1 86 Life and Health 



the abrupt projections and depressions of the general surface, 

 and in giving roundness and symmetry to the entire body. 

 The thickness of the skin varies in different parts of the 

 body. Where exposed to pressure and friction, as on the 



soles of the feet and in 

 the palms of the hands, it 

 is much thickened. 



The true skin is ^ to \ 

 of an inch in thickness, but 

 in certain parts, as in the 

 FIG. 95. A Layer of the Cuticle from lips and ear passages, it is 



the Palm of the Hand. (Detached often not more than i of 

 by maceration.) ... . - 1 . 



an inch thick. At the ori- 

 fices of the body, as at the mouth, ears, and nose, the skin 

 gradually passes into mucous membrane, the structure of 

 the two being practically identical. 



280. The Cutis Vera, or True Skin. The true skin con- 

 sists of elastic and white fibrous tissue, the bundles of 

 which interlace in every direction. Throughout this felt- 

 work structure are numerous muscular fibers, as about the 

 hair follicles and the oil glands. When these tiny muscles 

 contract from cold or emotion, the little hairs project upon 

 the surface, producing what is called " goose flesh." 



The true skin is richly supplied with blood vessels and 

 nerves, as shown by the fact that it bleeds freely when 

 cut and that it is very sensitive. The surface of the true 

 skin is thrown into a series of minute elevations, called 

 the papillae, upon which the outer skin is moulded. These 

 abound in blood vessels, lymphatics, and peculiar nerve 

 endings, which will be described in connection with the 

 organ of touch (sec. 371 and Fig. 104). 



The papillae are large and numerous in sensitive places, 

 as the palms of the hands, the soles of the feet, and the 



