608 OPERATIONS ON THE FOOT. 



corn of the wall, or laminated, that which has its seat in the 

 laminse which unites the wall to the tissues underneath, -viz., in 

 the keraphyllous and podophyllous tissues of the heels and bars, 

 and a corn of the sole, or velvety, that which has its seat in the 

 velvety tissue which unites the sole to the fleshy parts. The 

 laminated corn corresponds exactly to the " natural " of Lafosse 

 and to the " essential" of Bouley. It is due to lacerations ia the 

 movements of expansion of a badly-made foot. The other is due 

 to contusions. "Whatever may be the adopted divisions, we, with 

 Girard, and as admitted in practice, recognize in each category, 

 the dry, the moist and the suppurated corn. 



H. Etiology. — All feet are exposed, but not aU predisposed to 

 corns. They are more frequent in heavy feet, with those where 

 the heels are high or contracted in which there is a motion of re- 

 traction of the hoof which interferes with the displacement back- 

 ward of the third phalanx at the time of rest, and hence the lacera- 

 tions are easy ; besides, there is a continual pressure upon the 

 Uving parts of the posterior region of the nail. Corns are fre- 

 quently observed in excessively long feet where the hoof does not 

 receive the moisture necessary to its elasticity ; it then losses its 

 suppleness and fails to assist the internal motions of the parts 

 contained within. It is seen whenever the hoof is too dry, the 

 posterior diameter of the feet being then diminished. Corns are 

 seen on weak feet, on which the hoof is too thin to resist the 

 dUating effect of the internal structure, and spreads excessively. 

 Wide and flat feet, with low heels, in which the interior surface of 

 the branches of the sole is on a level with the plantar border of the 

 quarters and bars, are very often affected with corns. The pres- 

 sure of the shoe or the roughness of the ground produce these 

 bruises through the sole. Here the conditions are unfavorable 

 to the normal dilatations of the hoof ; the ungeal phalanx, being 

 unsupported by the convexity of the sole, has a tendency to drop 

 down lower, the tissues are easUy lacerated and bruised in its dis- 

 placement at the time the foot rests on the ground. 



The most serious causes of corns arise from the shoeing, which 

 not only sometimes gives to the hoof a shape predisposing to that 

 disease, but also very often is a determining cause itself of these 

 injuries. " As long," says Hartmann, " as horses will have corns, 

 horse-shoeing cannot pass as an art, and their too frequent pres- 

 ence is an evident proof of our imperfect means of protection to 



