Note 152 — Chapter VI · THE PHYSIOLOGICAL THEORY OF FERMENTATION. (continued 2)

It is important that we should here remark that, in the fermentation of pure solution of sugar by means of yeast, the oxygen originally dissolved in the water, as well as that appropriated by the globules of yeast in their contact with air, has a considerable effect on the activity of fermentation. As a matter of fact, if we pass a strong current of carbonic acid through the sugared water and the water in which the yeast has been treated, the fermentation will be rendered extremely sluggish, and the few new cells of yeast which form will assume strange and abnormal aspects. Indeed this might have been expected, for we have seen that yeast, when somewhat old, is incapable of development or of causing fermentation, even in a fermentable medium containing all the nutritive principles of yeast, if the liquid has been deprived of air; much more should we expect this to be the case in pure sugared water, likewise deprived of air.