The background to Eduard Buchner's discovery of cell-free fermentation

Eduard Buchner's discovery of cell-free fermentation in 1897 has long been celebrated as the resolution of one of the most famous scientific controversies of the nineteenth century, the controversy between Pasteur and Liebig over the nature of alcoholic fermentation. Was fermentation, as Pasteur contended, a vital physiological act of the living yeast cell, or was it due as Liebig claimed, to some purely chemical agent within the yeast cell? Could fermentation be separated from intact living yeast? Buchner showed that in a sense both sides were right: fermentation is carried out by soluble enzymes in yeast juice free of whole cells; but these enzymes are made by the living yeast cell. Buchner's work has also been long recognized as one of the most important foundations of the new science of biochemistry, which emerged in the early years of this century. The common ground of the small group of physiologists, chemists, and microbiologists who began to think of themselves as biochemists was the belief that all the physiological functions of the living cell would turn out to be mediated by enzymes. In time this idea became the "central dogma" of biochemistry. In 1897, however, it was highly subversive. Since the 1860's, when the protoplasm theories of cell structure and function made a clean sweep of cell biology" it had been universally assumed that the protoplasm as a whole carried out such essential functions as fermentation, respiration, and assimilation. Since only intact