130 THE ESSENTIALS OF HISTOLOGY. 



the palms of the hands and soles of the feet. The superficial or 

 vascular layer of the corium bears minute papillce, which project up 

 into the epidermis, which is moulded over them. These papillae for 

 the most part contain looped capillary vessels (fig. 153), but some, 

 especially those of the palmar surface of the hand and fingers, and the 

 corresponding part of the foot, contain tactile corpuscles, to which 

 medullated nerve-fibres pass (fig. 114, b, p. 99). 



FIG. 153. DUCT OF A SWEAT-GLAND PASSING THROUGH THE EPIDERMIS. 

 (Magnified 200 diameters.) (Heitzmann.) 



BP, papillae with blood-vessels injected ; V, rete mucosum between the papillae ; E, stratum 

 corneum ; PL, stratum granulosum ; D, duct, opening on the surface at p. 



In some parts of the body (scrotum, penis, nipple, and its areola), 

 involuntary muscular tissue occurs in the deeper portions of the cutis 

 vera, and in addition, wherever hairs occur, small bundles of this tissue 

 are attached to the hair-follicles. 



The blood-vessels of the skin are distributed almost entirely to the 

 surface, where they form a close capillary network, sending up loops 

 into the papillae (fig. 153). Special branches are also distributed to the 

 various appendages of the skin, viz. the sweat-glands and hair-follicles, 

 with their sebaceous glands and little muscles, as well as to the little 

 masses of adipose tissue which may be found in the deeper parts of the 

 cutis. 



The lymphatics originate near the surface in a network of vessels, 

 which is placed a little deeper than the blood-capillary network. They 

 receive branches from the papillae, and pass into larger vessels, which 

 are valved, and which run in the deeper or reticular part of the corium. 



