SPECIAL HISTOLOGY. 



OF THE EXTERNAL INTEGUMENT. 



Fig. 45. 



._ -c 



I. OF T^E SKIN IN THE STRICTER SENSE. 



A. CUTIS. 



31. The external skin, Integumentum commune (Fig. 45), consists 

 essentially of an internal 

 layer formed principally 

 of connective tissue, and 

 rich 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 contains 

 in addition many pecu- 

 liar, glandular and horny 

 organs. 



The cutis may be 

 again subdivided into 

 two layers, the subcu- 

 taneous cellular tissue, 

 tela cellulosa subcutanea 

 (Fig. 45, d); and the 

 proper corium (Fig. 45, 

 c) ; the latter of which, from its rich nervous and vascular supply, forms 

 the* most important part of the skin. 



32. The subcutaneous cellular tissue is a tolerably firm membrane, 

 constituted chiefly of connective tissue, which in by far the most parts 



FIG. 45. Perpendicular section through the whole skin of the ball of the thumb, trans- 

 versely through three ridges of the cutis: a, horny layer of the epidermis; b, its mucous 

 layer ; e, corium ; rf, panniculus adiposus (upper part) ; e, papillse of the cutis ; /, fat masses ; g, 

 sudoriparous glands; A, their canals; i, sweat-pores. Magnified 20 diameters. 



