THE HUMAN BODY. 



to the corium beneath. It is succeeded by several strata of 

 roundish cells, b, which in the outer layers become more 

 and more flattened in a plane parallel to the surface. The 

 outermost epidermic stratum is composed of many layers of 

 very flattened cells from which the nuclei (conspicuous in 

 the deeper layers) have disappeared. These superficial cells 

 are dead, and are constantly being shed from the surface of 

 the body, while their place is taken by new cells, formed in 

 the deeper layers, pushed up to the surface, and flattened in 

 their progress. The change in the form of the cells as they 

 travel outwards is accompanied by chemical changes ; they 

 finally constitute a semi-transparent dry horny stratum, a, 

 distinct from a deeper, more opaque, and softer layer, I and 

 d, of the epidermis. 



The rolls of material which are peeled off the skin on 

 rubbing it with a rough towel after a warm bath, are dead 

 outer scales of the horny stratum of the epidermis. 



Nerves penetrate the epidermis, but no blood-vessels 

 enter it. In dark races the color is due to a pigment con- 

 tained chiefly in the deeper-placed cells of the epidermis. 



The Corium, Cutis Vera, or True Skin, Fig. 76, consists 

 of a close feltwork of connective tissue, which, becoming 

 wider meshed below, passes gradually into the subcutane- 

 ous areolar tissue, in texture much like damp raw cotton, 

 which loosely attaches the skin to parts beneath. In tanning, 

 the cutis vera is turned into leather, its connective tissue 



What portion of it is constantly being cast off from the body ? 

 What is meant by the horny stratum of the epidermis ? Of what do 

 the rolls of matter consist which are peeled off the skin on vigorous 

 rubbing after a warm bath ? 



Does the epidermis contain nerves? Blood-vessels? 



Where does the coloring matter of the skin of negroes lie ? 



Of what does the true skin consist ? Into what does it pass on its 

 deeper side ? What is turned into leather when an ox-hide is tanned V 



