SPECIAL HISTOLOGY. 



OF THE EXTERNAL INTEGUMENT. 



I.— OF THE SKIN IN THE STRICTER SENSE. 



A. CUTIS. 



§ 31. 



The external skin, Integumentunx commune (fig. 45), consists 

 essentially of an internal layer formed principally of connective 



tissue, and rich 



Fig. 45. 



l.J 



e — 



L 



/- 



f- 



.-« 



-/ 



c 



d 



in vessels and 

 nerves, the true 

 skin, cutis, derma 

 (fig. 45, c, d); and 

 of an external 

 layer composed of 

 cells only, the 

 epidermis (fig. 45, 

 a, b) ; and it con- 

 tains in addition 

 many peculiar, 

 glandular and 

 horny organs. 



The cutis may 

 be again subdi- 

 vided into two 

 layers, the sub- 

 cutaneous cellu- 

 lar tissue, tela 



Fig. 45. Perpendicular section through the whole skin of the ball of the thumb, 

 transversely through three ridges of the cutis, x 20 : a, horny layer of the epidermis ; 

 h, its mucous layer; c, corium; d, panniculus adiposus (upper part) ; e, papillae of 

 the cutis; /, fat masses; y, sudoriparous glands: /;, their canals; i, sweat-pores. 



