DISEASES FEOM FAULTY CONFORMATION 191 



of the animal to place the foot squarely on the ground. 

 One is then led to manipulate the foot. The hoof is hot to 

 the touch. Percussion causes the animal to flinch, and to 

 flinch particularly when that portion of the wall adjoining 

 the corn is struck. Finally, exploration with the knife 

 reveals tlie serious extent to which the injury has developed. 

 In a neglected case of this description it is even possible to 

 detect the presence of pus by the amount of swelling and 

 fluctuating condition of the coronet. The suppurative pro- 

 cess has advanced in the direction of least resistance, and 

 is on the point of breaking through the tissues immedi- 

 ately above the horn. 



Lameness due to corn is oftentimes intermittent. With 

 a simple corn, dry or moist, this intermission is largely 

 dependent on the degree of dryness of the hoof or the road, 

 and also on the character of the road surface. With a 

 neglected, suppurating corn, on the other hand, variation 

 in the degree of lameness, in addition to depending on 

 circumstances such as these, is dependent to a larger 

 extent upon the changes occurring with the suppuration. 

 In this case the time of greatest lameness is immediately 

 before the pus gains outlet. Immediately after its exit at 

 the coronet the animal will go almost sound. Soundness 

 continues so long as the opening at the coronet remains 

 clear. The tendency, however, is for the opening thus 

 made to quickly close again. Pus again accumulates, 

 lameness arises as before, and disappears again with the 

 second discharge of the contents of the sinus now formed. 



Pathological Anatomy. — When dealing with their classifi- 

 cation we gave in outline the main pathological changes to 

 be met with in corns. It now only remains to give the 

 same matter in slightly greater detail. 



In dry corn the changes we meet with are those accom- 

 panying blood extravasation. From excessive compression 

 of the parts, or from the effects of direct injury, a portion 

 of the sensitive sole has become lacerated. The escaping 

 blood stains the surrounding soft tissues after the manner 

 of blood extravasation elsewhere. If the escape of blood is 



