twittering with glee; "two nice
dogs. One big and buff and bushy, with a much finer tail than the
proudest fox you ever saw; and the other small and white with some dark
spots, and as quick as a squirrel. This one has a short tail that sticks
up like a Wren's and a nose like a weasel; one ear stands up and the
other hangs down; and he has a _terrible_ wink in one eye. Even a poor
little Bank Swallow knows that where one of _these_ dogs lives the Bird
People need not fear either cats or rats!"

"I love dogs," said the black-and-white Downy Woodpecker, running up a
telegraph pole in search of grubs; "dogs have bones to eat and I like
to pick bones, especially in winter."

"Me too," chimed in the Nuthatch, who walks chiefly head down and wears
a fashionable white vest and black necktie with a gray coat; "and
sometimes they leave bits of fat about. Yes, dogs are very friendly
things indeed."

Then a joyful murmur ran all along the wires, and Farmer Griggs, who was
driving past, said to himself, "Powerful lot of 'lectricity on to-day;
should think them Swallers would get shock't and kil't." But it was only
the birds whispering together; agreeing to return to their old haunts at
Orchard Farm and give the House Children a chance to learn that there
are no such things as "common" birds.

CHAPTER II

THE DOCTOR'S WONDER ROOM

Nathaniel and Theodora, who were called Nat and Dodo for short, were
standing in the hallway outside Dr. Hunter's door, engaged in a very
lively argument.

"I say birds are animals," blustered Nat, pounding his fists together
after a fashion of his own.

"And I'm as sure as anything that they _can't_ be," persisted Dodo,
"because they have feathers, and nothing else has."

"That doesn't prove anything. Everything that lives and grows is either
an animal or a vegetable. Do you think that birds grow like potatoes and
are dug out of the ground, or come off trees like apples?" And Nat gave
himself an air of great wisdom, such as brothers are apt to wear when
they are in the fifth reader, and their sisters are only in the third.

"But isn't there anything besides animals and vegetables that they might
be? Perhaps they are minerals," said Dodo, brightening up as she thought
of the word.

"Oh! oh! what a stupid you are, Dodo! Minerals! Why those are rocks and
such things, that can't move and don't live." Nat laughed rather rudely,
and, putting his hands in his pockets, began to whistle.

"I