TRANSACTIONS. 
Notes on the Vinegar Plant. 
By Henjry J. Slack, F.G.S. 
(Read January 11th, 1865.) 
The term Vinegar Plant^^ is applied to a tough, leathery 
formation, which, under certain circumstances, makes its 
appearance in saccharine solutions undergoing the acetous 
fermentation. It is, no doubt, essentially the same plant as 
that which occurs in a less compact form, in the French 
vinegar vats, and which encrusts the birch twigs or shavings 
used in the German process. 
Vinegar plants are frequently employed in domestic 
economy for the manufacture of vinegar ; and a well-grown 
specimen bears considerable resemblance to a piece of buck- 
skin leather that has been soaked in water. If a young 
vinegar plant is placed in a vessel containing half a gallon 
of brown sugar and water, to which a little treacle may be 
added, and is kept in a dark warm place, it grows rapidly, 
chiefly by accessions to its under surface, and it extends 
laterally till it reaches the sides of the vessel, the form of 
which it assumes. In a month or six weeks the saccharine 
solution will be converted into strong, well-flavoured vinegar. 
The plant is then removed^ and the vinegar boiled to kill the 
spores it contains. 
At the close of this process of vinegar making, the plant 
will be found to have increased greatly in thickness, and the 
under, or newly formed portions will be of a softer and looser 
texture than the upper layers. In this condition the plant 
is readily divided by horizontal splitting into two or more 
layers, one of which, if placed in a fresh solution, will soon 
excite the vinegar fermentation, and increase in bulk while 
the acetic acid is formed. 
VOL. XIII. 
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