MOVEMENT OF BEARING MARGIN AND SOLE. 127 



producing the deepest depression. One result of this friction 

 is the wearing away of the bearing surface of the heel on the 

 shoe ; the loss of horn may amount to 5 millimetres or more 

 within a month. 



The advantages of expansion of the hoof are manifold. 1. 

 The yielding of the tissues protects the hoof and its contents 

 from injury, even under the greatest shocks. 2. It greatly 

 diminishes at its point of origin the concussion, which would 

 otherwise be transmitted to the body, thus assisting the action 

 of the limb and adding to its elasticity. 3. It favours nutri- 

 tive processes in the parts enclosed by tlie horny capsule, and 

 is of importance in the production of the hoof itself. Move- 

 ment is of great importance in insuring sound hoofs and the 

 production of healthy horn. If for any reason movement is 

 lessened or prevented the hoof suffers. 



Bearing of the above on Practical Shoeing. 



In the practice of shoeing, the chief precaution is to preserve 

 normal movement in the foot. We know that shoeing, by 

 diminishing or preventing contact between the horny sole and 

 frog and the ground, and by fixing the bearing surface of the 

 wall to an inflexible ring of iron, checks or prevents movement 

 at the bearing margin. One method of shoeing which avoids 

 this disadvantage is the tip or modified Charlier. The task of 

 the farrier is, therefore, to so form and affix his shoe as to 

 minimise ill consequences. In paring the hoof and frog, 

 intelligent ideas must prevail. The counter pressure of the 

 ground should, if possible, be preserved, and the parts allowed 

 to sustain weight each in its appropriate degree. For this 

 reason the flat shoe is the most natural. For diseased 

 feet the bar shoe is very advantageous ; it unites in itself all 

 the good points of the ordinary shoe with few of its disadvan- 

 tages. It arouses the normal movements of the foot when 

 in abeyance, regulates them when disordered, and, if properly 

 used, never injures but always improves the diseased or faulty 

 hoof. A further point of great importance is a horizontal 

 bearing surface in the posterior half of the shoe, equable dis- 

 tribution of pressure over the entire circumference of the wall, 

 and the insertion of nails in the anterior half of the shoe alone. 



