The Skin and the Kidneys 



fingers. They are arranged in paral- 

 lel curved lines, and form the elevated 

 ridges seen on the surf ace. of the outer 

 skin (Figs. 97 and 98). 

 ^^> 281. The Epidermis, or Cuticle. 

 Above the true skin is the epidermis, 

 which as seen under the microscope 

 resembles the scales of a fish. It is 

 this layer that is raised by a blister. 



As the epidermis has neither blood 

 vessels nor lymphatics, it may be 

 cut without bleeding. It contains no 

 nerves except in the deepest layers, 

 therefore the surface is not sensitive 

 to pain. The cuticle is made up of 

 several layers of cells, which next to 

 the true skin are soft and active, but 

 gradually become harder towards the 

 surface, where they are flattened and 

 scale-like. 



The upper scales are continually 

 being rubbed off and are replaced by 

 deeper cells from beneath. These 

 new cells continually push upward the 

 cells already existing, then gradually 

 become dry and are cast off as fine 

 white dust. 



Rubbing with a coarse towel after 

 a hot bath removes countless numbers 

 of these dead cells. During and after 

 an attack of scarlet fever the patient 

 "peels," that is, sheds an unusual 

 amount of the scaly cells of the cuticle. 



FIG. 96. Cross-Section 

 of Skin, with Blood 

 Vessels injected. 



(Magnified 30 diameters.) 



A, horny layer of cuticle ; 

 &, deeper layer of cuticle, 

 rete mucosum ; C, duct of 

 sweat gland; D, corium, 

 or true skin ; JE, subcutis, 

 or sub-layer of corium, 

 with columnar epidermic 

 cells in immediate contact 

 with dermis. (The blood 

 vessels are injected and in 

 this figure show black.) 



