Pasteur tried it, and it was so! A little later at a brilliant meeting where the brains and wit and art of Paris fought to get in, Pasteur told of his swan neck flask experiment in rapturous words. “Never will the doctrine of Spontaneous Generation recover from the mortal blow that this simple experiment has dealt it,” he shouted. If Balard was there you may be sure he applauded as enthusiastically as the rest. A rare soul was Balard. Then Pasteur invented an experiment that was--so far as one can tell from a careful search through the records--really his own. It was a grand experiment, a semi-public experiment, an experiment that meant rushing across France in trains, it was a test in which he had to slither around on glaciers. Once more his laboratory became a shambles of cluttered flasks and hurrying assistants and tinkling glassware and sputtering, bubbling pots of yeast soup. Pasteur and his enthusiastic slaves--they were more like fanatic monks than slaves--were getting ready hundreds of round bellied bottles. They filled each one of them part full of yeast soup and then, during many hours that shot by like moments--such was their excitement--they doused each bottle for a few minutes in boiling water. And while the soup was boiling they drew the flask necks out in a spitting blue flame until they were sealed shut. Each one of this regiment of bottles held boiled yeast soup--and a vacuum. Armed with these dozens of flasks, and fussing about them, Pasteur started on his travels. He went down first into the dank cellars of the Observatory of Paris, that famous Observatory where worked the great Le Verrier, who had done the proud feat of prophesying the existence of the planet Neptune. “Here the air is so still, so calm,” said Pasteur to his boys, “that there will be hardly any dust in it, and almost no microbes.” Then, holding the flasks far away from their bodies, using forceps that had been heated red hot in a flame, they cracked the necks of ten of the flasks in succession; as the neck came off each one, there was a hissing “s-s-s-s” of air rushing in. At once they sealed the bottles shut again in the flickering flame of an alcohol lamp. They did the same stunt in the yard of the observatory with another ten bottles, then hurried back to the little laboratory to crawl under the stairs to put the bottles in the incubating oven.