ity the one operating here. Apparently
there is a variance of opinion as to whether the condition is actually
canker or not. We think, however, that the character of the secretion of
the affected membranes, the appearance of the growths, the manner in which
they react to the hot iron, the comparative absence of pain, and other
points of similarity, point to the fact that the two conditions are
actually identical. In other words, the cause is precisely the same, and
the only point of difference is the alteration in the point of attack.

_Symptoms_.--Like canker, the disease is insidious in onset. In precisely
similar manner the horn, and in this case the skin of the coronet, is
underrun. Later there is the partial shedding and fissuring of the
undermined horn and the exuding of the characteristic discharge--in this
case not so watery as that of canker. The caseous material of canker is
also present, as is a disposition to hypertrophy of the exposed sensitive
structures. What horn is left becomes rough and irregularly fissured, and
has been likened by some observers to deeply-wrinkled bark of an old tree.
A peculiar characteristic of this condition is the state of the ergots and
chestnuts. Here the keratogenous membrane participates in the diseased
process, and their horn becomes dry and brittle, and readily splits into
small fibrous bundles very similar to the fibroid growth described in
canker. These excrescences are easily separated from the sensitive
structures beneath, and the exposed surface is seen to be more or less
moist, or even exhibiting a slight oozing of blood.

Again, as in canker, the deeper layers of the sensitive structures appear
to be normal, the horn-secreting layers being the only ones affected.
According to Malcolm, the disease is in its nature equally as inveterate as
canker, but it is easier to treat, on account of its more exposed position.

_Treatment_.--This is exactly that as described for canker.

[Illustration: FIG. 137.--SPECIFIC CORONITIS OF ALL FOUR FEET.]

[Illustration: FIG. 138.--OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS.]

_Recorded Case_.--The subject of this case was a young black cart gelding.
The disease is reported as having begun as thrush, and then extended to the
coronet. When I saw him he had been in a similar condition to that depicted
in Fig. 137 for, it was said, two or three months, the driver of the horse
meanwhile endeavouring to effect a cure by some potent dru