274 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1951 



tion. This revolutionary view was received with scorn by orthodox 

 chemists. Berzelius, the outstanding chemist of the day, reviewed 

 this work scathingly in his chemical journal, while Wohler wrote a 

 sarcastic skit on the whole business which was published by Liebig 

 in his Annalen. In this, yeast was described as consisting of eggs 

 which hatched out into minute animals shaped like a distillation 

 apparatus, into which sugar was taken as food and converted into 

 alcohol and carbon dioxide, and the whole process could be observed 

 quite easily under the microscope! Soon after this, Liebig set out 

 his views on the nature of fermentation. Yeast played no part in his 

 purely chemical theory which came to be widely held and was taught 

 for many years afterward. According to Liebig, the nitrogenous 

 material in fruit juice was a ferment, unstable in the presence of 

 air, which caused it to undergo a progressive change. While this 

 change was in progress, the ferment communicated its instability to 

 the sugar, which then broke down into alcohol and carbon dioxide. 

 Liebig was able to produce chemical analogies for this; for example, 

 silver is dissolved readily by nitric acid, but platinum is quite un- 

 affected, yet an alloy of the two dissolved quite easily and completely. 

 This was, he said, because the silver, in dissolving, communicated its 

 instability to the platinum. Louis Pasteur, on the other hand, strongly 

 opposed these nonvitalistic ideas, and developed his thesis of no fer- 

 mentation without life. He said that alcoholic fermentation never 

 occurred "without the simultaneous organization, development, mul- 

 tiplication of cells or the continued life of cells already formed." It 

 was true that Pasteur had to distinguish between what he called the 

 "organized ferments" as in yeast, and the "unorganized ferments" 

 (such as pepsin which is secreted into the stomach or ptyalin of saliva, 

 which breaks down starch), since such unorganized ferments could 

 be shown to act in a test tube. 



After prolonged discussion, during which no new decisive experi- 

 mental evidence was obtained, the Pasteur-Liebig controversy was 

 suddenly settled by a fortuitous and lucky observation of Hans and 

 Eduard Buchner in 1897. This discovery is one of the notable mile- 

 stones in the long path of physiological chemistry, and many regard 

 it as marking the beginning of modern biochemistry. The Buchners 

 had previously found that the cells of bacteria could be disrupted 

 by grinding with sand, and they extended their technique to yeast 

 cells. The macerated product obtained in this manner contained 

 much cell debris and it was very difficult to separate liquid from it, 

 so they modified the method by adding kieselguhr, an inert and 

 porous earth, to the yeast cells and sand. After grinding, a mass 

 that had the consistency of dough was obtained ; this was wrapped 

 in cloth and submitted to a pressure of about 1,500 pounds to the 



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