SHOEING. 



587 



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

 with three properties apparently opposed, but Avhieh 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 mjury -^^^ 374.— Side view of the foot with the part of the frog 

 mcessantly caused in previous cut removed, now in place, showing 



by wear on the ligaments, etc., under the lateral cartil- 



horny bed which 

 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. 



age which has been removed. 

 Drawn from Manikin. 



