As a great part of our life is spent in sleep during which we have sometimes pleasant and sometimes painful dreams, it becomes of some consequence to obtain the one kind and avoid the other; for whether real or imaginary, pain is pain and pleasure is pleasure. If we can sleep without dreaming, it is well that painful dreams are avoided. If while we sleep we can have any pleasing dream, it is, as the French say, autant de gagné, so much added to the pleasure of life.
To this end it is, in the first place, necessary to be careful in preserving health, by due exercise and great temperance; for, in sickness, the imagination is disturbed, and disagreeable, sometimes terrible, ideas are apt to present themselves. Exercise should precede meals, not immediately follow them; the first promotes, the latter, unless moderate, obstructs digestion. If, after exercise, we feed sparingly, the digestion will be easy and good, the body lightsome, the temper cheerful, and all the animal functions performed agreeably. Sleep, when it follows, will be natural and undisturbed; while indolence, with full feeding, occasions nightmares and horrors inexpressible; we fall from precipices, are assaulted by wild beasts, murderers and demons, and experience every variety of distress. Observe, however, that the quantities of food and exercise are relative things; those