THE HORSE. 51 



ceding backward like expanded wings, terminate at 

 the extremity of the heel, assisting to expand the 

 heels and quarters. The nut, or navicular bone, is 

 situate at the back of the coffin bone, and attached to 

 it and to the small pastern bone, affording a synovial 

 or slippery surface on which the flexor tendon, or 

 great back sinew, moves. The nut and coffin bones 

 form the coffin joint. The small pastern articulates, 

 that is to say, is joined with the coffin bone and the 

 nut bone below, and with the great pastern above. 

 The great flexor, back, or bending tendon is inserted 

 into the bottom of the coffin bone, and the extensor 

 tendon on its front and upper part. By the by, these 

 qualities of bending and extending, necessarily imply 

 and prove tendinous mobility and elasticity, in despite 

 of the early decrees of the College, since gradually 

 become obsolete and unfashionable. Finally, the in- 

 sensible foot consists of the external covering of horn, 

 the wall, horny sole, and frog ; the sensible or inter- 

 nal, of the laminated substance, at the upper part of 

 which there is a cartilaginous ring, coronary ligament 

 or frog band, which, instead of terminating at the 

 heels, is continued to the frog, imparting to it a con- 

 genial sensibility and motion. Thus, when the frog 

 is engaged in its natural function, that of being 

 pressed upon actively by the superincumbent weight, 

 it expands and contracts, whether or not it may be 

 capacious enough to reach the ground, communicat- 

 ing simultaneously, motion to the cartilages, coronary 

 ring, and to the heels and quarters of the hoof. As a 

 summary, the internal or sensible foot is composed 

 of the navicular or nut bone, the coffin bone, the late- 



