EXPLANATION OF THE PLATES. 



PLATE XXV. 



STRUCTURE OF NAILS. 



Fig. 1. A longitudinal section of the nail of the middle 

 finger magnified 130 diameters, showing the direc- 

 tion of the striae or laminae of cells of which the 

 nail is composed, and which usually pass from 

 above downwards and forwards. In the section 

 shown in the figure, the obliquity of the striae is 

 but slight ; the under surface of the nail is distin- 

 guished from the upper by its smooth outline. 



Fig. 2. The same, in which the striae are disposed more ob- 

 liquely, but in a contrary and unusual direction; 

 viz. from above downwards and backwards. 



Fig. 3. Other longitudinal sections, in one of which the 

 striae run, almost vertically. 



Fig. 4. A transverse section of nail magnified to the same 

 extent as the former figures ; in it the striae are 

 parallel to the surface, and are less strongly marked. 



Fig. 5. The detached cells of which the superimposed layers 

 of nails are composed ; the smaller cells are mag- 

 nified 130 diameters, the larger 670. 



Fig. 4. Plate XXVI. represents the peculiar and beautiful 

 manner in which the nail and the papillary layer 

 of the true skin are united. 



