the river woods so many times before. But why must I eat something,
uncle? I'm in such a hurry to go."

"Because, my boy, the life in us is like a fire that must be supplied
with fuel to keep it burning, only instead of wood or coal we need food.
Very early in the morning this life flame of ours, that is called
vitality, is very low, like a fire that has burned down, and if we go
out in the damp air and breathe the mists that rise from the ground our
vitality has not strength to resist them. But if we put fresh fuel on
our inward fire by eating something before we go out, then that bad
little mischief-maker, which we call malaria, has harder work to creep
into us."

"How funny! May I call Rap to tell him? Rap! Rap! come in and have milk
and something to eat, to make your inside fire burn up chills and
fever!"

Rap thought at first that Nat must be crazy, but very soon understood
what the Doctor meant, and was overjoyed at the prospect of having him
join the expedition.

"Dodo will cry when she wakes up and knows where we have gone," said
Nat, who had been much more kind and thoughtful of his sister since
coming to the Farm. But kindness is very catching, and at the Farm
everybody was kind, from the House People to the big gray horses in the
barn, which let the chickens pick up oats from between their powerful
hoofs, without ever frightening them by moving.

"It is too long a walk for little sister, but you must remember
everything that you see and hear, and tell her about it. Don't forget