mi: i\ 1 1 <,i .1/0 / i/. > MTI:\I>.\<,I - 



influence of iiny inflammatory cause (laminitis, ablation of the wall), tin -< 

 di -nticulte become largely developed, and transformed into vcritublo papillae. 

 Their sides are traversed by folds, about sixty in number, which j>a<s 

 imintcniptedly from top to lx)ttom. These secondary leaves, or lamellar , 

 an fixed obliquely on the sides of the laminae, as the barbules of a feather 

 are attached to the barbs. 



The podophyllous tissue is not in immediate contact with that of the 

 keraphyllous tissue, or horny laminae; between the two there is a mass of 

 soft, elliptical cells, always destitute of pigment, easily stained with carmine, 

 and appearing to stud the ramifications of the vascular laminae. A trans- 

 verse section of the union of the hoof with these lamina;, when treated with 

 carmine, presents a very fine aspect, appearing as so many fern or acacia-of- 

 . I udea leaves placed between the keraphyllous laminae : the principal nerve, 

 and the secondary nervules of the leaves, being represented by the lamina 

 and its lateral ridges, the limb of the leaves by the young cells spread 

 around the latter. 



The structure of the podophyllous membrane resembles that of the other 

 parts of the keratogenous apparatus. Its corium is, liko that of the peri- 

 pheral portion of the velvety tissue, separated from the os pedis by a fibrous 

 rcticithtm, which supports the veins, and forms, to some extent, the periosteum 

 of the third phalanx. 



The leaves of the podophyllous membrane are immense lamellar papilla;, 

 which should be included among the principal instruments concerned in the 

 tactile sensibility of the Horse's foot, and which play a really mechanical 

 part, in concurring, by their dovetailing with the keraphyllous (or horny) 

 lamina;, to assure the solidity of the union of the hoof with the living parts. 

 The cells which multiply on their surface have usually but little share in 

 the formation of the horn. This will, however, be alluded to hereafter. 



6. Description of the Hoof. 



The hoof of the Horse, considered as a whole, represents a kind of box 

 that envelops the inferior extremity of the digit, by fitting closely on the 

 keratogeuous membrane, to which it is united in the most intimate manner 

 by a reciprocal penetration of the prolongations into the cavities that exist 

 on the surfaces in contact. 



It* general shape is, as was demonstrated by Bracy Clark, that of the 

 nn-ietyof a cylinder cut obliquely across its middle, and resting on the 

 surface of this section. In nearly all feet, however, it is slightly conical. 



Prolonged maceration separates it into throe portions : the trail, sole, 

 and frog. 



WALL. The vxdl, also named the crust, is that part of the hoof which is 

 apparent when the foot rests on the ground. This thick plate of horn 

 c-.vers the anterior face of the foot, and, gradually narrowing in width and 

 diminishing in thickness, passes round each side until it reaches the bulbs 

 if the plantar cushion, when its extremities are sharply inflected inwards, 

 between the frog and internal border of the sole, becoming confounded with 

 the latter about its middle or anterior third, after being greatly reduced in 

 breadth nnd substance. 



The middle, or anterior part, of this horny envelope is popularly 

 ns the tot-, the two sides of which are designated as out*i<l- and /NX/./.' toe; 

 tli' lateral regions constitute the qtutrters ; the heels are formed by the angles 



