262 THE HORSE IN SERVICE 



borne down upon, and in the normal unshod foot further de- 

 pression is opposed by the contact of the frog with the ground. 

 The structures compressed between the pedal or coffin bone 

 above and the unyielding ground or roadway beneath are elastic, 

 and yield in the line of least resistance, which is laterally. 

 This sidewise expansion of the internal structures of the foot 

 presses the bars and lateral cartilages outward, and with them 

 the wall at the quarter, thus increasing the transverse diameter 

 of the foot from one-fiftieth to one-twelfth of an inch. As this 

 expansion is most marked in the back half of the foot, there is 

 a corresponding narrowing of the hoof head in front. 



Interference, by shoeing or otherwise, with this lateral ex- 

 pansion of the quarters, not only causes the full force of the con- 

 cussion incident to the contact of the foot with the ground to be 

 felt, but induces a cramped, stilty stride, as a result of the 

 horse's effort to come down easily and thus spare himself the 

 pain of concussion. It is a condition analogous to that of a man 

 "n-ith a tight, unyielding shoe which pinches at every stop as the 

 weight is borne on it. 



The destruction of the elasticity of the lateral cartilages by 

 ossification, in the formation of side bones, has the same effect, 

 marked both in the stride and in the altered form of the foot, 

 the quarters becoming more narrow and straight. 



Proper shoeing consists, first, in so dressing the foot that the 

 removal of surplus horn does not destroy the balance of the foot, 

 but leaves it with its axis unbroken either up or down, in or out, 

 thus insuring an even distribution of weight and wear on the 

 joints above (Figs. 135, 136 and 137). Only such horn should 

 be removed from the sole or frog as is loose; the bars, natural 

 braces to prevent contraction, should not be cut through, the 

 heels " opened up," nor the sole concaved. The shoe must be 

 made to fit the foot, not the converse, its upper surface being 

 perfectly level and smooth to favor the sliding of the wall in 

 the outward expansion of the quarters, not bevelled to turn the 

 heels out ; the nails should be placed far enough forward to leave 

 the back of the foot free to expand on the branches of the shoe. 

 Hot fitting, properly done, insures a better fit than is possible 

 when the shoe is fitted cold, and is not injurious to the horn ; in 



