316 SKIN, HAIR, NAILS. 



LESSON VII. 



THE SKIN HAIR NAILS. 



THE whole of our body is covered by skin. 

 The structure of the skin is very curious, and it is 

 impossible to look at it without being reminded of 

 the care which our Creator has bestowed upon us. 



The skin consists of three layers, or coats. The 

 outside one is called the epidermis, or scarf skin, 

 and is very elastic or stretching. It is pierced 

 with innumerable holes, through which the hair 

 passes, and the perspiration exudes. It is, more- 

 over, quite insensible, and appears to have no blood 

 vessels. With great care, we may thrust a needle 

 through it, and neither see blood, nor feel pain : and 

 when we are scalded or burnt, or have a blister 

 applied to us, it is seen raised in the form of a blad- 

 der. It is also half-transparent, and shows the 

 colour of the parts beneath it. 



The epidermis is stretched over some of our 

 limbs in little folds. Look at the joints of your 

 fingers. Bend them, and observe how these folds 

 disappear. Besides where we cannot see any folds, 

 the epidermis is capable of great extension. There 

 is a disease called emphysema, and another, 

 dropsy, in which it is stretched out amazingly, yet 

 when the cause is removed, it recovers its tone, 

 and, after a time, becomes smooth as before, though 

 at first it is a good deal wrinkled. 



Under the epidermis, lies a second coat. This 



