DILATATION AND CONTRACTION. 9 



be again elevated. While the sole performs its part in sustaining 

 the weight, that part is very slight on even, soft ground. 



Experiments have proven that the sole may be entirely removed 

 without the bones descending from their position, the coronary liga- 

 ment, and the tendons which run between the navicular bone and the 

 sensitive frog, being sufficient to carry the weight. Veterinarians 

 have argued that the descent of the sole proves that at times thei-e is 

 gi-eat weight thrown on this part of the foot, and point to a large 

 and wide-heeled foot as the most likely to suflfer in this way. There 

 mav be other causes which conduce to this state, and these causes we 

 will consider hereafter. To digi-ess, however, in this connection it 

 may be as well to describe another portion of the foot which has a 

 great deal to do in sustaining the weight, and that is the lamince, 

 or thin plates which interlace from the wall and the coffin bone. 

 There are about five hundred of these plates, and they come together 

 much the same as would the leaves of two books, if they were locked at 

 their edges. With even a slight pressure from the sides, it will be 

 found that it takes considerable force to push them apart ; and the 

 five hundred Icwiince, thin as they are, aid very materiall}' not only 

 in sustaining the weight, but also in breaking the jar. These lam- 

 ince permit the dilatation and contraction without injurious results, 

 as would be the case were the interior surface of the wall and the 

 outward portion of the bones smooth. In the latter case there would 

 be nothing to hold them in position while the foot was expanded, and 

 there would be a space between. 



The cut in the previous article showed the section of the foot an 

 inch in advance of the heel and where the commissures are the deepest, 

 but as that becomes shallower there is less depth of horn to move, 

 and less is required. The elasticity of the upper poi-tion of the foot 

 is the greatest at the back part of the coronary ligament, and the 

 equilibrium of expansion is thus retained. 



Miles, in his essay on horse-shoeing, wrote : " Unless the nail- 

 holes are placed so that the foot can expand, it must in the end be- 

 come unsound." "Frank Forester" thought so highly of his treatise 

 that he embodied it in his woi-k, and prefaced it with unqualified 

 praise, and his opinion was coincided in by the best informed horse- 



