

CHAPTER VIII. 

 Skin and its Appendages. 



SECT. I. SKIN. The skin consists of two distinct Epidermis, 

 layers : the first, superficial, and composed entirely of 

 cells, is the epidermis, or cuticle ; the second, beneath 

 this, which has for its basis a dense interlacement of 

 fibres of connecting tissue, containing in its meshes a 

 quantity of nerves, blood-vessels, glands, and masses 

 of adipose cells, is the derma, or true skin. 



In the epidermis there are three distinct strata. 

 The first, in contact with the true skin, consists of a 

 single layer of cylindrical cells with well marked 

 nuclei, and with their long diameters at right angles 

 to its surface (PL XXIII. fig. II. 3 ; fig. III. 1 ; fig. IV. 

 3). It is principally in this layer that the deposit of 

 black pigment is found which causes the dark color 

 of the negro, and in certain regions of the skin in the 

 white, as, for example, the nipple and the scrotum 

 (fig. III. 1), Upon this stratum of cylindrical cells 

 is another, five or six times the thickness of the first, 

 and likewise consisting of nucleated cells (fig. I. 3 ; 

 fig. II. 2). The deepest cells of this layer are oval, 

 the next in order, round, or regularly polygonal, and 

 the most superficial again oval ; but their long dia- 

 meters have a different direction from those of the 

 deep cells ; that is, they are parallel to the cutaneous 

 surface. It is these two united layers which form the 



