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the correlative movements and conditions of the various parts 

 of the foot, whether they be normal or abnormal, active or 

 passive. 



The whole body has a centre of motion, around which every 

 part of the entire system is perpetually playing and balancing 

 itself. Like the oscillation of a weighing beam, the elevation 

 of one end is accompanied by the depression of the other. I 

 extend this view to each limb, and to each section of a limb, 

 during progressive movements, and finally I carry it into the 

 comparatively passive conditions and relations of the various 

 parts of the foot, whether functionally employed or otherwise. 



CORRELATIVE MOVEMENTS. 



Thus I regard the fore and hind, and the upper and lower 

 parts of the foot, as having a counter-balancing and recipro- 

 cating effect upon each other. Each and every part has its 

 opposite. Whichever part is elevated, its opposite is depressed ; 

 and whichever is expanded, its opposite, or correlative, is con- 

 tracted. In one respect, at least, there is a three-fold relation 

 of this nature in the foot of the horse due to the peculiarities 

 of its structure. For example, contraction at the lower margin 

 of the posterior quarters, not only produces expansion at the 

 margin of the quarters where the quarter-crack takes place, 

 but causes expansion at the toe where toe-crack occurs. 



Thus the same cause that starts a crack in the hoof, on its 

 upper border posteriorly, starts it on its lower border anteriorly, 

 that is to say, at the toe. 



RATIONALE OF TREATMENT. 



Conversely if you take a foot with a quarter or toe-crack, 



and expand the lower posterior quarters, the upper posterior 



quarters will become contracted in its marginal outline, and 



the edges of the crack will approximate, and if kept expanded 



they will not separate, and the crack will disappear, not by 



the positive union of its edges, but by the process of growth 



from its respective secreting organs. This is equally true of 



I 



