U. S. VETERINARY MEDICAL ASSOCIATION. . 455 
From the evidence of these investigators we accept as proven that the quarters 
Fig. 5. 
and heels of the normal foot of the horse dilate under pressure, that is, when the 
animal is standing, and more so when it places increased weight on the foot 
in movement. I, however, agree with Lechner as to the rotation of the heels in 
some feet, and find that in contracted feet, this rotation is an important factor in 
increasing the disease. Lechner possibly experimented on slightly contracted 
high-heeled horses. We can conclude that anything which interferes with the 
dilatability of the hoof produces an abnormal condition, and must interfere with 
the vascular structures and nerves contained inside, producing atrophy of the 
tissues from diminished nutrition, and pain from pressure on the nerves. When 
any interference with the dilatation of the foot is permanent, it produces a 
diminution in the size of the organ. This reduction in size may be general, 
including the whole foot, or local, including only one or both heels; this condi¬ 
tion is known as contraction of the foot, or contracted heels. 
Contraction of the foot or contracted heels is evidenced by a diminution in the 
size of the horny covering of the foot or the hoof, with or without lameness. 
Contraction may be total or partial; in the first case, there is seen to be a gen¬ 
eral diminution of size, usually accompanied by an increased concavity of the 
sole, an anthropy at the frog and an approach of the walls of the quarters and 
heels toward a more vertical position ; the surface of the wall is frequently ex¬ 
cessively dry, and predisposed to superficial ridges or cracks ; in partial contrac¬ 
tion the alteration is usually confined to the heels. Contraction may be symmet¬ 
rical or unilateral ; in the former case, both sides being equally affected, there 
is usually total diminution in the size of the foot, while in the latter the alteration 
in shape is generally local and more easily remedied. The older veterinarians 
used the term true and false to designate a general or limited alteration in shape. 
True or total contraction, approaching in form the mule foot, narrowed from 
side to side, with vertical walls, a natural condition in the ass and mule, in the 
horse may be an acquired condition, in w T hich case it is usually incurable, or it 
may be a congenital condition, in which the contents have been formed, adapted 
to the altered circumstances; this can hardly be considered as morbid, but while 
it may not be a diseased foot in itself, it predisposes to all the other troubles 
which are found, the results of contraction from any other cause. 
ETIOLOGY. 
The study of the etiology of contraction of the feet is, in some cases, an 
easy matter, but in others it is complicated by various troubles, so that it be¬ 
comes difficult to determine the cause, or to distinguish it from the effect. In 
