156 THE HUMAN BODY. 



CHAPTER X. 

 THE SKIN. 



STRUCTURE OP THE SKIN. 



SECTION I. 1, The skin is the covering of the body. 

 It is soft and smooth, but strong. It fits perfectly ; but it 

 stretches and glides a little on the muscles beneath, and, 

 therefore, does not hinder our movements, as close-fitting 

 garments do. It is partly transparent, and shows the 

 blue color of the veins, and the red of the arteries, beneath 

 it. 



It becomes quite thick in places where a thick covering 

 is needed, as on the palms of a laboring-man, or the soles 

 of a barefoot boy. 



2, If we prick a blister, a little watery fluid comes out, 

 and it flattens down. It does not hurt to prick it, and it 

 draws no blood. So we find that the top layer of the skin 

 has no nerves or blood-vessels. But, when we " scrape the 

 skin off," we are hurt, and have a red, bleeding surface. 

 We do not often really scrape the skin off with trifling ac- 

 cidents; but we take off the top layer, and get down to the 

 deep layer, which contains both nerves and blood-vessels. 



3, Dandruff, which comes from the scalp, consists of 

 dry scales from the surface of the skin. From all of the 

 rest of the skin, little scales are constantly coming off. 



SUGGESTION TO TEACHERS. Illustrate this chapter by studies of the cuti- 

 cle and hairs of men and animals, with a microscope. A lens of one-inch 

 focus will show the pores on the palm. 



