At the flood season, before the turbulent tributaries of the Isisi River had been induced to return to their accustomed channels, Sanders came back to headquarters a very weary man, for he had spent a horrid week in an endeavour—successful, but none the less nerve-racking—to impress an indolent people that the swamping of their villages was less a matter of Providence and ghosts than the neglect of elementary precaution.

"For I told you, Ranabini," said an exasperated Sanders, "that you should keep the upper channel free from trees and branches, and I have paid you many bags of salt for your services."

"Lord, it is so," said Ranabini, scratching his brown leg thoughtfully.

"At the full of the moon, before the rains, did I not ask you if the channel was clear, and did you not say it was like the street of your village?" demanded Sanders, in wrath.

"Lord," said Ranabini frankly, "I lied to you, thinking your lordship was mad. For what other man would foresee with his wonderful eye that rains would come? Therefore, lord, I did not think of the upper channel, and many trees floated down and made a little dam. Lord, I am an ignorant man, and my mind is full of my own brother, who has come from a long distance to see me, for he is a very sick man."

Sanders's mind was occupied by no thought of Ranabini's sick brother, as the dazzling white Zaire went thrashing her way down stream. For he himself was a tired man, and needed rest, and there was a dose of malaria looming in the offing, as his aching head told him. It was as though his brains were arranged in slats, like a venetian blind, and these slats were opening and closing swiftly, bringing with each lightning flicker a momentary unconsciousness.

Captain Hamilton met him on the quay, and when Sanders landed—walking a thought unsteadily, and instantly began a long and disjointed account of his adventures on a Norwegian salmon river—Hamilton took him by the arm and led the way to the bungalow.

In ten minutes he was assisting Sanders into his pyjamas, Sanders protesting, albeit feebly, and when, after forcing an astonishing amount of quinine and arsenic down his chief's throat, Hamilton came from the semi-darkness of the bungalow to the white glare of the barrack square, Hamilton was thoughtful.

"Let one of your women watch by the bed of the lord Sandi," said he to Sergeant Abiboo, of the Houssas, "and she shall call me if he grows worse."

"On my life," said Abiboo, and was going off.

"Where is Tibbetti?" asked Hamilton.

The sergeant turned back and seemed embarrassed.

"Lord," he said, "Tibbetti has gone with the lady, your sister, to make a palaver with Jimbujini, the witch-doctor of the Akasava. They sit in the forest in a magic circle, and lo! Tibbetti grows very wise."

Hamilton swore under his breath. He had ordered Lieutenant Tibbetts, his second-in-command, prop, stay, and aide-de-camp, to superintend the drill of some raw Kano recruits who had been sent from the coast.

"Go tell the lord Tibbetti to come to me," he said, "but first send your woman to Sandi."

Lieutenant Tibbetts, with his plain, boyish face all red with his exertions, yet dignified withal, came hurriedly from his studies.

"Come aboard, sir," he said, and saluted extravagantly, blinking at his superior with a curious solemnity of mien which was his own peculiar expression.

"Bones," said Hamilton, "where the dickens have you been?"

Bones drew a long breath. He hesitated, then—

"Knowledge," he said shortly.Hamilton looked at his subordinate in alarm.

"Dash it, you aren't off your head, too, are you?"

Bones shook his head with vigour.

"Knowledge of the occult, sir and brother-officer," he said. "One is never too old to learn, sir, in this jolly old world."

"Quite right," said Hamilton; "in fact, I'm pretty certain that you'll never live long enough to learn everything."

"Thank you, sir," said Bones.

The girl, who had had less qualms than Bones when the summons arrived, and had, in consequence, returned more leisurely, came into the room.

"Pat," said her brother, "Sanders is down with fever."

"Fever!" she said a little breathlessly. "It isn't—dangerous?"

Bones, smiling indulgently, soothed her.

"Nothin' catchin', dear Miss Patricia Hamilton," he began.

"Please don't be stupid," she said so fiercely that Bones recoiled. "Do you think I'm afraid of catching anything? Is it dangerous for Mr. Sanders?" she asked her brother.

"No more dangerous than a cold in the head," he answered flippantly. "My dear child, we all have fever. You'll have it, too, if you go out at sunset without your mosquito boots."

He explained, with the easy indifference of a man inured to malaria, the habits of the mosquito—his predilection for ankles and wrists, where the big veins and arteries are nearer to the surface—but the girl was not reassured. She would have sat up with Sanders, but the idea so alarmed Hamilton that she abandoned it.

"He'd never forgive me," he said. "My dear girl, he'll be as right as a trivet in the morning."

She was sceptical, but, to her amazement, Sanders turned up at breakfast his usual self, save that he was a little weary-eyed, and that his hand shook when he raised his coffee-cup to his lips. A miracle, thought Patricia Hamilton, and said so.

"Not at all, dear miss," said Bones, now, as ever, accepting full credit for all phenomena she praised, whether natural or supernatural. "This is simply nothin' to what happened to me. Ham, dear old feller, do you remember when I was brought down from the Machengombi River? Simply delirious—ravin'—off my head."

"So much so," said Hamilton, slicing the top off his egg, "that we didn't think you were ill."

"If you'd seen me," Bones went on, solemnly shaking one skinny forefinger at the girl, "you'd have said: 'Bones is for the High Jump.'"

"I should have said nothing so vulgar, Bones," she retorted. "And was it malaria?"

"Ah," said Hamilton triumphantly, "I was too much of a gentleman to hint that it wasn't. Press the question, Pat."Bones shrugged his shoulders and cast a look of withering contempt upon his superior.

"In the execution of one's duty, dear Miss Patricia H," he said, "the calibre of the gun that lays a fellow low, an' plunges his relations an' creditors into mournin', is beside the point. The only consideration, as dear old Omar says, is—

"Is that Omar or Shakespeare?" asked the dazed Hamilton.

"Be quiet, dear. What was the illness, Bones?"

"Measles," said Hamilton brutally, "and German measles at that."

"Viciously put, dear old officer, but, nevertheless, true," said Bones buoyantly. "But when the hut's finished, I'll return good for evil. There's goin' to be a revolution, Miss Patricia Hamilton. No more fever, no more measles—health, wealth, an' wisdom, by gad!"

"Sunstroke," diagnosed Hamilton. "Pull yourself together, Bones—you're amongst friends."

But Bones was superior to sarcasm.

There was a creature of Lieutenant Tibbetts a solemn, brown man, who possessed, in addition to a vocabulary borrowed from a departed professor of bacteriology, a rough working knowledge of the classics. This man's name was, as I have already explained, Abid Ali or Ali Abid, and in him Bones discovered a treasure beyond price.

Bones had recently built himself a large square hut near the seashore—that is to say, he had, with the expenditure of a great amount of midnight oil, a pair of compasses, a box of paints, and a ?-square, evolved a somewhat complicated plan whereon certain blue oblongs stood for windows, and certain red cones indicated doors. To this he had added an elevation in the severe Georgian style.

With his plan beautifully drawn to scale, with sectional diagrams and side elevations embellishing its margin, he had summoned Mojeri of the Lower Isisi, famous throughout the land as a builder of great houses, and to him he had entrusted the execution of his design.

"This you shall build for me, Mojeri," said Bones, sucking the end of his pencil and gazing lovingly at the plan outspread before him, "and you shall be famous all through the world. This room shall be twice as large as that, and you shall cunningly contrive a passage so that I may move from one to the other, and none see me come or go. Also, this shall be my sleeping-place, and this a great room where I will practise powerful magics."

Mojeri took the plan in his hand and looked at it. He turned it upside down and looked at it that way. Then he looked at it sideways.

"Lord," said he, putting down the plan with a reverent hand, "all these wonders I shall remember."

"And did he?" asked Hamilton, when Bones described the interview.

Bones blinked and swallowed.

"He went away and built me a square hut—just a plain square hut. Mojeri is an ass, sir—a jolly old fraud an' humbug, sir. He——"

"Let me see the plan," said Hamilton, and his subordinate produced the cartridge paper.

"H'm!" said Hamilton, after a careful scrutiny. "Very pretty. But how did you get into your room?"

"Through the door, dear old officer," said the sarcastic Bones.

"I thought it might be through the roof," said Hamilton, "or possibly you made one of your famous dramatic entries through a star-trap in the floor—

"and up you pop amidst red fire and smoke."

A light dawned on Bones.

"Do you mean to tell me, jolly old Ham, that I forgot to put a door into my room?" he asked incredulously, and peered over his chief's shoulder."That is what I mean, Bones. And where does the passage lead to?"

"That goes straight from my sleepin' room to the room marked L," said Bones, in triumph.

"Then you were going to be a demon king," said the admiring Hamilton. "But fortunately for you, Bones, the descent to L is not so easy—you've drawn a party wall across——"

"L stands for laboratory," explained the architect hurriedly. "An' where's the wall? God bless my jolly old soul, so I have! Anyway, that could have been rectified in a jiffy."

"Speaking largely," said Hamilton, after a careful scrutiny of the plan, "I think Mojeri has acted wisely. You will have to be content with the one room. What was the general idea of the house, anyway?"

"Science an' general illumination of the human mind," said Bones comprehensively.

"I see," said Hamilton. "You were going to make fireworks. A splendid idea, Bones."

"Painful as it is to undeceive you, dear old sir," said Bones, with admirable patience, "I must tell you that I'm takin' up my medical studies where I left off. Recently I've been wastin' my time, sir: precious hours an' minutes have been passed in frivolous amusement—tempus fugit, sir an' captain, festina lente, an' I might add——"

"Don't," begged Hamilton; "you give me a headache."

There was a look of interest in Bones's eyes."If I may be allowed to prescribe, sir——" he began.

"Thanks, I'd rather have the headache," replied Hamilton hastily.

It was nearly a week before the laboratory was fitted that Bones gave a house-warming, which took the shape of an afternoon tea. Bones, arrayed in a long white coat, wearing a ferocious lint mask attached to huge mica goggles, through which he glared on the world, met the party at the door and bade them a muffled welcome. They found the interior of the hut a somewhat uncomfortable place. The glass retorts, test tubes, bottles, and the paraphernalia of science which Bones had imported crowded the big table, the shelves, and even overflowed on to the three available chairs.

"Welcome to my little workroom," said the hollow voice of Bones from behind the mask. "Wel——Don't put your foot in the crucible, dear old officer! You're sittin' on the methylated spirits, ma'am! Phew!"

Bones removed his mask and showed a hot, red face.

"Don't take it off, Bones," begged Hamilton; "it improves you."

Sanders was examining the microscope, which stood under a big glass shade.

"You're very complete, Bones," he said approvingly. "In what branch of science are you dabbling?""Tropical diseases, sir," said Bones promptly, and lifted the shade. "I'm hopin' you'll allow me to have a look at your blood after tea."

"Thank you," said Sanders. "You had better practise on Hamilton."

"Don't come near me!" threatened Hamilton.

It was Patricia who, when the tea-things had been removed, played the heroine.

"Take mine," she said, and extended her hand.

Bones found a needle, and sterilized it in the flame of a spirit lamp.

"This won't hurt you," he quavered, and brought the point near the white, firm flesh. Then he drew it back again.

"This won't hurt you, dear old miss," he croaked, and repeated the performance.

He stood up and wiped his streaming brow.

"I haven't the heart to do it," he said dismally.

"A pretty fine doctor you are, Bones!" she scoffed, and took the needle from his hand. "There!"

Bones put the tiny crimson speck between his slides, blobbed a drop of oil on top, and focussed the microscope.

He looked for a long time, then turned a scared face to the girl.

"Sleepin' sickness, poor dear old Miss Hamilton!" he gasped. "You're simply full of tryps! Good Lord! What a blessin' for you I discovered it!"

Sanders pushed the young scientist aside and looked. When he turned his head, the girl saw his face was white and drawn, and for a moment a sense of panic overcame her.

"You silly ass," growled the Commissioner, "they aren't trypnosomes! You haven't cleaned the infernal eyepiece!"

"Not trypnosomes?" said Bones.

"You seem disappointed, Bones," said Hamilton.

"As a man, I'm overjoyed," replied Bones gloomily; "as a scientist, it's a set-back, dear old officer—a distinct set-back."

The house-warming lasted a much shorter time than the host had intended. This was largely due to the failure of a very beautiful experiment which he had projected. In order that the rare and wonderful result at which he aimed should be achieved, Bones had the hut artificially darkened, and they sat in a hot and sticky blackness, whilst he knocked over bottles and swore softly at the instruments his groping hand could not discover. And the end of the experiment was a large, bad smell.

"The women and children first," said Hamilton, and dived for the door.

They took farewell of Bones at a respectful distance.

Hamilton went across to the Houssa lines, and Sanders walked back to the Residency with the girl. For a little while they spoke of Bones and his newest craze, and then suddenly the girl asked—"You didn't really think there were any of those funny things in my blood, did you?"

Sanders looked straight ahead.

"I thought—you see, we know—the tryp is a distinct little body, and anybody who had lived in this part of the world for a time can pick him out. Bones, of course, knows nothing thoroughly—I should have remembered that."

She said nothing until they reached the verandah, and she turned to go to her room.

"It wasn't nice, was it?" she said.

Sanders shook his head.

"It was a taste of hell," he said simply. And she fetched a quick, long sigh and patted his arm before she realized what she was doing.

Bones, returning from his hut, met Sanders hurrying across the square.

"Bones, I want you to go up to the Isisi," said the Commissioner. "There's an outbreak of some weird disease, probably due to the damming of the little river by Ranabini, and the flooding of the low forests."

Bones brightened up.

"Sir an' Excellency," he said gratefully, "comin' from you, this tribute to my scientific——"

"Don't be an ass, Bones!" said Sanders irritably. "Your job is to make these beggars work. They'll simply sit and die unless you start them on drainage work. Cut a few ditches with a fall to the river; kick Ranabini for me; take up a few kilos of quinine and dose them."Nevertheless, Bones managed to smuggle on board quite a respectable amount of scientific apparatus, and came in good heart to the despondent folk of the Lower Isisi.

Three weeks after Bones had taken his departure, Sanders was sitting at dinner in a very thoughtful mood.

Patricia had made several ineffectual attempts to draw him into a conversation, and had been answered in monosyllables. At first she had been piqued and a little angry, but, as the meal progressed, she realized that matters of more than ordinary seriousness were occupying his thoughts, and wisely changed her attitude of mind. A chance reference to Bones, however, succeeded where more pointed attempts had failed.

"Yes," said Sanders, in answer to the question she had put, "Bones has some rough idea of medical practice. He was a cub student at Bart.'s for two years before he realized that surgery and medicines weren't his forte."

"Don't you sometimes feel the need of a doctor here?" she asked, and Sanders smiled.

"There is very little necessity. The military doctor comes down occasionally from headquarters, and we have a native apothecary. We have few epidemics amongst the natives, and those the medical missions deal with—sleep-sickness, beri-beri and the like. Sometimes, of course, we have a pretty bad outbreak which spreads——Don't go, Hamilton—I want to see you for a minute."Hamilton had risen, and was making for his room, with a little nod to his sister.

At Sanders's word he turned.

"Walk with me for a few minutes," said Sanders, and, with an apology to the girl, he followed the other from the room.

"What is it?" asked Hamilton.

Sanders was perturbed—this he knew, and his own move towards his room was in the nature of a challenge for information.

"Bones," said the Commissioner shortly. "Do you realize that we have had no news from him since he left?"

Hamilton smiled.

"He's an erratic beggar, but nothing could have happened to him, or we should have heard about it."

Sanders did not reply at once. He paced up and down the gravelled path before the Residency, his hands behind him.

"No news has come from Ranabini's village for the simple reason that nobody has entered or left it since Bones arrived," he said. "It is situated, as you know, on a tongue of land at the confluence of two rivers. No boat has left the beaches, and an attempt to reach it by land has been prevented by force."

"By force?" repeated the startled Hamilton.

Sanders nodded.

"I had the report in this morning. Two men of the Isisi from another village went to call on some relations. They were greeted with arrows, and returned hurriedly. The headman of M'gomo village met with the same reception. This came to the ears of my chief spy Ahmet, who attempted to paddle to the island in his canoe. At a distance of two hundred yards he was fired upon."

"Then they've got Bones?" gasped Hamilton.

"On the contrary, Bones nearly got Ahmet, for Bones was the marksman."

The two men paced the path in silence.

"Either Bones has gone mad," said Hamilton, "or——"

"Or——?"

Hamilton laughed helplessly.

"I can't fathom the mystery," he said. "McMasters will be down to-morrow, to look at some sick men. We'll take him up, and examine the boy."

It was a subdued little party that boarded the Zaire the following morning, and Patricia Hamilton, who came to see them off, watched their departure with a sense of impending trouble.

Dr. McMasters alone was cheerful, for this excursion represented a break in a somewhat monotonous routine.

"It may be the sun," he suggested. "I have known several fellows who have gone a little nutty from that cause. I remember a man at Grand Bassam who shot——"

"Oh, shut up, Mac, you grisly devil!" snapped Hamilton. "Talk about butterflies."The Zaire swung round the bend of the river that hid Ranabini's village from view, but had scarcely come into sight when—

"Ping!"

Sanders saw the bullet strike the river ahead of the boat, and send a spiral column of water shooting into the air. He put up his glasses and focussed them on the village beach.

"Bones!" he said grimly. "Take her in, Abiboo."

As the steersman spun the wheel—

"Ping!"

This time the shot fell to the right.

The three white men looked at one another.

"Let every man take cover," said Sanders quietly. "We're going to that beach even if Bones has a battery of 75's!"

An exclamation from Hamilton arrested him.

"He's signalling," said the Houssa Captain, and Sanders put up his glasses again.

Bones's long arms were waving at ungainly angles as he semaphored his warning.

Hamilton opened his notebook and jotted down the message—

"Awfully sorry, dear old officer," he spelt, and grinned at the unnecessary exertion of this fine preliminary flourish, "but must keep you away. Bad outbreak of virulent smallpox——"

Sanders whistled, and pulled back the handle of the engine-room telegraph to "stop."

"My God!" said Hamilton through his teeth, for he had seen such an outbreak once, and knew something of its horrors. Whole districts had been devastated in a night. One tribe had been wiped out, and the rotting frames of their houses still showed amidst the tangle of elephant grass which had grown up through the ruins.

He wiped his forehead and read the message a little unsteadily, for his mind was on his sister—

Sanders looked at Hamilton, and McMasters chuckled.

"This is where I get a swift vacation," he said, and called his servant.

Hamilton leapt on to the rail, and steadying himself against a stanchion, waved a reply—

"We are sending you a doctor."

Back came the reply in agitated sweeps of arm—

"Doctor be blowed! What am I?"

"What shall I say, sir?" asked Hamilton after he had delivered the message.

"Just say 'a hero,'" said Sanders huskily.