SECT. 35.] 



CUTIS. 



75 



contains very little or even no fat, and measures only I to J of a 

 line. The most internal layer of the subcutaneous cellular tissue, 

 which upon the trunk and thighs presents a tolerably firm fatless 

 expansion, the fascia superficialis, lies upon various organs, as 

 fascire of muscles, periosteum, perichondrium, muscles, and the 

 deeper collections of fat ; and is connected, sometimes more loosely, 

 sometimes more firmly, with them. 



The external surface of the subcutaneous cellular tissue is, for 

 the most part, firmly attached to the cor mm, particularly where 

 hair -follicles dip into it, as on the head; on the other hand, when 

 it forms a thick, adipose layer, it can be easily separated. 



Fig. 32. 



§ 35. The proper corium is a compact and but slightly elastic 

 membrane, formed likewise principally of connective tissue. In the 

 thicker parts, it presents two, not, however, very distinctly 

 separated layers, which may be designated the reticular and the 

 papillary. The reticular part of the corium forms the inner layer, 

 and presents a white, reticulated, in its deepest portions often dis- 

 tinctly stratified, membrane, which contains, more especially, the 

 hair-follicles and glands of the skin, together with a considerable 

 quantity of fat. The papillary part is the reddish-grey external 

 portion of the corium, situated immediately below the epidermis, 

 which, in its dense firm tissue, contains the upper part of the hair- 

 follicles and cutaneous glands, and the ultimate expansions of the 

 vessels and nerves of 

 the skin. Its most 

 important constituents 

 are the papillae of the 

 corium, which, accord- 

 ing to their internal 

 structure, may be di- 

 vided into two species, 

 vascular and nervous 

 (fig. 32). They are 

 small, semi-transpa- 

 rent, pliant, but tole- 

 rably firm prominences of the external surface of the corium, which 

 arc generally conical or club-shaped, but in certain places run out 

 into several points {compound papilla). As regards number and 

 situation, it may be observed, that the papilla? of the matrix of 

 the nail, of the palm of the hand, and of the sole of the foot, are 

 very numerous {K. II. Weber calculates upon one square line of the 



a- 



Compound papillae of the surface of the nan (J, with two, three, 

 and four points, a. Base ot a papilla? ; bb. their separate processes ; 

 cc. processes of papillae, whose base is not visible. Magnified 60 

 diameters. 



