g known of it, and if we unlock it from its hard sheathing of
technical terms, we shall find it as simple and as easy to understand as
it is interesting. When we once hold the key, it will seem as if scales
had fallen from our eyes, and when we take our walks abroad through the
fields and woods, when we visit a zoological park, or even see the animals
in a circus, we shall feel as though a new world were opened to us.

No post offices, or even addresses, exist for birds and mammals; when the
children of the desert or the jungle are lost, no detective or policeman
hastens to find them, no telephone or telegraph aids in the search. Yet,
without any of these accessories, the wild creatures have marvellous
systems of communication. The five senses (and perhaps a mysterious sixth,
at which we can only guess) are the telephones and the police, the
automatic sentinels and alarms of our wild kindred. Most inferior are our
own abilities in using eyes, nose, and ears, when compared with the same
functions in birds and animals.

Eyes and noses are important keys to the bright colours of birds and
comparative sombreness of hairy-coated creatures. Take a dog and an oriole
as good examples of the two extremes. When a dog has lost his master, he
first looks about; then he strains his eyes with the intense look of a
near-sighted person, and after a few moments of this he usually yelps with
disappointment, drops his nose to the ground, and with unfailing accuracy
follows the track of his master. When the freshness of the trail tells him
that he is near its end he again resorts to his eyes, and is soon near
enough to recognise the face he seeks. A fox when running before a hound
may double back, and make a close reconnaissance near his trail, sometimes
passing in full view without the hound's seeing him or stopping in
following out the full curve of the trail, so completely does the
wonderful power of smell absorb the entire attention of the dog.

Let us now turn to the oriole. As we might infer, the nostrils incased in
horn render the sense of smell of but slight account. It is hard to tell
how much a bird can distinguish in this way--probably only the odour of
food near at hand. However, when we examine the eye of our bird, we see a
sense organ of a very high order. Bright, intelligent, full-circled, of
great size compared to the bulk of the skull, protected by three complete
eyelids; we realise that this must play an important part in