THE FOOT 



66$ 



a grey horse would have white feet, but a grey horse is not a white 

 horse ; and a grey with grey legs has dark feet, but a grey with 

 white legs has white feet. The number of white feet among grey 

 horses is very small.* The physiological importance of non-pig- 

 mented horn is its weakness, brittleness, and slow growth, as com- 

 pared with the pigmented variety. A white foot constitutes local 

 albinism (see p. 304). 



The wall is thickest and longest at the toe, thinnest and shortest 

 at the heel. A gradual decrease in thickness occurs from front 

 to rear (Fig. 228) ; but if a section of the wall be made in the direction 

 of its fibres, it will be found that whatever the thickness may be 

 at that particular part, it is maintained from the coronet to the 



Fig. 227. — The External Foot or Hoof. 



The fibrous appearance of the wall may be seen, also the periople marked X ; 

 the hair of the edge of the coronet is clipped away to show this band of white 

 horn, which for the purpose of the photojraph was swollen by immersion in 

 water. 



ground surface. The greater thickness of the wall at the toe and 

 quarters as compared with the heels is connected with the wear and 

 tear of the hoof, and the movements which the latter undergoes 

 under the influence of the body weight. If the wall were as thick 

 at the heels as at the toe it would have been a rigid box ; it is, 

 however, a yielding box, and the yielding occurs in the region of 

 the thin wall of the heels. The reason why the wall is thick at the 

 toe is that it is here where the greatest friction and strain occurs. 

 The wall at the heels is suddenly inflected (Fig. 228,5), running under 

 the foot in a forward direction for a short distance, and forming an 

 acute angle with the wall. This inflected portion of the wall is called 

 the Bars (Fig. 228, 6), and in the gap formed between the two bars is 

 lodged the footpad. Thus the wall is an incomplete circle of horn, 

 the circle being broken at the posterior part of the foot, and the piece 



* I am indebted to Captain Martin Millar, A.V.C., for exact information 

 respecting 500 grey horses : 57*3 per cent., had black feet, 34 per cent, 

 parti-coloured feet, and 8*7 per cent, white feet. He also observes that a 

 dark spot on a white coronet frequently colours the hoof out of all pro- 

 portion to its size. 



