_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.]