556 Veterinary-Captain Frederick Smith [May 3, 



holes in the horn, and the tubular formation of horn is due to the fact 

 that it is pierced at its origin for the reception of papillse. 



The wall of the horse's foot is divided, for convenience of descrip- 

 tion, into the toe, quarters and heels. The thickness is greatest at the 

 toe, and decreases gradually towards the heels where it is thinnest ; 

 but the wall at the heels, instead of being continued so as to complete 

 the circle of the foot, suddenly turns in and travels in a forward 

 direction between the sole and foot-pad. This portion is called the 

 bar, and the practical lesson which has to be learned is that the 

 bar is part of the wall, is intended to bear weight, and should 

 not be cut away in shoeing as is so commonly practised. In a foot 

 of a wild horse shot in Thibet — of which a plaster cast is placed on 

 this table — the most extraordinary development of the bars is shown. 



It is obvious that by the inflection of the wall the heels of the foot 

 are considerably strengthened ; and this is especially necessary, as the 

 circle of the wall is only an imperfect one. 



The amount of moisture in the wall varies, depending upon its 

 position relative to the horn-secreting surface. The horn-secreting 

 surface of the wall lies immediately under the upper edge of the hoof; 

 the nearer the horn is taken to this upper edge the more moisture it 

 contains, the further from the edge the less the moisture. It is 

 obvious, therefore, that as the wall grows longer it becomes drier ; 

 and moderate dryness of horn is only another name for toughness, so 

 that the portion of wall in contact with the ground is much harder 

 than the portion above the ground. 



The growth of the wall under normal conditions is the same at any 

 part of its surface : if it grows an inch at the toe it grows an inch 

 at the quarters and heels. You will observe that the wall at the heels 

 is, roughly, only half the height of the wall at the toe, and, bearing in 

 mind what has been previously said about horn becoming drier as it 

 increases in length, you will have no difficulty in understanding that the 

 horn at the toe is older and tougher than the horn at the heel, which, 

 from being much younger and shorter contains more moisture, and is 

 therefore elastic and yielding. If, for example, we assume the length 

 of the wall at the toe to be four inches, and that at the heel to be 

 two, it is obvious that the wall at the toe is double the age of that 

 at the heel ; and if we continue this investigation further by drawing 

 lines around the wall parallel with the upper edge of the hoof, it will 

 readily be seen that the portion in contact with the ground is of 

 varying age, being oldest at the toe and gradually decreasing in age to 

 the heel, in other words, being hardest at the toe and softest at the heel. 



There is an object in all this which w r e must now enquire into. 

 When a horse's foot comes to the ground in either the trot, canter 

 or gallop, viz. in any pace which causes concussion, the heel is the 

 first to make contact with the ground ; by this means, as we shall 

 hope to show, the shock of impact is considerably reduced, for the 

 soft tissues of the posterior part of the foot yield slightly under tbe 

 strain instead of offering rigid opposition, and this yielding, which 



