Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar.

Date:
1903
Catalogue details

Licence: In copyright

Credit: Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    motion which is transmitted from a substance in a state of chemical motion, that is, of decomposition, to other sub- stances the elements of which are loosely bound together. In his last work on fermentation (VIII. 2), he sought to bring this theory into agreement with the observations of ■ Louis Pasteur on auto-fermentation. Liebig’s explanation of the latter is that the cells contain a decomposing sub- stance which produces sugar for the auto-fermentation. Although he at first looked upon yeast as a lifeless mass, an albuminoid compound, yet he came gradually to the view that it consists of living cells. But, in his opinion, there could be no question of fermentation being a physio- logical process: in this respect he held to his chemical conception. At that time a vigorous dispute was taking place between the followers and the opponents of the doctrine of generatio sec^uivoca, i.e., of spontaneous generation. Let us look somewhat closer at this doctrine. By spon- taneous generation we understand the development of organisms from lifeless material without eggs, seeds or embryos. Needham (1745), an energetic supporter of this doctrine, was the first to make experiments endeavouring to prove it. For this purpose he heated meat extract in closed liasks, and, on organisms appearing in the flasks, he assumed that they had been produced by spontaneous generation. Spallanzani (1765) showed, however (I), that certain errors were made in these experiments; he sealed his flasks hermetically and boiled them for an hour, after which treatment no development of micro-organisms could be observed. From his experiments he concluded that the “ eggs ” of the micro-organisms are present in the air and only develop after they have found their way into the liquid. On these experiments the foundation of the techni(]ue I*