546 



^STHESIOLOGY. 



</roove, in which is loilgecl the coronary substance or bond. In 

 this groove are numerous minute orifices, in which are inserted 

 the secretory villi of the coronary band. The inferior border is 

 that part in contact with the ground, and to which the shoe is 

 ii'ted. In an unshod animal it is always in wear, and protrudes 

 beyond the rest, more especially round the outer quarter, and is 

 known as the spread. The inner surface of the inferior border 

 is united in a very intimate manner with the periphery of the 

 sole. The external layer of horn in the wall is distinctively 

 known as the crust, and is secreted by the coronary band ; the 

 xest being secreted by the sensitive laminae. 



Supposing the hoof to rest 

 on a perfectly level plane, the 

 line joining the toe to the 

 middle of the coronary border 

 should make with the ground 

 an angle of about 50 degrees 

 in the fore, and perhaps a little 

 more in the hind feet. An 

 angle exceeding or falling short 

 to any extent of this, would 

 indicate defective conformation. 

 In this particular, however, it 

 is necessary to make ^allow- 

 ances for many circumstances, 

 such as the breed and age of the animal, the condition of the 

 foot, &c., which may influence the angle. 



Fig. 211. 



Detftched hoof— supero-lateral view, a, Crust, 

 «r outer layer of the wall ; b. Homy laminae ; 

 «, Superior border ; d, Cutigeral groov© ; e. Inner 

 aurfnoo of sole ; /, Inner surface of frog ; /', Frog- 

 Mny. 



SOLE. 



The sole is a thick plate of horn, which helps to form the 

 inferior portion of the hoof. It is comprised between the inner 

 border of the inferior part of the wall and the inflections or bars, 

 and presents two surfaces and two borders. The inferior or 

 ^.zternal surface forms a vault, which is more or less concave 

 in difi'erent animals. The superior or internal surface is 

 unevenly convex, and is studded with a number of small orifices, 

 which run obliquely forwards ; into these are inserted the vascular 

 papillae of the sensitive sole. The external border or circum- 

 ference of the sole is convex, abuts upon, and is united through- 

 out its whole extent to the internal part of the inferior border of 



