REVIEWS—ON THE MANUFACTURE OF VINEGAR. 185 
signifies carbonate of soda or potassa. Cleopatra is said to have 
swallowed the value of a million sesterces in pearls dissolved in vine- 
gar. Geber in the eighth century first described the method of 
concentrating vinegar by distillation. Wood vinegar, which was 
long considered to be a distinct substance and known under the name 
of pyroligneous acid, was described as early as 1648 by Glauber, as 
resulting from the distillation of vegetable substances. Dr. Wethe- 
rill states that “this and alcohol are the only sources of acetic acid 
if we except the brilliant researches of Berthelot.” It may be 
remarked that the formation of acetic acid from the products 
resulting from the action of chlorine on sulphide of carbon, was 
known long before Berthelot commenced his researches. 
The first step towards improvement in the manufacture of vinegar 
dates from the year 1822, when Dobereiner discovered the possibility 
of converting alcohol into acetic acid by means of air and spongy 
platinum ; from this has arisen the so-called quick process of manu- 
facture which bids fair to supersede the older methods of fabrication. 
Our author states that on this continent this process is still held to 
be a secret and often sold for exorbitant prices, a statement which 
from our own experience we can perfectly confirm for Canada. 
The only advantage which the old process, consisting m a slow 
acetification or conversion into vinegar of beer or wine, possesses over 
the new, is derived from the fact that by the old process certain 
ethereal and aromatic substances are generated which do not appear 
when vinegar is made from alcohol, especially if pure, and to which 
the pleasant flavours of beer and wine vinegar seem to be due. This 
objection may, however, be obviated by the addition of a trace of these 
essences artificially prepared to the vinegar generated by the quick 
process. Dr. Wetherill enters into the subject of these fruit flavours 
rather largely, and fully confirms the opinion expressed by the writer 
in a former number of this journal, as to the harmlessness of the 
compounds thus used. Indeed our author submitted the matter, as 
regards one of the essences, to a very striking proof, a true experi- 
mentum crucis, for he states that in order to test the innocuousness 
of the so-called essence of Jargonelle pear, he consumed a whole 
pound of pear drops, without “experiencing any injurious effect.’ 
Any injury done, must we conceive have been to the contectioner, 
for it seems highly improbable that the Dr. would ever eat any more 
pear drops for the rest of his hfe. 
