Then a strange race started between Pasteur and Koch, which meant between France and Germany, to search out the microbe of this cholera that flared threatening on the horizon. Koch and Gaffky went armed with microscopes and a menagerie of animals from Berlin; Pasteur--who was desperately busy struggling to conquer the mysterious microbe of hydrophobia--sent the brilliant and devoted Émile Roux and the silent Thuillier, youngest of the microbe hunters of Europe. Koch and Gaffky worked forgetting to eat or sleep; they toiled in dreadful rooms cutting up the bodies of Egyptians dead of cholera; in their muggy laboratory with the air fairly dripping with a steamy heat, sweat dropping off the ends of their noses on to the lenses of their microscopes, they shot stuff from the tragic carcasses of just-dead Alexandrians into apes and dogs and hens and mice and cats. But while these rival teams of searchers hunted frantically the epidemic began to fade away as mysteriously as it came. None of them had yet found a microbe they could surely accuse, and all of them--there is a kind of twisted humor in this--grumbled as they saw death receding, their chance of trapping their prey slipping from them. [Illustration: ROBERT KOCH] Koch and Gaffky were getting ready to return to Berlin, when one morning a frightened messenger came to them and told them: “Dr. Thuillier, of the French Commission, is dead--of cholera.” Koch and Pasteur hated each other sincerely and enthusiastically, like the good patriots that they were, but now the two Germans went to the bereaved Roux and offered their help and their condolences; and Koch was one of those that carried in a plain box to its last home the body of Thuillier, this daring young Thuillier whom the miserably weak--but treacherous--cholera microbe had turned upon and done to death before he had ever had a chance to spy upon and trap it. At the grave Koch laid wreaths upon the coffin: “They are very simple,” he said, “but they are of laurel, such as are given to the brave.” The funeral of this first of the martyred microbe hunters over, Koch hurried back to Berlin with certain mysterious boxes that held specimens, that he had painted with powerful dyes, and these specimens had in them a curious microbe shaped like a comma. Koch made his report to the Minister of State: “I have found a germ,” he said, “in all cases of cholera ... but I haven’t _proved_ yet that it is the cause. Send me to India where cholera is always smoldering--what I have found justifies your sending me there.” So Koch sailed from Berlin for Calcutta, with the fate of Thuillier hanging over him, drolly chaperoning fifty mice and dreadfully annoyed by seasickness. I have often wondered what his fellow-passengers took him for--probably they guessed that he was some earnest little missionary or a serious professor intent to delve into ancient Hindu lore.