SKIN. 



[ 696 ] 



SKIN. 



(fig. 641 e)t which are frequently bifid, 

 lobed, or arise several from a common base. 

 In many parts of the skin they are arranged 

 in more or less regular rows. 



In certain papillae, the connective tissue 

 is often homogeneous, especially in the me- 

 dian portion, where it forms an oval trans- 

 parent body (fig. 642 a), surrounded by a 

 layer of imperfectly developed elastic tissue, 

 consisting of spindle-shaped cells and fibres 

 taking a horizontal or circular direction, 

 and giving the oval body a transversely 

 striated or laminated appearance. These 

 are called tactile corpuscles, and are most 

 abundant at the ends of the fingers and in 

 the lips. See also PACINIAN CORPUSCLES. 

 The cutaneous papillae are traversed by the 

 terminal loops of the capillaries (tig. 642 d) 

 and nerves (tig. 642 c). 



The cutis is continuous beneath with the 

 subcutaneous cellular or properly areolar 

 tissue (fig. 641 d), which is of a much more 

 lax texture than the cutis, presenting large 



Fig. 641. 



areolae filled in most but not all places with 

 fatty tissue (tig. 641 /). 



The cutis is everywhere covered externally 

 with a thin membrane, and this by the epi- 

 dermis, which is a semitransparent coat, 

 containing neither vessels nor nerves, mould- 

 ed as it were upon the surface (fig. 643) 

 and filling up the intervals between the pa- 

 pillae (fig. 644). The variously arranged lines 

 seen upon its outer surface are depressions 

 corresponding to those existing upon the 

 cutis between its rows or groups of papillae. 



The epidermis consists entirely of nu- 

 cleated cells ; and two distinct layers are 

 recognized in it (tig. 643), an inner forming 

 the rete mucosum (tig. 643 c), and an outer 

 or cuticle (tig. 643 d). The rete mucosum 

 is softer than the cuticle, and is fre- 

 quently of a brownish colour, from its 

 cells, especially the deepest, containing gra- 

 nules of pigment. These cells are not all of 

 the same form, those immediately applied 

 to the cutis being somewhat elongated and 



Fig. 642. 



Fig. 641. Perpendicular section of the skin of the under surface of the end of the thumb, through three furrows, 

 a, cuticle; 6, rete mucosum; c, cutis vera ; d, upper part of subcutaneous tissue; e, papiTse of the cuds ; f, fatty 

 tissue ; g, sudoriparous glands ; h, sudoriparous ducts ; i, orifice of the latter. Magnified 20 diameters. 



Fig. 642. Papillae from the skin of the under part of the end of the finger, a, axial body ; b, nerve ; c, its ter- 

 minal loop ; d, d, loops of capillary blood-vessels. Magnified 250 diameters. 



