890 CENTRAL VETERINARY MEDICAL SOCIETY. 
to prevent the foot rotating in its horny covering. The supposition 
that the horny laminae are secreted by the sensitive laminae he 
thought may be readily disproved by an examination of the spaces 
between the papillary tubes in the cutidural cavity, in which ridges 
or eminences are to be found as the result of secretion from the 
coronary cushion, and prove to be the commencement of the horny 
plates. In cases of disease, also, abundant proof appears evident, 
for where the wall has been destroyed horny laminae may be seen to 
originate at the top and grow downwards. Maceration serves to 
separate each part of the hoof, but the horny wall and laminae do 
not admit of separation by such means, and in transverse sections 
of the wall epidemic cells may be observed to enter in to form the 
horny plates, but in disease states are modified. In health the 
intertubulary substance is for the purpose of connecting the fibres 
of the wall and hoof, and preserve a degree of moisture and resiliency; 
in disease the hoof becomes dry and brittle as a result of the 
modified action. At the junction of horny wall and sole is a white, 
soft substance known as the white zone, placed there to prevent dis- 
junction, but not secreted by the sensitive laminae, which run down 
to and terminate in it. In disease the sensitive laminae are to be 
observed covered with scales which form horn, but it is no integral 
part of the natural hoof ; and likewise horny tumours formed upon 
the white zone or horny laminae are morbid productions, the result 
of diseased action at the part. They do not grow down from the 
top as the nature of their construction thoroughly proves ; besides 
the cells of the papillae are sent down vertically, while those in the 
laminae are horizontal, but no such orderly arrangement marks the 
adventitious products of morbid action, while it is conducive in the 
healthy structures to an efficient resistance to wear and fracture. 
The functions of the frog have been much misunderstood, and the 
theories of expansion and contraction have been most disastrous to 
the proper treatment of horses’ feet. He thought Mr. Hunting was 
quite right when he said the frog had no part in expanding the 
heels. It is doubtless to sustain weight at the back of the foot, to 
avert concussion, and protect the tendon and navicular point above. 
The coronary cushion also admirably sustains weight, and receives 
and distributes initial concussion. 
Mr. F. J. Mavor considered the wall to be the true supporter of 
weight on hard surfaces, and as it is constructed is most efficiently 
capable of conducting jar upwards, and thence causing it to pass 
off. He did not deny that upon soft ground the sole received 
pressure, but conceived that otherwise it is improper for it to do so. 
Mr. T. D. Broad contended that the sole can sustain a degree of 
pressure with benefit, and gave as an instance the fact of great 
improvement taking place in that part of thin shelly feet by the use 
of nonseated shoes. Among the evils in the practice of shoeing he 
places the knife first, calkins second, and seated shoes last in 
order. 
Mr. Alexander Lawson believed the crust should bear the greatest 
share of pressure [weight], frog next and the sole last. It is an 
