are fresh in the morning. The nerves do not carry messages as rapidly, nor the brain or body act as quickly. Then we help nature. We undress and lie down in the dark. We protect all the little surface nerves from sensations—try to give them no messages to carry. We shut our eyes for the same reason, and we make the house quiet to keep sounds from knocking at our ears. With no "ringing up" on the switch-board, much of the blood leaves the brain. The heart and lungs slow down, the stomach will not need food-fuel for twelve hours or more. So we go to sleep. Now some little "why" boy is sure to ask;
"Where do we go when we go to sleep?"
We don’t go anywhere. When we dream we go to places, it is because the outside world isn't quite shut out, or an overloaded stomach telegraphs trouble to the brain. We aren’t as fast asleep as we should be when we dream. The best kind of sleep is when we are all there and don't know it.
THE AGES OF ANIMALS
No one knows exactly how long animals live in a wild state, but records have been kept of animals that have been tamed by men. And scientists are able to come very close to the ages of wild animals by examining the teeth, bones and other parts of the body. Turtles, toads, crocodiles and many reptiles, all cold-blooded animals, are long-lived. Cold-blooded animals as a rule are sluggish in their movements, so you see there seems to be a relation between how fast things move and how long they live. With a few exceptions, another principle seems to be that the largest animals live the longest. An elephant, for example, may live to be 150 years old. The same rule seems to apply in the plant world. Grass which is so frail is the creature of a season. Trees live much longer and the big trees of California were hundreds, yes, thousands of years old, when Columbus discovered America. Domesticated animals are shorter-lived than their wild relatives. A dog is old at 12 and dies at 15. A few have been known to live, blind and feeble, until 20. But here again is an exception for a cat’s "nine lives," all put together, may reach (as you see by our picture talk) to 40 years, yet pussy’s big cousin, the lion, has never been known to live longer than 35 years. Insects—how lucky for us!—are short-lived because they are very small and many of them very active. As Mr. Dooley said of the mosquito, " ’Tis a short life and a merry wan!"
