OF THE SKIN. 121 



composed principally of connective tissue, which in the thicker parts 

 presents two, though not very well-defined layers, which may be desig- 

 nated the "reticular" and the " papillary" portions (p. reticularis and p. 

 papillaris). The former constitutes the inner layer of the corium, and 

 consists of a white, reticulated membrane, frequently distinctly lami- 

 nated in its deeper portions, and containing in special, narrow or wide, 

 scanty or numerous meshes, the hair follicles and cutaneous glands, 

 together with much fat. The papillary part of the corium is the reddish- 

 gray external superficial layer (Fig. 45), which in its dense, firm tissue, 

 contains the upper portion of the hair-follicles, and cutaneous glands, 

 and the terminal expansions of the vessels and nerves of the skin. Its 

 most important element consists in the cutaneous or tactile papillae, 

 papillce tactus (Fig. 46) ; small, semi-transparent, flexible, but tolerably 

 solid elevations of the external surface of the corium, which are ordi- 

 narily conical or clavate in form, but in certain places present numerous 

 points (compound papillce). With regard to their number and position, 

 the papilla? of the bed of the nail, of the palm of the hand, and of 

 the sole of the foot are very numerous (E. H. Weber enumerates 

 upon 1 square line of the vola manus, 81 compound or 150 to 200 



Fig. 46. Fig. 47. 



smaller papillce), and disposed with 

 tolerable regularity in two principal 

 series, each of which has 2 to 5 papillse 

 in the transverse direction, placed upon 

 linear elevations, ^ to of a line broad, 

 by 2\j to \ of a line high, the ridges of 

 the corium. The course of these ridges 

 is visible, even externally in the epidermis, 



FIG. 46. Compound papilla? of the surface of the hand, with two, three, and four 

 points : a, base of a papilla ; b b, their separate processes ; c c, processes of papilla whose base 

 is not visible. Magnified GO diameters. 



Fia. 47. Horizontal section of the skin of the heel through the apices of the papilla-, of one 

 entire and two half ridges. The serial arrangement of the papillae corresponding with the 

 ridges of the cutis, is obvious, a, Horny layer of the epidermis between the ridges, which 

 from their undulating course are cut through in making a section through the points of the 

 papillee. 6, Stratum Malpighii of the epidermis, c, Papilla? which are placed in more than 

 two rows; since, however, many of them are always seated upon a common base, there are, 

 so to say, only two rows of compound papilla? present, d, Stratum Malpighii between the 

 papilla; belonging to a common base, which, because it has a less thickness here, appears 

 somewhat clearer, e, Sweat canals. Magnified 60 diameters. 



