108 SPECIAL HISTOLOGY. 



effected, especially when the former contains an abundance of 

 fat, with the exception of certain situations (head, cheeks, 

 chin, &c), where the follicles of the larger and more closely set 

 hairs penetrate deeply into the panniculus adiposus. The 

 subcutaneous cellular tissue of the penis, scrotum (dartos), &c. 

 passes into the corium without any distinct limitation. 



The thickness of the subcutaneous cellular tissue varies 

 very considerably, as is well known, according to situation, 

 age, sex, and the individual. The fat-less subcutaneous cel- 

 lular tissue of the eyelids, and of the upper and outer part of 

 the ear, measures, according to Krause , 1 '", on the penis i"', on 

 the scrotum §'". The panniculus adiposus is 1'" thick on the 

 cranium, brow, nose, lobe of the ear, neck, dorsum of the hand 

 and foot, the knee and elbow ; in most other situations it is 

 2 to 6'", though in fat persons it may exceed 1" in thickness, 

 and in thin ones may sink below 1"'. 



§ 33. 

 The proper corium is a tough, slightly-elastic membrane, 

 and is composed principally of connective tissue, which in the 

 thicker parts presents two, though not very well-defined 

 layers, which may be designated the " reticular" and the 

 "papillary" portions {p. reticularis and p. papilla?'is). 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-grey 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, papilla tactds (fig. 46) ; small, semi-transparent, 

 flexible, but tolerably solid elevations of the external surface of 

 the corium, which are ordinarily conical or clavate in form, but 

 in certain places present numerous points (compound papilla). 

 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 



