REVIEW. 
694 
“internal parts,” but at once proceed to notice th e “ external” 
or corneous apparatus — the hoof. 
“The geometrical figure to which the hoof most nearly 
accords is that of a truncated cylinder, cut at its base and 
summit by two planes running oblique to its axis, but not 
parallel, the inferior converging, backwards, towards the supe- 
rior with a marked inclination towards the axis.” 
No exterior figure, however, can give any adequate idea of 
the hoof. To thoroughly comprehend its nature it must be 
resolved into its component parts: — 
“ 1. The wall , or crust. 2. The sole. 3. The frog, with 
its periople, which is nothing more than a circular continuation 
of it.” 
The discovery of the periople, or frog-band, M. Bouley 
assigns, without dispute, to Bracy Clark. 
“ It was Bracy Clark who first discovered and described it, 
and gave it the two names (periople and coronary frog-band) 
by which it is known at the present day. 
From the description of the hoof in its divisional form, in the 
examination of the several component parts of which M. Bouley 
has at great lengths entered with his usual accuracy and pre- 
cision, we arrive at the “ chapitre ” devoted to the consideration 
of the hoof generally i. e. re-instated, after having been taken to 
pieces, in its entirety of form. 
“ The horny tissue is inextensible, little pliable in a body, 
though very flexible when sliced into thin lamellae. To the 
naked eye it appears to be composed of an assemblage of fibres 
or filaments in juxta-position, firmly united by an agglutinative 
substance of the same nature. It was the learned Professor 
Gurlt, of the Veterinary School of Berlin, who demonstrated, 
through microscopic examination, that these apparent fibres or 
hairs were, in fact, a system of tubes open at their superior 
extremities in order that they might receive the villous prolong- 
ations from the keratogeneous surfaces for which they were so 
many sheaths. According to M. Gurlt, these tubes are formed 
of concentric lamellae, joined together by an amorphous horny 
substance, spotted with punctiform corpuscules, of which (sub- 
stance) there are marks upon the outer covering of the hoof 
and in the intervals between the villosities. M. Delafond 
agrees in opinion in his views of the tubular structure of the 
