THE HORSE’S FOOT. 
383 
Superficial cracks are not always attended with lameness; it 
is, on the contrary, often very severe when they are deep. The 
pain is generally in proportion to the depth and the degree of 
opening of the fissure, and also especially to any complications 
which may exist in the tissues beneath. The lameness seems at 
times to be due to the injury of the deep, soft tissues, and to be 
caused by the motions of the horny box when they become 
pinched, irritated and bruised. The affected animals are especially 
lame when the foot rests on the ground, and the lameness is 
greater on a hard than on a soft surface. If an animal suffering 
with toe-cracks is moved on descending ground, the lameness is 
greater than on ascending a hill, the weight of the toe in the 
latter case producing less opening of the edges of the solution of 
continuity. In quarter-cracks, the severity of the lameness is 
always in proportion to the rapidity of the gait; many horses 
which are but slightly lame on a jog, become much more so when 
the gait is accelerated, the dilatation of the heels being greater, 
and the separation of the borders of the crack increasing in propor¬ 
tion to the speed. When there is lameness, there is naturally an 
increase of heat and sensibility of the foot, especially at the seat 
of the crack. This is often discovered by feeling with the hand ; 
old cracks are generally accompanied by a thickening existing at a 
corresponding point of the hoof. A deep, but recent crack, is 
apt to be accompanied with hemorrhage ; there is blood which 
sometimes exudes between the borders of the crack, and flows in 
abundance when the movement is rapid; an old crack, in similar 
circumstances, may show pus, sometimes mixed with blood. A 
misstep, a sprain, may give rise to hemorrhage in cracks which 
are ordinarily dry. In toe-crack, the solution generally involves 
the thickness of the wall, through which it runs in a line almost 
parrallel to the median plane of the body, while in quarter-crack 
it is often oblique and irregular, not exactly following the direc¬ 
tion of the fibres, but following the thickness of the wall ob¬ 
liquely, in such a way that the external solution of continuity is 
more posterior than the internal. If the crack is rather old, and 
the foot where it exists is contracted, it is generally incurvated, 
one border covering the other, and sometimes they seem to be 
