336 DISEASES OF THE HORSE’S FOOT 
the hoof, breaks out at the coronet. Again, too, as with 
the simpler form of quittor, and as with coronitis, we may 
always regard as a predisposing cause the action of exces- 
sive cold in promoting septic infection of the wound when 
occurring at the coronet. 
Symptoms and Diagnosis—Where the fistulous wound 
has had its starting-point in an injury to the coronet diag- 
nosis is, of course, easy. The history of the case explains 
it. Nothing in this instance remains but to probe the 
opening, and ascertain its direction, depth, and extent. 
An animal with the wound thus open at the coronet, and 
freely discharging its contents, may, if no serious com- 
plications exist, walk tolerably sound. It is only when put 
to the trot that symptoms of lameness are apparent. 
It may so happen, however, that we first see the case 
when the symptoms are wholly those arising from a painful 
suppuration within the horny box. This occurs when the 
original injury has taken place at a more dependent posi- 
tion than the coronet. Either from violent blows upon the 
hoof, puncture from below, from corn or from sand-crack, 
or any other causes we have enumerated, suppuration is 
occurring deeply within the hoof, with as yet no opening 
upon the coronet. 
Even when an opening has already occurred on the 
coronet, the same condition of sub-horny suppuration may 
be met with in cases when the opening of the fistula has by 
some means or other become occluded. Granulation tissue, 
for instance, may have temporarily closed the mouth of 
the fistula. The pus, instead of continuing its discharge 
thereat, is made to burrow in other directions. 
In either of these cases pain is excessive, the animal 
walks on three legs, the foot is painful to percussion, and 
grave constitutional disturbance is noticeable. The pre- 
sence of pus is immediately suspected, and, in the absence 
of any indication of an opening having existed at the 
coronet, searched for at the sole. It may or may not be 
found. If found it is given exit, and the case ends as one 
of ordinary pricked foot, of suppurating corn, or some other 
