Muskrat.

"In the Laughing Brook, of course," replied Grandfather Frog.

"No such thing!" said Billy Mink. "I've been all the way down the
Laughing Brook to the Big River, and I didn't find a thing."

"Have you been all the way up the Laughing Brook to the place it starts
from?" asked Grandfather Frog.

"No-o," replied Billy Mink.

"Well, that's where the cause of all the trouble is," said Grandfather
Frog, just as if he knew all about it. "It's the water that comes down
the Laughing Brook that makes the Smiling Pool, and the Smiling Pool
never could dry up if the Laughing Brook didn't first stop running."

"That's so! I never had thought of that," cried Little Joe Otter. "I
tell you what, Billy Mink and I will go way up the Laughing Brook and
see what we can find."

"Chugarum! Let us all go," said Grandfather Frog.

Then the five put their heads together and decided that they would go up
the Laughing Brook to hunt for the trouble.

CHAPTER XII: A Hunt For Trouble

Ol' Mistah Buzzard, sailing high in the blue, blue sky, looked down on
a funny sight. Yes, Sir, it certainly was a funny sight. It was a little
procession of five of his friends of the Smiling Pool. First was Billy
Mink, who, because he is slim and nimble, moves so quickly it sometimes
is hard to follow him. Behind him was Little Joe Otter, whose legs are
so short that he almost looks as if he hadn't any. Behind Little Joe
was Jerry Muskrat, who is a better traveler in the water than on land.
Behind Jerry was Grandfather Frog, who neither walks nor runs but
travels with great jumps. Last of all was Spotty the Turtle, who travels
very, very slowly because, you know, he carries his house with him.
And all five were headed up the Laughing Brook, which laughed no more,
because there was not water enough in it.

Now Ol' Mistah Buzzard hadn't been over near the Smiling Pool for some
time, and he hadn't heard how the Smiling Pool had stopped smiling, and
the Laughing Brook had stopped laughing. When he looked down and saw how
the water was so nearly gone from them that the trout and the minnows
had hardly enough in which to live, he was so surprised that he kept
saying over and over to himself:

"Fo' the lan's sake! Fo' the lan's sake!"

Then, when he saw his five little friends marching up the Laughing
Brook, he guessed right away that it must be something to do with the
trouble in the Smiling Pool. Ol' Mistah Buzzard just turned his broad
wing