158 ANATOMY AND PHYSIOLOGY OF THE HORSE’S FOOT. 
this is abundant it swells out around the top of the hoof to 
form a soft, prominent, whitish-coloured ring ; but when it 
has lost much of its humidity, it is hard, shrunken, and 
rugged, and may even fall off in flaky fragments. Its con- 
sistence, therefore, depends upon its humidity. 
It is to be noted that this band is thickest and coarsest in 
texture in underbred horses, and thinnest and finest in those 
which are well bred ; it is usually thicker and more tenacious 
in young than in old horses. Its colour is always lighter 
than that of the wall, even when this is white. 
Like the frog, this coronary band has a fine, close, elastic 
and fibrous texture, which approximates to that of the wall in 
its deeper and contiguous layers. 
Its action is chiefly to protect that portion of the wall 
-which has not become strong enough to resist the injurious 
influence of heat and dessication ; this it effects by its close 
varnish-like properties. It has also been said that it concurs 
in fixing the foot in the hoof, like the band of a sandal-shoe. 
This, however, it can do only in a feeble manner, because of 
its tenuity and elasticity. It contributes in an especial 
manner to the formation of the cutigeral cavity ; for though 
constituting but a very narrow addition to that portion 
formed by the upper margin of the wall at its front and 
sides, it suddenly increases towards the points of the heels 
and at its junction with the frog, so as greatly to widen and 
deepen this important cavity, more than one half of which is 
here formed by the periople. Into this wide space on each 
side is received the posterior extremity of the corresponding 
very flexible lateral cartilage or bulb of the plantar cushion. 
From this disposition, it will be understood that towards the 
heels of the foot the Avail of this cavity is made up of ex- 
tremely elastic horn, which is occupied by equally elastic 
cartilage and peculiarly arranged fibrous tissue, a combina- 
tion and arrangement Avhich sufficiently indicates its role in 
the elastic functions of the organ. By its elasticity, the 
periople allows of that expansion or alteration in form of the 
coronary cushion which is so noticeable at the top of the 
hoof during motion, for at this part is to be found the alter- 
nate expansion and contraction some observers have fancied 
to be located at the loAver margin of the hoof. 
(To be continued.) 
