:notes on shoeing of horses. 3 



4. The external foot of the horse is mainly made ^JT^^^'^ 



'' oi the foot. 



up of three parts, viz. : 



1st. The crust, or outer homy wall. 



2nd. The sole, or concave ground surface. 



3rd. The frog, or elastic pad, or cushion at the 

 back. 



Each of these parts differ in structure and uses ; 

 and each may be divided as follows : — 



1st. The crust, into the external portion which 

 is commonly called the hoof ; and the internal, or 

 laminated structure, which connects the sensitive 

 with the insensitive parts of the foot. 



2ndly. The sole, into the insensitive, or ground 

 surface ; and the sensitive portion lying immedi- 

 ately above it, and from which the insensitive is 

 secreted. 



AndSrdly. The frog, into the insensitive, or ground 

 surface ; and the sensitive portion lying immediately 

 above it, and from which the insensitive is secreted. 



5. The crust, or wall of the outer circumference of the 



crust oi* Gx~ 



of the foot, sustains nearly the whole weight of temaiwau 

 the horse. In the shod horse, as horses are usually 

 shod, it may be assumed to sustain the whole weight. 

 The crust varies in thickness in different parts 

 of the foot, and also in different horses. It is 

 thickest at the toe, and thinner on the inside than 

 on the outside quarter. It is rarely more than 

 half an inch thick at any part. 



1—2 



