EPIDERMIS. 



of little pieces, called cells, joined together by a sort of 

 glue. The cells may be compared to the bricks, and the 



* a 



FIG. 21. A thin slice of epidermis, greatly magnified, a, the outer or horny layer 

 of the epidermis, made of old dry cells; , the deeper moist layer of the epidermis, 

 made of living growing cells; </, the deepest row of epidermic cells, lying next the 

 dermis; c, the uppermost layer of the dermis; (it is seen to be elevated to form a 

 papilla in which is a tuft of tubes,/, g, containing blood;) A, the duct of a sweat- 

 gland. 



glue to the mortar, of a wall. Each cell is so small that 

 a powerful microscope would be needed to see one by 



