In 1880, Pasteur was playing with the very tiny microbe that kills chickens with a malady known as chicken cholera. Doctor Peronçito had discovered this microbe, so tiny that it was hardly more than a quivering point before the strongest lens. Pasteur was the first microbe hunter to grow it pure, in a soup that he cooked for it from chicken meat. And after he had watched these dancing points multiply into millions in a few hours, he let fall the smallest part of a drop of this bug-swarming broth onto a crumb of bread--and fed this bread to a chicken. In a few hours the unfortunate beast stopped clucking and refused to eat, her feathers ruffled until she looked like a fluffy ball, and the next day Pasteur came in to find the bird tottering, its eyes shut in a kind of invincible drowsiness that turned quickly into death. Roux and Chamberland nursed these terrible wee microbes along carefully; day after day they dipped a clean platinum needle into a bottle of chicken broth that teemed with germs and then carefully shook the same still-wet needle into a fresh flask of soup that held no microbe at all--so day after day these transplantations went on--always with new myriads of germs growing from the few that had come in on the moistened needle. The benches of the laboratory became cluttered with abandoned cultures, some of them weeks old. “We’ll have to clean this mess up to-morrow,” thought Pasteur. Then the god of good accidents whispered in his ear, and Pasteur said to Roux: “We know the chicken cholera microbes are still alive in this bottle ... they’re several weeks old, it is true ... but just try shooting a few drops of this old cultivation into some chickens....” Roux followed these directions and the chickens promptly got sick, turned drowsy, lost their customary lively frivolousness. But next morning, when Pasteur came into the laboratory looking for these birds, to put them on the post-mortem board--he was sure they would be dead--he found them perfectly happy and gay! “This is strange,” pondered Pasteur, “always before this the microbes from our cultivations have killed twenty chickens out of twenty....” But the time for his discovery was not yet, and next day, after these strangely recovered chickens had been put in charge of the caretaker, Pasteur and his family and Roux and Chamberland went off on their summer vacations. They forgot about those birds.... But at last one day Pasteur told the laboratory servant: “Bring up some healthy birds, new chickens, and get them ready for inoculation.” “But we only have a couple of unused chickens left, Mr. Pasteur--remember, you used the last ones before you went away--you injected the old cultures into them, and they got sick but didn’t die?”