SHOEING. 



587 



To adapt it to these triple functions, nature has endowed it 

 with three properties apparently opposed, but which are neverthe- 

 less here made compatible with each other ; namely, in the first 

 place, extreme external hardness, which is found in the envelope of 

 horny substance ; 

 secondly, a certain 

 flexibility, the 

 combined result of 

 the physical prop- 

 erties of this corti- 

 cal envelope and 

 of the mechanical 

 arrangement o f 

 the different parts 

 of which it is made 

 up ; and, thirdly, 

 a highly devel- 

 oped sensitiveness, 

 the result of the 

 exquisite organi- 

 zation of its integ- 

 umentary mem- 

 brane. 



But, to make 

 good the injury 

 incessantly caused 

 by Wear On the 



horny bed which 



i ii -i 1 f 



clothes it, the foot 

 should possess the faculty of reproducing it in a manner so contin- 

 uous that the activity of the reconstruction should be exactly pro- 

 portioned to the rapidity of the destruction. This is, indeed, what 

 actually takes place ; the foot is the seat of a highly important 

 secretion the horny secretion. 



The nutritive functions, also, in the digital region are endowed 

 with great activity, indicated especially by the great development 

 of its vascular apparatus, the remarkable disposition of which is 

 made known to us by anatomy. 



374> _ Side view of the foot ^^ the part of the frog 



i n previous cut removed, now in place, showing 

 ligaments, etc., under the lateral cartil- 



a ^ e which ha8 been Amoved. 



Drawn from Manikin. 



