662 A MANUAL OF VETERINARY PHYSIOLOGY 



a perfect counterpart of the sensitive foot. The hoof is composed 

 of a wall, with its inflections the bars, a sole, and a foot-pad (frog) ; 

 each of these must be considered separately. 



The Wall is that part of the hoof which can be seen when the foot 

 is on the ground ; its division into toe, quarters, and heels is for con- 

 venience of description, as no natural division exists. On the 

 exterior of the wall, at the meeting of the hair and hoof, is a rim 

 of peculiar non-pigmented horn, previously spoken of as the peripole. 

 Under natural conditions, it is grey in colour, soft to the touch, 

 and it cements the skin to the hoof. Its non-pigmented condition 

 is only rendered evident when the foot has been soaked in water 

 or poulticed ; the cells then swell, and a white curdy rim occurs all 

 round the top of the wall (see Fig. 22.7, X) . It is wider at the bulbs of 

 the heel, where it cements over the union not only of skin with foot- 

 pad, but of the meeting-place of the wall and foot-pad (Fig. 224, /, 7). 



Fig. 226. — The Venous System of the Horse's Foot (Storch). 



The periople provides the wall with an extremely thin covering, 

 resembling a delicate coat of varnish, which is intended to prevent 

 undue evaporation from the horn beneath. 



The Colour of the horn of the hoof is commonly described as black 

 or white ; to be strictly accurate, it is neither. The so-called black 

 horn consists of various tints of slate colour ; the white is pale 

 yellow or buff. It is, however, convenient to speak of black and 

 white feet. In dealing with the skin (p. 305), the colour of feet was 

 touched upon, and it was made clear that it depended upon the 

 colour of the hair of the coronet. If this is white, there is no pigment 

 in the skin, and consequently none in the horn ; if it is partly black 

 and white, the foot is striped accordingly. If the coronet is of any 

 other colour than black, the feet are dark ; but if these colours are 

 mixed with white, the feet are striped.* It might be imagined that 



* Colonel Nuthall, A.V.S., informs me that of some 2,500 horses he 

 caused to be inspected, five were recorded to have striped feet with no 

 white on the coronet. This is unusual, and doubtless due to absence of 

 pigment from certain portions of the wall- secreting membrane within the 

 hoof. 



