Note 36 — Chapter III · On the Origin of Ferments properly so called.

The experiments that we have described give rise to a useful remark. All the organic liquids, boiled or not, in the course of time must take up oxygen from the air. At the same time, and certainly under this influence, they assume an amber or brownish colour, but this effect is only produced when the liquids are placed under conditions of unalterability. Should fermentation or the development of fungoid growths be possible, scarcely any change of colour will take place. Doubtless this non-coloration may be attributed to the fact that these organisms consume the oxygen necessary for coloration. In these experiments on must, all the unchanged flasks assumed a pale yellowish brown colour; those which fermented or contained fungoid growths remained colourless, or nearly so.