Note 165 — Chapter VII · New Process for the Manufacture of Beer.
Frank Faulkner translation
It has been observed by brewers that, sometimes, without any apparent cause, a yeast suddenly becomes inactive and fermentation ceases. Accidents of this kind may probably be explained in the same manner as the facts of which we are speaking. If a wort has not been aerated, or if it has been deprived of oxygen by a commencing development of microscopic organisms, the yeast formed in it will be very inferior, and the fermentation may stop at its commencement or soon afterwards. In such a case, an aeration of the yeast and wort would be the best remedy.