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are the oxalic , citric , tartaric , benzoic , acetic , mec- 
onzc, /zc, gallic , and prussic acid. 
Ail these acids, except the acetic, malic, and 
prussic acids, are white crystalised bodies. The 
acetic, malic, and prussic acids have been obtained 
in the only fluid state ; they are all more or less 
soluble in water ; all have a sour taste except the 
gallic and prussic acids ; of which the first has an 
astringent taste, and the latter a taste like that of 
bitter almonds. The meconic acid exists in opium. 
The oxalic acid exists, un combined, in the liquor 
which exudes from the Chich pea ( Cicer arietinum ), 
and may be procured from wood Sorrel (Ox alls 
aceto sella ), common sorrel, and other species of 
Rumex : and from the Geranium acidum . Oxalic 
acid is easily discovered and distinguished from 
other acids by its property of decomposing all 
calcareous salts, and forming with lime a salt inso- 
luble in water ; and by its crystallising in four-sided 
prisms. 
The citric acid is the peculiar acid existing in 
the juice of lemons and oranges. It may likewise 
be obtained from the cranberry, whortleberry, 
and hip. 
Citric acid is distinguished by its forming a salt 
insoluble in water with lime ; but decomposable 
by the mineral acids. 
The tartaric acid may be obtained from the juice 
of mulberries and grapes; and likewise from the 
pulp of the tamarind. It is characterised by its 
property of forming a difficultly soluble salt with 
potassa, and an insoluble salt decomposable by the 
mineral acids with lime. 
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