"Oh, I don't know; more than fifty, I should think."

"A cat with fifty tails." And the little boy laughed. "Did you ever
see a kitty with fifty tails?"

"All sticking straight up in the air!" said the foreman. "That _would_
be funny. She'd look like a porcupine."

"What _is_ a porcupine?" David asked. "Did I ever see one?"

"I guess not," the foreman answered. "Anyway, I never did. It's a
little animal all covered with sharp things. It's just as if your
kitty's fur was about three or four times as long as it is, and every
hair was stiff and sharp. There's a great rattling as they walk, I'm
told. The Indians used to sew the quills--the sharp things--on their
soft leather slippers, because they looked pretty."

"Tell me some more about them," said David.

"I don't know any more. See, Davie, the men are putting up another
stick."

So David watched the men put up that stick, and he forgot about the
porcupine, which was what the foreman wanted.

And then he watched them put up another, and then another.

"They look as if they were the bones of the house," he said.

"So they do, Davie," the foreman said, "and so they are. And the whole
frame, before it's boarded in--before any boards are nailed on--looks
like the skeleton of a house, and so it is. They'll have pretty near
the whole frame up by the time you eat your supper; or to-morrow
morning, at any rate. Then you look and see. It's much the same way
that your body's made: your ribs and the other bones are the frame,
and inside you there are a lot of rooms, and it's all covered with
soft skin instead of boards."

"Am I? What are my ribs?"

"These bones." And the foreman stooped and ran his finger quickly down
David's ribs, and David shrieked with laughter.

"Tickles," said David. "Show me my ribs again."

"It isn't good for little boys to be tickled too much," said the
foreman. "Now we'll go over to the sand-pile for a while. I don't want
to take you into the house until they get the frame all up and some
floors down. It isn't safe."

So they turned around and went to the sand-pile, and the foreman
stayed there a little while and played in the sand.

Then he had to go away; and the mortar man had gone away, and nobody
was there but David and his cat.

And David thought that he would help the mortar man, so he filled his
cart with sand and dragged it over to the mortar box and shoveled it
in.

Then he took up the handle of his cart, and he called his