132 



SPECIAL HISTOLOGY. 



Fig. 55 B. 



more strongly ; on the other hand, the papillae produce either 

 no perceptible projection, or hardly any. 



The epidermis consists of two layers, chemically and morpho- 

 logically distinct, and which are separated by a tolerably 

 sharp line of demarcation, viz., the mucous layer and the horny 

 layer. 



§ 41. 



The mucous layer, stratum Malpiyhii, rete or mucus Mal- 

 piyhii {rete mucosum), of many authors, is that part of the 

 epidermis which lies immediately upon the. corium, and almost 

 everywhere appears undulated; in many places it is distin- 

 guishable even to the naked eye by its colour, which is whitish 

 or variously tinged with brown, and it is further charac- 

 terized by its small, soft, easily destroyed, peculiarly dis- 

 posed cells. 



The form of these cells and 



their disposition are not the 



same in all localities. The 



H§H; innermost of them (fig. 55 b), 



^ which, without interspersed free 



nuclei or semi-fluid substance, 

 Ip form a single layer resting im- 

 mediately upon the free surface 

 of the corium, are elongated, 

 and not unfrequently resemble 

 the cells of cylinder-epithelium ; 

 they are placed perpendicularly 

 upon the corium; their length is 

 f /'- about from 0-0033— 0006'", their 



breadth 00025— 0003'". Upon 

 these immediately follow, in most 

 places, elongated or even round cells of 0-003 — 004'" in 

 many layers; but in a few localities, as in the hand and foot, 

 at the free margin of the eyelids, in the mucous layer of the 

 nails and hairs (vide infra), there are interposed here and 



Fig. 55 B. Perpendicular section of the skin of the Negro (from the leg), x 250 : 

 aa, cutis-papillae ; b, deepest intensely-coloured layer of perpendicularly elongated 

 cells of the stratum mucosum; c, upper layer of the stratum mucosum: d, horny 

 layer. 



%F 





