ANATOMY AND PHYSIOLOGY OF THE HORSe’s FOOT. 147 
of the cavity, gradually becoming finer as we examine them 
at the higher border or external surface. 
When describing the vascular tufts on the white zone of 
the coronary cushion, it was noted that they were arranged 
in somewhat parallel and vertical rows, with a narrow slit or 
depression between them, and that they were of a larger size 
than those of the cushion proper; and we have also just 
stated that the horny laminae apparently commence in the 
cutigeral cavity, and not on the inner surface of the wall. A 
careful scrutiny of this cavity with the naked eye will demon- 
strate the presence of minute ridges crossing the direction 
and width of the imprint of this zone, and passing inwards to 
become continuous with the horny laminae ; in fact, these 
ridges are the commencement of the leaves. They are, of 
course, shortest in front of the cavity, and longest towards the 
heels, where the imprint is widest ; they pass between the 
rows of perforations into which the villosities of the zone 
enter, and correspond to the narrow intervillous depressions 
between these tufts, — an important point to remember when 
discussing the manner in which the keraphyllae are formed. 
The inferior border of the wall does not offer anything very 
noteworthy in its structure. On its plane or lower surface, 
which meets the ground, the horn-fibres terminate, while its 
inner or concave face shows the continuations of the horny 
leaves, even to the level of the sole or beyond its surface, 
depending on the length to which the wall has attained. It 
is through their interposition that so firm a union is esta- 
blished between the sole and crust, that nothing but long- 
continued maceration or a very high temperature can separate 
them. This union is evidenced in the living animal, whose 
sole has been just pared according to custom, by a narrow 
white or yellow zone or band, in which we can trace these 
laminae. More especially is this the case with hoofs that 
have been allowed to become overgrown, and then exposed to 
desiccation; a slight separation then appears to be effected 
between the sole and wall, and the terminations of the horn- 
leaves are visible for some distance. In certain cases of 
disease this zone is also the first to show a change of colour, 
by reason of the infiltration of blood or other fluid through 
the softer horn of which it is composed. 
The lower or ground aspect of the wall — that portion which 
shows the ends of the horn-fibres — usually has a different tint 
to the other portions, and is relatively much more dense, 
tough, and resisting in its substance. This is the part that 
has generally to sustain wear and strain in the unshod horse, 
and on which the shoe rests with the animal that has been 
