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A MANUAL OF VETERINARY PHYSIOLOGY 



of wall which might have completed the circle is sharply bent on itself 

 and caused to run in practically the opposite direction. When this 

 arrangement is considered, it is easy to see the advantages gained. 

 The foot is not a rigid body, but a yielding one ; and it would be 

 difficult to understand how any lateral movement could take place had 

 the wall been a complete circle. From their position the bars afford 

 additional strength as weight-bearers, for they represent the wall 

 carried under the foot ; they also prevent any rupture occurring 

 between the wall and foot-pad during the lateral movements of the 

 foot. 



The hind-feet differ from the fore in shape, being more upright and 

 narrower. They do less work, for they are only employed in assist- 



Fig. 228. — The Hoof seen from its Ground Surface. 



1, 2, 3, 8, The foot-pad, 2 being the cleft ; 4, the wall ; 5, its inflection at the 

 heels to form 6, the ' bars '; 7. the white line ; 9, the sole. 



ing to propel the body in the walk and trot, while, from the natural 

 attitude of the horse at rest (p. 601), they are alternately relieved 

 of weight. 



On examining the inside of the hoof- wall, a very complex arrange- 

 ment presents itself. At the upper edge, corresponding to the 

 coronet, is a deep semicircular groove, in which is lodged the thick 

 welt of tissue previously described as the wall-secreting substance. 

 Covering the entire surface of this groove are innumerable pin-point 

 holes, into which the papillae projecting from the ' substance ' are 

 lodged. The thickness of the wall at any one place corresponds to 



