actual 
measurements will show, the wall near the solar edge is 
really contracting, for reasons which we have just described 
connected with shoeing. Its ‘appearance’ of normal width 
is accounted for thus: The contraction at a, a is caused by 
the dragging inwards of the coronary cushion brought about 
by the sinking downwards of the plantar cushion, with 
which body it will be remembered the coronary cushion is 
continuous. With the constant dragging in and down of 
the coronary cushion there is given to the horn-secreting 
papilla, studding both the lower third of its outer face and 
its lowermost surface, a distinct ‘cant’ outwards. Below 
the lowermost limit of the coronary cushion, then, by reason 
of the cant outwards of the coronary papille in the 
situations mentioned, the horn of the wall takes a more 
outward direction than normal, a fact which lessens in 
