THE SKIN. 341 



The Malpighian layer is made up of growing epi- 

 thelial cells and constitutes the deeper parts of the 

 epidermis. Its lower surface is beset with numerous 

 depressions that receive connective-tissue papillae 

 from the dermis. The epidermis and dermis thus 

 interlock by means of an extensive system of papillae 

 from each layer. The Malpighian layer is thicker than 

 the horny layer, excepting in the sole of the foot and 

 the palm of the hand. It consists of ten to fifteen 

 layers of epithelial cells. The cells in the lower row 

 are columnar and are so arranged that their long axis 

 is vertical to that surface. In colored races these 

 cells are pigmented and impart to the skin the par- 

 ticular color of the race. Pigmentation has been 

 discussed on page 73, to which the reader is re- 

 ferred. The other cells of the Malpighian layer are 

 cubical or flattened and so placed that their long 

 axis lies parallel to the surface of the body. The 

 cells of the deeper strata have numerous minute 

 short processes and have been called prickle cells. 

 These processes form intercellular bridges, which 

 give rise to a complex system of minute intercellular 

 channels that permit more freely the passage of 

 nourishment. These cells are constantly dividing 

 and adding new strata to the horny layer that is ex- 

 foliating at the same rate. 



The dermis, corium, or cutis vera, is of connective- 

 tissue origin and lies just beneath and intimately 

 associated with the epidermis. It may be divided 

 into a papillary portion, next to the epidermis, and 

 a deeper reticular portion which shades off into the 

 subdermal fascia. The papillary portion consists of 



