378 
EXPERIMENTS ON THE 
the foot touched the heels of the shoe; at the same time, whilst the 
horse’s foot was on the ground, and the position of the wax being 
then examined, I could see there was a space of a quarter of an inch 
between the upper part of the wax opposite the coronet and the iron, 
and this space regularly decreased until it ended in a point at the 
lower surface, thus shewing the angle of declination. On lifting 
the foot the wax was immediately close to the iron. On making 
the horse walk about (in this and the preceding case, and, indeed, in 
every other experiment of a like character) I found that there was 
a deep indentation in the wax at the upper part from the bulging 
out of the coronet. 
Observation .—It is, at all events, very plain from this experi¬ 
ment, as well as from every day’s experience, that the foot will 
yield backwards if the heels are sprung. 
23 d Experiment. 
I performed several experiments, by first placing a shoe on a 
horse’s foot evenly to the heels, and having well oiled the sole, fill¬ 
ing it at various parts with prepared wax, and then making the 
horse walk about; but I could not perceive that any separation 
whatever appeared to take place between the sole and the wax 
at any part of the foot. I then applied a shoe sprung at the heels, 
and, having filled it with wax as before, I found that at the quar¬ 
ters of the foot the wax became separated, with an interstice be¬ 
tween it and the sole, from the yielding of the whole hoof back¬ 
wards. 
Observations .—The sensible sole is much thicker and less vascu¬ 
lar at the heels of the coffin-bone, which is also tipped with carti¬ 
lage, apparently to allow of this backward action of the foot: and 
how prone are the heels of horses to bruises producing corns from 
this cause! I am of opinion that, under common circumstances of 
shoeing, there is scarcely any descent of the horny sole; and I be¬ 
lieve the sole is frequently much benefited by a certain degree of 
pressure, or rather support, at its anterior part; that a shoe with a 
flat upper surface, in moderately good feet, is desirable, and that 
the lamina are relieved by the sole taking a certain degree of pres¬ 
sure. I may here remark, that it frequently happens, with heavy 
horses having flat feet and shelly crusts, the horn, from many causes, 
will at last not hold a nail, and that the crust is broken off: under 
these circumstances the horse is, perhaps, turned loose into an ordi¬ 
narily paved stable, until the wall of the crust grows down. But 
do we not find, by this treatment, we must of necessity force the 
sole to bear a very great amount of pressure, and that it is attended 
