PEEPARATION OF THE FOOT. 225 



by tlie slice limiting, if not destroying, the expansive 

 power of that part of the horn to which it is nailed ; 

 whereby a change of structure in the membrane itself, as 

 well as absorption of the attaching portions of the bone, is 

 induced ; for it is an invariable law of the animal economy 

 not to continue to unemployed structures the same meas- 

 ure of efficient reparation that is extended to parts con- 

 stantly 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 sim- 

 plify 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 

 backwards, and support the " lateral cartilages" 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 bone, — 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 correspond- 

 ing to the sensitive sole, but also the peculiar spongy 

 elastic substance which intervenes between it and the na- 

 vicular joint, and fills the space between the cartilages. 

 The proper sensitive frog is thicker, and less finely organ- 

 ized, than the sensitive sole, possessing fewer blood-ves- 

 sels and nerves. 



Before treating of the preparation of the foot for the 

 reception of a shoe, it is desirable to correct the generally 

 received, but erroneous opinion, that the shape of a per- 

 10^ . . 



