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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. . . .

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 your 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