“Where in your families will you find a young man whose curiosity and interest will not immediately be awakened when you put into his hands a potato, and when with that potato he may produce sugar, and with that sugar alcohol, and with that alcohol ether and vinegar?” he shouted enthusiastically one evening to an audience of prosperous manufacturers and their wives. Then one day Mr. Bigo, a distiller of alcohol from sugar beets, came to his laboratory in distress. “We’re having trouble with our fermentations, Professor,” he complained; “we’re losing thousands of francs every day. I wonder if you could come over to the factory and help us out?” said the good Bigo. Bigo’s son was a student in the science course and Pasteur hastened to oblige. He went to the distillery and sniffed at the vats that were sick, that wouldn’t make alcohol; he fished up some samples of the grayish slimy mess and put them in bottles to take to his laboratory--and he didn’t fail to take some of the beet pulp from the healthy foamy vats where good amounts of alcohol were being made. Pasteur had no idea he could help Bigo, he knew nothing of how sugar ferments into alcohol--indeed, no chemist in the world knew anything about it. He got back to his laboratory, scratched his head, and decided to examine the stuff from the healthy vats first. He put some of this stuff--a drop of it--before his microscope, maybe with an aimless idea of looking for crystals, and he found this drop was full of tiny globules, much smaller than any crystal, and these little globes were yellowish in color, and their insides were full of a swarm of curious dancing specks. “What can these things be,” he muttered. Then suddenly he remembered-- “Of course, I should have known--these are the yeasts you find in all stews that have sugar which is fermenting into alcohol!” He looked again and saw the wee spheres alone; he saw some in bunches, others in chains, and then to his wonder he came on some with queer buds sprouting from their sides--they looked like sprouts on infinitely tiny seeds. “Cagniard de la Tour is right. These yeasts are alive. It must be the yeasts that change beet sugar into alcohol!” he cried. “But that doesn’t help Mr. Bigo--what on earth can be the matter with the stuff in the sick vats?” He grabbed for the bottle that held the stuff from the sick vat, he sniffed at it, he peered at it with a little magnifying glass, he tasted it, he dipped little strips of blue paper in it and watched them turn red.... Then he put a drop from it before his microscope and looked....