22 ELEMENTS OF PHYSIOLOGY 



32. The skin is the chief organ for regulating the temper- 

 ature. It accomplishes this by means of the perspiration. 



33. Clothing does not give heat to the body, but helps 

 to prevent the escape of bodily heat. Linen and cotton 

 absorb moisture readily and allow it to evaporate rapidly. 

 They thus serve, when worn next to the skin, to keep 

 the body dry ; the evaporation, if very rapid, may chill the 

 body. Woolen absorbs moisture quickly, but parts with 

 it slowly, and in the case of those who perspire freely, 

 the damp clothing next to the skin may conduct away 

 the heat. But dry woolen contains much air in the 

 meshes of the cloth ; and as this is a non-conductor of heat, 

 such clothing is the warmest of all, silk ranking next. In 

 cold climates woolen should be worn next to the skin, and 

 should not be laid aside until the heat of summer begins. 

 In warm climates, like that of the Gulf States, it should not 

 be worn next to the skin at all, even in winter, unless by 

 the very delicate, and it is a question as to whether woolen 

 does not do more harm than good, even to the delicate, as 

 it relaxes and weakens the skin. If it is worn in such 

 climates, with the warmth of spring it should be changed 

 for less relaxing fabrics. White clothing reflects the heat 

 of the sun ; dark clothing absorbs the sun's heat. Rubber 

 clothing prevents moisture from penetrating to the body 

 and also prevents perspiration from escaping. 



34. Bathing. A bath is necessary for cleanliness, once 

 a week in winter and perhaps daily in summer. Frequent 

 bathing, if accompanied by the use of soap and friction, 

 makes the skin too thin and sensitive. A warm bath 

 should be succeeded by a dash of cold water to overcome 

 its relaxing effects. A warm bath is more suitable on retir- 

 ing than on rising ; it is also more suitable than a cold 

 bath for a person that is much fatigued. A cold bath is 

 more invigorating than a warm bath, and should be followed 

 by a reaction or glow caused by the return of the blood to 



