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A MANUAL OF VETERINARY PHYSIOLOGY 



above the level of the hoof and filling in completely the hollow of the 

 heel. Its inferior face is V-shaped (Fig. 221), and a complete counter- 

 part of the horn-cushion or foot-pad above which it lies. Its position 

 is shown in section in Fig. 220, 7, 7, and the manner in which it pro- 

 tects the navicular bursa and tendon. The cushion is softer pos- 

 teriorly than anteriorly, where at its apex it is dense and fibrous. 

 The cushion does not secrete horn, but its surface is covered by a 

 delicate papillated membrane which secretes the horn of the foot- 

 pad. 



Sweat-glands exist in the plantar cushion, situated in and on the 

 side of its central depression. The glands, as figured by Franck, are 



Fig. 221. — The Plantar Surface of the Internal Foot. 



1, 2, 3, The sensitive foot-pad, or plantar cushion, 1 being the bulbs, 2 the cleft, 



4, the termination of the wall-secreting body of the heel, where it blends 

 with the plantar cushion : the numerous papillae on its surface can be seen ; 



5, the vascular or sensitive sole, covered by papillae ; 6, terminal ends of 

 the sensitive laminae, which may be seen around the entire rim : it is at this 

 point where each lamina terminates in four or five papillae ; 7, the laminae 

 of the wall inflected at the heel, and here forming the sensitive ' bars.' 



shown in Fig. 222. A more modern description is given by Mettam. 

 They are large, coiled, single or multiple glands opening on the sur- 

 face of the horn in the so-called ' cleft ' of the frog by means of 

 tubes, which take a very spiral course. They secrete an unctuous 

 fluid, which helps to maintain the horn in a pliable condition. 

 »^The Corium of the foot completely covers the whole of the pedal 

 bone, plantar cushion, and a large surface of the lateral cartilages. 

 This tissue has received various names — viz., from its colour, the 



