THE VARIOUS LAYERS 153 



various shapes. Four of these layers are 

 distinguishable. 



' First. The Stratum corneum, which con- 

 sists of many layers of horny scales. The 

 different thickness of the epidermis in different 

 regions of the body is chiefly due to variations 

 in the thickness of this layer, e.g., on the 

 horny parts of the palm of the hand and 

 soles of the feet it is of great thickness. 



6 Second. The Stratum lucidum, a bright 

 homogeneous membrane, consisting of squamous 

 cells, closely arranged, in some of which a 

 nucleus can be seen. 



1 Third. The Stratum granulosum, consisting 

 of one layer of flattened cells, which are dis- 

 tinctly nucleated. A number of granules 

 extend from the nucleus to the margins of 

 the cells. 



' Fourth. The Bete mucosum, which consists 

 of many strata. The deeper cells are columnar 

 with oval nuclei, then follow several layers with 

 spherical nuclei. The deeper surface of the 

 Eete mucosum is accurately adapted to the 

 papillae of the true skin, being, as it were, 



