HORSESHOEING. 



39 



control. The sensory nerves terminate in the skin and in the 

 soft tissues just under the horny box or hoof (pododerm), and 

 render these parts sensitive ; that is, they convey certain feelings, 

 as, for example, the pain caused by bruising, pricking, or close- 

 nailing, to the brain and consciousness. 



F. The Protective Organs of the Foot. 



The protective organs are the skin and the horny box or hoof. 



The external shin, or hide, covers the entire body ; in the feet it 

 covers the bones, tendons, and ligaments, even passing in under 

 the hoof and directly covering the os pedis. This portion of 

 the skin, enclosed by the hoof and therefore invisible, is called 

 the pododerm or foot-skin. In Germany it is called the hoof-skin 

 (huflederhaut), because it is 



a continuation of the outer ^i<3- 23. 



visible skin, and because it 

 secretes the hoof, — that is, 

 the hoof is produced by 

 it. That part of the skin 

 which is covered with hair 

 is known as the external or 

 hair-shin. 



(a) The hair-skin (Fig. 

 23, a) consists of three su- 

 perposed layers, — (1) the 

 external superficial layer, or 

 ejyidermisj (2) the middle 

 layer, derm or leather-skin 

 (so-called because leather 

 is made from it) ; (3) the 

 internal layer, or subcuta- 

 neous connective tissue. 



1. The external layer, or epidermis, is composed merely of single 

 flattened, horn-like cells (scales) lying side by side and over one 

 another, and uniting to form one entire structure,— a thin, horn- 



Foot from which the hoiny capsule, or hoof, has 

 been removed by prolonged soa ; kinga, skin ; on 

 the left the hair has been rubbed away ; 6, perioplic 

 band ; c, coronary cushion ; d, podophyllous tissue 

 (fleshy leaves) ; at the lower border of the figure 

 can be seen the minute thread-like processes or 

 villi which grow down from the lower end of each 

 fleshy leaf. 



