That kind of fever is known in the Congo, and the doctor was reassured, and bade his boat-boys pull up again.  Yet because of the evil liver within him, his temper was short, and his questioning acid.  But Captain Rabeira was stiff and unruffled and wily as ever, and handed in his papers and answered questions, and swore to anything that was asked, as though care and he were divorced forever.

Kettle watched the scene with a drawn, moist face.  He did not know what to do for the best.  It seemed to him quite certain that this oily, smiling scoundrel, whom he had more than half suspected of a particularly callous and brutal double murder, would be given pratique for his ship, and be able to make his profits unrestrained.  The shipmaster’s esprit de corps prevented him from interfering personally, but he very much desired that the heavens would fall—­somehow or other—­so that justice might be done.

A dens ex machina came to fill his wishes.  The barter of words and the conning of documents had gone on; the doctor’s doubts were on the point of being lulled for good; and in a matter of another ten seconds pratique would have been given.  But from the forecastle-head there came a yell, a chatter of barbaric voices, a scuffle and a scream; a gray-black figure mounted the rail, and poised there a moment, an offence to the sunlight, and then, falling convulsively downwards, hit the yellow water with a smack and a spatter of spray, and sank from sight.

A couple of seconds later the creature reappeared, swimming frenziedly, as a dog swims, and by a swirl of the current (before anybody quite knew what was happening) was swept down against the doctor’s boat, and gripped ten bony fingers upon the gunwhale and lifted towards her people a face and shoulders eloquent of a horrible disorder.

Instantly there was an alarm, and a sudden panic. “Sacre nom d’un pipe,” rapped out the Belgian doctor; “variole!”

“Small-pox lib,” whimpered his boat-boys, and before their master could interfere, beat at the delirious wretch with their oars.  He hung on tenaciously, enduring a perfect avalanche of blows.  But mere flesh and bone had to wither under that onslaught, and at last, by sheer weight of battering, he was driven from his hold, and the beer-colored river covered him then and for always.

After that, there was no further doubt of the next move.  The yellow-faced doctor sank back exhausted in the stern sheets of the gig, and gave out sentence in gasps.  The ship was declared unclean until further notice; she was ordered to take up a berth a mile away against the opposite bank of the river till she was cleared of infection; she was commanded to proceed there at once, to anchor, and then to blow off all her steam.

The doctor’s tortured liver prompted him, and he spoke with spite.  He called Rabeira every vile name which came to his mind, and wound up his harangue by rowing off to Chingka to make sure that the guns of the fort should back up his commands.