Pasteur, in a muddle, tried to invent ways of getting unheated air into a boiled yeast soup--and yet keep it from swarming with living sub-visible creatures. He fumbled at getting a way to do this; he muddled--keeping all the time a brave face toward the princes and professors and publicists that were now beginning to swarm to watch his miracles. The authorities had promoted him from his rat-infested attic to a little building of four or five two-by-four rooms at the gate of the Normal School. It would not be considered good enough to house the guinea-pigs of the great Institutes of to-day, but it was here that Pasteur set out on his famous adventure to prove that there was nothing to the notion that microbes could arise without parents. It was an adventure that was part good experiment, part unseemly scuffle--a scuffle that threatened at certain hilariously vulgar moments to be settled by a fist fight. He messed around, I say, and his apparatus kept getting more and more complicated, and his experiments kept getting easier to object to and less clear, he began to replace his customary easy experiments that convinced with sledge-hammer force, by long drools of words. He was stuck. Then one day old Professor Balard walked into his workroom. Balard had started life as a druggist; he had been an owlish original druggist who had amazed the scientific world by making the discovery of the element bromine, not in a fine laboratory, but on the prescription counter in the back room of a drugstore. This had got him fame and his job of professor of chemistry in Paris. Balard was not ambitious; he had no yearning to make all the discoveries in the world--discovering bromine was enough for one man’s lifetime--but Balard did like to nose around to watch what went on in other laboratories. “You say you’re stuck, you say you do not see how to get air and boiled yeast soup together without getting living creatures into the yeast soup, my friend?” you can hear the lazy Balard asking the then confused Pasteur. “Look here, you and I both believe there is no such thing as microbes rising in a yeast soup by themselves--we both believe they fall in or creep in with the dust of the air, is it not so?” “Yes,” answered Pasteur, “but----” “Wait a minute!” interrupted Balard. “Why don’t you just try the trick of putting some yeast soup in a bottle, boiling it, then fixing the opening so the dust can’t fall in. At the same time the air can get in all it wants to.” “But how?” asked Pasteur. “Easy,” replied the now forgotten Balard. “Take one of your round flasks, put the yeast soup into it, then soften the glass of the flask neck in your blast lamp--and draw the neck out and downward into a thin little tube--turn this little tube down the way a swan bends his neck when he’s picking something out of the water. Then just leave the end of the tube open. It’s like this----” and Balard sketched a diagram: [Illustration: (line drawing of glass flask with curved neck)]