526 AKT OF SHOEING. 



the inner from external agencies, snch as a dry atmosphere, 

 excessive moisture, &c., performing, in fact, the same func- 

 tions as the cuticular covering does to the true skin of all 

 animals over the whole body. 



The depth and strength of the wall are greatest at the point 

 or toe. Posteriorly, on each side, it is inflected inwards, so 

 as to form an internal wall. These inflections have been 

 described as separate organs, and named the bars, and accord- 

 ingly, a function has been erroneously ascribed to them, viz., 

 that of propping open the heels. 



Fig. 220. Frog of the horse, showing the separation of flakes. 



The sole is the next division of the hoof to be noticed, 

 and viewed in connection with the wall, it may be regarded 

 as the arched support of the foot; it is an irregular thick plate 

 of horn, presenting to the ground a more or less concave 

 surface; its outer margin furnishes a broad surface for at- 

 tachment to the inside of this part of the wall, where it 

 blends with the horn plates. 



