EPIDERMIC PRODUCTS 255 



as regards the resemblance which exists between these 

 organs of support, but, further, because it constitutes a 

 mnemonic which enables us, on condition that we remember 

 the form of the human foot, to recall the above-described 

 character of that of the horse. 



The greater convexity of the outer portion of the hoof is 

 found equally on the human foot ; the external border of 

 this foot is more convex than the opposite one. 



The inferior border of the wall (Fig. 100) is, in the case of 

 unshod horses, always in wear when in contact with the 

 ground. It is intimately united to the circumference of the 

 sole (see further on). 



The superior border is hollowed on its internal surface by 

 a groove, the cutigerous cavity or basil, which lodges the 



A 



A' 



Fig. 99. — Vertical and Transverse Section of a Left Human Foot : 

 Outline of the Divided Surface of the Posterior Segment 

 OF THIS Section (Diagrammatic Figure). 



A A', Vertical axis passing through the middle of the leg and the second 

 toe ; I, outer side ; 2, inner side. 



cushion (see Fig. 95). We have described this latter above, 

 in connection with the flesh of the foot. 



The substance of the wall presents a fibrous appearance 

 which is pretty strongly pronounced. The constituent 

 fibres from which this appearance results are directed 

 from the superior border towards the inferior in parallel and 

 regular lines. 



The sole is a horny plate which occupies the inferior surface 

 of the hoof (Fig. 100). It is situated between the inferior 

 border of the wall and the bars ; and, on account of the 

 oblique direction of these latter, it presents a strongly- 

 marked groove of a V-form, with the opening directed back- 

 wards. In this depression is lodged the frog. 



