And now Pasteur began--God knows why--to stick little hollow glass tubes into the gaping mouths of dogs writhing mad with rabies. While two servants pried apart and held open the jowls of a powerful bulldog, Pasteur stuck his beard within a couple of inches of those fangs whose snap meant the worst of deaths, and, sprinkled sometimes with a maybe fatal spray, he sucked up the froth into his tube--to get a specimen in which to hunt for the microbe of hydrophobia. I wish to forget, now, everything that I have said about his showmanship, his unsearcherlike go-gettings. This business of his gray eyes looking that bulldog in the mouth--this was no grandstand stuff. Why did Pasteur set out to trap the germ of rabies? That is a mystery, because there were a dozen other serious diseases, just then, whose microbes had not yet been found, diseases that killed many more people than rabies had ever put to death, diseases that were not nearly so surely deadly to an adventurous experimenter as rabies would be--if one of those dogs should get loose.... It must have been the artist, the poet in him that urged him on to this most hard and dangerous hunting, for Pasteur himself said: “I have always been haunted by the cries of those victims of the mad wolf that came down the street of Arbois when I was a little boy....” Pasteur knew the way the yells of a mad dog curdle the blood of every one. He remembered that less than a hundred years before in France, laws had to be passed against the poisoning, the strangling, the shooting of wretched people whom frightened fellow-townsmen just suspected of having rabies. Doubtless he saw himself the deliverer of men from such crazy fear--such hopeless suffering. And then, in this most magnificent and truest of all his searchings, Pasteur started out, as he so often did, by making mistakes. In the saliva of a little child dying from hydrophobia he discovered a strange motionless germ that he gave the unscientific name of “microbe-like-an-eight.” He read papers at the Academy that hinted about this figure-eight germ having something to do with the mysterious cause of hydrophobia. But in a little while this trail proved to be a blind one, for with Roux and Chamberland he found--after he had settled down and got his teeth into this search--that this eight-microbe could be found in the mouths of many healthy people who had never been anywhere near a mad dog. Presently, late in 1882, he ran on to his first clew. “Mad dogs are scarce just now, old Bourrel the veterinarian brings me very few of them, and people with hydrophobia are still harder to get hold of--we’ve got to produce this rabies in animals in our laboratory and keep it going there--otherwise we won’t be able to go on studying it steadily,” he pondered. He was more than sixty, and he was tired.