Never was there a more conscientious searcher than this Loeffler, nor one with less of a wild imagination to liven--or to spoil--his almost automatic exactness. He sat himself down; he wrote a careful scientific paper; it was modest, it was cold, it was not hopeful, it was a most unlawyer-like report reciting all of the fors and againsts on the question of whether or no this new bacillus was the cause of diphtheria. He leaned over backward to be honest--he put last the facts that were against it! “This microbe _may_ be the cause,” you can hear him mumbling as he wrote, “but in a few children dead of diphtheria I could not find these germs ... none of my inoculated animals get paralysis as children do ... what is most against me is that I’ve discovered this same microbe--it was vicious against guinea-pigs and rabbits too!--in the throat of a child with never a sign of diphtheria.” He even went so far as to underestimate the importance of his exact fine searching, but at the end of his treatise he gave a clew to the more imaginative Roux and Behring who came after him. A strange man, this Loeffler! Without seeming to be able to make a move to do it himself, he predicted what others must find: “This bacillus stays on a little patch of dead tissue in the throat of a baby; it lurks on a little point under a guinea-pig’s skin; it never swarms in millions--yet it kills! How? “It must make a poison--a toxin that leaks out of it, sneaking from it to some vital spot in the body. Such a toxin must be found, in the organs of a dead child, in the carcass of a guinea-pig dead of the disease--yes--and in the broth where the bacillus grows so well.... The man finding this poison will prove what I have failed to demonstrate.” Such was the dream Loeffler put into Roux’s head.... II Four years later Loeffler’s words came true--by what seemed an utterly silly, but what was surely a most fantastical experiment you would have thought could only result in drowning a guinea-pig. What a hectic microbe hunting went on in Paris just then! Pasteur, in a state of collapse after his triumph of the dog bite vaccine, was feebly superintending the building of his million-franc Institute in the Rue Dutot. The wild, half-charlatan Metchnikoff had come out of Odessa in Russia to belch quaint theories about how phagocytes gobble up malignant germs. Pasteurians were packing microscopes in satchels and hurrying to Saigon in Indo-China and to Australia to try to discover microbes of weird diseases that did not exist. Hopefully frantic women were burying Pasteur--he was too tired!--under letters begging him to save their children from a dozen horrid diseases. “If you will,” one woman wrote him, “you can surely find a remedy for the horrible disease called diphtheria. Our children, to whom we teach your name as a great benefactor, will owe their lives to you!”