BHOEINQ, 181 



absorption of the attaching portions of the bone, is induced ; for 

 it is an invariable hiw of the animal economy not to continue 

 to unemployed structures the same measure of efficient repara- 

 tion that is extended to parts constantly engaged in performing 

 their allotted tasks. The shoe restricts or prevents expansion ; 

 while nature, as the secret influence is called, immediately sets 

 to work to simplify the apparatus for producing the expansion, 

 which art has thus rendered impracticable, and substitutes for 

 it a new structure, less finely organized, but admirably suited 

 to the altered condition of the parts. 



The wings extend from the body of the bone directly back- 

 w^ard, and support the lateral cartilage of the foot. 



The sensitive sole, or, as it is sometimes called, the fleshy sole, 

 is about the eighth of an inch thick, and is almost entirely made 

 up of blood-vessels and nerves ; it is one of the most vascular 

 and sensitive parts of the body, and is attached to the lower 

 edge of the sensitive covering of the coffin ^one, to the bars, 

 and point of the frog, and also with great firmness to the whole 

 of the arched under-surface of the coffin bone. 



The sensitive frog includes not only the part corresponding 

 to the sensitive sole, but also the peculiar spongy elastic sub- 

 stance which intervenes between it and the navicular joint, and 

 fills the space between the cartilages. The proper sensitive 

 frog is thicker, and less finely organized, than the sensitive sole, 

 possessing fewer blood-vessels and nerves. 



It is a common, but very erroneous, opinion, that the shape 

 of the perfect foot is circular, or very nearly so. This induces 

 most smiths to endeavor to reduce the foot to that shape as soon 

 as possible. There are very few things in nature so little varied 

 as the form of the ground surface of horses' feet j for whether the 



