278 OUTLINES OF EQUINE ANATO:\IY. 



quarters, while their anterior part is rather flat. The hoof 

 in general is more upright than the fore ; the thickest horn 

 is at the quarters, and the sole is very concave, the frog 

 being smaller and narrower. The heels also are longer 

 than those of the fore foot. 



The sensitive structures of the foot are generally exposed 

 by heating the foot in a forge fire, removing the heated 

 horn from the outer margin of the plantar surface of the 

 foot by means of a drawing knife, as far down as the sen- 

 sitive structures, and wrenching the wall and sole thus 

 separated off by means of pincers, the foot having been 

 fixed in a vice. The frog will be removed with the sole. 

 Some art is required in the operation, slow traction being 

 preferable to sudden jerks. By this means we expose a 

 red and highly vascular structure, investing the digit from 

 the coronet downwards. Opposite the centre of the external 

 surface of the lateral cartilage, extending round the foot 

 anteriorly and posteriorly, is a line marking where the 

 skin commences to change its characters. The epidermis 

 at first becomes soft and light in colour, and then modified 

 to form the hoof, some hairs from the coronet being em- 

 bedded in the white cheesy upper rim of the hoof. The 

 ordinary skin terminates in a regular and well-marked 

 line, light in colour, covered with fine papillae, and 

 growing wider at the posterior part, becoming blended 

 with the bulbs of the sensitive frog. Below this, ex- 

 tending in a downward direction for about half an inch, 

 is the 



Vascular layer of the coronary secreting substance. It 

 gradually decreases in size in a direction backwards, more 

 so on the inner than on the outer side, and at the posterior 

 part, against the bulbs of the frog, it terminates in an 

 acute point, being thickest just before this, in consequence 

 of its inflection forwards to join with the vascular sole, 

 towards which it runs, being here about two inches in 

 length, a quarter of an inch in width, separating the sensi- 

 tive laminae of the bars from the sensitive frog. It differs 

 slightly from the above description in the hind foot, in 

 accordance with the different shape of the hoof. The vas- 

 cular or sensitive coronary secreting substance is covered 

 with papillae, which are minute superiorly, but inferiorly 

 become very marked. In some cases a few may be seen 

 running from the upper part of the vascular laminae, 



