192 ANATOMY AND PHYSIOLOGY FOR NURSES 



deeper of which are soft and protoplasmic, while the 

 superficial layers are hard and horny. Between the two 

 layers is a fairly distinct line of granular-looking cells, the 

 granules in which have been thought to form the horny 

 matter in the superficial cells. In the colored races the 

 single layer of elongated cells next to the corium contains 

 pigment-granules . 



The epidermis, which throughout the body is of horny 

 consistence, but so thin as readily to admit of flexibility, 

 is on the ends of the fingers replaced by a thicker and 

 more permanent texture of horny substance, called the 

 nails (clavus). 



In the palms of the hands and on the soles of the feet 

 the skin is thickened and more firm, according as the parts 

 are exposed to friction or wear. 



The outer surface of the skin is covered by numer- 

 ous small eminences or papilla, which are the termina- 

 tions of the nerves and vessels, each papilla containing a 

 nerve and one or more vessels. 



The corium, as has been said, possesses great sensi- 

 bility, and is commonly regarded as the starting-point of 

 the nervous system to palpable feeling. It is, therefore, 

 very largely supplied with nerves, and is also well furnished 

 with blood. 



The outer layer, or epidermis, possesses no sensibility, 

 and yet, being extremely thin and delicate, it offers but 

 little resistance to the sense of touch. It serves chiefly 

 as a covering or shield for the under parts, to prevent irri- 

 tation, corrosion, and the absorption of pernicious sub- 

 stances into the circulation. 



The Sudorific and Sebaceous Glands. The skin 

 is furnished with numerous small glands termed secre- 

 tory organs. 



The sudorific glands secrete sweat or perspirable fluid 

 from the circulation. Their function is of great import- 



