It is very important that we learn how to observe things closely.
9.

Exercise in the open air rests and clears the brain by helping the blood to circulate.
10.

Plenty of wholesome and simple food is necessary to keep the brain and nerves in good health.

Spices, condiments, and rich foods in general are stimulating and harmful.
11.

Plenty of sleep is needed to rest the brain and nerves.
12.