18 RATIONAL HOBSE-SHOEING. 



calks a wide toe-calk, the usual heel-calks, 

 and two calks, one on each side, midway 

 between the toe and heel thus putting the 

 bearing equally upon all the parts of the 

 foot. 



This calking has a double object. In the 

 common system of shoeing, to avoid slip- 

 ping in winter upon the ice, and in the cities 

 upon the wet, slimy surface of pavement, or 

 to assist draft, it is customary to weld a 

 calk upon the toe of a shoe, and to turn up 

 the heels to correspond. In this motion the 

 horse is placed upon a tripod, his weight be- 

 ing entirely upon three points of his foot, and 

 those not the parts intended to bear the shock 

 of travel or to sustain his weight. The posi- 

 tion of the frog is of course one of hopeless 

 inaction, and the motion of the unsupported 

 bones within the hoof produce inflammation at 

 the points of extreme pressure, so that, in case 

 of all old horses accustomed to go upon calks, 

 there is ulceration of the heels, in the form of 

 "corns," which the smith informs the owner 

 is the effect of hard roads bruising the heel 

 from the outside; he usually "cuts out the 



