CC1V 



THE SKIN. 



substance of the corium wherever hairs occur ; and their connection with 

 fehe latter will be afterwards explained. Muscular bundles of the same 

 kind are found in the subcutaneous tissue of the scrotum, penis, perineum, 

 and areola of the nipple, as well as in the nipple itself. They join to form 

 reticular superimposed layers, which are separated from the parts beneath 

 by a stratum of simple lax areolar tissue, but towards the surface they 

 are immediately applied to the corium. In the areola they are disposed 

 circularly. 



In consequence of this gradual transition of the corium into the subjacent 

 tissue, its thickness cannot be assigned with perfect precision. It is gene- 

 rally said to measure from a quarter of a line or less to nearly a line and a 

 half. -As a general rule, it is thicker on the posterior aspect of the head, 

 neck, and trunk, than in front ; and thicker on the outer than on the inner 

 side of the limbs. The corium, as well as the cuticle, is remarkably thick 

 on the soles of the feet and palms of the hands. The skin of the female is 

 thinner than that of the male. 



For convenience of description it is not unusual to speak of the corium as 

 consisting of two layers, the " reticular" and the " papillary." The former, 

 the more deeply seated, takes no part in the construction of the papilla, 

 but contains in its meshes hair-follicles, cutaneous glands, and fat. The 

 latter is divided into papillae, and receives only the upper portion of the 

 hair-follicles and glands, together with the terminal expansion of the vessels 

 and nerves. 



The free surface of the corium is marked in various places with larger or 

 smaller furrows, which also affect the super] acent cuticle. The larger of 

 them are seen opposite the flexures of the joints, as those so well known in 

 the palm of the hand and ut the joints of the fingers. The finer furrows 

 intersect each other at various angles, and may be seen almost all over the 

 surface ; they are very conspicuous on the back of the hands. These fur- 

 rows are not merely the consequence of the frequent folding of the skin by 

 the action of muscles or the bending of joints, for they exist in the foetus. 

 The wrinkles of old persons are of a different nature, and are caused 

 by the wasting of the soft parts which the skin covers. Fine curvili- 

 near ridges, with intervening furrows, mark the skin of the palm and 

 sole ; these are caused by ranges of the papillse, to be immediately de- 

 scribed. 



. The free surface of the corium is be^et with small enrnences 



Fig. CIX. 



Fig. CX. 



Fig. CIX. PAPILLA, AS SEEN WITH A MICROSCOPE, ON A PORTION OF THE TRUE SKIN, 



FROM WHICH THE ClJTICLE HAS BEEN REMOVED (after Breschet). 



Fig. CX. COMPOUND PAPILLA FROM THE PALM OF THE HAND, MAGNIFIED 60 DIAMETERS. 

 a, basis of a papilla ; 5, b, divisions or branches of the same ; c, c, branches belonging 

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



