PAPILLiE OF THE COEIUM, 



215 



a different nature, and are caused by tlie wasting of the soft parts which 

 the skin covers. Fine curvilinear ridges, with intervening furrows, 

 mark the skin of the pahn and sole ; these are caused by ranges of the 

 papilla?, to be immediately described. 



Papillae. — The free surface of the corium is beset with small emi- 

 nences thus named, which seem chiefly intended to contribute to the 



FifT. Ii2. 



Fig. 141. — Papill-e, as seex with a ^Microscope, ox a portion of the Tkue Skin, 



FROM WHICH THE CUTICLE HAS BEEN KKMOVED (after Brescliet). 



Fig. 142. — Compound Papill.e from the Palm of the Hand, magnified 60 Diameters. 



a, basis of a papilla ; b, h, divisions or branches of the same ; c, c, branches belonging 

 to jjapillifi of which the bases are hidden from view (after Kolliker). 



perfection of the skin as an organ of touch, seeing that they are highly 

 developed where the sense of touch is exquisite, and vice versa: They 

 serve also to extend the surface for the production of the cuticular 

 tissue, and hence are large-sized and numerous under the nail. The 

 papillte are large, and in close array on the palm and palmar surface of 

 the fingers, and on the corresponding parts of the foot (fig, 142). There 

 they are ranged in lines forming the curvilinear ridges seen when the 

 skin is still covered with its thick epidermis. They are of a conical 

 figure, rounded or blunt at the top, and sometimes cleft into two or more 

 points, when they are named compound papilliE. They are received into 

 corresponding pits on the under surface of the cuticle. In structure 

 they resemble the superficial layer of the corium generalh', and consist 

 of a homogeneous tissue, presenting only faint traces of fibrillation, 

 together with a few fine elastic fibres. On the palm, sole, and nipple, 

 where they are mostly of the compound variety, they measure from ^-^ 

 to y^o of an inch in height. In the ridges, the larger papillae are 

 placed sometimes in single but more commonly in double rows, with 

 smaller ones between them (fig. 156), that is, also on the ridges, for 

 there are none in the intervening grooves. These ridges are marked at 

 short and tolerably regular intervals with notches, or short transverse 

 furrows, in each of which, about its middle, is the minute funnel-shaped 

 orifice of the duct of a sweat-gland (fig. 143). In other parts of the 

 skin endowed with less sensibility, the papiihe are smaller, shorter, 

 fewer in number, and irregularly scattered. On the face they are 

 reduced to from y,}^ to -^^ of an inch ; and here they at parts 

 disappear altogether, or are replaced by slightly elevated reticular ■ 

 ridges. In parts where they are naturally small, they often become 

 enlarged by chronic inflammation round the margin of sores and ulcers 



