Alcoholic fermentation / by Arthur Harden.

  • Arthur Harden
Date:
1932
Catalogue details

Licence: In copyright

Credit: Alcoholic fermentation / by Arthur Harden. Source: Wellcome Collection.

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    provided with a flange in which the gelatinised candle is held by a compressed india-rubber ring, and is shown in section in Fig. 5. Two such apparatus are used, each capable of holding about 70 c.c. of the liquid to be filtered. The tubes, after being filled with the yeast-juice, are connected by means of a screw joint with a cylinder of compressed air and the filtration carried out under a pressure of 50 atmospheres, the arrangement employed being shown in Fig. 6. In the earlier ex- periments 25 to 50 c.c. of yeast-juice were placed in each tube and the Fig. 6. filtration continued until no more liquid passed through. The residue was then washed several times in situ by adding water and forcing it through the candle. The time occupied in this process varied from six to twelve hours with different preparations of yeast-juice. The candle was then removed from the brass casing and the thick, brown- coloured residue scraped off, dissolved in water, and at once examined. It was subsequently found to be possible to dry this residue in vacuo over sulphuric acid without seriously altering the fermenting power, and this led to a slight modification of the method, which is now
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