505 
bottles can be used, because there is less carbonic acid than in the 
two former cases. They should be laid flat when filled, in order to 
retain the carbonic acid. 
Acetification of Cider. 
The apple or the pear juice having been transformed into cider 
or into perry it can be used as such, or a step further may be gone 
and it may be manufactured into vinegar. It is essential for this 
“purpose that the liquid becomes clear and free of the carbonie acid 
gas with which it was charged at the close of its alcoholic fermenta- 
tion, as these conditions would interfere with the spread over the 
surface of the mycodermic veil which forms during the process of 
acetification. 
VINEGAR. 
The name is given to alcoholic liquids which have undergone 
acetific fermentation—wine, lees, “cider, perry, beer, in fact any 
weak alcoholic solution may be transformed into vinegar by the 
action of the Mycoderma aceti organism. Wood vinegar is an ex- 
ception, being the product of the distillation of wood when sub- 
jected to a high temperature. 
The floating veil of Mycoderma aceti works normally in liquids 
which already contain acetic acid, otherwise under the influence of 
air and a suitable temperature it. is replaced or interfered with by 
another form, viz., Mycoderma vini, illustrated on page 490, under, 
the name of “Flowers of Wine,” and which weakens the alcoholic 
mixture by the direct transformation of alcohol into water and car- 
bonie acid gas, a process which accounts for a weaker vinegar being 
produced. For this reason, wine or cider used in the manufacture 
of vinegar should receive as a starter a certain quantity of that 
product. 
As a condiment wine or cider vinegar, in addition to acetic 
acid contain organic and inorganic salts, ethers which give the 
bouquet, glycerine, in reality, all the elements which constitute the 
-original liquid. Cheaper grades of vinegar are also made with 
diluted cheap spirits; these possess none of the hygienic constituents 
of the first-named kinds and are more or less injurious to weak 
digestions. 
Pasteur discovered that under the action of Mycoderma aceti, 
which is classed among the group of aerobian ferments, i.e., requir- 
ing the oxygen of the air to exist, alcohol is oxidised and acetie acid 
and water results. A certain amount of heat is generated during 
that transformation. The micro-organism (mother of vinegar) 
forms the veil floating on the surface and does its best work at tem- 
peratures ranging between 67deg. and 87deg. F. (20-31deg. C.), 
outside these limits the ferments suffer and eventually cease to 
work. 
