Ferments and their actions / by Carl Oppenheimer ; Translated from the German by C. Ainsworth Mitchell.

Date:
1901
Catalogue details

Licence: In copyright

Credit: Ferments and their actions / by Carl Oppenheimer ; Translated from the German by C. Ainsworth Mitchell. 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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    energy of the cells; but if we attempted to do the same with the alcohol-producing ferment we should soon be convinced that without exception all the agents which injured the vital functions of the yeast also injured its fermentative energy to the same extent. As soon as the parent cell is killed or severely injured, the very unstable ferment is also very rapidly destroyed. The fact that high temperatures and strong acids and bases destroy the cell with the ferment is also in complete analogy with the ordinary enzymes. As soon, however, as we try the protoplasm-poisons to which ordinary enzymes are nearly indifferent, the condition of affairs is completely changed. All those poisons which destroy the living cells,' also interfere with the fermentative function of the yeast. Of the substances which are thus used for the demonstration of the enzymes of yeast, we need only mention here chloroform, toluene, and mercuric chloride. On the other hand, many salts—e.g., those of iron and manganese—are not injurious; whilst others—e.g., potassium cyanide and sodium sulphide—are markedly so. Strychnine and quinoline are harm- less ; quinine slightly injurious.1 Aluminium salts have even a stimulating effect, as also phosphoric acid and its salts, and asparagine (Effront2). Sodium arsenate has but little influence upon yeast, but considerable action upon other fission-fungi (Schaffer and Bohm3). Special attention has been given by Schulz4 and his pupils to the investigation of the influence of poisons upon yeast. They found that small doses, e.g., of formic acid, &c., stimulated its action, but that larger quantities were injurious. As regards the action of metallic salts upon yeast, Mann5 concludes that there is a combination between them and the phosphates in the cell. Carbon dioxide has a restrictive influence (Foth6 7). Sulphur dioxide in strong solutions (200 c.c. of gas to 1 litre of water) kills yeast very rapidly (Linossier '), specially in acid fluids. Sodium fluoride, which, as is well known, does not fail to destroy putrefactive bacteria, when its solution contains about 1 per cent., has a weaker action upon yeast, and hence its use, as proposed by Effront, has been advocated in breweries to exclude bacteria. In the case of the fluorine compounds we also find one of those instances mentioned above, in which there appears to be a certain difference between the purely vital and 1 For bibliography and further particulars see A. Mayer, loc. cit., 147. 3 Effront, Bull. Soc. Chim. [3], ix., 151, 1893. 3 Schaeffer and Bohm, Sitzb. d. Erlanger phys. med. Soc., N.S., hi.,. 238, 1872. 4 Schulz, Virch. Arch., cviii., 427, 1887; Pfiiig. Arch., xlii., 517, 1888. 5 Mann, Ann. Inst. Pasteur, viii., 785, 1894. 6 Foth, Z. ges. Brauw., 182, 1889. 7 Linossier, Ann. Inst. Past., v., 171, 1891.