the
equivalent of "subject" in monarchies of feudal origin. For the rules
governing the obtaining of citizenship in this latter sense in the
United States and elsewhere see NATURALIZATION.

CITOLE, also spelled SYTOLE, CYTHOLE, GYTOLLE, &c. (probably a Fr.
diminutive form of _cithara_, and not from Lat. _cista_, a box), an
obsolete musical instrument of which the exact form is uncertain. It is
frequently mentioned by poetical writers of the 13th to the 15th
centuries, and is found in Wycliffe's Bible (1360) in 2 Samuel vi. 5,
"Harpis and sitols and tympane." The Authorized Version has
"psaltiries," and the Vulgate "lyrae." It has been supposed to be
another name for the psaltery (q.v.), a box-shaped instrument often seen
in the illuminated missals of the middle ages.

CITRIC ACID, _Acidum citricum_, or OXYTRICARBALLYLIC ACID,
C3H4(OH) (CO.OH)3, a tetrahydroxytribasic acid, first obtained
in the solid state by Karl Wilhelm Scheele, in 1784, from the juice of
lemons. It is present also in oranges, citrons, currants, gooseberries
and many other fruits, and in several bulbs and tubers. It is made on a
large scale from lime or lemon juice, and also by the fermentation of
glucose under the influence of _Citromycetes pfefferianus, C. glaber_
and other ferments. Lemon juice is fermented for some time to free it
from mucilage, then boiled and filtered, and neutralized with powdered
chalk and a little milk of lime; the precipitate of calcium citrate so
obtained is decomposed with dilute sulphuric acid, the solution
filtered, evaporated to remove calcium sulphate and concentrated,
preferably in vacuum pans. The acid is thus obtained in colourless
rhombic prisms of the composition C6H8O7 + H2O. Crystals of
a different form are deposited from a strong boiling solution of the
acid. About 20 gallons of lemon juice should yield about 10 lb of
crystallized citric acid. The acid may also be prepared from the juice
of unripe gooseberries. Calcium citrate must be manufactured with care
to avoid an excess of chalk or lime, which would precipitate
constituents of the juice that cause the fermentation of the citrate and
the production of calcium acetate and butyrate.

The synthesis of citric acid was accomplished by L.E. Grimaux and P.
Adam in 1881. Glycerin when treated with hydrochloric acid gives
propenyl dichlorhydrin, which may be oxidized to s-dichloracetone. This
compound combines with hydrocyanic acid to form a nitrile