ACETIC FERMENTATION. 75 



forty-eight hours at most, the mycoderm covers the 

 whole liquid, so easy and rapid is its development. 

 After some days all the wine has become vinegar. 



On one occasion, in a discussion which he was hold- 

 ing at the Academy of Sciences, Pasteur, wishing to 

 affirm the prodigious activity of the life and multipli- 

 cation of this little organism, expressed himself thus : 



' I would undertake in the space of twenty-four 

 hours to cover with niycoderma aceti a surface of 

 vinous liquid as large as the hall in which we are 

 here assembled. I should only have to sow in it the 

 day before almost invisible particles of newly-formed 

 mycoderma aceti.' 



Let the reader try to imagine the millions upon 

 millions of little mycoderma particles which would 

 come to life in that one day. 



But how is the mycoderm seed to be obtained in the 

 first instance ? Nothing more simple. The mycoderma 

 aceti is one of those little so-called ' spontaneous ' pro- 

 ductions which are sure to appear of themselves on the 

 surface of liquids or infusions suitable to their develop- 

 ment. In wine, in vinegar, or suspended in air, every- 

 where around us, in our towns, in our houses, there 

 exist germs of this little plant. If we wish to procure 

 some fresh mycoderm it is only necessary to put a 

 mixture of wine and vinegar into a warm place. In 

 a few days, generally, if not always, there appear here 

 and there little greyish patches scattering the light 



