CHAPTER 1. 



HISTOLOGY OF HORN, 



By studying a hoof which has recently been removed and 

 carefully cleansed, we see that the wall presents a fine vertical 

 striation in addition to the longitudinal ring formation already 

 referred to. This striation is also apparent on the surface of 



Fig. 56. — Pei'peiuliculav section from horn of wall (magnified) . The pai'allel dark striaj are 

 horn tubes ; the lighter intervening portions represent inter-tubular horn. The por- 

 tion from a-b represents the outer (dark-coloured) portion of the wall ; b-c, the inner 

 (whitish) portion of wall ; c-d, margin between protective sheath and horn laminte ; 

 d-e, horn laminic. At /are seen splits in the laminre, running in an oblique upward 

 direction. 



vertical sections through any portion of the wall ; it usually 

 appears best marked in the inner third of the thickness of the 

 wall, that is, in the portion nearest the laminal sheath, which 

 even in dark hoofs appears light coloured. By removing a 

 thin slice of the dirty or burnt horn from the ground surface 

 of the wall, a number of small, closely packed points will 

 be seen, somewhat resembling the little openings which we 

 have already studied in the cutigeral groove. Little more 

 than this can be seen, and therefore, in studying the finer 

 structure of the wall, we have recourse to thin sections 

 and high magnification. By making a thin section in the 

 direction of the striation noted, selecting either the outer 



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