By now the hottest weather had passed, it was September, and in Field No. 2, the northern cattle, all four of them, kept on grazing and grew fat—there were no ticks there. And Smith muttered: “We'll see if it's the ticks who are to blame!” and he took two of these unharmed northern beasts and led them into Field No. 1, where so many beasts had died—in a week a few of the little red-brown bugs were crawling up these new cows' legs. In a little more than two weeks one of these cows was dead, and the other sick, of Texas fever.
But there never was a man who needed more experiences to convince him of something he wanted to believe. He must be sure! And there was still another simple trick he could try—call it an experiment if you wish. From North Carolina, from the fatal fields down there, came large cans and these cans were filled with grass, that swarmed with ticks, crawling, thirsty for the blood of cows. These cans Theobald Smith took on to Field No. 3, where no southern cattle or their bloodsucking parasites had ever been, and he plodded up and down this field, and all over it he sowed his maybe fatal seed—of ticks. Then four northern cattle were led by Kilborne on to this field—and in a few weeks their blood ran thin, and one died, and two of the remaining three had severe bouts of Texas fever but recovered.
6
So, first of all microbe hunters, Theobald Smith traced out the exact path by which a sub-visible assassin goes from one animal to another. In the field where there were southern cattle and ticks, the northern cattle died of Texas fever; in the field where there were southern cattle without ticks the northern cows grew fat and remained, happy; in the field where there were no southern cattle but only ticks—there too, the northern cattle came down with Texas fever. It must be the tick. By such simple, two-plus-two-make-four—but oh! what endlessly careful experiments, Theobald Smith proved those western cowmen to have observed a great new fact of nature. . . He chiseled that fact out of folk-shrewdness, just as the anonymous invention of the wheel has been taken out of folk-inventiveness and put to the uses of modern whirring dynamos. . .
You would think he thought he had proved enough—those experiments were so clear. You would think he would have advised the government to start an exterminating war on ticks, but that was not the kind of searcher Theobald Smith was. Instead, he waited for the heat of the summer of 1890 to come, and then he started doing the same experiments over, and some new ones too, all of them simple tricks, but each of them necessary to nail down the fact that the tick was the real criminal. “How do those bugs carry the disease from a southern cow to a northern one?” he pondered. “We know now one tick lives its whole life on just one cow—it doesn't flit from beast to beast like a fly. . . ” This was a knotty question—too subtle for the crude science of the ranchers—and Smith set himself to chew that knot. . .
“It must be,” he meditated, “that ticks, when they have sucked enough blood, and are ripe, drop off, and are crushed, and leave the little pear-shaped microbes on the grass—to be eaten by the northern cattle!”
So he took thousands of ticks, sent up in those cans from North Carolina, and mixed them with hay, and fed them to a susceptible northern cow kept carefully in a special stable. But nothing happened; the cow seemed to relish her new food; she got fat. He tried drenching another cow with mashed up ticks made into a soup-but that cow too seemed to enjoy her strange dose. She prospered on it.
It was no go—cows didn't, apparently, get the microbe by eating ticks; he was mixed up for a while. And other plaguey questions kept him awake nights. Why was it that it took thirty days or more, after the southern tick-loaded cows came on the field, for such a field to become dangerous? Stockmen knew this too; they knew they could mix just-arrived southern cows with northern ones, and keep them together twenty days or so, and then if they took the northern ones away—they would never get Texas fever; but if you left them in that field a little longer (even if the southern cows were taken away) bang! would come the fatal epidemic into the herd of northerners. That was a poser!
Then one day in this summer of 1890, by the most strange, the most completely unforeseen of accidents, every jagged piece of the puzzle fell into its proper place. The solution of the riddle fairly clubbed Theobald Smith; it yelled at him; it forced itself on him while he was busy doing other things. He was at all kinds of experiments just then; he was bleeding northern cows for gallons of blood to give them an anemia—to make sure those funny little pear-shaped objects he had found in the corpuscles of Texas fever cattle were microbes, and not simply little changes in blood that might come from anemia. He was learning to hatch nice clean young ticks artificially in glass dishes in his laboratory; he was still laboriously picking ticks off southern cows—and sometimes he failed to get them all off and the experiments went wrong—to prove that tickless southern cows are harmless to northern ones; he was discovering the strange fact that northern calves get only a mild fever on a field fatal to their mothers. He fussed about finding every single effect a tick might have on a northern cow—it might do other damages besides giving her Texas fever. . .?
Then came that happy accident. He asked himself: “If I should put good clean young ticks, hatched in glass dishes in my attic, ticks who never have been on cattle or on a dangerous field—if I should put such ticks on a northern cow and let them suck their fill of her blood—could those ticks take out enough blood to give the cow an anemia?” It seems to me to have been an aimless question. His thoughts were a thousand miles away from Texas fever. . .
But he tried it. He took a good fat yearling heifer, put her in a box-stall, and day after day put hundreds of clean baby ticks on her, holding her while these varmints crawled away beneath her hair to get a good grip on her hide. Then day after day, while the ticks made their meals, he cut little gashes in her skin to get a drop of blood to see if she was becoming anemic. And one morning Theobald Smith came into her stall—for the usual routine—he put his hand on that heifer. . . What was this? She felt hot! Very hot! Suspiciously too hot! She dropped her head, and would not eat—and her blood which before had welled out from the gashes thick and rich and red—that blood ran very thin and darkish. He hurried back to his attic with samples of the blood between little pieces of glass. . . Under the microscope it went, and sure enough!—here were twisted, jagged, wrecked blood corpuscles instead of good even round ones with edges smooth as a worn dime. And inside these broken cells—it was fantastical, this business!—were the little pear-shaped microbes. . . Here was the fact, stranger than any pipe-dream—for these microbes must have come up from North Carolina on old ticks, had gone out of the old ticks into the eggs they had laid in the glass dishes, they had survived in the baby ticks hatched out these eggs—and these babies had at last shot them back, ready to kill, into their destined but completely accidental victim, that yearling heifer!
In a flash all those mysterious questions cleared up for Theobald Smith.
It was not the old, blood-stuffed tick but its child, the baby tick, who sneaked the assassin into the northern cows; it was this little five- or ten-day-old bug who carried the murderer.
Now he saw why it was that fields took so long to become dangerous—the mother ticks have to drop off the southern cattle; it takes them some days to lay their eggs; these eggs take twenty days or more to hatch; the tick babies have to scamper about to find a cow's leg to crawl up on—all that takes many days, weeks. “Never was there a simpler answer to a problem which, without this strange chance, might not yet be solved. . .
So soon as he could hatch out other thousands of ticks in warm glass dishes, Theobald Smith proceeded to confirm his marvelous discovery; he proved it clean. For every northern cow, on whom he stuck his regiments of incubator ticks, came down with Texas fever. But he was a glutton for proofs, as you have seen, and when the summer of 1890 waned and it grew cold, he installed a coal-stove in a stable, hatched the ticks in a heated place, put a cow in the hot stable, stuck the little ticks diligently onto the hide of the cow, the stove instead of the sun made them grow as they
should—and the cow got Texas fever in the winter, a thing which never happens in nature!
For two more summers Smith and Kilborne tramped about their fields, caulking up every seam in the ship of their research, answering every argument, devising astounding simple but admirably adequate answers to every objection the savant horse doctors might make—before these critics ever had a chance to make objections. They found strange facts about immunity. They saw northern calves get mild attacks of Texas fever, a couple of attacks in one summer maybe, and then next year, more or less grown up, graze unconcerned on fields absolutely murderous to a non-immune northern cow. . . So they explained why southern cattle never die of Texas fever. This fell disease is everywhere that ticks are in the South—and ticks are everywhere; ticks are biting southern cattle and shooting the fatal queer pears into them all the time; these cattle carry the microbes about with them in their blood—but it doesn't matter, for the little sickness in their calfhood has made them immune.
Finally, after four of these stifling but triumphant summers, Theobald Smith sat down, in 1893, to answer all the perplexing questions about Texas fever—and to tell how the disease can be absolutely wiped out (just then the ancient Pasteur who had prophesied that about all disease was getting ready to die). Never—and I do not forget the masterpieces of Leeuwenhoek or Koch or any genius in the line of microbe hunters—never, I say, has there been written a more simple but at the same time more solid answer to an enigma of nature. A bright boy could understand it; Isaac Newton would have taken off his hat to it. He loved Beethoven, did young Smith, and for me this “Investigation into the Nature, Causation, and Prevention of Texas or Southern Cattle Fever” has the quality of that Eighth Symphony of Beethoven's sour later years. Absurdly simple in their themes they both are, but unearthly varied and complete in the working out of those themes—just as nature is at once simple and infinitely complex. . .
7
And so, with this report, Theobald Smith made mankind turn a corner, showed men an entirely new and fantastic way a disease may be carried—by an insect. And only by that insect. Wipe out that insect, dip all of your cattle to kill all their ticks, keep our northern cattle in fields where there are no ticks, and Texas fever will disappear from the earth. To-day whole states are dipping their cattle and to-day Texas fever which once threatened the great myriads of American cattle is no longer a matter for concern. But that is only the beginning of the beneficent deeds of this plain report, this classic unappreciated and completely out of print. For presently, on the veldt and in the dangerous bush of southern Africa, a burly Scotch surgeon-major swore at the bite of a tsetse fly—and wondered what else besides merely annoying one, these tsetse flies might do. And a little later in India, and at the same time in Italy, an Englishman and an Italian listened to the whining song of swarms of mosquitoes, and dreamed and wondered and planned strange experiments—
But those are the stories the next chapters will celebrate. They tell of ancient plagues now in reach of mankind's complete control—they tell of a deadly yellow disease now almost entirely abolished. They tell of men projecting pictures of swarming human life and turreted cities of the future reaching up and up, built on jungles now fit only for man-killing wild beasts and lizards. It was this now nearly forgotten microbe hunting of Theobald Smith that first gave men the right to have visions of a world transformed.
9. BRUCE:
Trail of the Tsetse
1
“Young man!”—the face of the Director-General of the British Army Medical Service changed from an irritated red to an indignant mauve-color—“young man, I will send you to India, I will send you to Zanzibar, I will send you to Timbuctoo—I will send you anywhere I please”—(the majestic old gentleman was shouting now, and his face was a positively furious purple) “but you may be damned sure I shall not send you to Natal!. . . ” Reverberations. . .
What could David Bruce do, but salute, and withdraw from his Presence? He had schemed, he had begged, and pulled wires, finally he had dared the anger of this Jupiter, so that he might go hunt microbes in South Africa. It was in the early eighteen nineties; Theobald Smith, in America, had just made that revolutionary jump ahead in microbe hunting—he had just shown how death may be carried by a tick, and only by a tick, from one animal to another. And now this David Bruce, physically as adventurous as Theobald Smith was mildly professorial, wanted to turn that corner after Smith. . . Africa swarmed with mysterious viruses that made the continent a hell to live in; in the olive-green mimosa thickets and the jungle hummed and sizzled a hundred kinds of flies and ticks and gnats. . . What a place for discoveries, for swashbuckling-microscopings and lone-wolf bug-huntings Africa must be!
It was in the nature of David Bruce to do things his superiors and elders didn't want him to do. Just out of medical school in Edinburgh, he had joined the British Army Medical Service, not to fight, nor to save lives, nor (at that time) to get a chance to hunt microbes—not for any such noble objects. He had joined it because he wanted to marry. They hadn't a shilling, neither Bruce nor his sweetheart; their folks called them thirteen kinds of romantic idiots—why couldn't they wait until David had established himself in a nice practice?
So Bruce joined the army, and married on a salary of one thousand dollars a year.
In certain ways he was not a model soldier. He was disobedient, and, what is much worse, tactless. Still a lieutenant, he one day disapproved of the conduct of his colonel, and offered to knock him down. . . If you could see him now, past seventy, with shoulders of a longshoreman and a barrel-chest sloping down to his burly equator, if you could hear him swear through a mustache Hindenburg would be proud to own, you would understand he could, had it been necessary, have put that colonel on his back, and laughed at the court-martial that would have been sure to follow. He was ordered to the English garrison on the Island of Malta in the Mediterranean; with him went Mrs. Bruce—it was their honeymoon. Here again he showed himself to be things soldiers seldom are. He was energetic, as well as romantic. There was a mysterious disease in the island. It was called Malta fever. It was an ill that sent pains up and down the shin bones of soldiers and made them curse the day they took the Queen's shilling. Bruce saw it was silly to sit patting the heads of these sufferers, and futile to prescribe pills for them—he must find the cause of Malta fever!
So he got himself into a mess. In an abandoned shack he set up a laboratory (little enough he knew about laboratories!) and here he spent weeks learning how to make a culture medium, out of beef broth and agar-agar, to grow the unknown germ of Malta fever in. It ought to be simple to discover it. His ignorance made him think that; and in his inexperience he got the sticky agar-agar over hands and face; it stained his uniform; the stuff set into obstinate jelly when he tried to filter it; he spent weeks doing a job a modern laboratory helper would accomplish in a couple of hours. He said unmentionable things; he called Mrs. Bruce from the tennis lawn, and demanded (surely any woman knew better how to cook) that she help him. Out of his thousand dollars a year he bought monkeys—improvidently—at one dollar and seventy-five cents apiece. He tried to inject the blood of the tortured soldiers into these creatures; but they wriggled out of his hands and bit him and scratched him and were in general infernally lively nuisances. He called to his wife: “Will you hold this monkey for me?”
That was the way she became his assistant, and as you will see, for thirty years she remained his right hand, going with him into the most pestilential dirty holes any microbe hunter has ever seen, sharing his poverty, beaming on his obscure glories; she was so important to his tremendous but not notorious conquests. . .
They were such muddlers at first, it is hard to believe it, but together these newly wed bacteriologists worked and discovered the microbe of Malta fever—and were ordered from Malta for their pains. “What was Bruce up to, anyway?” So asked the high medical officers of the garrison. “Why wasn't he treating the suffering soldiers—what for was he sticking himself away
there in the hole he called his laboratory?” And they denounced him as an idiot, a visionary, a good-for-nothing monkey-tamer and dabbler with test-tubes. And just—he did do this twenty years later—as he might have discovered how the little bacillus of Malta fever sneaks from the udders of goats into the blood of British Tommies, he was ordered away to Egypt.
2
Then he was ordered back to England, to the Army Medical School at Netley, to teach microbe hunting there—for hadn't he discovered the germ of an important disease? Here he met (at last God was good to him) His Excellency, the Honorable Sir Walter Hely-Hutchinson, Governor of Natal and Zululand, et cetera, et cetera. Together these two adventurers saw visions and made plans. His Excellency knew nothing about microbes and had perhaps never heard of Theobald Smith—but he had a colonial administrator's dream of Africa buzzing with prosperity under the Union Jack. Bruce cared no fig for expansion of the Empire, but he knew there must be viruses sneaking from beast to beast and man to man on the stingers of bugs and flies. He wanted (and so did Mrs. Bruce) to investigate strange diseases in impossible places.
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