THE LIMBS 



185 



is one of the peculiarities of the horse's foot. The 

 covering of the sole is continuous posteriorly with that 

 of the plantar cushion, which has also a villous surface. 



Over the whole of this soft, sensitive, and highly- 

 vascular derm is, as before said, a very thick epidermic 

 layer, which is distinguished by the name of 'hoof.' 

 One of the properties of the horny material of which this 

 is composed, which specially fits it for the function it 

 has to perform, is that it is a non-conductor of heat. It 

 is also moderately hard, tough, and elastic, and, like all 

 epidermic structures, not sensitive itself, though it will 

 transmit impressions through its tissue to the sensitive 

 structures below. 



From the foot of the dead animal the hoof may be 

 removed entire by maceration or by immersion in hot 

 water, when it will be seen to form a hollow box or 

 case of somewhat complex form, its inner surface being 

 exactly moulded on the parts around which it grows. 

 Its general shape is that of an obliquely truncated cone, 

 considerably higher in front than behind. As in the 

 vascular surface beneath it, several distinct portions 

 or regions can be distinguished. The densest and 

 most important part is the £ wall ' or c crust,' which 

 exactly corresponds to the whole of the human nail, 

 though differing in its much greater thickness and in 

 the sides being not only greatly prolonged backwards, 

 but also sharply bent inwards and forwards, forming 



