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cockroachy attic even to those burning fields—Theobald Smith journeyed out to his open air laboratory where Kilborne the future hardware dealer was in command. He went to Field No. 1 to see if ticks had got on to any of the northern cattle yet, to see if they were getting hot, if their heads drooped; he crossed over to Field No. 2 to pick a few more ticks off those three North Carolina cows—a few new ones always seemed to be popping up, grown from ones too small to see that first day!—it was nervous business, making sure those three cows stayed clean of ticks. . . . It was, to tell the truth, a perspiring and not too interesting waiting until that day a little past the middle of August, when the first northern cow began to show ticks, and presently to stand with her back arched, refusing to eat. Then the ticks appeared on all the northerners; they burned with fever, their blood turned to water, their ribs stuck out and their flanks grew bony—and ticks? They seemed to be alive with ticks!

But on Field No. 2, where there were no ticks, the northern cows stayed as healthy as their North Carolina mates. . . .

Each day the fever of the northern beasts in Field No. 1 went higher—then one by one they died; the barns ran red with the blood of the post mortems, and there were rushings to and fro between the dead beasts on the field and the microscopes in the attic—even Alexander, dimly sensing the momentous things afoot, even Alexander got busy. And Theobald Smith looked at the thin blood of the dead cows. "It is the blood the unknown Texas fever microbe attacks—something seems to get into the blood corpuscles of the cows and burst them open—it is inside the blood cells I must look for the germ," pondered Smith. Now, though he distrusted the reports of alleged microscope experts, he was nevertheless himself mighty sharp with this machine. He turned his most powerful lens onto the blood of the first cow that died, and—here was luck!—in the very first specimen he spied queer little punched-out pear-shaped spaces in the otherwise solid discs of the blood corpuscles. At first they simply looked like holes,