CLOTHING. 79 



great production of heat in the internal organs. Then 

 the sweat-glands act, and the skin becomes full of blood 

 even on a winter's day. You know that if you sit still 

 in a cold room your skin becomes pale and you do not 

 perspire; while, so long as you are in health, a good run 

 in the coldest weather will flush the skin and cause per- 

 spiration. 



15. Clothing. Clothes are employed by mankind for 

 many purposes of ornament and ostentation; and these 

 unimportant uses are sometimes allowed to interfere 

 very seriously with their main objects. The real uses of 

 clothing are physiological and hygienic. These uses are, 

 (i) to aid the skin in regulating the temperature of the 

 body; (2) to protect the skin itself from too rapid heat- 

 ing or cooling; (3) to prevent a sudden rush of blood 

 from the skin to internal organs when the air around the 

 body is quickly cooled. 



16. What Properties the Materials used for Clothing 

 should Possess. Nature has provided all warm-blooded 

 animals who thrive in parts of the earth where the 

 climate is variable, except man, with a covering of fur or 

 feathers. This covering becomes thicker in the cold 

 seasons of the year, and thinner in the warm. It also is 

 made of materials which greatly hinder the passage of 

 heat through them. Fur and feathers are accordingly 

 known as bad conductors of heat. In winter they check 



15. For what unimportant uses is clothing employed ? What its 

 real uses ? 



16. What clothing does Nature provide for most warm-blooded 

 animals? How does it change with the seasons? What are the prop- 

 erties of its materials as regards the transmission of heat ? How do 

 fur and feathers protect the skin from sudden changes of tempera- 

 ture ? What lessons should man learn from the clothing provided 

 for lower animals bv Nature? 



