160 



SPECIAL HISTOLOGY. 



the further out the ridges lie, and eventually are directed forwards like 

 the others. At a distance of 2| to 3| lines from their origin, thej all 

 at once become more prominent, and take on the form of true lamince 

 of 0-024 to 0-1 of aline in depth, which run directly almost to the anterior 

 edge of the bed of the nail, and then end suddenly, as if truncated. 

 The line of transition of the ridges into the lammce is convex anteriorly, 

 and divides the bed of the nail into two sections, differing both in their 

 extent and in their color : the posterior smaller one is nearly covered 

 by the wall of the nail and underlies its root, the anterior and reddish- 

 colored division underlying its body. The ridges and lamin?e of the bed 

 of the nail, the number of which varies between 50 and 90, are, at their 

 edges, beset with a series of short papilla of 0-008-0-016 of a line. In 

 addition, I can confirm Henld's statement that the bottom of the fold of 

 the nail exhibits a few transverse ridges with larger papillas directed 

 forwards ; further forwards where the lamina' cease, there are also long 

 isolated papillte. On the nail of the little toe, the papillae are frequently 

 rot seated upon ridges, but are more dispersed. 



The wall of the nail has no ridges upon its lower surface, and rarely 

 a papilla here and there. These commence again upon its margin, 

 "where they are of some length, and are continued thence upon its upper 

 surface, which is in no respect distinguishable from the cutis of the back 

 of the fingers and toes. 



The coriuni of the wall and of the bed of the nail 

 is dense, and for a considerable distance contains 

 but little fat; in the ridges and laminae with their 

 papillag, it is abundantly provided with fine elastic 

 fibres. The vessels are particularly numerous in 

 the anterior segment of the bed of the nail ; behind, 

 where the root of the nail lies, and in the wall they 

 are more scanty; their capillaries, 0"005-0'008 of 

 a line, form very distinct simple loops in the papilla?, 

 and single trunks often pass, even into many papillae. 

 The nerves have the same relations below as in the skin, but I have 

 hitherto been unable to detect their terminal loops or divisions in them. 

 In the nail itself we may distinguish, the root, the hody, and i\\e free 

 edge (Fig. 60). The soft root (Fig. 60 I) corresponds in its extent to the 

 posterior ridged segment of the bed of the nail, and is either wholly hidden 

 in the fold, or exposes a small semilunar surface, the lunula. The poste- 

 rior edge is attenuated, sliglitly bent upwards, and is the thinnest and most 

 flexible part of the nail. The hard body, which increases in thickness and 

 breadth from behind forwards [k), lies for the most part with its upper sur- 

 face uncovered; its somewhat sharp thin edges are hidden in the lateral 



Fig. 59. 



Fig. 59. — Capillaries of the bed of the nail, after Berres. 



