HORSESHOEING. 



45 



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

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



over one another, and uniting to form one entire structure, — a 

 thin, horn-like layer, Avithout blood-vessels or nerves. It extends 

 over the entire surface of the body, and protects the underlying, 

 very sensitive middle layer from external influences. The 

 oldest cell-layers lie on the outer surface, and are being con- 

 tinuously brushed off in patches or scales, while new ones are 

 constantly being formed on 

 the outer surface of the 

 middle layer. 



2. The middle layer, 

 leather-shin or dermis, is 

 composed of solid, fibrous, 

 and elastic tissues, and eon- 

 tains many blood-vessels, 

 small nerves, sweat- and oil- 

 glands, and hair follicles 

 from which the hair grows. 

 The hair upon the posterior 

 surface of the fetlock- joint 

 is usually long and coarse, 

 forming a tuft knoA\Ti as the 

 " footlock," which encloses 

 a homy spur, called the 

 ergot. Common bred horses 

 have, as a rule, larger and 



coarser footlocks than thoroughbreds. The derm or leather- 

 skin, which produces the hair and epiderm, is the thickest and 

 most important layer of the skin. 



3. The inner layer, or suhcutaneons tissue, unites the middle 

 layer with the muscles, tendons, ligaments, bones, or other 

 structures. It is that loose fibrous mesh or net-work through 

 which the butclier cuts in removing the hide from the carcass. 



{h) The hoof-skin (Figs. 27 and 28, &, c, c^), or pododerm, 



Foot from which the horny capsule or hoof, haa 

 been removed by prolonged soaking: o, skin; on 

 the left the hair has been rubbed awaj'; 6, perio- 

 plic band; c, coronary cushion; d, podophyllous 

 tissue (fleshy leaves) ; at the lower Ijorder of the 

 figure can be seen the minute thread-like pro- 

 cesses or villi which grow down from the lower 

 end of each fleshy leaf. 



