ACETIC FERMENTATION. 79 



the little plant is sown as before, and the same facts 

 are reproduced in the second as in the first operation. 



In the vessels where vinegar is preserved, whether 

 in the manufactories, in private houses, or in grocers' 

 shops, it often happens that the liquid becomes turbid, 

 and impoverished in an extraordinary manner ; it even 

 ends in putrefaction, if a remedy be not promptly 

 applied. Pasteur has pointed out the cause of these 

 phenomena. After the alcohol has become acetic acid 

 by the combustive action of the mycoderm, the ques- 

 tion remains, what becomes of the mycoderm ? Most 

 frequently it falls to the bottom of the vessel, having 

 no more work to accomplish. This is a phase of the 

 manufacture which must be watched with care. It 

 is shown by the experiments of Pasteur that the 

 mycoderma aceti can live on vinegar already formed, 

 maintaining its power of fixing the oxygen on certain 

 constituents of the liquid. In this case the acetic 

 acid itself is the seat of the chemical action in other 

 words, the oxygen unites with the carbon of the 

 acetic acid, and transforms it into carbonic acid, and 

 as the acetic acid has a composition which can be 

 represented by carbon and water, it follows that if 

 the combustion is allowed to take its course, instead 

 of vinegar we have eventually nothing but water 

 mixed with a small proportion of nitrogenous and 

 mineral matters, and the remains of the mycoderm. 



