k in, and the skin has got to be
kept warm. See, he's getting cold, now!"

The negro suited the action to the word. He rubbed with all his
strength, and the ointment, concocted from some pungent herb, reddened
the skin where it went in. But, a moment or two after, the redness
disappeared and the bluish look of cold returned.

"Faster and harder!" cried the old doctor.

Sweat poured down from the negro's face. He ripped off jacket and shirt,
and, bare to the waist, scrubbed at the boy's skin. And, if ever he
stopped a moment to wipe the sweat from his forehead, the doctor cried,

"Faster and harder!"

Little by little, the reddening of the skin lasted longer, little by
little the bluish tints began to go, little by little the stiffening
which had begun, relaxed.

"He's coming round," cried the doctor. "Harder, now! Put your back into
it, Mark!"

Nearly an hour had passed when the negro, exhausted and trembling from
his exertions, sank into a chair. The doctor eyed him keenly, gave him a
stiff dose from a medicine glass, and returned to his patient.

"He'll do now," he said. "In half an hour he'll feel as well as ever,
and by tomorrow he'll be terribly ill."

"For de sake, Mister Ol' Doc, I got to rub um tomorrow?" pleaded the
negro.

"No, not tomorrow. From now on, I've got to 'potion um,' as you put it."

He put his hand in his pocket.

"Here, Mark," he said, "is half a sovereign. That isn't for saving the
boy's life, you understand, for you'd have done that any way, but for
working on him as you have."

The negro pocketed the coin with a wide smile, but lingered.

"I want to see um come 'round," he explained.

As the doctor had forecast, in half an hour's time, the color flowed
back into Stuart's cheeks, his breathing became normal, and, presently,
he stirred and looked around.

"What--What----" he began, bewildered.

"You went to sleep under the shade of some poison-trees, manchineel
trees, we call them here," the doctor explained. "Did you eat any of the
fruit?"

"I--I don't know," replied Stuart, trying to remember. "I--I sort of
went to sleep, that is, my body seemed to and my head didn't. And then I
saw crabs coming. At first they were only small ones, then bigger ones
came, and bigger, and bigger----"

He shivered and hid his face at the remembrance.

"There was nothing there except the regular red land-crabs," said the
doctor, "maybe eighteen inches across, but with a body the size of y