THE SKIN AND ITS APPENDAGES. 



1137 



In structure the epidermis consists of several layers of epithelial cells agglutinated 

 together and having a laminated arrangement. These several layers may be 

 described as composed of four different strata from within outward : (1) The stratum 

 Malpighii, composed of several layers of epithelial cells, of which the deepest layer 

 is columnar in shape and placed perpendicularly on the surface of the corium, 



Stratum corneum. 



Stratum Incut/tut. ( 

 Stratum granulosum. T 



Stratum Malpighii.< 



Stratum germinativum 



-Nerve-fibrils. 



FIG. 678. Section of epidermis. (Ranvier. 



their lower ends being denticulate, to fit into corresponding denticulations of the 

 true skin ; this deepest layer is sometimes termed the basilar layer or stratum 

 germinativum ; the succeeding laminae consist of cells of a more rounded or polyhe- 

 dral form, the contents of which are soft, opaque, granular, and soluble in acetic acid. 



FIG. 679, Microscopic section of skin, showing the epidermis and derma ; a hair in its follicle ; the erector 

 pili muscle; sebaceous and sudoriferous glands. 



They are often marked on their surfaces with ridges and furrows, and are covered 

 with numerous fibrils, which connect the surfaces of the cells : these are known as 

 prickle cells. (See page 1075.) They contain numerous epidermic fibrils, which 

 are stained violet with hsematoxylin and red by carmine, and form threads of union 



72 



