192 
ON THE CONFORMATION OF HORSES. 
the toe, and both heels are alike in level. In the third, the level 
of the sensible parts is the reverse of the first variety. 
A reference to the lowest level of the sensible parts of the foot 
in horses of peculiar conformation will serve to explain why we 
occasionally find a horse with very high heels ; and the farrier 
will tell you that he cannot “ lower these heels,” because in paring 
he comes too near the sensible parts at the quarters. Hence it is 
that the knowledge of the lowest level of the sensible parts in 
horses’ feet is of the greatest importance. The smith can only 
ascertain this by the application of his thumbs, and can do this 
only when the sole is thin and yielding; a state which I shall 
hereafter shew is an unnatural and injurious condition of it, and 
in which, from diminished substance of horn, there is also dimi- 
nished power in the hoof to perform its functions, whether they be 
those of defending the soft parts within, or acting as springs to the 
animal while supporting the weight of the body. 
When there is little or no shelving at the Base of 
THE Foot it is circular in shape ; but when shelving exists, 
there is a divergence from the circle, and it measures then in the 
proportion of 12 across the foot to 13 from toe to heel. The im- 
pression of the sensible foot upon its horny covering inside, cor- 
responding to the tread of the foot, is circular, and, measured by 
the same rule, is 10 by 10 (as any one will ascertain by dissec- 
tion). But the base of the sensible foot altogether is as 10 by 12; 
because 2 T 1 oths of it incline upwards and backwards to the bulbs of 
the heels, behind the inflexions of the bars; therefore 2 T ^ths of the 
sensible foot are posterior to the corn places; and since the base of 
the sensible foot is covered by a continuous highly vascular mem- 
brane, up to the bulbs of the heels, how can paring out of the corn 
places give any immediate descent I Can the 2 T 1 2ths of the sensible 
foot which are behind the inflexions be wedged into the angle of 
the heels'? And I presume, as it is covered by a continuous highly 
vascular membrane, that a part of it cannot do so without the 
whole, else laceration of the membrane must ensue. 
I therefore think it is evident, that the theory of the corn- 
places being pared out to allow of the descent of the heels of the 
coffin-bone will hardly bear investigation, and that we must look 
to something else as a cause for the bruising of the sensible parts 
which occasionally takes place at the heels. I am of opinion, that 
it will be found to be the restrained downward and backward mo- 
tion of the foot, in the line of direction of the force or weight im- 
pressed on it, in horses of certain conformation where this action is 
imperatively required, and we thus usually find corns to take place 
at the inner heel. 
I think it is very plain that no immediate descent of the heels 
