IOQ APPLIED PHYSIOLOGY 



188. Fur. Fur lets the least heat pass off and so 

 makes the best winter coat. The air between its separate 

 fibers is a great help in keeping in the heat. When the 

 fur is matted down, it lets more heat pass out and is not 

 so warm. 



189. Woolen. Next to fur in warmth is woolen cloth- 

 ing. Soft cloth is warmer than hard or stiff cloth, for it 

 holds more air. Silk is even better than wool to keep 

 in the heat. 



190. Cotton. Cotton lets heat pass through it readily, 

 and so is cold clothing. Linen lets heat pass through still 

 more easily, and is still colder; but if enough cotton or 

 linen is worn, it will keep in the heat, and so keep the 

 body warm on a cold day. When linen or cotton under- 

 clothing is worn, a slight draft of air chills the body, for 

 the underclothing does not keep in the heat, and so a 

 person is liable to take cold. 



191. How to clothe the body. If a person wears woolen 

 underclothing, little drafts of air have no effect in taking 

 away the heat, and so he does not notice slight changes 

 of the weather. In warm weather we wish to let the heat 

 of the body pass off, and so we wear cotton or linen. 

 Black cloth lets more of the sun's heat pass through it 

 than white cloth, so white clothing is the cooler when we 

 are exposed to the sun. 



In winter we should wear woolen next to the skin so as 

 not to feel sudden changes of temperature. Delicate 

 persons should wear woolen all the year. 



When we go from a warm room into the cold air we 

 should put on an overcoat or wrap of some kind so as to 

 avoid a sudden chill. When we work hard and become 

 very warm we should not stop to rest without putting on 

 our coat. 



