THE LAMINAL OR CONNECTING SHEATH. 



83 



and horuy sole, together with the horn filling their interspaces, 

 are termed the white line, as will be explained in treating of 

 the horny sole. 



If more closely examined the individual laminae in the fresh 

 state are each seen to present a striped appearance (fig. 56, 

 d-e), the stria tions extending in an 

 oblique direction from the free border 

 upwards and outwards ; attempts to 



tear through a lamina succeed best ^;f:i^^::'/^:^^'y>iy:^^?f^;^A 

 when made in this direction (fig. 56,/). ^^^^^^^^^^S^ 

 Until recently, it was generally stated 

 that the horny, like the sensitive, 

 laminae possessed secondary laminae 

 running in the direction of their 

 greatest length. Professor Mettam, 

 however, who has given special atten- 

 tion to the subject, is sceptical of the existence of secondary 



Fig. 49. — A portion of the inner sur- 

 face of the hoof where horny wull 

 and horny sole join (about natural 

 size), a, laminal sheath ; b, line 

 of union ; between the individual 

 laminae are seen spaces which ac- 

 commodate the horn -secreting 

 papillaj ; c, horny sole. 



?^ C ^' 



«J- 



^^^&mMm 



e 



Fig. 50. — Transverse incision through the laminal sheath, a, inmost part of the middle 

 sheath ; the horn tubules are seen to reach right up to the horny lamina) ; 6, body of the 

 sensitive wall; c, cornitied portion of lamina) connected with middle sheath of wall ; d , 

 irregular laminse, which do not extend as far as body of sensitive wall ; c", non-cornified 

 portion of rete mucosum ; d, vascular laminaj ; d', vascular laminae which during de- 

 velopment have split, thence given rise to the irregular horny laniime d ; «, injected 

 artery. 



horny laminae. He says : — " The cells formed by the secondary 

 sensitive laminae had not changed to horn, and consequently, 

 when a section of the horny wall and laminie is viewed, no 

 projections are seen on the latter." The relation of the horny 

 to the sensitive laminae will be seen by reference to fig. 50, 



