CHAPTER VII. 

 HYGIENE OF THE SKIN. ANIMAL HEAT. CLOTHING. 



1. Why the Skin should be Kept Clean. A film tends 

 to collect on the skin daily. This film consists chiefly of 

 dry dead cells from the surface of the epidermis, of oily 

 matter from the sebaceous secretion, and of dust and 

 dirt. A certain amount of sebaceous secretion is useful 

 for reasons already given; but it may collect in harmful 

 excess. If the accumulation of the above-named matters 

 is not regularly removed from the skin it tends to choke 

 the mouths of the sweat-glands, the so-called "pores of 

 the skin," and interfere with their activity. These glands 

 not only serve to regulate the heat of the body, but sepa- 

 rate waste matters from it, among them a considerable 

 amount of water which has served its purpose and needs 

 to be removed. If the sweat-glands do not work well, 

 other organs, the lungs and kidneys, whose duty it also 

 is to remove water and wastes, have too much work 

 thrown upon them. The entire skin should therefore 

 be washed every day, except that on the top of the head. 

 The hair takes so long to dry that it is not usually prac- 



i. Of what is the film composed which collects on the skin every 

 day ? Why should it be removed ? What are the pores of the skin ? 

 The uses of the sweat-glands? What organs' are overworked when 

 the sweat-glands do not act properly ? What other reasons are there 

 for keeping the skin clean ? 



