EXPLANATION OF THE PLATES. 



PLATE XXIV. 



STRUCTURE OF EPIDERMIS. 



Fig. 1. A portion of the epidermis of the palm of the hand, 

 magnified with a simple lens, showing the direction 

 of the ruga3 in that situation, and the arrangement 

 of the apertures of the sudoriferous glands. Each 

 of the ridges figured is made up of square compart- 

 ments, the divisional lines of which run at right 

 angles to the ridges, passing across the apertures 

 referred to. These several compartments again are 

 indented on their under surface with the papilla? 

 of the sensitive skin. 



Fig. 2. A portion of the same magnified 100 diameters. 



Fig. 3. A transverse section of the ridges of the epidermis of 

 the palm of the hand, showing a side view of the 

 apertures of the sudoriferous glands, their spiral 

 ducts, the thickness of the epidermis in the situa- 

 tion mentioned, its composition of superimposed 

 layers of cells, and its mode of connexion with the 

 true skin. 



Fig. 4. A longitudinal section of one of the ridges magnified 

 to the same extent as the previous figure, viz. 100 

 diameters : in this the composition of the thickened 

 epidermis of adherent layers of cells is better seen, 

 and the difference in the form of the superficial 

 and deeper seated cells may also be observed. 



Fig. 5. A portion of the epidermis removed from the back 

 and outer part of the hand, showing the, disposition 

 of the folds in that situation, the arrangement of 

 the papillae, the disposition of the hair follicles and 



