t's
better; there's nothing whatever the matter with me; and you are taking
advantage of your position and are about to force me to swallow a lot of
your horrid stuff. I won't, though; see if I do!"

"You see, Mr Murray," said the doctor, smiling in a way which irritated
one of his hearers almost beyond bearing, "he is proving all I have said
to the full. There, be calm, Roberts, my dear boy; we have left the
horrible river and coast behind, and a few days out upon the broad ocean
will with my help soon clear away the unpleasant symptoms from which you
have been suffering, and--"

"Not interfering, am I, doctor?" said a voice which made the two lads
start round.

"Not in the least, Anderson; not in the least. Mr Roberts here is a
trifle the worse for our run up that muddy river, but I shall soon put
that right with our trip through the healthier portions of our globe."

"Through the healthier portions of the globe, doctor!" said the chief
officer. "Why, what do you mean?"

"Mean? Only that the West Coast of Africa is about as horrible a
station as unhappy man could be placed in by the powers that be, while
now we are going where--"

"Why, doctor, you don't mean to say that you do not understand where we
are going?"

"I mean to say I do know, sir--away from the swampy exhalations and
black fevers of the horrible district where we have been cruising, and
out upon the high seas."

"Yes, to cross them, doctor," said the lieutenant drily. "We are going
to leave the black fevers behind, but in all probability to encounter
the yellow."

"What!" cried the doctor. "I did not understand--"

"What the captain said? Well, I did, sir. The skipper has only just
now been vowing to me that he will never rest until he has run down that
slaver."

"Ah! Yes, I understand that," said the doctor. "Then that means--?"

"A long stern chase through the West Indian Islands, and perhaps in and
out and along the coasts of the Southern American States--wherever, in
fact, the plantations are worked by slaves whose supplies are kept up by
traders such as the scoundrel who cheated us into a run up that river
where his schooner was lying. Why, doctor, it seems to me that we are
only going out of the frying-pan into the fire."

"Dear me, yes," said the doctor. "You are quite right. Then under
these circumstances, Mr Roberts," he continued, turning sharply round
upon the midshipman, "the sooner you commence your treatment t