360 A Manual of Veterinary Physiology. 



the enormous weight of the horse's body should be carried 

 upon — or, rather, slung upon — these delicate strips of sensi- 

 tive material on the one hand, and correspondingly delicate 

 strips of horn on the other, is perhaps the most remarkable 

 feature in the physiology of the foot. We know how firm 

 the union is, we know the extreme difficulty of separating 

 these two parts even by mechanical means in a state of 

 health, and we readily recognise the delicate structure of 

 the parts yielding this firm yet flexible union. 



The horse's weight is supported in the foot by the dove- 

 tailing of 500 or more sensitive lamina? with 500 or more 

 horny lamina.', the union being made the more complete by 

 each primary sensitive and horny lamina containing 100 or 

 more secondary lamina?. These lamina^ afford an immense 

 surface of support, which is longest at the toe, shorter at 

 the quarter, and still shorter at the heel ; but though the 

 slinging surface is so much shorter at the quarters and heels, 

 yet its strength is increased by the direction in which the 

 weight of the body comes upon it. Instead of bearing the 

 weight on the length of the lamina?, as at the toe, it bears it 

 on the width in such a manner that where we have, say, one 

 lamina at the toe, there are twenty at the quarter. It is 

 not possible to clearly describe this, but Fig. 46 will ex- 

 plain. 



These lamina? are attached at the anterior and part of 

 the lateral face of the foot to bone, but for the remaining 

 lateral face and posterior part of the foot they are attached 

 to stout cartilage ;* if a line be drawn through the foot 

 separating the osseous attachment of the lamina? from the 

 cartilaginous attachment (see Fig. 49), it will be found that 

 roughly speaking one-half is cartilaginous and one-half 

 osseous ; the cartilaginous portion is situated just where 

 elasticity is required, viz., the posterior face of the wall ; one 

 function of the lateral cartilages of the foot is to afford an 

 elastic wall attachment to the sensitive lamina 1 . 



A horse's sole carries but little of his weight, only the 



* Some of the laminae axe attached to the tendon of the extensor 

 pedis, and the lateral ligaments of the foot joint. 



