802 VETERINARY HYGIENE 



the ammonia of the urme, there can only be one result so 

 far as the foot is concerned. 



The excessive wear of the foot which results from work 

 necessitates some protection being afforded, and this is 

 given by shoeing. There are other advantages from 

 shoeing, such as saving concussion, but its chief object 

 is to save undue wear and tear. 



In the application of a shoe to the foot the functions of 

 the various parts must be borne in mind, and though the 

 function of a part is the field of physiology, it is permissible 

 here to state the main features of the case. 



A horse's weight is carried by the wall of the foot and 

 that part of the sole adjacent to it, by the bars and 

 foot pad. All of these parts in an unshod foot are in 

 contact with the ground. The sole, being concave, would 

 not rest upon the ground excepting in soft soil, nor is it 

 intended to carry weight, excepting where it joins with 

 the wall. 



When a shoe is placed on the foot the natural condition 

 just mentioned should as far as possible be complied with, 

 the shoe should rest on the wall, adjacent circumference of 

 the sole, and the bars. The foot pad should rest on the 

 ground ; it is one of the great anti-concussion mechanisms, 

 and cannot perform this function unless on the ground. 

 Further, if it does not rest on the ground, the pad becomes 

 smaller, and the foot in consequence narrows. 



The wall of the foot is strongest at the toe, and gradually 

 gets thinner and thinner towards the heels ; this is to 

 allow of a certain amount of lateral play at the posterior 

 part of the foot which occurs when the weight comes on 

 the limb. From this it is evident that the toe and quarters 

 of the foot are the only places where nails can with safety 

 be driven, and that not only are the heels of the wall too 

 weak to stand a nail, but such would interfere with the 

 slight lateral movement known as expansion. 



The wall of the foot at the toe forms a certain angle with 

 the ground, and all the horn fibres, whether of sole, foot 

 pad, or wall conform to this angle ; any section of the wall 



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