CONFORMATION OF HORSES 5 FEET. 551 
worst shoeing that can possibly be would not produce con¬ 
traction. In the 2d Hanoverian cavalry not one horse’s foot 
was contracted; all were circular. The horses had high 
action, and this had been increased by habit and art, and the 
consequence was, it produced so much more pressure in the 
horny frog, which expands the cartilages and heels.” Here 
the change is distinctly stated to arise from difference in the 
conformation of horses, habit, and art, and to be the result of 
long growth. 
“ Why should Hanoverian horses be exempt from con¬ 
traction, as they are equally exposed to nails and other 
supposed causes ? Because they put down the feet nearly in 
the place where they took them up. This forces down the 
sole oftener, for the shorter the distance before the body the 
feet are put down, the oftener weight is thrown upon the fore 
extremities, and consequently upon the frog and sole; here 
the power to contract is only equal to two, and the power to 
expand is equal to three, so he has no contraction: but if you 
have a horse of light weight before, and he goes near the 
ground, the influence of weight is only equal to two, and the 
occasional causes are equal to three, and he has contraction. 
If you even give the frog pressure and nail round the toe, 
you will have contraction, because the weight is not sufficient 
to counteract the occasional causes. I do not agree with 
Mr. B. Clark in opinion, that nails alone will do it; but 
where horses have light fore quarters and low action, and 
are exposed to slight exciting causes, lameness will occur 
from contraction. For other horses although exposed to 
all the causes, yet are not subject to lameness from con¬ 
traction: such are dray-horses in London ; so far from being 
equally subject to it, I have to see, what I never saw yet, lame¬ 
ness from contraction in dray-horses. Although the shoe is 
turned up at the heels, and the frog cut, the pressure and 
weight on the sole are such, that the frog still touches convex 
bodies, the foot being filled up with dirt: contraction does 
not occur in defiance of all these causes. No animal can 
have a disease without two circumstances,—the susceptibility 
of having disease, and the application of a cause. 
“The predisposing causes are so great in light horses, that 
one existing cause is sufficient to produce lameness; so you 
may apply the causes of contraction two-fold to a dray-horse, 
yet, from want of susceptibility, he will not have lameness 
from contraction.” What can be plainer? The late Professor 
never alluded to the subject of contraction without insisting 
on reference to conformation. Predisposition he considered 
sufficient explanation of its cause or non-existence. True he 
