36 THE ANATOMY OP THE HORSE. 



that has been executed. The following is a preferable method of pro- 

 cedure : — Procure a foot severed a few inches above the fetlock, and 

 inject the arteries and veins from the metacarpal vessels. When the 

 injection has solidified, roll the foot in a piece of wet cloth, and bury it 

 in a fermenting heap of stable manure. Decomposition will speedily 

 set in, and after a week the preparation should be examined at intervals 

 of two or three days, the metacarpal bone being fixed in a vice while 

 forcible attempts are made to pull off the hoof. When this has been 

 efl^eoted, the foot and removed hoof should be immersed for a day in a 

 saturated solution of carbolic acid in water, to which a little methylated 

 spirit may be added. This will speedily remove all odour of decompo- 

 sition, and dissection may then be proceeded with. 



The Hoof (Plate 10, Figs. 4 and 6). This is made up of the wall, the 

 bars, the sole, and the frog. 



The Wall is that part of the hoof which is exposed when the foot 

 rests in its natural position on a flat surface. It is divided,' though 

 not by any well-defined boundaries, into toe, quarter's, and heels. The toe 

 includes an area on each side of the middle line of the wall in front ; 

 and it passes on each side into the quarter, which comprises the lateral 

 region of the wall. Behind the quarter on each side of the hoof is the 

 lieel, which, when the foot rests on the ground, appears to be the terminal 

 part of the wall. In reality, however, the wall does not stop at the heel, 

 but is reflected inwards and forwards, and it is this concealed continua- 

 tion that is termed the har. In a well-formed fore-hoof the wall in the 

 region of the toe slopes at an angle of about 45°, and in a hind-hoof 

 at about 50°. 



The External Surface of the wall is, in a state of nature, covered by a 

 kind of epithelial varnish termed the periople, which is thickest at the 

 top of the wall, just under the hair, and is secreted by the so-called 

 perioplic ring. This is a natural varnish provided to check evaporaiion 

 and consequent cracking of the subjacent horn, and it ought not to be 

 rasped away in shoeing. The periople is most conspicuous after macera- 

 tion of the foot in water, and it may be traced all round the top of the 

 hoof just under the hair, as a band of soft elastic horn. At the back 

 of the foot it is blended with the horny frog. The inienml surface of 

 the wall is traversed in a vertical direction by the series of horny 

 lamince. These number about five or six hundred ; and before separa- 

 tion of the hoof they were interleaved with the sensitive laminae to be 

 presently described. The superior border of the wall shows a kind of 

 gutter, termed the coronary or cutigeral groove, which is the mould left 

 by the coronary cushion. The floor of this groove hasa closely punc- 

 tuated appearance, each minute perforation being the upper end of one 

 of the horn tubes of the wall, and lodging, in the natural state, one of 

 the papillae of the coronary cushion. The inferior border embraces the 



