382 
A. ZUNDEL. 
are superficial or deep, according to the thickness of the wall in¬ 
volved. The}’ - are complete when they extend from the coronary 
band down to the plantar border ; incomplete when more limited. 
In this last case, those which do not extend up to the skin are 
the more disposed to recovery, and will grow down with the 
growth of the wall, while those which extend to the coronary 
band are more serious, being continually aggravated as the 
growth of the hoof progresses. According to the date of their 
formation, they are called recent and old. Simple cracks are 
those which only involve the wall; they are complicated where 
there is a more or less serious lesion of the tissues beneath, such 
as inflammation of the laminse, hemorrhage, or caries of the bone. 
A serious complication is that of keraphylocele. 
II. Symptoms .—Often the solution of continuity is the only 
one observed, and it is the special characteristic of the disease. 
But the fissure may be masked, either accidentally or by design. 
It may be concealed by the hairs ; by the mud; or covered by 
hoof-ointment, tar, wax, or even a putty of gutta-percha. Con 
cealed internal cracks have sometimes been discovered, such as 
fissures involving the internal face of the wall, which, conse¬ 
quently, were not noticed from the outside, or showing but a slight 
depression on the surface of the wall. These cracks are only 
discoverable when the foot has been well pared down. As 
slight as the solution of continuity may be, it participates in 
the motion of dilatation of the foot, and is better detected when 
the foot is raised than when it rests on the ground. This is the 
case when it is a toe-crack, but on the contrary, the quarter-crack 
is more open when the animal rests its weight on the leg ; in 
which case, the separation of the borders of the cracks may be 
from two to four millimetres, and may expose the bottom of the 
fissure. Ordinarily, cracks appear first at the coronet, and there 
is then but a slight opening, but as they become older, and grow 
down, they have a tendency to become deeper and more complete. 
When of old standing, their borders are rough and scaly, having 
between them an ulcerated tissue and sometimes a fungus growth, 
from which escapes a sanious fluid. In other cases, as of quarter- 
crack, the edges have a tendency to cover each other. 
