96 MICROBES, FERMENTS, AND MOULDS. 
chains or curved rods. They multiply by the trans- 
verse fission of the cell, a fission preceded by a median 
constriction. These are characteristics of the bac- 
terium, strictly so called. 
_ The nutrition of this microbe resembles that of 
beer-yeast: it requires mineral salts, phosphates of the 
alkaline metals and of the metals of the alkaline 
earths, proteid matters, or ammoniacal salts. 
This ferment is an oxidizing ferment, which with- 
draws oxygen from the air and transfers it to the 
alcohol, thus converting it into acetic acid; hence it 
can only subsist in contact with the air, and perishes 
when it is submerged, so that acetification is then 
arrested. The oxidizing power of this microbe is 
such that it can even oxidize alcohol and transform it 
into carbonic acid gas—a fact which explains how the 
strength of wine is lowered by the other and larger 
species, Mycoderma vini, of which we have given an 
illustration (Figs. 48, 44). This action is less lively 
in the presence of a considerable quantity of vinegar, 
and at Orleans acetification is always effected in vats 
which contain a large amount. 
What is called the Orleans process, which is the 
one generally employed in France, consists in filling 
tuns which can hold about 200 litres with 100 litres 
of vinegar and 10 litres of white or red wine; once a 
week 10 litres of vinegar are drawn off, and replaced 
by 10 litres of wine. The temperature should be 
about 30°. Oxygen is supplied by a proper system of 
