278 EXPERIMENTAL GENERAL SCIENCE 



is continuous and the surplus must be as continuously thrown 

 off, otherwise the body would soon reach a temperature high 

 enough to cause the death of the tissues. Fever is simply 

 the excess heat which remains in the body under certain con- 

 ditions. When the atmosphere is cool, most of the surplus 

 heat is lost by radiation (77). In winter it is necessary to 

 put on additional clothing to prevent too rapid radiation of 

 the heat, but in summer, when the temperature of the air is 

 high, mere radiation is not sufficient and the nerves stimulate 

 the sweat glands to pour out a large amount of perspiration 

 which, evaporating, takes much heat from the body (92). 

 By this means the bodily temperature is kept uniform. The 

 average temperature of the human body is 98.6 F. but the 

 skin is usually somewhat cooler and some parts of the body, 

 notably the liver, is several degrees warmer. Certain drugs, 

 by affecting the nerves, may also promote the pouring out 

 of the perspiration. Since the air taken into the lungs is 

 warmed during its journey through the air passages, a 

 considerable amount of heat is also lost in breathing. 



240. Care of the Skin. The skin should be washed often 

 enough to keep it free from the dirt and germs with which it 

 comes in contact, as well as to rid it of the secretions left 

 behind when the perspiration evaporates. A bath at least 

 once a week is desirable. Daily bathing, while not absolutely 

 necessary, is valuable for its beneficial effects upon the skin. 

 Sufficient clothing should be worn at all times to protect the 

 body from being chilled, but an unusual amount of clothes 

 for wear in the house in winter is likely to prove harmful. 

 It is much better to add extra wraps when going out into the 

 cold than to dress too warmly indoors. Nor is it desirable 

 that the temperature of the living rooms be high in winter. 

 A temperature of 68F. or 70F. is the proper one. Since the 

 evaporation of the perspiration depends upon the amount of 

 moisture in^the air, being greatest when the humidity is low, 



