34 Microbes and You 



mental method, Pasteur went to work in his laboratory. He did not 

 sit down and try to explain reactions until he had enough careful 

 experimentation to back up his contentions. He v/as a Professor 

 at the University of Lille, France, right in the heart of the wine 

 and beer industries, and just at this time France was experiencing 

 serious wine spoilage which no one seemed able to control. 

 Pasteur was commissioned to undertake a study in the hope that a 

 "cure" might be found for the "disease" of the wine. In his in- 

 vestigations he found that each type of microbe will produce a 

 predictable ferment. Pasteur's first paper on fermentation appeared 

 in 1857. He described a grayish color in sugars undergoing fer- 

 mentation, and his microscopic observations revealed the presence 

 of small globules or short rods which, when transferred to fresh 

 sugar solutions, perpetuated the process. Heating solutions so 

 inoculated resulted in no fermentation. He stressed that spoilage 

 of wine could be directly attributed to the action of certain microbes 

 which produced undesirable end products and "diseased" the wines. 

 By selectivelv heating the fresh juice after it was bottled, such 

 diseases could be prevented. This prescribed heating has since 

 been given the designation of pasteurization. 



In further studies on fermentation, Pasteur reported that among 

 other end products in the reaction v/as amyl alcohol. If von 

 Liebig's theory were true, then amyl alcohol should be a constituent 

 of sugar merelv waiting release when the larger molecules shat- 

 tered. This discovery made such a theory untenable since amyl 

 alcohol is too difterent from sugar in its structure. Lavoisier and 

 Gay-Lussac had reported that the weight of carbon dioxide gas and 

 alcohol formed in sugar fermentation was practically equal to the 

 weight of the sugar. By a series of clever experiments, Pasteur was 

 able to give uncontestable proof that fermentation was a biological 

 process, initiated and perpetuated bv living substances. 



Moritz Traube (1826-1894) in 1858 was apparently the first 

 person to suggest the existence of enzymes, those remarkable 

 digestive juices so essential to all life. The work of Edward 

 Buchner (1860-1917) in 1897 conn med the enzyme theory when 



