Gradually, it was hardly a year after the miracle of Pouilly-le-Fort, it began to be evident that Pasteur, though a most original microbe hunter, was not an infallible God. Disturbing letters began to pile up on his desk; complaints from Montpothier and a dozen towns of France, and from Packisch and Kapuvar in Hungary. Sheep were dying from anthrax--not natural anthrax they had picked up in dangerous fields, but anthrax they had got from those vaccines that were meant to save them! From other places came sinister stories of how the vaccine had failed to work--the vaccine had been paid for, whole flocks of sheep had been injected, the farmers had gone to bed breathing Thank-God-For-Our-Great-Man-Pasteur, only to wake up in the morning to find their fields littered with the carcasses of dead sheep, and these sheep--which ought to have been immune--had died from the lurking anthrax spores that lay in their fields.... Pasteur began to hate to open his letters; he wanted to stop his ears against snickers that sounded from around corners, and then--the worst thing that could possibly happen--came a cold terribly exact scientific report from the laboratory of that nasty little German Koch in Berlin, and this report ripped the practicalness of the anthrax vaccine to tatters. Pasteur knew that Koch was the most accurate microbe hunter in the world. There is no doubt that Pasteur lost some sleep from this aftermath of his glorious discovery, but, God rest him, he was a gallant man. It was not in him to admit, either to the public or to himself, that his sweeping claims were wrong. “Have not _I_ said that my vaccines made sheep a little sick with anthrax, but never killed them, and protected them perfectly? Well, I must stick to that,” you can hear him mutter between his teeth. [Illustration: VACCINATING SHEEP FOR ANTHRAX] What a searcher this Pasteur was, and yet how little of that fine selfless candor of Socrates or Rabelais is to be found in him. But he is not in any way to be blamed for that, for those two last were only, in their way, looking for truth, while Pasteur’s work carried him more and more into the frantic business of saving lives, and in this matter truth is not of the first importance.... In 1882, while his desk was loaded with reports of disasters, Pasteur went to Geneva, and there before the cream of disease-fighters of the world he gave a thrilling speech, subject: “How to guard living creatures from virulent maladies by injecting them with weakened microbes.” Pasteur assured them that: “The general principles have been found and one cannot refuse to believe that the future is rich with the greatest hopes.” “We are all animated with a superior passion, the passion for progress and for truth!” he shouted--but unhappily he said no word about those numerous occasions when his vaccine had killed sheep instead of protecting them.