540 CORNS. 



usually found upon the inside of the foot, when we learn 

 that tlie inner wall and heel are weaker, and also as they 

 bear a greater portion of superincumbent weight than the 

 outer parts endure. The coffin bone, not reaching to the 

 heels, is the reason why these structures are the seats of 

 corn, for the coffin bone is the active agent in its production. 

 This bone is moved upwards and downwards at either end, 

 as the weight rests upon one extremity or the other of its 

 articular surface. It is the wings of the coffin bone which 

 causes corns. The descent of its wings squeezes the 

 vascular sensitive sole between it and the shoe in open feet, 

 the shoe in this case being the passive agent ; but in the con- 

 tracted foot, the high, thick, hard and unyielding sole 

 becomes the passive agent, and between that and the wing of 

 the coffin bone the sensitive sole is bruised. These corns 

 may occur in the stable, in the field, or on the road, in short, 

 on any spot where the slightest motion is possible. Too 

 little horn also subjects the feet to corns, because a slight 

 pressure will indent weak feet, which are notoriously sub- 

 ject to them. The best shoe, suffered to remain on a foot 

 too long, will produce a corn or corns. Neglecting to 

 prepare the foot for the shoe is also a fruitful source of 

 corns ; for in preparing a foot, this angular portion should be 

 so pared as to remove it from contact with the iron, without 

 weakening the horny covering of the sensible sole. Another 

 common cause is the neglect of removing or renewing the 

 shoes at proper intervals : when a shoe has been long worn, 

 the growth of the hoof carries it forwards, by which the 

 parts originally opposed to the heels are carried beyond 

 them, and now press on the sole, often becoming indented 

 within the line of the crust, and producing a most injurious 

 pressure. Sometimes, also, either from the original form 

 of the shoes, or by long wear, they become loose or 

 ' springy ' at the heels, as smiths call it ; in which cases 

 gravel is apt to make its way between the shoe and foot, 

 which, by the pressure of the heels during action, is indented 

 into the substance of the horn ; other gravel becomes re- 

 ceived in the same manner, which presses still onward, 

 until at last it harms the sensitive part of the sole : extrava- 

 sation of pure blood ensues, and forms a corn, or it may 

 proceed to suppuration. 



