370 BIOLOGY AND HUMAN LIFE 



tion in combating tuberculosis ; but one should not feel ag- 

 grieved if he cannot have a sleeping porch, for it is quite pos- 

 sible to get sufficient air by sleeping at an open window or even 

 by securing a good circulation of air through the room. A rather 

 hard mattress, but one without lumps and irregularities, is best 

 for everybody, even infants, to lie upon, and light woolen 

 blankets are best for covers. In colder weather additional cov- 

 ering can be used. Feather beds are undesirable because they 

 interfere with the free circulation of air about the body, because 

 they are too soft, because they increase the chances of cultivat- 

 ing bedbugs, and because they are hard to keep clean. 



Regular hours for sleeping are especially important for chil- 

 dren. An infant, from his first day, should be trained to sleep at 

 fixed hours ; and as the child grows older and his waking hours 

 increase, it is still well to have a fixed time for going to sleep. 

 ]\Iany adults complain of sleeplessness or of being unable to go 

 to sleep when they go to bed ; but in very many cases the diffi- 

 culty is largely one of bad habits. By letting our minds wander 

 in reviewing the day's experiences, or in wishing or planning for 

 the future, or in worrying about what cannot be helped, we not 

 only lose valuable sleep but do our thinking or planning waste- 

 fully. Children need more sleep than adults, and one of the 

 hardships involved in inadequate housing is the fact that chil- 

 dren are obliged to stay up until the whole family is ready to 

 retire. Young children are found to benefit greatly from an 

 afternoon nap. The time they lose in sleep is more than made 

 up by the keener enjoyment of their play for the rest of the day. 

 There is no danger, as a rule, that children will sleep too much. 



280. Health education. By the time a young person is old 

 enough to go to high school or to work he should have learned 

 all the important things he needs to know about taking care of 

 his body and keeping it in good condition. The fact is, however, 

 that most of the grown people in this country do not know these 

 things, which they should have learned in childhood. There are 

 two sets of reasons for this general ignorance: (i) There has 

 been a great shifting of populations during the past two or three 



