Highlights in the History of Microbiology 35 



he was able to demonstrate the presence of zymase, the ferment 



which attacks gkicose. A temporary wave of excitement arose 



when Buchner demonstrated that a yeast-free extract could still 



cause fermentation— apparent evidence in favor of von Liebig's 



original non-biological concept. But it had to be admitted by even 



the most ardent supporters of the mechanistic theory that the 



enzvmes had originallv come from a living cell; not any old juice 



could start the reaction on its w^ay. 



Durins: the course of his feiTnentation studies, Pasteur dis- 

 ci ^ 



covered anaerobes, those interesting microorganisms which grow 

 in the absence of free atmospheric oxygen, in contrast to the 

 aerobes which can develop only when free atmospheric oxygen is 

 available. Fermentation is life without air, according to Pasteur. 

 The first step involves growth of the organisms, and air is the source 

 of assimilated oxygen. Alcohol production in this stage of fermen- 

 tation is insicrnificant. During; the second stao;e the veast is com- 

 pelled to act upon the sugar in the absence of atmospheric oxygen, 

 and the essential gas is abstracted from the sugar. Pasteur's final 

 conclusions were that (1) ferments are living organisms, (2) each 

 ferment is produced by a special organism, and (3) ferments are 

 not formed spontaneouslv. Liebig and his proponents believed 

 fermentation to be a function of death, but Pasteur proved it to be 

 a function of life. 



If wine could be diseased, the next logical step was to assume 

 that human beings and other living things could also be afflicted as 

 the result of specific microbial activity. It is of interest to note 

 that Robert Boyle (1627-1691) in 1663 had stated that until the 

 nature of fermxCntation v/as clearly understood, we could ha dly 

 expect a logical explanation of disease. As a direct result of the 

 Pasteur-von Liebig controversy, the solution of many other prob- 

 lems, including the disposal of wastes, the purification of water, 

 etc., were given a decided impetus, and progress was recorded. 

 Lord Joseph Lister (1827-1912), a surgeon of Glasgow, Scotland, 

 was so impressed with Pasteur's conclusions with respect to fer- 

 mentation that he decided to apply these same biological principles 



