THE FOOT AND SHOEING. 219 



The hoof. — Horn, wherever it grows, is the same in structure, and Structure 

 consists of a hard, tough, gluey substance, in which is embejided a number °^ horn, 

 of hair-like tubes. It may differ considerably in consistence, some 

 varieties being almost as hard as a brick ; and others as elastic as india- 

 rubber ; a difference largely due to the amount of moisture which the 

 individual specimen contains. This moisture is contained in the tubes ; 

 all horn has a certain quantity in its composition, and its presence 

 produces that toughness which always characterises a healthy growth. 

 The horn of the hoof, whether originating from the coronary band, fleshy Gro^yth of 

 sole or fleshy frog, grows in the same direction, namely, sloping down- hoof, 

 wards and forwards, at the same angle that the toe makes with the 

 ground. 



The wall is that part of the hoof which is visible when the foot is on The wall, 

 the ground (fig. 45). At the extremity of the heels it bends sharply back, 

 and runs forwards for a short distance, this recurved portion being called 

 the "bar." The upper edge of the wall, at the coronet, is thin and soft ; 

 and its inner side is hollowed into a groove which accommodates the 

 coronary band. Below this groove the wall is uniformly thick from top to 

 bottom at any given point, whether toe, quarter (side of hoof), or heel be 

 examined. From the toe, however, the horn gets gradually thinner towards 

 the quarters and heels, but where it turns round to form the bars, it again 

 suddenly thickens and then gradually thins off to nothing as it runs 

 forward. (Fig. 45.) The inner side of the wall, including the " bar," is 

 lined by a number of horny leaves, corresponding in arrangement with 

 the fleshy leaves which cover the coffin bone, and dovetailing with them. 

 The outside horn of the wall is extremely hard, but it gets softer and 

 lighter in colour as the leaves are approached, and on the ground surface 

 of the foot, the relative position of these, i.e., the junction of the wall and 

 sole, is marked by a distinct "white line." Around the upper edge of the 

 wall is a thin, rough-looking band which runs all round the hoof to join 

 the horn of the frog ; it is sometimes called the " coronary frog band," 

 and is very prominent and white when the foot has been soaked in water. 



The wall grows from the coronary band ; each of the minute fleshy 

 fingers previously mentioned, being the starting point of one of the tubes 

 and the surrounding horn substance w^hich binds them together. 



If untouched, being neither worn nor cut, the horn of the wall will 

 grow on indefinitely, and the rate of growth at the toe being greater than 

 at the heels, it will soon become disproportionately long and may then be 

 a cause of stumbling. 



The sole conforms in shape to the under surface of the pedal bone, its The sole, 

 outer edge resting on the ground, from which it is slightly arched towards 



