Pasteur looked, then suddenly saw the magnificent ingeniousness of this little experiment. “Why, then microbes can’t fall into the flask, because the dust they stick to can’t very well fall upward--marvelous! I see it now!” “Exactly,” smiled Balard. “Try it and find out if it works--see you later,” and he left to continue his genial round of the laboratories. Pasteur had bottle washers and assistants now, and he ordered them to hurry and prepare the flasks. In a moment the laboratory was buzzing with the stuttering ear-shattering b-r-r-r-r-r of the enameler’s lamps; he fell to work savagely. He took flasks and put yeast soup into them and then melted their necks and drew them out and curved them downward--into swan’s necks and pigtails and Chinaman’s queues and a half-dozen fantastic shapes. Next he boiled the soup in them--that drove out all the air--but as the flasks cooled down new air came in--unheated air, perfectly clean air. The flasks ready, Pasteur crawled on his hands and knees, back and forth with a comical dignity on his hands and knees, carrying one flask at a time, through a low cubby hole under the stairs to his incubating oven. Next morning he was first at the laboratory, and in a jiffy, battered notebook in his hand, if you had been there you would have seen his rear elevation disappearing underneath the stairway. Like a beagle to its rabbit Pasteur was drawn to this oven with its swan neck flasks. Family, love, breakfast, and the rest of a silly world no longer existed for him. Had you still been there a half hour later, you would have seen him come crawling out, his eyes shining through his fogged glasses. He had a right to be happy, for every one of the long twisty necked bottles in which the yeast soup had been boiled was perfectly clear--there was not a living creature in them. The next day they remained the same and the next. There was no doubt now that Balard’s scheme had worked. There was no doubt that spontaneous generation was nonsense. “What a fine experiment is this experiment of mine--this proves that you can leave any kind of soup, after you’ve boiled it, you can leave it open to the ordinary air, and nothing will grow in it--so long as the air gets into it through a narrow twisty tube.” Balard came back and smiled as Pasteur poured the news of the experiment over him. “I thought it would work--you see, when the air comes back in, as the flask cools, the dusts and their germs start in through the narrow neck--but they get caught on the moist walls of the little tube.” “Yes, but how can we prove that?” puzzled Pasteur. “Just take one of those flasks that has been in your oven all these days, a flask where no living things have appeared, and shake that flask so that the soup sloshes over and back and forth into the swan’s neck part of it. Put it back in the oven, and next morning the soup will be cloudy with thick swarms of little beasts--children of the ones that were caught in the neck.”