Romance of low life amongst plants : facts and phenomena of cryptogamic vegetation / by M.C. Cooke.

  • Mordecai Cubitt Cooke
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Romance of low life amongst plants : facts and phenomena of cryptogamic vegetation / by M.C. Cooke. Source: Wellcome Collection.

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    It is not enough that in one or two cases we find quantities of these bodies present when alcohol or saccharine matter is converted into vinegar; the question is, are they always present, and do they seem to be the particular agents by which the vinegar-making is carried on ? When vinegar is obtained from a saccharine solution, the cane sugar is converted into grape sugar, the grape sugar into alcohol, and the alcohol into vinegar. Thus the vinegar-plant appears to perform the double function of first alcoholizing and then acetifying the solution. Do the yeast-like cells accomplish one portion of this task, and the bacterium bodies the other? The mycoderm of wine does not in its ordinary state give rise to vinegar. Its own vital processes merely supply the means by which the changes incidental to vinous fermentation take place, but it occasionally happens that brewers are greatly teased by the acetous fer- mentation of their beer occurring after the alcoholic change has finished. I have heard of several instances this summer in which great annoyance has been experienced from this cause, and it would seem either that spores of the vinegar-plant were diffused to a greater extent than usual, or that portions of yeast remaining in the beer had developed into the vinegar- plant form. M. Pasteur’s view of fermentation does not coincide with the common statement that the yeast-plant merely separates sugar into carbonic acid and alcohol—at any rate he does not represent that as the entire process, because he tells us that when experiments were performed in close vessels contain- ing, besides the fermenting liquid, a known quantity
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