The present aspect of the antiseptic question : being the substance of the oration for the year 1883, delivered before the Medical Society of London / by Edward Lund.

  • Lund, Edward.
Date:
1883
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Licence: Public Domain Mark

Credit: The present aspect of the antiseptic question : being the substance of the oration for the year 1883, delivered before the Medical Society of London / by Edward Lund. Source: Wellcome Collection.

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    mining the commencement and the progress of the saccharine or alcoholic fermentation. Professor Huxley, in a lecture on yeast, after stating that the fermentation of sugar, the splitting of sugar into alcohol and carbonic acid, glycerine, and succinic acid, is the result of nothing but the vital activity of this little fungus, the Torida cerevisice, goes on to say—Now comes the further exceedingly difficult inquiry, how is it that this plant, the Torula, produces this singular operation of the splitting up of the sugar? Fabroni imagined that the effervescence of fer- mentation was produced in this way, namely, that the yeast was a kind of acid, and that the sugar was a combination of carbonic acid and some base, to form the alcohol; and that the yeast combined with this substance, and set free the carbonic acid; just as when you add carbonate of soda to acid you turn out the carbonic acid. Another view was taken by the French chemist, Thenard, and is still held by an eminent chemist, M. Pasteur, namely, that the yeast, so to speak, eats a little of the sugar, turns a little of it to its own purpose, that is, feeds upon it, and by so doing gives such a shape to the sugar that the rest of it breaks up into carbonic acid and alcohol. Another distinguished chemist, Liebig, rejecting both theories, declared that the particles of the sugar are as it were shaken asunder by the forces at' work in the yeast plant, and that they undergo a rearrangement, the outcome of which is the formation of alcohol, the evolution of carbonic acid, and other changes. To put these three hypotheses in a semi-popular form, Huxley compares the sugar to a card-house—a pack of cards adroitly raised up, poised on one another until a light but high pile or structure is built up. The yeast may then be compared to a child going near the card house. Fabroni's hypothesis would be that the child took half the cards away, but Thenard and Pasteur's that the child pulls out the bottom card and thus makes the house tumble to pieces; whilst