Microbe Hunters

by Paul De Kruif

  A bellow from Bruce: “I've got one!” The rest crowd round, squint in turn, exclaim as they watch the writhing trypanosome poke his exploring whip about in the gray field of the lens. Then they go back to their places—to shout discovery in their turn. So it went, from breakfast till the swift dusk of evening. In every single sample of spinal fluid from each one of his more than forty sleeping-sickness patients, Bruce and his companions found those trypanosomes.

  “But they may be in healthy people's spines tool” said Bruce. Bruce knew that if he found them in healthy negroes, all this excitement would be only a wild-goose chase—he must prove they were to be found only in folks with sleeping sickness. But to get fluid out of healthy people's spines? Folks dopey from the sleeping death didn't mind it so much—but to jab one of those big needles into the back of healthy wide-awake colored people, who had no wish to be martyrs to science. . . Can you blame them? It is no picnic having such a spear stuck into your spine. Then Bruce hit on a crafty scheme. He went to the hospital, where there was a fine array of patients with all kinds of diseases—but no sleeping sickness—and then, flimflamming them into thinking the operation would do them good, this liar in the holy cause of microbe hunting jabbed his needles into the smalls of the backs of negroes with broken legs and with headaches, into youngsters who had just been circumcised, and into their brothers or sisters who were suffering from yaws, or the itch; from all of them he got spinal fluid.

  And it was a great success. Not one of these folks—who had no sleeping sickness—harbored a single trypanosome in the fluid of their spines. Maybe the operation did do them some good—but no matter, they had served their purpose. The trypanosome, Castellani and Bruce now knew, was the cause of sleeping sickness!

  Now—and this is rare in the dreamers who find fundamental facts in science—Bruce was a fiend for practical applications, not poetically like Pasteur, for Bruce wasn't given to such lofty soarings, nor was he practical in the dangerous manner of the strange genius I tell of in the last chapter of this story; but the moment he turned to the study of a new plague, Bruce's gray eyes would dart round, he would begin asking himself questions: What is the natural home of the virus of this disease?—How does it get from sick to healthy?—What is its fountain and origin?—Is there anything peculiar in the way this sleeping sickness has spread?

  That was the way he went at it now. He had discovered the trypanosome that was the cause. There were a thousand pretty little researches to tempt the scholar in him, but he brushed all these aside. Old crafty hand at searching that he was, he fished round in his memories, and came to nagana, and screwed up his eyes: “Is there anything peculiar about the way sleeping sickness is located in this country?” He pondered.

  He sniffed around. With Mrs. Bruce he explored the high-treed shores of the lake, the islands, the rivers, the jungle. Then the common-sense eye which sees things a hundred searchers might stumble over and go by—showed him the answer. It was strange—suspiciously strange—that sleeping sickness was only found in a very narrow strip of country—along the water, only along the water, on the islands, up the river—even by the Ripon Falls where Victoria Nyanza gives herself up to the making of the Nile, there were cases of it, but never inland. That must mean some insect, a blood-sucking insect, which lives only near water, must carry the disease. That was his guess, why, I cannot tell you. “Maybe it is a tsetse fly, a special one living only near lake shores and river banks!”

  So Bruce went around asking everybody about tsetse flies in Uganda. He inquired of local bug experts: no, they were sure tsetse flies could not live at an altitude above three thousand feet. He asked the native headmen, even the black Prime Minister of Uganda: sorry, we have a blood-sucking fly, called Kivu—but there are no tsetse flies in Uganda. But there must be!

  6

  And there were. One day, as they walked through the Botanical Garden at Entebbe, Bruce pushing his bulky body between the rows of tropic plants ahead of his small wife—there was a glad shriek from her. . . “Why, David! There are two tsetse—on your back!” That woman was a scientific Diana. She swooped on those two tsetses, and caught them, and gave them a practical pinch—just enough to kill them, and then showed them to her husband. They had been perched, ready to strike, within a few inches of his neck. Now they knew they were on the trail.

  Hard work began in the laboratory; already Bruce had found an excellent experimental animal—the monkey, which he could put into a beautiful fatal sleep, just like that of a man, by injecting fluid from the spines of doomed negroes. But now to catch tsetse flies. They armed themselves with butterfly nets and the glass-windowed cages they had invented in Zululand. Then these inseparable searchers climbed into canoes; lusty crews of black boys shot them across the lake. Along the banks they walked—it was charming in the shade there—but listen! Yes, there was the buzz of the tsetse. . . They tried to avoid being bitten. They were bit—and stayed awake nights wondering what would happen—they went back to the laboratory and clapped the cages on the backs of monkeys. It was a good time for them.

  That is the secret of those fine discoveries Bruce made. It was because he was a hunter. Not only with his mind—but a bold everlastingly curious snouting hunter with his body too. If he had sat back and listened to those missionaries, or stayed listening to those bug experts—he would never have learned that Kivu was the Uganda name for the tsetse. He would never have found the tsetse. But he carried the fight to the enemy—and as for Mrs. Bruce, that woman was better than a third hand or two extra pairs of eyes for him.

  Now they planned and did terrible experiments. Day after day they caused tsetse flies to feed on patients near to death (already too deep in sleep to be annoyed by the insects); they interrupted the flies in the midst of their meal, and put the angry, half-satisfied cages of them on the backs of monkeys. With all the tenderness of high-priced nurses watching over Park Avenue babies they saw to it that only their experimental flies, and no chance flies from outside, got a meal off those beasts. Other searchers might have rolled their thumbs waiting to see what happened to the monkeys, but not Bruce.

  He proceeded to call in a strange gang of co-workers to help him in one of the most amazing tests of all microbe hunting. Bruce asked for an audience from the high-plumed gay-robed potentate, Apolo Kagwa, Prime Minister of Uganda. He told Apolo he had discovered the microbe of the sleeping death which was killing so many thousands of his people. He informed him many thousands more already had the parasite in their blood, and were doomed. “But there is a way to stop the ruin that faces your country, for I have reason to believe it is the tsetse fly—the insect you call Kivu—and only this insect, that carries the poisonous germ from a sick man to a healthy one—”

  The magnificent Apolo broke in: “But I cannot believe that is so—Kivu has been on the Lake shore always, and my people have only begun to be taken by the sleeping sickness during the last few years—”

  Bruce didn't argue. He bluffed, as follows: “If you do not believe me, give me a chance to prove it to you. Go down, Apolo Kagwa, to the Crocodile Point on the Lake shore where Kivu swarms so. Sit on the shore there with your feet in the water for five minutes. Don't keep off the flies—and I'll promise you'll be a dead man in two years!”

  The bluff was perfect: “What then, is to be done, Colonel Bruce?” asked Apolo.

  “Well, I must be dead sure I am right,” Bruce told him. Then he showed Apolo a great map of Uganda. “If I'm right, where there is sleeping sickness—there we will find tsetse flies too. Where there are no tsetse—there should be no sleeping sickness.”

  So Bruce gave Apolo butterfly nets, and killing bottles, and envelopes; he gave directions about the exact way to set down all the facts, and he told how Apolo's darky minions might pinch the flies without getting stabbed themselves. “And then we will put our findings down on this map—and see if I'm right.”

  Apolo was nothing if not intelligent, and efficient. He said he would see what could be done. There wer
e bows and amiable formalities. In a jiffy the black Prime Minister had called for his head chief, the Sekibobo, and all the paraphernalia, with rigid directions, went from the Sekibobo to the lesser headmen, and from them down to the canoe men—the wheels of that perfect feudal system were set going. . .

  Presently the envelopes began to pour in on Bruce and called him away from his monkey experiments. They cluttered the laboratory, they called him from his peering into the intestines of tsetse flies where he looked for trypanosomes. Rapidly, with perfectly recorded facts—most of them set down by intelligent blacks and some by missionaries—the envelopes came in. It was a kind of scientific co-working you would have a hard time finding among white folks, even white medical men. Each envelope had a grubby assorted mess of biting flies, they had a dirty time sorting them, but every time they found a tsetse, a red-headed pin went into that spot on the map—and if a report of “sleeping sickness present” came with that fly, a black-headed pin joined it. From the impressive Sekibobo down to the lowest fly-boy, Apolo's men had done their work with an automatic perfection. At last the red and black dots on the map showed that where there were tsetses, there was the sleeping death—and where there were no tsetses—there was no single case of sleeping sickness!

  The job looked finished. The unhappy monkeys bit by the flies who had sucked the blood of dying negroes—these monkeys' mouths fell open while they tried to eat their beloved bananas; they went to sleep and died. Other monkeys never bit by flies—but kept in the same cages, eating out of the same dishes—those monkeys never showed a sign of the disease. Here were experiments as clean, as pretty as the best ones Theobald Smith had made. . .

  7

  But now for action! Whatever of the dreamer and laboratory experimenter there was in him—and there was much—those creative parts of David Bruce went to sleep, or evaporated out of him; he became the surgeon of Ladysmith once more, and the rampageous shooter of lions and killer of koodoos. . . To wipe out the sleeping sickness! That seemed the most brilliantly simple job now. Not that there weren't countless thousands of blacks with trypanosomes in their blood, and all these folks must die, of course; not that there weren't buzzing billions of tsetses singing their hellish tune on the Lake shore—but here was the point: Those flies lived only on the lake shore! And if they had no more sleeping-sickness blood to suck, then. . . And Apolo Kagwa was absolute Tsar of all Uganda. . . Apolo, Bruce knew, trusted him, adored him. . .

  Now to wipe sleeping sickness from the earth!

  To conference with Bruce once more came Apolo and the Sekibobo and the lesser chiefs. Bruce told them the simple logic of what was to be done.

  “Of course—that can be done,” said Apolo. He had seen the map. He was convinced. He made a dignified wave of the hand to his chiefs, and gave a few words of explanation. So Bruce and Mrs. Bruce went back to England. Apolo gave his order, and then the pitiful population of black men and their families streamed inland out of the lake shore villages, away—not to return for years, or ever—from those dear shady places where they and the long line of their forefathers had fished and played and bargained and begot their kind; canoes, loaded with mats and earthen pots and pickaninnies set out (not to return) from the thickly peopled island—and the weird outlandish beating of the tom-toms no longer boomed across the water.

  “Not one of you,” commanded Apolo, “may live within fifteen miles of the Lake shore—not one of you is to visit the Lake again. Then the sleeping death will die out, for the fly Kivu lives only by the water, and when you are gone she will no longer have a single sick one from whom to suck the fatal poison. When all of our people who are now sick have died, you may go back—and it will be safe to live by the Lake shore for always.”

  Without a word—it is incredible to us law-abiding folks—they obeyed their potentate.

  The country around Lake Victoria Nyanza grew, in the frantic way tropical green things grow, back into the primordial jungle; crocodiles snoozed on the banks where big villages had been. Hippopotami waddled onto the shore and sniffed in the deserted huts. . . The tribes of the lake, inland, were happy, for no more of them came down with that fatal drowsiness. So Bruce began to rid Africa of sleeping sickness.

  It was a triumph—in a time of great victories in the fight of men against death. The secret of the spread of malaria—you will hear the not too savory story of it presently—had been found in India and Italy. And as for yellow fever—it seemed as if the yellow jack was to be put to sleep for good. Great Eminences of the medical profession pointed in speeches amid cheers to the deeds of medicine. . . The British Empire rang with hosannahs for David Bruce. He was promoted Colonel. He was dubbed Knight Commander of the Bath. Lady Bruce? Well, she was proud of him and stayed his assistant, obscurely. And Bruce still paid, out of his miserable colonel's salary, her fare on those expeditions they were always making.

  Africa looked safe for the black men, and open to the benevolent white men. But nature had other notions. She had cards up her sleeve. She almost never lets herself be conquered at a swoop, Napoleonically—as Bruce and Apolo (and who can blame them?) thought they had done. Nature was not going to let her vast specimen cabinet be robbed so easily of every last one of those pretty parasites, the trypanosomes of sleeping sickness. A couple of years passed, and suddenly the Kavirondo people, on the east shore of the Lake where sleeping death had never been—these folks began to go to sleep and not wake up. And there were disturbing reports of hunters coming down with sleeping sickness, even in those places that should have been safe, in the country from which all human life had been moved away. The Royal Society sent out another Commission (Bruce was busy with that affair of goat's milk giving Malta fever) and one of these new commissioners was a bright young microbe hunter, Tulloch. He went on a picnic one day to a nice part of the shore whose dark green was dotted with scarlet flowers. It must be safe there now, they thought, but a tsetse buzzed, and in less than a year Tulloch had drowsed into his last cold sleep. The Commission went home. . .

  Bruce—you would think he would be looking by this time for some swivel-chair button-pressing job—packed his kit-bag and went back to Uganda, to see what he had left out of those experiments that had looked so sure. He had gone off half-cocked, with that Napoleonic plan of moving a nation, but who can blame him? It had looked so simple, and how expect even the craftiest of the cheaters of Nature to find out, in a year, every single nook where Nature hides the living poisons to kill the presumptuous men who cheat her! Lady Bruce as usual went with him, and they found new epidemics of sleeping sickness flaring up in unwonted places. It was a miserable discouraging business.

  Bruce was a modest man, who had no foolish vanity to tell him that his own theories were superior to brute facts. “My plan has been a washout,” you can hear him grumbling. “Somewhere, aside from the human being, those tsetses must get the trypanosomes—maybe it's like the nagana—maybe they can live in wild beasts' blood too. . .”

  Now if Bruce had theories that were a little too simple he was just the same an exceedingly crafty experimenter; if he had a foolish faith in his experiments, he had the persistence to claw his way out of the bogs of disappointment that his simplicity and love of gorgeous deeds got him into. What a stubborn man he was! For, when you think of the menagerie of birds, beasts, fishes and reptiles Uganda is, you wonder why he didn't pack his bags and start back for England. But no. Once more the canoe man paddled Bruce and his lady across to that tangled shore, and they caught flies in places where for three years no man had been. Strange experiments they made in a heat to embarrass a salamander—one laborious complicated record in his notes tells of two thousand, eight hundred and seventy-six flies (which could never have bitten a human sleeping-sickness patient) fed on five monkeys—and two of these monkeys came down with the disease!

  “The trypanosomes must be hiding in wild animals!” Bruce cries. So they go to the dangerous Crocodile Point, and catch wild pigs and African gray and purple herons; they bleed sac
red ibises and glossy ones; they stab and get blood from plovers and kingfishers and cormorants—and even crocodiles! Everywhere they look for those deadly, hiding, thousandth-of-an-inch-long wigglers.

  They caught tsetse flies on Crocodile Point. See the fantastic picture of them there, gravely toiling at a job fit for a hundred searchers to take ten years at. Bruce sits with his wife on the sand in the middle of a ring of barebacked paddlers who squat round them. The tsetses buzz down onto the paddlers' backs. The fly-boys pounce on them, hand them to Bruce, who snips off their heads, waves the buzzing devils away from his own neck, determines the sex of each fly caught, dissects out its intestine—and smears the blood in them on thin glass slides. . .

  Washouts, most of these experiments; but one day, in the blood of a native cow from the Island of Kome, not hurting that cow at all, but ready to be sucked up by the tsetse for stabbing under the skin of the first man it meets, Bruce found the trypanosome of sleeping sickness. He sent out word, and presently a lot of bulls and cows were driven up the hill to Mpumu by order of Apolo Kagwa. Bruce, himself in the thick of it, directed dusty fly-bitings of these cattle—yes! there was no doubt the sleeping-sickness virus could live in them. Then there were scuffles in the hot pens with fresh-caught antelope; they were thrown, they were tied, Bruce held dying monkeys across their flanks, and let harmless tsetses, bred in the laboratory, feed on the monkey and then on the buck. . .

  “The fly country around the Lake shore will have to be cleared of antelope, too, as well as men—before the Kivu become harmless,” Bruce said at last to Apolo.