THE FOOT. 2T5 



foramina, into whicli the papillae of tlie vascular coronary 

 secreting substance pass. The wall is divided into crust 

 and horny Jamince ; the horny laminae are leaf-like plates 

 projecting from the inner surface of the crust, taking a 

 direction corresponding to the fibres of the wall, commenc- 

 ing superiorly at the inferior margin of the above men- 

 tioned perforated surface. They are longest at the toe 

 and become insensibly merged in the wall at the anterior 

 extremity of the bars. Between each pair of these in the 

 fresh subject for the greater part of their length lies a sen- 

 sitive lamina, and the surfaces of the horny laminae present 

 foramina into which pass papillae from the sensitive coun- 

 terpart. The outer utargm of each lamina is continuous 

 with the crust, the inner is free. The superior extremity 

 terminates in a point in blending with the above described 

 concave surface, the inferior terminates on the ground sur- 

 face at the line of junction of the wall with the sole, at which 

 part the outer laminated edge of the sole fits between the 

 horny laminae as the sensitive laminae do in other parts ; 

 the extent of this junction depends upon the variable 

 thickness of the sole. The horny laminae are produced by 

 the sensitive laminae, and the crust by the coronary secret- 

 ing substance ; in consequence, therefore, of the constant 

 additions to its thickness the wall has a tendency to 

 greater bulk in its lower than in its upper part. That 

 portion of the wall situated at the extreme superior edge, 

 which is secreted by the line of vascular substance which 

 presents very minute papillae and seems to be the first stage 

 of change in the character of the skin, thus presents fibres 

 more delicate than those of the rest of the wall, correspond- 

 ing to those of the frog, extending for but a short distance 

 downwards, about half an inch. It is narrowest anteriorly 

 and becomes deepest at the heels in blending with the frog. 

 This is the coronary frog band of Bracy Clark (the original 

 specimen of this by Bracy Clark in the museum of the 

 Eoyal Veterinary College is much too thick anteriorly, 

 where a small portion of coarser substance has been left) . 

 The wall is thickest at the toe, it gradually decreases in 

 thickness towards the heels, and again increases slightly at 

 the extreme posterior part, where it is inflected forwards 

 to form the bars. In no part is the wall so thin as the 

 coronary frog band at the extreme superior part. The 

 angle the toe of the hoof should make with the ground has 



