SCOUTING FOR GIRLS 
259 
during and immediately following menstruation. How- 
ever, she should remember that a reasonable amount of 
exercise at this time is quite normal and beneficial, ex- 
cept where there is an actual disorder of some sort 
In this case a physician should be consulted. 
3. Rest and Conserve Energy — Go to bed early and 
sleep from eight to eleven hours, according to age. Sleep 
with windows open all the year round. Rest sometime 
during the day, flat on the back if possible, but even 
five minutes sitting quietly with hands in the lap and 
eyes closed is better than nothing. The following table 
shows the number of hours of sleep that are needed at 
different ages : 
Age Hours of Sleep 
10 and 11 years...- to 11 
12 and 13 years 9 to 10^4 
14 and 15 years 8 to 10 
16 and 17 years 8 to 9j4 
18 and 19 years 8 to 9 
20 and over at least 8 
Save Your Eyes 
The reason it is important to rest and to sleep enough 
is because it is while at rest that the body regains energy 
lost during activity, and stores it up for future work and 
play. There are other ways of saving energy, and one 
of them is by keeping the body in such good repair that 
like a good machine it does its work with a minimum 
expenditure of force and heat. This is the main reason 
for the setting-up exercises, or' indeed for any sort of 
exercises. Perhaps the single best way to save energy 
is by saving your eyes. There is almost no work or play 
that does not involve the use of our eyes. If people are 
blind they can learn to do many things without vision, 
but it is infinitely harder than with it* Modern life, 
