128 LAMENESS IN THE HORSE. 



uuyielding horny box and the os pedis, are very apt to be 

 pressed upon even when but slight changes in the crust 

 occnr. As a consequence of such pressure, pain results and 

 the animal goes lame. Nevertheless this horny box is a 

 powerful protection to the parts enclosed by it, effectually 

 resisting a great many destructive agents. Sbould separa- 

 tion of any part of the horny box occur, thus establishing 

 a direct communication between the soft parts contained in 

 it and the external world, a favorable condition for the 

 entrance of septic material is created, and inflammation is 

 likely to follow. 



Inflammation of the podophyllous membrane can be 

 septic, asceptic, acute or chronic, and the latter superficial 

 and deep, also designated parenchymatous. To appreciate 

 inflammation of this membrane, especially its seat and 

 extent, means to be familiar with its structural arrange- 

 ment. Unless the one examining a horse for hoof lameness 

 is thus acquainted with it, his diagnosis, as to the seat of 

 the lameness, is only guess work. 



The podophyllous membrane is related in its make-up to 

 the skin. It shows a strongly developed rete malphigii, 

 which covers the cutis proper. The papillary body of the 

 cutis is exceedingly prominent. The sole, frog, and especi- 

 ally the coronary cushion, are closely studded with large 

 papillae. In the region corresponding to the wall of the 

 hoof, an enormous development of the papillary body is 

 met with in the shape of the primary and secondary laminae, 

 protected by a strong rete malphigii. Next to the papillary 

 body and below it is the vascular layer, composed of many 

 vessels imbedded in a loose connective tissue. The deepest 

 layer ensheathes the os pedis, representing the periosteum. 

 The subcutis, the basis for all these layers, is irregularly 



