KEGIONAL ANATOMY 37 



Examined on the foot, deprived of its horny covering, 

 the sensitive laminse are, the majority of them, in close 

 contact with each other. In the normal state this is not 

 so. The interstices between the leaves are then occupied 

 by the horny leaves, to be afterwards described as existing 

 on the inner surface of the wall. 



Beaching and rounding the heels, the sensitive laminse 

 extend forward for a short distance, where they interleave 

 with the horny laminaB of the bars. 



Much discussion has centred round the point as to 

 whether or no the cells of the sensitive laminae take any 

 share in the formation of the horn of the wall. This will 

 be alluded to in a future chapter. 



I. THEfHOOF. 



Eemoved from the foot by maceration a well-shaped hoof 

 is cylindro-conical in form, and appears to the ordinary 

 observer to consist of a box or case cast in one single piece 

 of horn. Prolonged maceration, however, will show that 

 the apparently single piece is divisible into three. These 

 are known as (1) The Wall, (2) The Sole, and (3) The 

 Frog. In addition to these, we have also an appendage 

 or circular continuation of the frog named (4) The Peri- 

 OPLE, or Coronary Frog Band. These various divisions we 

 will study separately. 



1. The Wall is that portion of the hoof seen in front 

 and laterally when the horse's foot is on the ground. 

 Posteriorly, instead of being continued round the heels to 

 complete the circle, its extremities become suddenly 

 inflected downwards, forwards, and inwards. These in- 

 flections can only be seen with the foot lifted from the 

 floor, and form the so-called Bars. It will be noticed, too, 

 with the foot lifted, that the wall projects beyond the level 

 of the other structures of the plantar surface, taking upon 

 itself the bearing of the greatest part of the animal's 

 weight. 



The horn of the wall, viewed immediately from the front. 



