THE EAR, THE EYE, THE SKIN, AND THE FOOT 181 



minute tubular fibers resembling hairs firmly cemented together 

 make up the hoof. From the standpoint of horseshoeing it is 

 next in importance to the shoe; from that of utility it is para- 

 mount, as it is a reliable guide to the condition of the important 

 parts which it covers. The hoof is divided into the wall, the 

 sole, and the frog (Figs. 58, 59). 



The wall is all that portion which is seen when the foot rests 

 upon the ground. It gives the foot its form. This horn is 

 very hard and solid and affords adequate protection to the sensi- 



Periople 



Coronary 



groove 



Lamina 



White line 



Sole by bar and frog 



Pcriople of heel 

 Ridge formed 



Fig. 58. — Half of hoof of horse, internal surface. (Sisson, Anatomy of Domestic 



Animals.) 



tive structures beneath it. The wall is arbitrarily divided into 

 toe, quarters, and heels. The toe is the highest part; from this 

 point backward the wall gradually decreases in height, passes 

 around the bulbs of the heels, and turns forward and inward to 

 form the bars, which are finally lost in the edge of the sole near 

 the apex of the frog. It thus forms at each heel an angle known 

 as the buttress. Each buttress encloses a branch of the horny 

 sole. The inner surface of the wall presents about six hundred 

 horny leaves or laminae which dovetail with the sensitive laminse. 

 A firm union is thus made, so that it is very difficult to separate 

 the two. The upper edge of the wall is thin, flexible, and grooved 

 for lodgment of the coronary band. The lower edge is called 

 the "bearing surface," and is the part to which the shoe is fitted. 

 At the toe the wall is thickest; as the quarters are approached it 

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