DISEASES. 611 



III. jSi/mptonis. — The ordinary symptoms of corns are noticed 

 in the abnormal position of the leg at rest, in the lameness and the 

 sensibility of the region. 



When lame with a corn the horse carries the leg forward of 

 the plumb line, and keeps it semi-flexed at the fetlock; he tries 

 to relieve the painful region by resting ; sometimes he manifests 

 his pain by pawing and moving his feet from forward backward, 

 pushing his bed under him. The lameness is not characteristic ; 

 it varies greatly in intensity, from a slight soreness to lameness on 

 three legs. It is generally proportioned to the intensity of the 

 disease. However, there are horses so accustomed to their corns 

 that they do not go lame, while others are very much so for a 

 trifling injury. Sometimes it is intermittent, and diminishes when 

 the suppui'ation has made its way between hair and hoof. The 

 sensibility of the heel — seat of a com — is discovered by an explo- 

 ration with the blacksmith's nippers. Sometimes it is made known 

 by pressure of the fingers, the cases varying, of course, according 

 to the severity of the disease. There is often heat, especially at 

 the coronet, which may be tumified, particularly so when the corn 

 is of a compHcated suppurative character. To obtain an accurate 

 view of the disease the foot should be well pared, and this opera- 

 tion may be greatly facilitated by the application of povdtices for 

 twenty-four or forty-eight hours previously. 



It is only by the objective examination and the pathological 

 anatomy, so to speak, of the corn that the moist or suppiu'ative 

 variety can be distinguished from the dry, and we shall find either 

 a simple ecchymotic spot, or a complete disintegration of tissues. 



rV. Pathological Anatomy. — The lesions vary according to 

 the severity of the disease. In dry corn, we find an infiltration 

 of blood in the horny structure. This is blood which has transu- 

 dated through the laminated or irritated velvety tissue from the 

 injured blood vessels. This blood gives to the hoof various tints, 

 more or less pronounced, not unfrequently yellowish, according to 

 the intensity and duration of the disease. The hoof sometimes 

 loses consistency and becomes brittle ; at others, it is hard and 

 dry, and then resembles healthy hoof minus its coloration. If 

 the ecchymotic spot involves the whole thickness of the horn, 

 from its surface to its depth, it is an evidence of the continued 

 activity of the cause. A deep mark indicates a recent injury; a 

 superficial one is an evidence of an older corn, which disappears, 



