XI
You should see, hanging from a hole in some old apple tree, a long thin snake-skin! It is the latch-string of the great crested flycatcher. Now why does this bird always use a snake-skin in his nest? and why does he usually leave it hanging loose outside the hole? Questions, these, for you to think about. And if you will look sharp, you will see in even the commonest things questions enough to keep you thinking as long as you live.
