48 PHYSIOLOGY AND TEMPERANCE. 



CHAPTEK IV. 



THE SKIN. 



1. The Covering of the Body. The body is everywhere 

 covered rand protected by the skin. It varies in thickness, 

 according to the use of the part. It is also loose in some 

 places arid close-fitting in others. In the fingers and palms 

 it fits snugly. The scalp, or skin of the head, is quite loose. 

 This makes it a better protection to the brain, for a blow that 

 might break the skull sometimes glides off without further 

 injury than carrying a portion of the scalp with it. 



2. The Epidermis. There are two layers of skin. The 

 outer, called the scarf-skin, cuticle or epidermis, serves as a 

 covering to the second layer, the true skin. The epidermis 

 protects the delicate little blood-vessels and the net-work of 

 sensitive nerves which form a large part of the true skin. 

 The sense of touch, which belongs to the true skin, is only 

 bearable when the sensation to the nerve is made through 

 the outer coat. Strip off this outer covering, and the part 

 is sensitive to pain rather than to touch. The two layers 

 are not easily separated. If we receive a burn sufficiently 

 severe to form a blister, the fluid which collects raises the 

 outer from the inner layer. The outer layer consists of 

 a hard, horny-like material, the surface part of which is 

 constantly being detached in thin, flat scales. Thus the skin 

 is all the time wearing out and being cast off. It does not 

 become thinner, however, as this loss is regularly supplied 

 from the true skin. It sometimes happens that the outer 

 skin is worn off faster than it can be supplied, and the part 

 becomes tender. Put a man at handling bricks for the first 



