1 N 



lo6 SCIENCE PRIMERS. [§ vii. 



razor gets down to this, you bleed. It is not made up 

 of cells like the epidermis, bvt of thai fibrous sub- 

 stance which you early learnt to call connective tissue 

 (see p. 9). Its top is rarely level, but generally 

 raised irto little hillocks, called papillae, as in tlie 

 figure; the epidermis forming a thick cap over each 

 papillae, and filling up the hollows ^between them. 

 Most of the papillae are full of blood-vessels. 



Now, then, I think you will understand why your 

 skin is not red, but flesh-coloured, and why it is gene- 

 rally dry. The true skin under the epidermis is always 

 moist, because of the blood-vessels there \ the waste 

 and fluid parts of the blood pass readily through the 

 wails of the capillaries, as you have learnt, by osmosis, 

 and so keep everything round them moist. But this 

 moisture is not enough to soak through the' thick 

 coating of epidermis, and so the top part of the 

 epidermis remains dry and scaly. 



The true skin underneath the epidermis is always 

 red ; you know that if you shave off the surface of your 

 skin anywhere, it gets redder and redder the deeper you 

 go down, even though you do not fetch blood. It is 

 red because of the immense number of capillaries, all 

 full of red blood, which are crowded into it. When 

 you look at these capillaries through a great thickness 

 of epidermis, the redness is partly hidden from you, 

 as when you put a sheet of thin white paper over a 

 red cloth, and the skin seems pink or flesh-coloured ; 

 and where the epidermis is very thick, as at the heel, 

 the skin is not even pink, but white or yellow, more 

 or less dirty according to circumstances. 



46. But if the moist true skin is thus everywhere 

 covered by a thick coat of epidermis, which keeps the 



