HORSESHOEING. 175 



flammation of the pododerm. In the latter case a veterinariau 

 should be called. Lameness is usually pronounced. 



3. Chronic Corns. — In this case there is vivid discoloration 

 of horn in all possible hues. The horn is either soft, moist, 

 and lardy, or crumbling, cracked, and at times bloody. The 

 inner surface of the horn capsule has lost its normal character, 

 and is covered with horny swellings or nodules (Fig. 192, a). 

 Sometimes the wing of the os pedis on tliat side has become 

 morbidly enlarged and loosened. A short, cautious gait alter- 

 nates with well-marked lameness; the latter appears whenever 

 the shoe presses too firmly on 

 the corn, or when the hoof be- 

 comes too dry. 



The causes, aside from the 

 form and quality of the hoofs 

 and the position of the limbs, 

 lie in injudicious dressing of 

 the hoof and in faulty shoes. 

 Too much trimming of wide and 

 flat hoofs, excessive weakening ^^^^^ aspect of a quarter of a hoof, 



' 1 T_ J showing changes in the horn-leaves due to 



of the quarters, sole, bars, and chronic corns: a, homy tumor resulting 

 j> J? n xi 1 c 1 •! ii from the disease. 



irog 01 all other hoois, while the 



toe is usually left too long, are the usual causes. Shortening one 

 quarter too much in relation to the other, so that the foot is un- 

 balanced and the lower side overloaded, is a frequent cause. 

 Hollowing the sole and bars excessively and unnecessary thinning 

 of the branches of the sole in the search for corns are also causes. 

 Among faulty shoes we may mention those not level on the 

 hoof-surface, trough-shaped, too short, in the branches, shoes 

 which do not completely cover the bearing-surface of the hoof, 

 or whose bearing-surface at the ends of the branches is directed 

 do-^Tiward and inward so that the quarters are squeezed to- 

 gether w^hen the weight is put on the foot. Insufficient con- 

 caving of the shoe is often an exciting cause of corns in flat feet 

 and in those with dropped soles. A well-formed shoe which 



