STRUCTURE OF WALL, WHITE LINE, AND SOLE. 



95 



striae appear as thicker, thread-like lines, and are then very 

 distinct. 



By making a horizontal section, embracing portions of the 

 bearing surface of the wall, of the white line and of the sole 

 (fig. 58), we see that the spaces between the individual horny 

 laminae are not filled by connective horn alone, but that a 

 number of horn tubes are included. The horny laminae possess 

 no horn tubes. Their surfaces show slight striai and small 

 secondary laminae or lamellae, more or less vertical (fig. 56, d and 

 e), resembling those of the sensitive laminae abeady described 

 at p. 71. Transverse sections of the horny laminie show these 

 secondary laminae as small radiating prominences (fig. 66, d), 

 which are to be found both in old and young hoofs. The horn 



Fig. 58. — Horizontal section through a part of the wall, the white line and the sole, a, horn 

 wall ; b, horn laminae. The horn surrounding the laniina; contains horn tubes c, cut 

 through obliquely ; d, horn sole. 



of the hoof, therefore, with the exception of the horny laminae, 

 consists of innumerable distinct, parallel, closely -packed horn 

 tubes, running obliquely downwards and forwards, and sur- 

 rounded by an inter-tubular horn which cements them firmly 

 together. 



We may next go a step further, and seek to discover the 

 nature and mutual relations of the horn tubes and of the inter- 

 tubular horn which connects them. The moderate amplifica- 

 tion which revealed the tubular structure of the hoof is now 

 insufficient. Powers of 200 to 300 diameters are required, 

 and the examination will be found to present peculiar difficulties. 

 To facilitate cutting we must employ horn which has been long 

 macerated, or, if possible, parts from young animals, and some- 



