THE: SKIN. 



353 



in chromatin and are doubtless capable of active 

 multiplication. A few scaly epithelial cells are 

 always found in the body of each lamella, but in 

 the substance of each lamina the tissue appears 

 to be compact and of a fibrous variety. It is this 

 compact tissue that is called collectively the insen- 

 sitive lamina. This fibrous tissue can be traced 

 outward to the bases of the laminae, where it mingles 

 with and is ultimately lost in the epithelial horn 

 wall of the hoof. While nuclei are absent, the 

 tissue should be regarded as made up of scaly epi- 



Horny tubes and wall matrix. 



Secondary laminae or lamella. 



Fig. 2486. Diagram of horizontal section through wall of hoof. 



thelial plates so arranged as to give it a fibrous ap- 

 pearance very similar to the stratum lucidum of the 

 human skin. 



Vascular Lamina. These structures, collectively 

 known as the podophyllous tissue, are leaf-like 

 growths of the dermis, which interlock very snugly 

 with the horny laminae and lamellae just described. 

 They form an expansive fibrous and vascular tissue 

 uniting the distal phalanx with the horny epidermal 

 laminae of the hoof. They are also called the sensi- 

 tive lamina, and, while the nerve endings in them have 

 23 



